stratigraphic architecture and facies analysis of the

Transcription

STRATIGRAPHIC ARCHITECTURE AND FACIES ANALYSIS OF THE LOWER
CRETACEOUS DINA MEMBER OF THE MANNVILLE GROUP IN NORTHWEST
SASKATCHEWAN
A Thesis
Submitted to the Faculty of Graduate Studies and Research
In Partial Fulfillment of the Requirements
For the Degree of
Master of Science
In Geology
University of Regina
By
Daniel Jonathon Kohlruss
Regina, Saskatchewan
October, 2012
Copyright 2012, D.J. Kohlruss
UNIVERSITY OF REGINA
FACULTY OF GRADUATE STUDIES AND RESEARCH
SUPERVISORY AND EXAMINING COMMITTEE
Daniel Jonathon Kohlruss, candidate for the degree of Master of Science in Geology, has
presented a thesis titled, Stratigraphic Architecture and Facies Analysis of the Lower
Cretaceous Dina Member of the Mannville Group in Northwest Saskatchewan, in an
oral examination held on October 5, 2012. The following committee members have found
the thesis acceptable in form and content, and that the candidate demonstrated
satisfactory knowledge of the subject material.
External Examiner:
Dr. Steven Hubbard, University of Calgary
Co-Supervisor:
Dr. Guoxiang Chi, Department of Geology
Co-Supervisor:
Dr. Per Kent Pederson, Adjunct
Committee Member:
Dr. Maria Velez Caicedo, Department of Geology
Chair of Defense:
Dr. Renata Raina, Department of Chemistry & Biochemistry
*Not present at defense
ABSTRACT
Recent exploration activity in northwest Saskatchewan, north of the Clearwater
River Valley along the Alberta provincial border, has revealed an extensive bitumen
resource. 1.4 billion barrels to 2.3 billion barrels (222 million m3 to 371 million m3) of
bitumen is estimated in place. The bitumen-bearing sandstones belong to the Dina
Member of the Lower Cretaceous Mannville Group, stratigraphically equivalent to
Alberta’s McMurray Formation. The purpose of this study is to determine the
stratigraphic architecture of the Dina Member and its control on bitumen distribution in
the study area.
The Dina Member in northwest Saskatchewan was deposited unconformably on
top of the underlying Devonian Elk Point Group with the thickest Dina sandstones
residing within paleo-topographic lows on the unconformity surface. The Dina Member
was extensively eroded by Pleistocene glacial processes and is unconformably overlain
by Pleistocene glacial tills. Analysis of 83 stratigraphic test hole drill cores and 255
geophysical well log suites has revealed 8 recurring facies and 5 facies associations. The
facies are comprised of siliciclastic sediments, including sandstones, siltstones,
mudstones and in rare instances, coal. These facies are predominantly non-marine in
origin, including fluvial sediments and associated over-bank deposits. Many fluvial facies
exhibit a significant tidal and/or seasonal brackish water influence. Tidal indicators are
manifested as rhythmic grain size striping, reactivation surfaces and co- and back-flow
structures. Brackish conditions are indicated by impoverished, mono-specific
assemblages of diminutive trace fossils in mud beds and discrete sand layers, along with
marine palynmorphs and microfossils.
I
Deposition of the Dina Member is interpreted to have occurred within an incised
valley system formed as a result of a relative base-level drop, which initiated trenching
and deepening of pre-existing valleys. Braided channel deposits proceeded to fill the
lowest portions of the valley during the lowstand and part of the subsequent
transgression. As the valley was gradually filled and the lateral accommodation space
increased, fluvial style changed from braided to meandering, with deposition of laterally
accreted point-bar deposits. These manifest as inclined stratification (IS) and inclined
heterolithic stratification (IHS) overlying basal trough cross-bed sets. Mud filled, oxbow
lake deposits were also observed in close association with the point-bar deposits.
Bitumen distribution throughout the study area is not uniform and has several
controls. Bitumen saturation is highest where braided fluvial and IS deposits are found,
especially when stacked. Conversely, IHS deposits and mud filled oxbow lake deposits
restrict oil flow and in cases act as flow barriers to oil migration. Bitumen is trapped
laterally by the incised valley walls created by the sub-Cretaceous unconformity, where
bitumen saturated sand pinches out against the impermeable carbonates. The Dina
sandstones, in turn, were sealed above by shales of the Clearwater Formation/ Cummings
Member of the Mannville Group.
II
ACKNOWLEDGEMENTS
Funding for a large portion of this project was provided by the Saskatchewan
Ministry of Energy and Resources, most notably was a grant to Dr. Guoxiang Chi and Dr.
Per Kent Pedersen at the University of Regina.
Many individuals have contributed to this thesis in many different ways, through
technical support, inspiration and motivation. I would like to thank Dr. Guoxiang Chi and
Dr. Per Kent Pedersen for their technical support, patience and the freedom to think,
work and act independently throughout the process. Their many hours of editing and
valuable feedback are greatly appreciated.
I’d like to thank all my colleagues at the Ministry of Energy and Resources,
specifically, Arden Marsh, for his technical expertise with data management and mapping
software, as well for our many discussions surrounding sedimentology and stratigraphy.
I’d also like to thank Melinda Yurkowski who always believed I would finish this project
and provided the time needed to accomplish my goal. I’d also like to thank Jeff Coolican,
who “took-up-the-slack” in our shared work duties, while I focused on research. I’d like
to thank Gavin Jensen and Arden Marsh for their assistance preparing for our Clearwater
field season as well their time and energy while in the field. I’d also like to thank Megan
Love and Tyler Music, who provided technical support while assembling my thesis.
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DEDICATION
I would like to dedicate this thesis to my two children. Without them I would not
have the patience, maturity or strength to accomplish a goal of this magnitude. They
teach me more than I will ever be able to teach them and they make me a better person.
My son Ethan is the strongest individual I know and whenever I feel I can not
accomplish a goal, I look to him for motivation. He truly is my hero and I am blessed to
be his dad.
My daughter Avery inspires me every day with her beautiful personality, endless
curiosity and love of rocks and dogs. She makes me feel privileged to have the career
I’ve chosen and appreciate every day I am a geologist. I look forward to working with her
someday.
Finally, I owe a very special thanks and dedication to my wife Melanie, who
provided endless love, patience, encouragement and inspiration. She is always there when
I need her most and without her I would not have attempted, let alone finished this thesis.
“If you want to take the island, burn the boats!” –Tony Robbins
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TABLE OF CONTENTS
ABSTRACT……………………………………………………………………………… I
ACKNOWLEDGEMENTS...…………………………………………………………... III
DEDICATION.……………………………………………………………...………….. IV
TABLE OF CONTENTS…………………………………………………………………V
LIST OF TABLES……………………………………………………………………..VIII
LIST OF FIGURES……………………………………………………………………...IX
1. INTRODUCTION ......................................................................................................... 1
1.1
Purpose and Objectives ........................................................................................ 3
1.2
Previous Work ...................................................................................................... 5
1.3
A Review of Estuary Depositional Models .......................................................... 8
1.3.1
Introduction ................................................................................................... 8
1.3.2
Physical Processes ........................................................................................ 9
1.3.2.1
River and Tidal Currents ......................................................................... 11
1.3.3
Chemical Processes and Water Circulation ................................................ 13
1.3.4
Biological Processes ................................................................................... 15
1.3.5
Morphology................................................................................................. 16
1.3.6
Cross-Bedding and Tidal Indicators ........................................................... 18
1.3.7
Grain Size Distribution ............................................................................... 19
1.3.8
Estuarine Depositional Model..................................................................... 21
1.4
Study Area .......................................................................................................... 22
1.5
Study Methods.................................................................................................... 22
1.5.1
Net Pay and Net Water/Lean Mapping ....................................................... 25
1.5.2
Geological Isopach and Structure Maps ..................................................... 26
1.5.3
Geological Cross-Sections .......................................................................... 27
2. GEOLOGICAL SETTING .......................................................................................... 28
3
2.1
Regional Geology ............................................................................................... 28
2.2
McMurray Sub-Basin ......................................................................................... 36
FACIES DESCRIPTIONS AND DEPOSITIONAL INTERPRETATIONS ........... 41
3.1
Introduction ........................................................................................................ 41
3.2
Facies Descriptions and Interpretations ............................................................. 41
3.2.1
Facies 1: Massive Sandstone ...................................................................... 41
V
3.2.2
Facies 2: Ripple Cross laminated Sandstone .............................................. 46
3.2.3
Facies 3: Planar Cross-bedded Sandstone................................................... 48
3.2.4
Facies 4: Trough Cross-Bedded Sandstone ................................................ 54
3.2.4.1
Facies 4a: Medium to Very Coarse Trough Cross-Bedded Sandstone ... 54
3.2.4.2
Facies 4b: Massive to Trough Cross-Bedded Pebbly Sandstone ............ 59
3.2.5
Facies 5: Pebble Conglomerate ................................................................... 62
3.2.6
Facies 6: Inter-bedded Sandstone and Bioturbated Mudstone.................... 65
3.2.7
Facies 7: Siltstone, Mudstone, and Coal ..................................................... 73
3.2.8
Facies 8: Laminated Siltstone to Very Fine Sandstone .............................. 77
3.3
Facies Associations ............................................................................................ 80
3.3.1
Facies Association 1: Braided Fluvial Channel .......................................... 80
3.3.2
Facies Association 2: Tidally Influenced Meander Channel Deposits ...... 88
3.3.3
Facies Association 3: Oxbow Lake Fill ...................................................... 99
3.3.4
Facies Association 4: Flood Plain Crevasse Splay ................................... 102
3.3.5
Facies Association 5: Floodplain Deposits ............................................... 105
4. STRATIGRAPHIC ARCHITECTURE AND DEPOSITIONAL MODEL .............. 109
4.1
Introduction ...................................................................................................... 109
4.2
Structural and Isopach Maps ............................................................................ 109
4.3
Facies Association Structural Cross-Sections .................................................. 115
4.3.1
Cross-section A-A’ ................................................................................... 116
4.3.2
Cross-section B-B’ .................................................................................... 119
4.3.3
Cross-section C-C’ .................................................................................... 121
4.3.4
Cross-section D-D’ ................................................................................... 123
4.3.5
Cross-section E-E’ .................................................................................... 126
4.3.6
Cross-section F-F’..................................................................................... 128
4.4
5.
6.
Depositional Model .......................................................................................... 131
BITUMEN DISTRIBUTION ................................................................................. 137
5.1
Introduction ...................................................................................................... 137
5.2
Bitumen Distribution ........................................................................................ 137
5.3
Trapping and Bitumen Distribution Controls................................................... 149
CONCLUSIONS..................................................................................................... 156
LIST OF REFERENCES.………………………………………………………………158
VI
APPENDIX I : Formation and Facies Association Tops..………………………….….168
APPENDIX II : Bitumen Saturation Calculations….………………………………….177
APPENDIX III : Palynological Report..………………………………………..………185
VII
LIST OF TABLES
Table 3.1 Summary of facies within study area....………………………………………43
Table 3.2 Description interpretation and sequence stratigraphic nomenclature of facies
associations in the study area………………….…………………………………………81
VIII
LIST OF FIGURES
Figure 1.1 Stratigraphic correlation chart for study area ................................................... 2
Figure 1.2 Oil sands activity map ...................................................................................... 4
Figure 1.3 Tide dominated estuary facies map ................................................................ 10
Figure 1.4 Morphology map of tide-dominated estuary .................................................. 12
Figure 1.5 Classification of estuaries based on internal water circulation patterns ......... 14
Figure 1.6 Map of study area ........................................................................................... 23
Figure 1.7 Map of detailed study area ............................................................................. 24
Figure 2.1 Structure map of the Sub-Cretaceous Unconformity surface ......................... 29
Figure 2.2 Regional stratigraphic cross-section of Western Canada Sedimentary Basin 30
Figure 2.3 Terrane accretion model during Mannville deposition .................................. 31
Figure 2.4 Sequence stratigraphy breakdown of the Mannville group ............................ 32
Figure 2.5 Major drainage systems on the sub-Cretaceous unconformity....................... 34
Figure 2.6 Inferred Firebag Tributary system .................................................................. 37
Figure 2.7 Stratigraphic correlation chart of Alberta’s lower Cretacious, Mississippian
and Devonian .................................................................................................................... 38
Figure 3.1 Core photograph of facies 1: massive sandstone ............................................ 42
Figure 3.2 Core photograph of massive sandstone with Gyrolithes burrows .................. 45
Figure 3.3 Core photograph of facies 2: ripple laminated sandstone .............................. 47
Figure 3.4 Core photographs of facies 3: planar cross-bedded sandstone ....................... 49
Figure 3.5 Core photograph of reactivation surface within facies 3 ................................ 50
Figure 3.6 Block diagram illustrating facies within a braided fluvial system ................. 53
Figure 3.7 Core photograph of facies 4a: trough cross-bedded sandstone ...................... 55
Figure 3.8 Outcrop photograph of mud rip-up clasts in facies 4a ................................... 56
Figure 3.9 Thin section photograph of facies 4a.............................................................. 58
Figure 3.10 Core photograph of facies 4b: pebbly trough cross-bedded sandstone ........ 60
Figure 3.11 Core photograph of facies 5: pebble conglomerate ...................................... 63
Figure 3.12 Thin section photograph of polycrystalline quartz grain in facies 5 ............ 64
Figure 3.13 Core photograph of facies 6: inter-bedded sandstone and bioturbated
mudstone ........................................................................................................................... 66
Figure 3.14 Core photographs of facies 6: trace fossils ................................................... 69
IX
Figure 3.15 Photomicrographs of pollen, spores, dinoflagellate cysts and scoleodont ... 70
Figure 3.16 Point bar and counter point bar morphology ................................................ 72
Figure 3.17 Core photograph of facies 7: paleosol .......................................................... 74
Figure 3.18 Core photograph of facies 7: Naktodemasis continental insect burrow ....... 75
Figure 3.19 Photomicrograph of root within facies 7 siltstone ........................................ 76
Figure 3.20 Core photograph of facies 8: laminated siltstone ......................................... 78
Figure 3.21 Smectite in SEM image at varying magnifications ...................................... 79
Figure 3.22a Core litholog of well 16-32-94-25W3 ........................................................ 82
Figure 3.22b Litholog legend ........................................................................................... 83
Figure 3.23 Isopach map of facies association1 .............................................................. 84
Figure 3.24 Schematic diagram of fluvial architecture in the study area ........................ 85
Figure 3.25 Outcrop photo of facies association 1 .......................................................... 87
Figure 3.26 Outcrop photo of bitumen impregnated log in facies association 1 ............. 89
Figure 3.27 Core litholog of well 16-28-94-25W3 .......................................................... 90
Figure 3.28 Gamma ray trace of well 6-20-94-25W3 illustrating channel stacking
patterns of facies association 2 ......................................................................................... 91
Figure 3.29 Schematic of idealized point bar facies distribution in a tidally influenced
meandering river channel system...................................................................................... 93
Figure 3.30 Isopach map of facies association 2 ............................................................. 96
Figure 3.31 Isopach map of facies 6 ................................................................................ 97
Figure 3.32 Illustration of esturine circulation ................................................................ 98
Figure 3.33 Core litholog of facies association 3 .......................................................... 100
Figure 3.34 Isopach map of facies association 3 ........................................................... 101
Figure 3.35 Core litholog of facies association 4 .......................................................... 103
Figure 3.37 Illustration of crevasse splay ...................................................................... 106
Figure 4.1 Map showing well coverage, logged cores and structural cross-sections .... 110
Figure 4.2 Structural map of the Sub-Cretaceous Unconformity surface ...................... 112
Figure 4.3 Isopach map of the Dina Member/McMurray Formation ............................ 113
Figure 4.4 Structural map of the base of the Quaternary glacial deposits ..................... 114
X
Figure 4.5 Structural cross-section A-A’ ....................................................................... 117
Figure 4.6 Structural cross-section B-B’ ....................................................................... 120
Figure 4.7 Structural cross-section C-C’ ....................................................................... 122
Figure 4.8 Structural cross-section D-D’ ....................................................................... 124
Figure 4.9 Structural cross-section E-E’ ........................................................................ 127
Figure 4.10 Structural cross-section F-F’ ...................................................................... 129
Figure 4.11 Plan view sketches of incised-valley system through time ........................ 133
Figure 5.1 Core photograph of well 16-28-94-25W3 highlighting “perched” water
saturated zone.................................................................................................................. 138
Figure 5.2 Map of net bitumen pay ................................................................................ 139
Figure 5.3 Map of weighted average bitumen saturations ............................................. 141
Figure 5.4 Map of weighted bitumen saturations excluding water-lean zones.............. 142
Figure 5.5 Structural cross-section A-A’, illustrating oil water contacts ...................... 143
Figure 5.6 Structural cross-section F-F’, illustrating oil water contacts ........................ 144
Figure 5.7 Map of net thickness of water-lean zones .................................................... 145
Figure 5.8 Overlay of total net bitumen pay map with weighted average bitumen
saturation map ................................................................................................................. 146
Figure 5.9 Overlay of total net bitumen pay map with weighted average bitumen
saturation map excluding bottom or “perched” water zones .......................................... 147
Figure 5.10 Map overlay of total net bitumen pay and net thickness of water-lean zones
......................................................................................................................................... 148
Figure 5.11 Map of Athabasca oil sands deposit ........................................................... 150
Figure 5.12 Schematic diagram of lateral spill and fill trapping ................................... 152
Figure 5.13 Map illustrating bitumen stratigraphic trapping ......................................... 154
Figure 5.14 Map overlay of net water-lean zones and facies 6/facies association 3
distribution ...................................................................................................................... 155
XI
1. INTRODUCTION
The Athabasca oil sands in Alberta represent one of the world’s largest
hydrocarbon accumulations (AEUB 2007), and a number of studies have been carried out
on the sedimentology and stratigraphy of the bitumen bearing McMurray Formation of
the Mannville Group (Carrigy, 1959a, 1963, 1966, 1971; Nelson and Glaister, 1978;
Mossop, 1980; Pemberton et al., 1982; Flach and Mossop, 1983, 1985; Smith, 1988;
Wightman and Pemberton, 1997; Ranger and Pemberton, 1997; Stroble et al., 1997; Hein
and Cotterill, 2006; Crerar and Arnott, 2007; Fustic et al., 2008; Hubbard et al., 2011). In
contrast, little attention has been paid to the Saskatchewan part of the oil sands, which
has been recognized since the mid 1970’s (Paterson et al., 1978). The first stratigraphic
test holes were drilled by Shell Canada and Gulf Canada between 1974 and 1976 in an
effort to expand the known oil sands resource of Alberta’s Athabasca Oil Sands deposit
(Ranger, 2006; Kohlruss et al., 2010a).
In these early test holes, two wells intersected bitumen bearing sandstones in the
Dina Member of the Mannville Group, which is stratigraphically equivalent to the
McMurray Formation (Figure 1.1), but the exploration permits were subsequently
relinquished back to the Provincial Government, likely due to technological limitations,
poor economics or perhaps poor understanding of the potential resource. Regardless of
the reasons, further industry exploration for oil sands ceased. In a Saskatchewan Mineral
Resources report written in 1978, bitumen staining was also identified in Mannville
outcrops along the Clearwater River valley (Paterson et al., 1978).
1
Figure 1.1. Stratigraphic chart of strata in northwestern Saskatchewan and northeastern
Alberta (Kohlruss et al., 2010b).
2
In 2004, Oilsands Quest Inc. acquired Saskatchewan oil sands permits in
northwestern Saskatchewan, and in 2005 the company began extensive exploratory
drilling. The initial test holes intersecting bitumen were subsequently described and
reported by Hoffman and Kimball (2006), and Ranger (2006). Further drilling of 355 test
holes resulted in intersections of abundant bitumen saturated sandstones and
consequently a large resource has since been identified.
Oilsands Quest Inc. estimates a resource of 222 million m3 to 371 million m3 (1.4
billion barrels to 2.3 billion barrels) of bitumen in place (Oilsands Quest Inc., 2010).
These lands are located directly adjacent to the Alberta border in very close proximity to
the Athabasca oil sands deposits, which have a total in-place oil reserve of 161.1 billion
m3 (1.013 Trillion barrels) (AEUB 2007), and just north of the Clearwater River (Figure
1.2).
This thesis represents the first systematic sedimentological and stratigraphic
analysis of the Dina Member, the primary host of Saskatchewan’s oil sands. The research
is based on examination of drill cores from Oilsands Quests Inc.’s Saskatchewan
properties, supplemented by study of outcrops of the Dina Member along the nearby
Clearwater River valley.
1.1
Purpose and Objectives
The sandstones of the bitumen bearing Dina Member (Mannville Group) in
northwestern Saskatchewan occur at approximately 200 m below surface and
3
Figure 1.2. Location map of current active oil sands exploration licenses in
Saskatchewan along the Alberta-Saskatchewan border, directly adjacent to Alberta oil
sands agreements, and immediately north of the Clearwater River valley (Modified after
Alberta Energy, 2012). Note location of Pre-Cambrian shield and Provincial border.
(Information for this graphic obtained with permission from Alberta Energy, original
source file http://www.energy.alberta.ca/LandAccess/pdfs/OSAagreeStats.pdf )
4
subsequently the resource would require in-situ techniques to develop. In-situ
development requires much more detailed understanding of reservoir characteristics than
that of surface mining projects (Hubbard et al., 2011; Fustic et al., 2011; Labrecque et al.,
2011; Fustic et al., 2012).
Vertical and horizontal facies changes within the reservoir can impact in-situ
development techniques and strategies and a detailed geological model of the reservoir
would aid in an efficient development of the resource (Strobl et al., 1997; Hubbard et al.,
2011; Fustic et al., 2011; Labrecque et al., 2011; Fustic et al., 2012).
The purpose of this study is to determine the stratigraphic architecture of the Dina
Member in northwestern Saskatchewan and its control on bitumen distribution. The
objectives are to identify and characterize facies and facies associations of the Dina
Member, to determine their depositional environments, to produce stratigraphic cross
sections, and correlate the units to the McMurray Formation in the Athabasca Oil Sands
area of Alberta. Results from these studies are used to decipher the relationships between
facies, facies associations, stratigraphic architecture and bitumen distribution.
1.2
Previous Work
A number of studies have been carried out on the sedimentology and stratigraphy of the
McMurray Formation in Alberta. The first modern detailed work documenting the
sedimentology of the McMurray Formation was conducted by Carrigy (1959a, b, 1962,
1963, 1966, 1967, 1971). Carrigy (1959a) devised a three part, informal subdivision of
the McMurray Formation (the Lower, Middle and Upper units) that is still used today,
although the boundaries between the three units are often difficult to place (Ranger and
5
Gingras, 2006). Carrigy (1971) interpreted the depositional environment of the
McMurray Formation to be a fluvial-dominated delta, and was later supported by other
studies, specifically that of Nelson and Glaister (1978).
Concurrently, Christopher (1974, 1980, 1984) and Paterson et al. (1978) were
conducting pioneering research on Mannville Group stratigraphy throughout
Saskatchewan, including synthesizing the depositional history of the Mannville for the
entire province. Part of this research documented the Dina and Cummings members,
including the first descriptions of bitumen-bearing Mannville Sandstones in the La Loche
area, outcropping along the Clearwater River Valley (Paterson et al., 1978).
Throughout the 1980’s Peter Flach and Grant Mossop (Mossop, 1980; Pemberton
et al., 1982; Mossop and Flach, 1983; Flach, 1984; Flach and Mossop, 1985) further
advanced the understanding of Alberta’s McMurray Formation, both through subsurface
drill core and outcrop studies. They carried out detailed subsurface mapping and
correlations, estimated paleochannel depths and widths, utilized ichnological data to aid
determining the depositional setting of the McMurray Formation, and studied the
economic impact of reservoir variability. Flach and Mossop (1985) proposed the
McMurray Formation was predominantly fluvial, aggrading to keep pace with rising sea
level, forming complex mosaics of meandering channels associated with brackish bays
and shallow lakes. Despite the rising sea level, Flach and Mossop (1985) still interpreted
the depositional system to be part of a delta plain, since typical estuarine features like bidirectional current indicators and a funnel shaped morphology were absent.
Although most researchers described the McMurray Formation as deltaic, it was
recognized that this was not an ideal model, since the facies successions vary from the
6
typical delta depositional models. Unlike the coarsening upward succession typically
found in a delta system, resulting from delta front sands prograding over marine muds
(Flach and Mossop, 1985), the McMurray Formation exhibits a fining upward profile
with increasing marine influence at the top, which is more typical of an estuary
(Pemberton et al., 1982). The first interpretation of the McMurray Formation as being
deposited in estuarine environments was put forward by Stewart and MacCallum (1978).
They suggested that the McMurray is comprised of a lower fluvial unit, middle estuarine
unit and an upper marine unit, and they subsequently mapped these three facies
associations.
Ichnological studies undertaken by Pemberton et al. (1982), Keith et et al. (1988),
Ranger and Pemberton (1988), Beynon et al. (1988), Ranger and Pemberton (1992), and
Ranger and Pemberton (1997) identified marine trace fossils within the Middle
McMurray unit, demonstrating a marine influence on the fluvial meandering channel
sands. This, along with the identification of tidal bundles by Smith (1988), strongly
points to the Middle McMurray as having been deposited in a tidally influenced
depositional environment. It has become commonly accepted that the Lower and Middle
units of the McMurray Formation were formed in broad valleys that were in-filled with
fluvial and tidally influenced meandering channel deposits (Wightman and Pemberton,
1997; Hein et al., 2000; Crerar and Arnott, 2007; Hubbard et al., 2011).
The Alberta Energy and Utilities Board has recently provided overviews of the
Athabasca Wabiskaw-McMurray succession, primarily within the surface mineable areas
(Hein 2000, 2004, 2006; Hein et al 2000, 2006). Studies documenting the facies and
depositional environments of the Firebag-Sunrise area in northeastern Alberta have also
7
been carried out (Hein et al., 2007). The most recent studies within the McMurray
Formation have specifically focused on individual company properties in an effort to
develop high resolution sedimentological models (e.g., Hubbard et al. 2011, Fustic et al.,
2012; Fustic et al., 2011). These studies have identified very complex McMurray
Formation stratigraphy produced by point bar and counter point bar deposits of tidally
influenced fluvial meander systems.
Christopher (2003) provided a comprehensive depositional model for the entire
Mannville Group of Saskatchewan. Bauer et al. (2009) studied the Dina-Cummings
interval in west central Saskatchewan, describing incised valley-fill deposition
characterized by brackish-water dominated units, emphasizing the similarities to the
McMurray Formation. Ranger (2006) and Hoffman and Kimball (2006) were the first to
document the northwestern Saskatchewan oil sands exploration activity. Ranger (2006)
described depositional controls and identified the location of the Firebag tributary system
which extends from the McMurray Valley system eastward into Saskatchewan.
1.3
A Review of Estuary Depositional Models
1.3.1
Introduction
The definition of Estuary can be widely variable, but from a geological
perspective Dalrymple et al. (1992) defines an estuary as: the seaward portion of a
drowned valley system which receives sediment from both fluvial and marine sources and
which contains facies influenced by tide, wave and fluvial processes. The estuary is
considered to extend from the landward limit of tidal facies at its head to the seaward
8
limit of coastal facies at its mouth (Figure 1.3). Some definitions utilize salinity to define
the estuarine environment, but deltas can also experience brackish-water conditions
(Dalrymple and Choi, 2007).
Estuaries form in fluvial incised valleys during transgression when the creation of
accommodation space outpaces sediment input and is differentiated from deltas, in that,
estuaries have a net landward movement of sediment while deltas have a net sediment
transport seaward (Dalrymple et al., 1992; Zaitlin et al., 1995).
The McMurray Formation and Dina Member have been interpreted to be
deposited not just in the fluvial environment, but also within the fluvial-to-marine
transition zone, where fluvial waters mix with tidal waters (Wightman and Pemberton,
1997; Hein et al., 2000, 2001, Langenberg et al., 2002; Crerar, 2003; Lettley, 2004;
Crerar and Arnott, 2007; Fustic, 2007; Ranger and Gingras, 2006; Hubbard et al., 2011;
Fustic et al., 2012). For this reason, it is worth reviewing the current understanding of
how facies change within an estuary and what processes are occurring due to the many
terrestrial and marine processes interacting there. This review also paves the ground for
description, interpretation and discussion of the various facies encountered in this study
and their depositional environments.
1.3.2
Physical Processes
Two of the most significant physical processes controlling the deposition of the
McMurray Formation/Dina member in the Athabasca oil sands areas are river currents
and tidal currents and therefore an understanding of these processes is warranted.
9
Figure 1.3. (A) Schematic facies map of a tide dominated estuary. (B) Longitudinal
salinity variations along the estuary, with the shaded area indicating fluctuations through
time of the salinity gradient, influenced by river discharge. (C) Profiles showing
longitudinal variability of invertebrate organisms, size and density (after Dalrymple and
Choi, 2007). Side scales are for relative comparison only.
10
1.3.2.1 River and Tidal Currents
The most important consideration with river currents is that they decrease in
strength and influence in a distal or seaward direction and this occurs in both estuaries
and deltas (Dalrymple and Choi, 2007). Tidal currents, on the other hand, subject tidal
action starting at the seaward portion of an estuary or delta and produce flood (landward)
and ebb (seaward) currents. Tidal currents increase landward through tidal wave
compression. The currents speed up as the tidal wave moves progressively into narrower
channels, and then gradually decrease landward due to the friction. The greatest tidalcurrent speeds are achieved within the middle area of the estuary, due to the resonance
effect, called the tidal-maximum (Dalrymple and Choi, 2007) (Figure 1.4).
Without considering density-driven circulation, the current velocities are the total
of tide and river produced water movement. Within the river portion, velocities vary
based upon seasonal response and storm related input. These changes are relatively slow
compared to semi-diurnal current fluctuations that result from tides (Dalrymple and Choi,
2007).
One of the recognizable tidal influences on rivers is a tidally induced fluctuation of the
flow velocity in rivers. Though flow is always seaward, river flow slows down during
flood tides and accelerates during ebb tide. Moving further seaward, the effects of tides
become strong enough to stop the river flow, and then finally, a point is reached where
the tide effects are strong enough to induce intermittent flow reversals landward
(Dalrymple and Choi, 2007).
The most landward portions of an estuary are river dominated and the most distal
seaward portions would be tidally dominated (Figure 1.4). The tidal-limit of an estuary is
not a static location and can be located anywhere from the first proximal observation of
11
Figure 1.4. Schematic map of a tide-dominated estuary. Note longitudinal change in
channel morphology from straight-meander-straight in a seaward direction. Also note the
longitudinal variations in current intensity of the river and tides. Note the location of the
tidal maximum and the diminished energy within the area of mixing. Note that the area of
mixing is also the area of highest suspended sediment, bed-load convergence and the area
of highest river sinuosity (after Dalrymple and Choi, 2007)
12
flow reversals to the most proximal occurrences of tidally induced flow fluctuations. This
can be separated by 10s to 100s of kilometers. The tidal limit can also move as a result of
seasonal fluctuations of river out-put or neap-spring changes in tidal range. During times
of high river flow the tidal limit will be pushed seaward while during times of low river
input the same area may be affected significantly by tidal conditions. Areas considered
mainly fluvial may have irregular tidal depositional features due to variability in the
position of the tidal limit.
1.3.3
Chemical Processes and Water Circulation
In all estuaries and deltas salt and fresh water mixing is a significant component
of the physical processes. Overall, salinity increases from the river to the sea but can be
quite variable depending upon tidal current intensity and river input. The range of this
brackish-water zone can therefore be variable, from only a few kilometres to hundreds of
kilometres long (Allen et al., 1980; Allen, 1991; Dalrymple et al., 1992; Dalrymple and
Choi, 2007). In all cases the landward brackish water limit (salinity limit) is always
seaward of the tidal limit. Like the tidal limit, the salinity limit is pushed seaward during
times of high river flow and migrates landward further with high salinities during time of
low river flow. This can therefore create salinity variations in discrete locations.
Water circulation within estuaries can be divided into three distinct categories and
can create three types of estuaries. Depending on which category of water circulation
pattern, different sediment transport patterns will exist (Dyer, 1995; Lettley, 2004).
The first type is a stratified estuary or salt-wedge estuary (Figure 1.5). Here there is
relatively little tidal flow and the less dense fresh river water flows over the more dense,
13
Figure 1.5. Classification of estuaries based on internal water circulation patterns. (A)
Salt wedge estuaries typical of micro-tidal estuaries. (B) Partially mixed estuaries, where
input of tidal and fluvial currents is near equal. This is similar to the McMurray/Dina
depositional system. In partially mixed estuaries, the formation of a salt-wedge in the
zone of mixing, results in density driven circulation, trapping of suspended sediments and
the development of the turbidity maximum (C) A well mixed estuary experiences
dominant tidal energies with little river energy (modified after Lettley 2004)
14
stable wedge of salt water, therefore little mixing occurs. This type is most common
where the tidal range is micro-tidal (< 2 m range) (Dyer, 1995; Lettley, 2004).
The second type is a partially mixed estuary. This type has increased tidal energy
and is prevalent where river flow and tidal currents both contribute significantly to the
estuarine system (Dyer, 1995; Lettley, 2004; Dalrymple and Choi, 2007). It is this type of
system that portions of the McMurray Formation are interpreted to have been deposited
and therefore has the most relevance to this study (Lettley, 2004). Mixing of saltwater
upwards into freshwater and freshwater downwards into saltwater is caused by turbulent
flow associated with tidal current friction. The friction is a result of the tidal currents
interacting with the bed of the estuary. As saline water is mixed upward into the fresh
water flow and subsequently carried seaward, a significant landward flow at the bottom
layer also occurs to compensate for volume loss. This creates a much larger salt wedge
than that of the stratified estuary. This process is known as vertical gravitational
circulation. In these cases, density driven circulation and salinity stratification are
especially pronounced during high river flow periods (Figure 1.5) (Dyer, 1995; Lettley
2004; Dalrymple and Choi, 2007).
Finally, where tidal processes dominate over fluvial energy, a well-mixed estuary
exists. This completely mixes the water vertically and salinity variations are horizontal.
In these cases there are often separate flood and ebb channels (Figure 1.5) (Dyer, 1995;
Lettley, 2004; Dalrymple and Choi, 2007).
1.3.4
Biological Processes
The fluvial-to-marine transition, whether in a delta or estuary, is subjected to
brackish-water conditions. These conditions, as previously stated, can be highly variable
15
due to changes both seasonally from fluctuations in river out-put and within single tidal
cycles. This along with water turbidity and frequent sediment disturbances by river and
tidal currents make the estuarine environment a stressed setting for organisms.
Consequently, few organisms are adapted to survive there, but some organisms
have made adaptive changes. The group of organisms present generally exhibit low
diversity, the lowest of which is associated with the lowest salinities landward, whereas
species diversity increases seaward (Figure 1.3). The species in the brackish environment
reflect an impoverished marine assemblage rather than a mixture of fresh water and
marine (Beynon et al., 1988). Also, due to the stresses of salinity variability these
organisms tend to be reduced in size compared to the fully marine equivalents. The
organisms are often opportunistic and can colonize surfaces very quickly, occur in large
numbers and in mono-specific assemblages (Beynon et al., 1988). The organisms in this
environment often live within the sediment producing simple vertical or horizontal
structures (Beynon et al., 1988; Ranger and Pemberton, 1992; Buatois et al., 2005;
Dalrymple and Choi, 2007).
1.3.5
Morphology
Estuaries are initially formed at the start of a transgression and move landward, up
the incised valley, as relative sea-level rises. Tide dominated estuaries typically exhibit a
tripartite zonation through the plan-form of the channel. Dalrymple et al. (1992) describes
this zonation as a straight-meandering-straight plan-form morphology (Figure 1.3).
Beginning at the seaward limit, the inlet, the initial “straight” portion is characterized by
mid-channel and bank attached bars, and is relatively broad at the inlet mouth and tapers
16
to a single channel. Continuing upstream from this point, the system passes into a highly
sinuous reach and is characterized by laterally migrating point bars displaying tight
meanders. This is the lowest energy zone where net bed-load converges and grain size in
the channel becomes finest in this area from both upstream and downstream directions
(Dalrymple et al., 1992; Zaitlin et al., 1995). Finally, moving further inland to the inner
“straight” channel zone, there is a transition from meandering to braided river
morphology (Figure 1.4). The cross-sectional area of the channel also decreases upstream
as a function of decreased tidal related energy and water volume further inland. The
location where the channel system ceases to decrease in cross-sectional area generally
coincides with the landward extent of tidal influence.
All tidal environments are channelized and are similar to meandering fluvial
systems with predominantly laterally accreted channel margins and vertically accreted
overbank areas. Braided rivers can have tidal influence at their mouths but the zone is
generally very narrow due to the relative steep gradient of braided rivers (Zaitlin et al.,
1995; Dalrymple et al., 1992; Dalrymple and Choi, 2007)
Due to tidal water flux, the cross-sectional area of tidal channels displays a
seaward exponential increase. This cross-sectional increase is responsible for the typical
funnel-shape of a tide dominated estuary succession. Another morphological feature of
fluvial and tidal channels is that they are almost all curved to a certain degree. Wide
channels, with larger discharge, tend to be straighter while narrow channels tend to be
more sinuous (Dalrymple and Choi, 2007). So, more distal channels tend to be straighter
than the more proximal, until steeper gradients produce faster currents, which results in
straighter channels as well. This fits well with the straight-meander-straight zonation.
17
Bars develop differently in response to the different hydraulic regimes. In the
narrow, sinuous portions of the tidal system, bars are laterally accreting point bars and in
the wider, straighter, more distal areas of a tidal system the bars are elongate. These
elongate tidal bars migrate laterally as well, commonly not in the direction of dominant
current as might be expected, but rather behave very similarly to point bars (Dalrymple
and Choi, 2007).
Lateral accretion bedding of point bars and elongate bars are erosively based due
to the lateral movement across the thalweg of the adjacent channel and have a fining
upward vertical profile (Bridge, 1985). This may eventually develop into inclined
heterolithic stratification (IHS) as described by Thomas et al., (1987) or inclined
stratification (IS). IHS beds formed within the proximal limit of the tidal-fluvial system
have coarse grained layers produced by river flooding or seasonal high river output.
1.3.6
Cross-Bedding and Tidal Indicators
In the fully fluvial areas beyond the tidal limit, cross stratification is
unidirectional with all flow indicators pointing seaward. Moving further seaward, where
tidal action is represented as fluctuations in river speed due to slowing caused by flood
tide and increased speed due to ebb tide, flow direction is still unidirectional, but the
change of hydrodynamic regime may be reflected by rhythmic grain size striping, where
medium or coarse sand grains are deposited during ebb tide and finer sand during flood
tides (M. Gingras, pers. Com. 2009; Ranger and Gingras, 2006; Dalrymple and Choi,
2007). This can be used to suggest semidiurnal processes when seen in the rock record.
Continuing to move seaward, stronger tidal currents produce slack-water periods,
leading to deposition of suspended sediments. These can occur as single or double mud
18
drapes depending upon one or two slack water periods. Mud drapes can also be
dependent on seasonal variations since during seasonally high river flow the areas of mud
accumulation would be pushed significantly seaward (Lettley, 2004). Mud drapes can
therefore be present in what appears to be a fully fluvial area. The mud would have
accumulated during the seasonal low flow times when tidal waters can push much farther
landward.
Further seaward, current reversals and reactivation surfaces form. These features
should become increasingly more frequent towards the inlet where tidal currents become
progressively stronger. Surprisingly, bi-directional current indicators such as herringbone cross bedding are not as abundant as one would expect; rather cross-bedding
associated tidal dunes, which is generally planar tabular and two dimensional in nature, is
most common (Dalrymple and Rhodes, 1995; Dalrymple and Choi, 2007).
1.3.7
Grain Size Distribution
Coarse grained sediments within the fluvial or tidal system become finer grained
in the direction of decreasing energy of transport (McLaren and Bowles, 1985;
Dalrymple and Choi, 2007). Grain size decreases both from the seaward limits and the
landward limits towards the middle of the estuary. Therefore, the finest grains are found
at the area of bed-load convergence (Figure 1.4).
As suspended sediment is carried from the freshwater fluvial system into
brackish-water, an electrical attraction between ions in the water and the unsatisfied
bonds at the edges of clay particle crystal lattices occurs. This process then starts to form
loose bundles of clay particles called flocs and is most prevalent where salinity is 1-10
19
wt.% (Nichols and Biggs, 1985; Dyer, 1995). This results in increased settling of silt and
clay sized sediment, particularly at the fresh-salt water interface. This is enhanced in
wedged estuaries and partially mixed estuaries where fresh water rides over top of a base
salt water wedge (Dyer, 1995; Lettley, 2004). The landward bed flow in the salt wedge
carries the fines into the estuary as it settles out of the overlying fluvial discharge (Dyer,
1995).
This process creates a zone of highly concentrated suspended sediment that
occurs slightly landward of the landward limit of the saltwater intrusion. Salinities range
from approximately 1-5% in the landward direction to approximately 20% in the seaward
direction (Nichols and Biggs, 1985; Dyer, 1995; Dalrymple and Choi, 2007) (Figure 1.5).
This zone is known as the Turbidity Maximum and is developed through the combination
of tidal current asymmetry and density circulation (Allen, 1991). The turbidity maximum
location is primarily influenced by changes in fluvial out-put, migrating seaward with
increasing flow and landward with low flow (Allen et al., 1980; Dyer, 1995; Lettley,
2004). The turbidity maximum also moves with tide, moving landward with the flood
tide and seaward with the ebb tide.
The turbidity maximum is therefore a dynamic feature resulting in transport and
deposition, particularly of muds and silts, and changes its location through time. Of high
importance is the seasonal variability of the turbidity maximum’s location. The turbidity
maximum’s position varies significantly in relation to river out-put and the consequent
changes in water circulation (Allen et al., 1980). During seasonal periods where river
flow is lowest, the turbidity maximum is mainly controlled by tidal activity on the diurnal
and neap-spring (14 day) scales (Allen, 1991). During periods of high river out-put,
20
density circulation controls the turbidity maximum and it is concentrated much further
downstream (Allen, 1991; Dyer, 1995; Lettley, 2004). The result is cyclic deposition of
muds and sand in areas where the turbidity maximum is seasonally migrating.
1.3.8
Estuarine Depositional Model
Despite what appears to be an extremely complex depositional setting, a high
degree of organization occurs and a model with predictable longitudinal variation of
fluvial to marine processes can be developed in estuaries. The coarsest grains are
supplied and deposited by fluvial and marine processes in the upstream and seaward
areas of the estuary, where either tidal processes or river processes dominate (Figure 1.4).
In the most landward portions of the system, high fluvial out-put transports and
deposits coarse bed load sediment. During relative low fluvial out-put, the same area is of
low energy and can be influenced by a migratory turbidity maximum which promotes the
development of flocculation and mud deposition. This can result in a depositonal pattern
of inter-bedded sands and muds, as preserved in inclined heterolithic stratification (IHS)
(Thomas et al., 1987).
At the most seaward portions, periods of high river out-put drives the turbidity
maximum towards the inlet and increases the effects of density circulation. This process
along with the increase in suspended sediment derived from the high river flow and high
volumes of fines will result in significant deposition of silts and muds. Alternatively,
during low river flow, this same area will be dominated by tidal currents, rather than
density currents and higher salinities. This will result in sand deposition pushed landward
from the inlet in the form of elongate sand bars.
21
Where bed-load convergence occurs in the centre of the system, low energy
dominates with deposition of fine grained sediment deposition. Deposition in this region
is primarily controlled by turbidity maximum, variations in river discharge and variations
in tidal strength.
1.4
Study Area
The study area is located in the extreme northwestern corner of Saskatchewan’s
portion of the Western Canadian Sedimentary Basin, directly adjacent to the Alberta
border at the northeastern limit of the Athabasca oil sands deposit (Figure 1.6). The study
area ranges from Township 88 Range 19 West of the 3rd Meridian to Township 101
Range 25 West of the 3rd Meridian, which include outcrops along the Clearwater River
valley (Figure 1.6). A more focused, detailed study was carried out in the most intensely
drilled area ranging from Township 94 Range 24 West of the 3rd Meridian to Township
95 Range 25 West of the 3rd Meridian (Figures 1.6 and 1.7), which is encompassed by the
exploration permit lands of Oilsands Quest Inc. The detailed study was performed due to
the abundant available cores.
1.5
Study Methods
A database of 244 geophysical well logs was used to correlate major formation
tops, unconformity surfaces and facies within the Dina Member in the study area. The
geophysical well logs are of very good quality since all were acquired between 2005 to
2008. All stratigraphic test holes included gamma-ray, neutron-density porosity, photo
electric, spontaneous potential, resistivity and sonic logs.
22
Figure 1.6. Location of the study area in northwestern Saskatchewan. Note the detailed
mapping area where the majority of Oilsands Quest Inc’s drilling has been undertaken.
Also note detail of outcrop area along the Clearwater River (after Kohlruss et al., 2010a).
23
Figure 1.7. Map of detailed study area showing the distribution of stratigraphic test
holes.
24
The full suite of modern logs helped for formation and facies recognition and correlation.
These were used to create a series of structure and isopach maps based on stratigraphic
correlations. Eighty three drill cores were described in detail for facies characteristics,
that included observations on lithology, ichnology, sedimentary structures and bitumen
distribution. This data, along with geophysical well logs was used for environmental
interpretations. Twenty-five thin sections were analyzed, specifically from each identified
facies to determine mineralogy, potential sediment source areas, textural attributes and
bitumen staining. Seven samples from three wells were processed and analyzed for
palynmorphs by L. Bloom of the Department of Geoscience, at the University of Calgary
(L. Bloom, pers. com. 2010).
1.5.1
Net Pay and Net Water/Lean Mapping
Two hundred forty-four (244) core analyses were utilized to produce net pay
maps of the study area. The core analysis submitted to the Saskatchewan Provincial
Government by Oilsands Quest Inc. (analyzed by Norwest Labs) recorded sample
interval, bitumen saturation based on bulk mass, bulk mass of water, saturation based on
grain mass, and porosity. The methods used to construct “Net Pay” maps were the same
as those used by the Alberta Energy and Utilities Board (AEUB, 2003) (Hein et al.,
2005). Bitumen saturation, based on weight, was utilized for the Net Pay calculations. A
value of 6 wt% bitumen saturation was used as a minimum cut-off value. All increments
within the Dina Member that meet the cut-off were accumulated into a net bitumen pay
thickness. The AEUB utilizes a 6 wt% bitumen saturation cut-off since it approximates a
combined 50% bitumen saturation cut-off and a 27% porosity cut-off (AEUB, 2003). For
25
continuity and ease of comparison, these parameters were used in this study as well.
Maps were then generated utilizing Golden Software’s Surfer 9 mapping program. The
contours generated for net pay maps were constructed utilizing a Kriging algorithm.
Net Water/Lean Zone Isopach maps were also constructed. Once the net pay
thickness for each stratigraphic test hole was calculated, the net pay thickness value was
subtracted from the Dina Member/McMurray Formation isopach thickness value to
produce the Net Water/Lean Zone thickness.
Also, along with the net pay and net water maps, two bitumen saturation average
maps were produced. One included water saturated values within each core and the other
excluded water saturation zones and utilized intervals with bitumen saturation values
only. Since each sample varied in thickness, a weighted approach was taken to give each
sample a weighted percentage. To achieve a weighted value, each sample interval was
divided by the total sample interval. This was then multiplied by the bitumen saturation
for the interval, producing a weighted saturation value for that sample interval. All the
values from each subsequent calculated weighted interval were then summed to achieve a
bitumen saturation average for that well, over the course of its overall net pay.
1.5.2
Geological Isopach and Structure Maps
Geological isopach and structure maps were constructed using formation and
member top depths determined from drill core analysis and geophysical well-log
signatures. The formation and member top depths were entered into Microsoft Excel
2007 spread sheet and were mapped using Golden Software’s Surfer 9 mapping program.
The contours generated for the isopach and structure maps were constructed utilizing
Golden Software’s Surfer 9 Kriging algorithm.
26
1.5.3
Geological Cross-Sections
Five cross-sections perpendicular to inferred paleo-channel direction and one
along the thalweg of inferred paleo-channel were constructed to show detailed,
“property” scale stratigraphic framework for the Dina Member in the study area, as well
as bitumen distribution. These cross-sections were based on geophysical well logs,
principally gamma ray, and detailed drill core descriptions. The lack of a recognizable
and/or correlatable stratigraphic datum resulted in the decision to use mean Sea Level as
a structural datum for all cross-sections in the study area. Reasonable facies association
correlations and generalized interpretations of the depositional environment and its
history were still possible despite the use of a structural rather than a stratigraphic datum.
27
2. GEOLOGICAL SETTING
2.1
Regional Geology
The Mannville Group is the basal part of the Cretaceous sedimentary succession
that developed as a southwest dipping clastic wedge in the foreland basin associated with
the development of the Cordillera orogeny. The Mannville Group is underlain by the
regional sub-Cretaceous unconformity (Jackson, 1984; Cant, 1996). The ages of the subcropping strata underlying the sub-Cretaceous unconformity progressively change from
Jurassic to Cambrian from southwest to northeast (Figures 2.1 and 2.2). (Jackson, 1984;
Hayes et al., 1994; Cant, 1996; Ranger and Pemberton, 1997). This surface was a mature
erosional surface prior to the Late Jurassic-Early Cretaceous uplift of the Cordillera
(Jackson, 1984; Ranger and Pemberton, 1997). Thrusting in the Cordillera loaded the
western edge of the foreland basin, causing flexure of the lithosphere to create an area of
maximum subsidence adjacent to the load (Figure 2.3) (Jackson, 1984; Cant and
Stockmal, 1989). The rising Cordillera lead to a subsequent influx of sediment into the
subsiding basin. The lower portion of the Mannville was deposited during an overall
transgression systems tract (TST) and then a regression or Highstand systems tract
(HST) created by the large pulse of Cordilleran sediment (Christopher, 1980; Jackson,
1984; Cant, 1996; Cant and Abrahamson, 1996; Christopher, 1997; Christopher, 2003).
The TST and HST are separated by a maximum flooding surface within the Clearwater
Shale/ Cummings shale (Figure 2.4) (Cant and Abrahamson, 1996). The Dina Member
and McMurray Formation were deposited as part of the initial transgression of the Boreal
Sea from the North-Northwest (Vigrass, 1968; Christopher, 1980; Jackson, 1984; Cant,
1996; Christopher, 1997; Christopher, 2003).
28
Figure 2.1. Structure map of the sub-Cretaceous unconformity surface. Various colours
indicate the age of sub-cropping strata underlying the unconformity. The strata become
progressively older to the north and east. The contacts between the sub-cropping strata
are often preferentially eroded creating paleo-channel systems parallel to strike. Note
map covers Manitoba, Saskatchewan, Alberta and B.C. (after Hayes et al., 1994).
29
Figure 2.2.Stratigraphic cross-section from southwest to northeast, perpendicular to strike
of the Western Canadian Sedimentary Basin. Note the dipping strata into the foreland
basin to the southwest (after Ranger and Gingras, 2006).
30
Figure 2.3. Model for terrane accretion during creation of the Mannville depositional
basin. (a) Initial accretion causing peripheral bulge creating unconformity; (b) Deep
water conditions in foreland basin due to flexure induced subsidence; (c) Time of high
rates of sedimentation and filling of foreland basin; (d) Basin rebound (after Cant and
Stockmal, 1989)
31
Figure 2.4. Formations and Members of the Mannville Group. This diagram illustrates
the TST and HST (transgressive and highstand systems tracts) of the entire Mannville
Group (modified after Cant, 1996)
32
Three major drainage systems developed as a result of the lithosphere flexure and
subsidence of the foreland basin (Figure 2.5). A major drainage system (most
southwestern) occurs in western Alberta, referred to as the Spirit River Valley located
along the axis of the developing foreland trough of the North American Cordillera
(Figure 2.5) (Christopher, 1980; Jackson, 1984; Ranger and Pemberton, 1997).
A second major valley system has its headwaters in the Swift Current Platform of
southeast Alberta and southwest Saskatchewan and flowed toward the northwest
(Christopher, 1980; Jackson, 1984; Ranger and Pemberton, 1997). This is known as the
Edmonton Valley System (Figure 2.5). It is not well known where the mouth of the
system resided but it is believed it may have emptied directly into the Boreal sea
(Jackson, 1984). It has also been suggested that it may have connected with and been a
tributary of the Spirit River Valley (Christopher, 1980; Jackson, 1984; Ranger and
Pemberton, 1997).
To the east of the Edmonton Channel valley was a major axial ridge of resistant
Devonian carbonates known as the Wainwright Ridge in Central Alberta and the
Grosmont High in northeastern Alberta. East of the Wainwright Ridge lies a third major
drainage system known as the Assiniboia Valley System (Figure 2.5) (McMurray Valley
System in Alberta) (Christopher, 1997; Ranger and Pemberton, 1997). It is within this
channel system, running approximately parallel to the orogen/foreland subsidence
gradient, the Athabasca Oil Sands deposits of the McMurray Formation and Dina
Member are confined. The channel system is restricted by the Canadian Shield to the
northeast and its axis follows parallel to the strike of the Canadian Shield through
33
Figure 2.5. Major paleo-drainage systems on the sub-Cretaceous unconformity. Note the
Assiniboia / McMurray Valley extending from northern Alberta, across Saskatchewan to
Manitoba. The Assiniboia / McMurray Valley follows near parallel to the Prairie
Evaporite dissolution edge (modified after Christopher, 2003)
34
Saskatchewan down to Manitoba (Christopher, 1980; Ranger and Pemberton, 1997;
Christopher, 1997) (Figure 2.5).
The Assiniboia/McMurray Valley system occupies a regional collapse low
created by Devonian salt dissolution of the Prairie Evaporite (Figure 2.5) (Vigrass, 1968;
Christopher, 1980; Jackson, 1984; Cant, 1996). The dissolution caused structural
subsidence of the overlying basin, before, during and after deposition of the McMurray
Formation and Dina Member.
The upper Assiniboia/ McMurray Valley system is eroded down into the Middle
to Lower Devonian carbonates of the Elk Point Group in western Saskatchewan and
Upper Devonian carbonates of the Woodbend Group in eastern Alberta (Wightman et al.,
1997, Ranger, 2006). The Devonian carbonates are often porous and are believed to have
Karst topography (Belyea, 1952; Ranger and Pemberton, 1997; Hein, 2006; Hein et al.,
2007). The angular discordance between the Cretaceous and the Devonian is very subtle
and in outcrop appears to be conformable. It is only with regional mapping that an
angular relationship is apparent. The topography on this surface is very significant since
this is the surface in which deep, intricate valleys were eroded and the McMurray and
Dina were deposited (Jackson, 1984; Ranger et al., 1988; Hayes et al., 1994; Cant, 1996;
Christopher, 1997).
Sediments within the Assiniboia/McMurray Valley system were likely derived in
part from erosion of Jurassic deposits and from the Canadian Shield. Valley fill is
comprised of fluvial, marginal marine and estuarine deposits arranged in an overall
transgressive vertical stacking pattern (Jackson, 1984; Flach, 1984; Cant and Stockmal,
1989; Cant and Abrahamson, 1996).
35
2.2
McMurray Sub-Basin
The McMurray sub-basin is limited by the north trending ridge of the Grosmont
High in the west where the McMurray Formation is absent and also by the Canadian
Shield in the east (Ranger and Pemberton, 1997) (Figure 2.5). Tributaries flow off the
“highs” of the Grosmont and Canadian Shield and drain into the north-northwest trending
main trunk valley of the Assiniboia/McMurray Valley system.
Tributary Valley systems that drained parts of the Precambrian shield
immediately east of the McMurray sub-basin were likely supplied with sands from the
Precambrian Athabasca Group (Helikian age) (Ranger and Pemberton, 1997; Ranger,
2006; Hein et al., 2007). Exploration in the far northeast region of the Athabasca Oil
Sand deposit in Alberta has identified a tributary valley system known informally as the
Firebag valley (Figure 2.6). The sands in this area contain very coarse material,
suggesting a proximal, fluvial to fluvio-estuarine channel origin (Ranger, 2006; Hein,
2006; Hein et al., 2007). It is this valley system that extends eastward into Saskatchewan
along the Alberta border into the study area at township 94 and 95, Ranges 24 and 25W3
(Figure 2.6). In this area the Elk Point Group is exposed by the sub-Cretaceous
unconformity and sub-crops below the Dina Formation (Paterson et al., 1978; Ranger
2006).
2.3. Stratigraphy of the lower Mannville Group
Different subdivisions and nomenclatures are used for the Mannville Group in
Alberta and Saskatchewan. In northeastern Alberta, the Mannville Group is divided into
36
Figure 2.6. Location map showing Firebag valley system on the sub-Cretaceous
unconformity in northeastern Alberta and northwestern Saskatchewan. Note the Firebag
tributary is inferred to extend landward into Saskatchewan, into the study area. Also,
note, the Firebag tributary runs approximately east west and drains into the Athabasca
main valley (modified after Ranger, 2006)
37
Figure 2.7. Alberta stratigraphic chart illustrating lower Cretaceous stratigraphy, in
particular, the Devonian stratigraphic relationship with the McMurray Formation (after
Ranger and Gingras, 2006)
38
the lower McMurray Formation, middle Clearwater Formation, and upper Grand Rapids
Formation (Figures 2.7 and 1.1). In northwestern Saskatchewan, the Mannville consists
of a lower Cantuar Formation and an upper Pense Formation. The Cantuar Formation is
divided into seven members, which are, from lower to upper, Dina, Cummings,
Lloydminster, Rex, General Petroleums, Sparky, and Waseca, and the Pense Formation is
comprised of the lower McClaren Member and the upper Colony Member (Figure 1.1).
The Dina Member is equivalent to the lower portions of Alberta’s McMurray Formation,
which is the main reservoir for the Athabasca Oil Sands deposit.
In Alberta, the McMurray Formation has been informally sub-divided into the
Lower, Middle and Upper units (Carrigy, 1959a) and is interpreted as continental,
prograding tide dominated delta/estuary and wave dominated delta shoreface deposits
respectively (Ranger and Gingras, 2006). The McMurray outcrops along the Athabasca
River north of the town of Fort McMurray, equivalents outcrops of the Dina Member are
exposed along the Clearwater River in northwestern Saskatchewan.
The Dina Member in northwestern Saskatchewan is a stratigraphically complex
siliciclastic depositional system with abrupt lateral facies changes that makes correlation
difficult even between closely spaced wells (Carrigy, 1971; Ranger and Pemberton, 1997;
Ranger and Gingras, 2006). The Dina Member is comprised of unconsolidated sands and
shales overlying the sub-Cretaceous unconformity which was developed predominantly
on Devonian carbonates (Paterson et al., 1978; Christopher, 1997; Christopher, 2003).
Like Alberta’s McMurray Formation, deposition of the Dina Member was subsequently
controlled by regional depressions in the sub-Cretaceous erosional surface. This
topography was in part controlled and enhanced by dissolution of the Devonian Prairie
39
Evaporite Formation as well as karstification of Devonian carbonates (Belyea, 1952;
Vigrass, 1968; Christopher, 1980; Ranger and Pemberton, 1997; Hein, 2006; Hein et al.,
2007).
Northwestern Saskatchewan lies near the present day erosional edge of the
Athabasca oil sands deposit, where potential reservoirs lie at relatively shallow depth, and
in many instances has been eroded severely by Pleistocene glaciation processes (Paterson
et al., 1978; Ranger, 2006; Kohlruss et a., 2010a,b). Pleistocene glacial drift lies directly
on top of eroded Dina/McMurray reservoir and when present, is normally a sand on sand
contact. Where there is a sand on sand contact, it is very difficult to determine formation
top picks in geophysical well logs. When this is combined with the fact that fresh water
occupies the Pleistocene aquifer, stratigraphic interpretation from geophysical well logs
becomes very difficult since freshwater reads very high on resistivity logs making it
difficult to discern from the high resistivity readings of bitumen. Without utilizing drill
core, the evaluation of northwestern Saskatchewan’s bitumen potential is extremely
challenging (Ranger, 2006; Kohlruss et al., 2010a).
40
3.
3.1
FACIES DESCRIPTIONS AND DEPOSITIONAL INTERPRETATIONS
Introduction
Within the detailed study area, the Lower Cretaceous Dina Member has been
divided into eight distinct recurring facies. These facies divisions are based upon the
combination of lithology, grain size, and sedimentary and biogenic structures. Facies 4
has further been subdivided into 2 sub-facies. These facies are then organized into 5
facies associations based on stacking patterns and genetic relationships. The facies
descriptions and interpretations are summarized in Table 3.1, and are elaborated on
below.
3.2
Facies Descriptions and Interpretations
3.2.1
Facies 1: Massive Sandstone
Facies 1 (F1) is composed of very well sorted, generally sub-rounded to sub-
angular fine grained quartz sandstones with no visible sedimentary structures or
burrowing, and is distinctive with its massive appearance. Commonly the sandstones of
this facies display high levels of bitumen saturation adding to the massive appearance.
The bitumen acts as the “cement” for the quartz grains that would otherwise be friable
and poorly indurated (Figure 3.1). Occasionally mud chips and carbonaceous debris were
observed.
F1 is observed within 16 of the logged cores and ranges in thickness from less
than 1m to a maximum total of 19 m with an average of 5.3 m. F1 is commonly observed
overlying F3 and inter-bedded with F2 and F6 (Table 3.1).
41
Figure 3.1. Massive sandstone (Facies 1) composed of lower to upper medium sized
grains: the sandstone appears structureless and is commonly highly bitumen saturated;
well 05-12-95-25W3, 189.0 m.
42
Table 3.1. Summary of facies within the study area
43
In thin sections, silt sized fraction was commonly observed as matrix between the
fine grained quartz grains. 1-3% fine grained muscovite and rare fine grained microcline
plagioclase was also observed. Quartz grains exhibit common undulose extinction under
cross-polarized light. Quartz grains are mostly monocrystalline, occasionally
polycrystalline. Very rare quartz overgrowths and no other cements, were observed.
Although there is rare disruption of sand and sedimentary structures due to
bioturbation, this facies has sparse, diminutive Cylindrichnus and Gyrolithes observed as
mud lined or mud filled burrows. These burrows tend to be constrained to discrete
horizontal layers (Figure 3.2).
The apparent homogeneity of F1 can be interpreted in multiple ways. Most likely,
the abundance of oil saturation has masked subtle primary physical structures, such as
ripple cross laminations, and/or biogenic structures. Alternatively, the sands may have
been deposited very quickly resulting in sandstones with no visible stratification. Since
F1 is in close association with Facies 2, which is interpreted as formed in a low flow
depositional regime, and has never been observed without complete bitumen saturation, it
is very likely F1 is a product of low energy flow and the extreme bitumen saturation is
masking the primary structures. The presence of sparse and diminutive simple vertical
trace fossils such as Cylindrichnus and Gyrolithes suggest brackish water conditions,
perhaps locally or over a short period of time (Beynon et al., 1988). This is likely a result
of a migrating salt wedge whose position is controlled by neap-spring tidal cycles, rate of
fluvial discharge or storms producing tidal surges. This is in contrast with freshwater
deposits, which are generally unburrowed or contain horizontal insect traces. Freshwater
trace fossils are generally short-lived and rarely preserved.
44
Figure 3.2. Massive sandstone (Facies 1) composed of lower to upper medium-sized
grains: Note Gyrolithes burrows penetrating into sand layers from overlying discrete bed.
Also note variation in bitumen staining between sand layers separated by burrow bed,
likely reflecting lower porosity/permeability of these beds; well 06-29-94-25W3,
198.75m.
45
3.2.2
Facies 2: Ripple Cross laminated Sandstone
Facies 2 (F2) is comprised of light to moderate bitumen cemented, centimetre
scale ripple cross laminated, lower to upper medium grained sandstones. The grains are
subangular to rounded and very well sorted. F2 commonly hosts sparse and diminutive
mud lined or mud filled Cylindrichnus, Thalassinoides and Gyrolithes constrained to
discrete horizontal layers.
F2 is observed within 17 of the logged core and occurs primarily within decimeter
thick beds with a rare net accumulation up to 14 m present discontinuously in one
stratigraphic drill core. Thickness averages 2.7 m. Individual ripple cross laminated beds
rarely exceed 10 to 20 cm in thickness and individual ripples measure 1-2 cm in height
(Figure 3.3). F2 occurs in close relationship with F1 and F6 and is almost always found
inter-bedded, directly above, or directly below one of these two facies (Table 3.1).
In thin section, the grains are primarily grain supported with no visible
cementation and no visible matrix clays or fines. Quartz grains were often observed to
have undulose extinction under cross-polarized light. Minor amounts of pyrite were also
observed.
The structures in F2 indicate unidirectional flow under relatively lower energy
conditions. This facies was likely deposited as small-scale current ripples migrating
within fluvial and/or estuarine channels. This could occur along the bottom of channels or
more likely along the inside meanders of low flow point bars.
46
Figure 3.3. Ripple laminated medium grained sandstone (Facies 2); note the relatively
low bitumen saturation; well 16-28-94-25W3, 191.45 m.
47
3.2.3
Facies 3: Planar Cross-bedded Sandstone
Facies 3 (F3) is comprised of planar cross-bedded, well to moderately sorted, sub-
rounded to sub-angular, medium grained to very coarse grained sandstones (Figure 3.4).
Less than 5% fine muscovite grains have also been observed scattered throughout the
facies. Planar cross-bed sets are generally metre scale in thickness and composed of
uniform fining upward, centimetre scale, depositional lamina recognizable as grain-size
striping (M. Gingras, pers. com. 2009; Ranger and Gingras, 2006; Dalrymple and Choi,
2007). Bed-set boundaries can be sharp or can be separated by horizontal lamina or coflow or back-flow ripple cross laminations. These lamina commonly contain fine
carbonaceous debris and/or mud rip-ups (Figure 3.5). Mud rip-up clasts and wood
fragments are also commonly observed throughout F3. Bioturbation was rarely observed
within this facies. F3 has the highest observed bitumen saturation values, however,
throughout the southern region (south of, and portion of Township 94) of the general
study area, this facies is typically water wet. When present, bitumen acts as a
“cementing” agent, but when absent the sandstones are commonly friable and poorly
indurated.
F3 is a very common facies, observed within 37 of the logged cores, and ranges in
thickness from as little as ~1m to a maximum of 25m with an average of 8.4m. F3 is
commonly observed underlying F2, F3 or F6 and overlying F4. The contact between F4
and F3 is generally erosive in nature (Table 3.1). F3 has also been observed in outcrops
along the Clearwater River valley, as described by Kohlruss et al. (2010a).
F3 is interpreted to be deposited under high energy conditions. Reactivation
surfaces, co-flow and back flow ripple cross laminations, rip-ups and planar cross
48
Figure 3.4. Planar cross-bedded sandstone (Facies 3); Note bitumen stained and water wet
variations; A) Unstained well 13-16-94-25W3, 185.5m; B). Bitumen stained well 16-28-9425W3, 190.30m
49
Figure 3.5. Facies 3 showing reactivation surface (red arrow) separating planar crossbedded sandstone. Note a mud rip-up clast just above reactivation surface; well 05-29-9425W3, 223.27m
50
bedding are interpreted to indicate that deposition occurred as metre scale dunes
migrating within meandering fluvial to upper estuarine channels. The extremely low
abundance of biogenic structures (very rare Cylindrichnus) supports the interpretation of
an environment where water conditions would be primarily fresh to brackish (Pemberton
et al., 2001; Ranger and Gingras, 2006). A pin-stripe rhythmic grain size couplet or grain
size “striping” appearance within the planar cross-bed sets (M. Gingras, pers. com. 2009;
Dalrymple and Choi, 2007) are interpreted to suggest semidiurnal processes and tidal
influence and used as evidence for tidally influenced sediment bundles (Dalrymple and
Choi 2007; Ranger and Gingras, 2006). The coarse grained portion would have been
deposited during ebb tides, when flow seaward would be the fastest, and the fine grained
portions deposited during flood tide stages, when tidal processes worked against river
flow and slowed river currents resulting in finer grained sediment deposits (Ranger and
Gingras, 2006). There are also common horizontal lamina at the planar cross-bed-set
boundaries, typical of the toe-sets of sigmoidal cross-bedding. Also, commonly co-flow
or back-flow ripple cross laminations at bed-set boundaries are observed which is
indicative of a dominant current, slack-water and subordinate current component within
the bed-sets. This suggests the grain-size striping, in combination with the bed-set
boundary characteristics, when present, likely represent a tidal influence and deposition
would have been as mid-channel tidal bars or meander point bars. Alternatively, the
back-flow ripples may be a result of a flow-separation vortex in the troughs of dunes.
Along with the tidal component interpretation, the deposition of F3 requires flow
conditions where either there were low concentrations of suspended fines, or energy
51
conditions were rarely low enough for silt or mud to settle out. Carbonaceous debris
deposits may have been formed during slack-water periods.
Many of the planar cross-bedded sandstones, where stacked and separated by coflow or back flow structures, likely formed as laterally migrating metre scale mid-channel
dunes within a tidally influenced fluvial meander channel complex near to the bayline,
up-stream from the turbidity maximum (Figure 3.5) but still within tidal influence. In
other cases, where back-flow and co-flow structures are absent, F3 likely represents
Inclined Strata (IS). Here IS beds are likely part of the lowest portions of a laterally
accreting point bar within a meandering channel complex.
F3 has been observed both in core and outcrop to be inter-bedded with trough
cross-bed sets of F4, occurring as single bed sets. In these instances, F3 may be
exclusively part of the fluvial braided stream environment. The planar cross-bed sets in
these cases likely represent cross channel bars developed as sand flats in the braided
channel complex (Cant, 1978) (Figure 3.6). Within the meander complex, planar crossbeds deposited by point bars would be found topographically above the trough cross-bed
sets of the main channel, while planar cross-bed sets found in the braided environment
could be found at any level (Cant, 1978).
Ranger and Gingras (2006) have also observed a similar facies within outcrops of
the McMurray Formation along the Athabasca river valley, north of Fort McMurray. In
the Athabasca outcrops they have interpreted the facies to represent the lower portion of a
prograding delta complex, proximal to the mouth, with flow velocities magnified by tidal
effects. The planar cross-beds in the Athabasca outcrops were interpreted as prograding
mega-ripples produced by distributary mouth tidal bars. These structures do not seem to
52
Figure 3.6. Three dimensional block diagram and vertical facies profiles of the braided
South Saskatchewan River. Note the overall fining upwards succession, and random
stacking patterns of trough and planar cross beds (after Smith et al., 2006).
53
be present in this study area and an interpretation of F3 deposition in upstream channels
is more appropriate.
3.2.4
Facies 4: Trough Cross-Bedded Sandstone
Facies 4 (F4) is comprised of trough cross-bedded sandstone with variable grain
size. This facies is commonly highly bitumen saturated and is an important reservoir
facies with respect to the bitumen resource within the study area. F4 has been subdivided
into two sub-facies based primarily on grain size.
3.2.4.1 Facies 4a: Medium to Very Coarse Trough Cross-Bedded Sandstone
Facies 4a (F4a) is comprised of moderately sorted, sub-rounded to sub-angular,
medium to very coarse grained trough cross-bedded sandstone. Within F4a cross bed sets
fine upwards and are typically bitumen “cemented”. Bed sets within F4a are typically
highly variable in thickness and can range from centimetre to decimetre scale. The
direction of dip of bedding planes is typically highly variable in orientation and often
tangential, yet a grain-size striping appearance is still evident (Figure 3.7). Angular mud
rip-up clasts and wood fragments are typically present and found at bed-form bounding
surfaces (Figure 3.8). There are no visible biogenic structures observed within this facies
(Figure 3.7).
F4a is very common in the study area and was observed within 36 of the logged
cores. It ranges in thickness from ~2 m to a maximum of 19 m, with an average of 7.9 m.
F4a is often observed inter-bedded with F4b and can be found overlying any of the other
facies. The lower contact is almost always erosional in nature although it can grade into
F4b. If not inter-bedded with F4b, the upper contact can be gradational, but most often
54
Figure 3.7. Bitumen saturated medium to very coarse trough cross-bedded sandstones
from Facies 4a; well 07-01-95-25W3, 189.5 m.
55
Figure 3.8. Mud rip-up clasts in Facies 4a sandstones along Clearwater River Valley.
Note lens cap for scale.
56
sharp with F3 (Table 3.1). This facies was also observed in outcrop, first by Paterson et
al., (1978) and again by Kohlruss et al. (2010a) along the Clearwater River valley.
In thin section, F4a is comprised primarily of coarse to medium grained
monocrystalline and polycrystalline quartz grains (Figure 3.9). Polycrystalline quartz
grains were commonly found in the coarser fractions. All quartz exhibit undulose
extinction under cross-polarized light, suggesting that sediment source was from
metamorphic terranes. Grains are primarily rounded to sub-rounded and well sorted. Rare
microcline plagioclase and muscovite were also observed, while no chert grains were
observed. No visible cementation (including overgrowths) was observed, and there are no
visible mud or silt fines present.
F4a is interpreted to have formed in a unidirectional, high energy depositional
system within fluvial meander or braided channels. The bed forms were likely deposited
as 3D dunes in the lower portion of river meanders or braided channel sequences along
the bases of the channels, and migrated in a downstream direction. The normal grading
that produces the bed forms is likely a result of fluctuations in flow velocity and possibly
channel depth due to seasonal discharge variation. Angular mud clasts suggest limited
transport distances and the mud clasts may have been sourced from bank collapse due to
channel undercuts. The absence of mud matrix also points to high energy flow
conditions, where clay size particles would have remained in suspension. The complete
lack of trace fossils also suggests deposition was within a dominantly non-marine fluvial
setting.
Despite very strong and clear evidence that F4a was deposited in a non-marine
fluvial system, the presence of rhythmic grain-size striping defining the trough cross-beds
57
Figure 3.9. Thin section photomicrograph of F4a sandstones under cross-polarized light;
Note rounded to sub-angular grains and polycrystalline grains. Polycrystalline grains
feature sutured boundaries.
58
could indicate a slight tidal influence on this facies, since the physical influences of tides
can extend upstream well beyond the salinity limit (Allen, 1991; Ranger and Pemberton,
1997; Dalrymple and Choi, 2007). Alternatively, the grain size variations may merely be
a function in flow velocity variations caused by storms or seasonal variation. Though no
suitable cores were observed, a statistical analysis of cross-bedding thickness variations
over a vertical transect may display neap-tide variations and would further support the
tidal influence interpretation.
3.2.4.2 Facies 4b: Massive to Trough Cross-Bedded Pebbly Sandstone
Facies 4b (F4b) is notably coarser than F4a. Most evident is the presence of
pebble sized chert and quartz grains at the bounding surfaces and within the decimetre
scale trough cross-bed sets. This facies is also composed of poorly sorted, sub-rounded to
sub-angular, medium to very coarse grained quartz sandstone with cross laminated bedsets that fine upward from pebbly to medium grains. Pebbles are typically 5-6 mm in
size. F4b sandstone is commonly bitumen “cemented”, and also contains common mud
rip-up clasts, wood fragments or coally debris. Rare pyrite “nodules” have also been
observed at sporadic intervals (Figure 3.10). In places F4b lacks cross-bedding and a
massive appearance is prevalent. F4b is completely void of any visible bioturbation.
F4b is common in the study area and is observed within 24 of the logged cores
and ranges in thickness from ~2 m up to 13 m, averaging 6.9 m. F4b is often inter-bedded
with F4a and can be found overlying any of the other facies. Like F4a, the lower contact
is almost always erosional in nature although the lower contact can grade into F5 or F4a.
59
Figure 3.10. Highly bitumen saturated pebbly trough cross-bedded sandstone (Facies
4b); well 05-12-95-25W, 201.71 m.
60
The upper contact can either be gradational or erosional in relationship with F3,
F4a or F5 (Table 3.1).
In thin section F4b is comprised of predominantly pebble sized to medium sized
polycrystalline quartz gains. These grains exhibit orientated elongate crystals with
common sutured contacts. Pebbles are commonly 5-6 mm in diameter and comprised of
quartz and feldspars. All quartz grains and crystals exhibit undulose extinction under
cross-polarized light, suggesting that sediment was sourced from metamorphic terranes.
Grains are primarily sub-angular to sub-rounded and poorly sorted. Commonly up to 20%
of F4b is comprised of detrital matrix clay and silt. No visible cementation was observed
and rare diminutive quartz overgrowths were present.
F4b is interpreted to represent a very high energy, unidirectional depositional
system. Textural and mineralogical immaturity suggests transport from sediment source
area was likely short and sediment reworking was minimal. The pebbly trough cross-beds
within this facies exhibit frequent internal erosion surfaces and are considered to have
been deposited as three dimensional subaqueous dune forms migrating downstream
within the lower portions of a rapidly shifting meander or braided fluvial sequence. Interbeds of massive versions of F4b suggest deposition from rapid decrease in flow or
possible bank collapse (Rust and Jones, 1986). The abrupt differences in grain sizes also
suggest frequent fluctuations in flow energy. The common coally debris, and mud rip-ups
along with the absence of trace fossils also indicates that F4b was a result of
predominantly high energy conditions, most likely under fluvial environments.
61
3.2.5
Facies 5: Pebble Conglomerate
Facies 5 (F5) is primarily comprised of pebble sized quartz grains with minor interstitial
coarse and medium quartz grains. The conglomerate is very poorly sorted with angular to
sub-angular pebbles and grains (Figure 3.11). This facies is commonly bitumen
“cemented”, however it has the lowest porosity (20%) of any of the Dina Member facies
within the study area. The limited porosity is due to the poor sorting of the sediments, and
as such this facies is considered to have relatively low reservoir potential compared to F3
and F4. This facies can be clast or matrix supported, massive, chaotic or graded. F5 has
common wood fragments and/or mud clasts throughout. Where present overlying the subCretaceous unconformity, pebbles of Devonian origin are often present.
Facies 5 (F5) has been observed in 21 of the logged cores ranging in thickness
from 0.5 m to 13.5 m with an average thickness of 2.8 m. Facies 5 was also observed and
described in outcrops along the Clearwater River valley by Patterson et al. (1978) and
Kohlruss et al. (2010a).
In thin section F5 is comprised of predominantly pebble sized polycrystalline
quartz grains, to medium sized monocrystalline and polycrystalline quartz grains (Figure
3.12). Pebbles are commonly 5-6 mm in diameter and though comprised primarily of
quartz, they contain approximately 10% microcline potassium feldspar. The
polycrystalline quartz grains exhibit elongated crystals with preferred orientation and
many having sutured contacts. All quartz grains and crystals exhibit undulose extinction
under cross-polarized light. Grains are primarily sub-angular to rarely sub-rounded and
poorly sorted. Commonly, detrital clay and silt contribute up to 25-30% of the matrix. No
62
Figure 3.11. Bitumen saturated, poorly sorted pebble conglomerate (Facies 5); well 1632-94-25W3, 215.45 m
63
Figure 3.12. Photomicrograph under cross polarized light showing large sutured
polycrystalline quartz grain in facies 5; Well 06-33-94-25W3, 198.35m
64
chert grains were observed as part of the pebble fraction. No visible cementation was
observed and rare diminutive quartz overgrowths are present.
F5 was likely deposited within the highest energy depositional environment of all
the facies observed, and is considered to represent deposition in the upper most reaches
of the alluvial plain within a braided stream system and/or the channel lag deposits within
a point bar sequence. The largest grains were likely transported by traction during bankfull flow, sliding or rolling along the bed. Bank-full flow was likely a result of seasonally
increased flow events likely due to rainy season in a humid climate. The massive nature
of F5 suggests deposition was a result of a rapid decrease in flow or possibly bank
collapse (Rust and Jones, 1986). The abundant detrital clay and silt would have also
settled and been deposited during rapid flow depletion and suggests deposition related to
an ephemeral braided stream environment. F5 sedimentation therefore took place where
insufficient discharge is present to carry the sediment load. There is also the possibility
that this facies was formed along the thalweg of a meander belt channel system,
especially when present at the base of the section. These possibilities will be further
explored later in the discussion of facies associations.
3.2.6
Facies 6: Inter-bedded Sandstone and Bioturbated Mudstone
Facies 6 (F6) is comprised dominantly of massive and/or ripple laminated
sandstone, inter-bedded with variably bioturbated siltstone/mudstone (Figure 3.13). The
contact between sandstone and siltstone/mudstone layers tend to be sharp but the lower
contact of mudstone/siltstone layers may appear wavy or irregular due to bioturbation or
soft sediment deformation (Figure 3.13). The upper contact of the mudstone/siltstone
65
Top
F6
F6
F3
F4a
F2
F3
Bottom
Figure 3.13. Inter-bedded sandstone with bioturbated mudstone (Facies 6); Note inclined
heterolithic stratification (IHS); well 16-28-94-25W3 (189.4 - 194.6m). Note the variable
bitumen saturation.
66
layers is generally sharp due to erosion. F6 is almost always sand dominated and the
silt/mud layers generally comprise 10% of the total rock volume or less (Figure 3.13). In
rare cases siltstone/mudstone layers comprise up to 70% of the facies.
The sandstone portions are predominantly fine grained, rounded to sub-rounded,
well sorted, commonly nongraded and generally bitumen cemented. This facies is
sedimentologically similar to F1 and/or F2, exhibiting either massive or ripple laminated
sedimentary structures and represents a gradational transition from either of F1 or F2.
Individual sandstone layers are typically heavily bitumen saturated. The sandstone layers
are irregularly thick, ranging from 5 - 150 cm and ~ 10-30 cm thick on average (Table
3.1). Although sandstone layers are generally unbioturbated, uncommon diminutive mud
lined Cylindricnus or Gyrolithes occur along discrete bedding planes with no associated
mudstone/siltstone layers (Figure 3.13). Facies 6 has been observed in 19 of the logged
cores, ranging in thickness from ~1.0 m to 23.0 m with an average thickness of 6.8 m
(Table 3.1).
In thin section, the sand is comprised of upper very fine to lower fine quartz
grains. The grains are rounded to sub-rounded with rare angular grains, and are very well
sorted. Polycrystaline quartz grains were occasionally observed along with minor
plagioclase. Cylindrichnus burrows are mud lined and sand filled.
Mudstone/siltstone layers generally vary in thickness from thin mm scale laminae
up to 30cm thick beds (Figure 3.13), averaging 3-10 cm thick. In rare mudstone
dominated cases, mudstone dominated intervals might be upto 3 m in thickness. The
mudstone/siltstone layers exhibit variable sedimentary character from featureless and
massive in appearance to finely laminated. Rarely, a fine sand fraction is observed as thin
67
lenticular beds within the mudstone/siltstone. Presence of bioturbation is highly variable,
ranging from rare to common, and when present, can often be seen within the
mudstone/siltstone layers and most obvious at the lower bedding contacts with the
underlying sandstone, with burrows often penetrating down into the underlying sandstone
beds. Burrowing, when present, often obliterates the primary sedimentary structures of
the siltstone/mudstone layers. Trace fossils are generally diminutive and exhibit a
relatively low diversity assemblage that includes common Cylindrichnus, while
Thalassinoides, Skolithos, Gyrolythes,and Teichicnus are rare (Figure 3.14). Generally,
the intensity of bioturbation and frequency of mudstone/siltstone layers increases
upwards within F6.
Five palynological samples from three wells were taken from the
mudstone/siltstone layers and processed by L. Bloom at the Department of Geoscience,
University of Calgary. Although the majority of the palynmorphs were terrestrial
bisaccate pollen grains and trilete miospores, marine dinoflagelate cysts and scoleodonts
were also observed (Figure 3.15) (L. Bloom, pers. com. 2010). This together with the
trace fossil assemblage suggest a slight marine influence on the depositional setting of the
mudstone/siltstone beds.
F6 has a very similar, if not the same, character as the Epsilon Cross-Strata/
Inclined Heterolithic Stratification (IHS) beds described in outcrop and cores along the
Athabasca River in northeastern Alberta (Mossop, 1978; Pemberton et al., 1982; Flach,
1984; Flach and Mossop, 1985; Thomas et al., 1987; Smith, 1988; Ranger and
Pemberton, 1992; Strobl et al., 1997; Wightman and Pemberton, 1997; Ranger et al.,
2008; Ranger and Gingras, 2006). In particular, F6 most resembles the sand dominated
68
Figure 3.14. A) Inter-bedded sandstone with bioturbated mudstone (Facies 6); trace
fossils include Cylindrichnus (Cy): well 16-28-94-25W3, 191.30m. B) Inter-bedded
sandstone with bioturbated mudstone(Facies 6); trace fossils include Teichichnus (Te):
well 05-12-95-25W3, 213.50m. C) Interbedded sandstone with bioturbated mudstone
(Facies 6); trace fossils include Thalassinoides (Th): well 16-28-94-25W3, 182.93m.
69
Figure 3.15. Photomicrographs of some of the pollen, miospores, dinoflagellate and
scoleodont observed from wells 16-28-94-25W3, 5-12-95-25W3 and 13-21-95-25W3.
Note mix of marine and terrestrial palynmorphs (L. Bloom, pers. com. 2010).
70
IHS (Ranger and Pemberton, 1992; Ranger and Gingras, 2006). The term IHS was
introduced by Thomas et al. (1987) to describe dipping, alternating sand and mud
deposits and has since evolved to also include lateral accretion deposits produced by the
migration of fluvial or estuarine point bars. The use of the term epsilon cross
stratification has predominantly been abandoned since it is non-descriptive and the use of
“cross-stratification” as a descriptor is inappropriate since the formation of IHS is a result
of lateral accretion rather than bed-form migration (Thomas et al., 1987). Similar to the
sand dominated facies observed along the Athabasca River, F6 is likely a result of lateral
accretion deposition associated with point-bar migration. Many modern and ancient
examples of IHS deposits are a result of tidal influences on fluvial or estuarine channel
systems where fluctuating energy produces alternating sand and mud sets (Thomas et al.,
1987; Ranger and Pemberton, 1992). IHS can also be produced in purely fluvial settings
and the deposition of muddy sediments can be linked to counter point bar deposits
(CPBD) (Smith et al., 2009). CPBD have concave scroll patterns, rather than the typical
convex point bar pattern and are dominated by silt and mud. The CPBD deposition
occurs at a meander inflection point, where the river transitions from convex to concave
and is observed to thicken downstream (Smith et al., 2009) (Figure 3.16).
The presence of marine trace fossils in F6 indicates marine influence. Pemberton
et al. (1982) also recognized the influence of brackish water in the McMurray Formation
outcrops and cores along the Athabasca River of northeastern Alberta based upon trace
fossil assemblages. Brackish-water assemblages are typified by the combination of their
diminutive size, simplistic form and low diversity indicative of highly variable stress
conditions (Pemebrton et al., 1982; Beynon et al., 1988; Pemberton et al., 2001; Ranger
71
Figure 3.16. Morphology of point bar and counter point bar deposits with inclined
heterolithic stratifications (after Smith et al., 2009).
72
and Gingras, 2006). Where trace fossils such as Cylindrichnus, Gyrolithes and
Thalasanoides are present within F6, they exhibit the mono-specific or low diversity and
diminutive signature of a brackish water assemblage. The co-existence of both terrestrial
palynomorphs and marine microfossils supports the interpretation of F6 as a
predominantly fluvial environment with some marine influence.
3.2.7 Facies 7: Siltstone, Mudstone, and Coal
Facies 7 (F7) consists of light coloured (very light grey to white) siltstone
commonly grading into mudstone. Rootlets are commonly observed within the mudstone
intervals (Figure 3.17) (Table 3.1). F7 mudstones are in places carbonaceous, grading
into coal. The mudstones and siltstones can both contain convoluted bedding, suggesting
some degree of soft sediment deformation.
Besides coal beds, rare coal fragments and wood fragments are also observed.
Bioturbation tends to be absent, but in the 13-21-95-24W3 core, a continental insect
burrow was observed (Naktodemasis) (Figure 3.18) (Smith et al., 2008, Ranger et al.,
2008; M. Ranger, pers.com. 2010). Palynological analysis undertaken in F7 identified
both terrestrial Trilete spores and marine dinoflagellate cysts (L. Bloom, pers. com 2010).
Facies 7 (F7) is relatively rare in the study area, and has been observed in only 10
of the logged drill cores. It ranges in thickness from 1.0 m to 14.0 m, with an average
thickness of 6.3 m where present.
In thin section, silt sized and very fine grains were observed “floating” within a
clay matrix (Figure 3.19). Approximately 10% of the quartz grains exhibited undulose
extinction. Grains are well rounded and of mainly equal size. Visible organic matter was
73
Figure 3.17. Rooted organic-rich siltstone and light coloured mudstone (Facies 7); note
pedogenic fabric with rootlets (R): well13-21-95-24W3, 181.45 m.
74
Figure 3.18. Organic-rich mudstone (Facies 7); note trace fossils including continental
insect burrow, Naktodemasis (Nk); well 13-21-95-24W3, 180.47 m.
75
Figure 3.19. Photomicrograph of siltstone of Facies 7. Note carbonaceous material
infilling crack, likely a plant root; well 13-21-95-24W3, 186.20m
76
observed infilling “cracks”. This is likely coally material from plant rootlets penetrating
into the sediment (Figure 3.19). The presence of coal or highly carbonaceous mudstone is
reflected by a sharp deflection on both density curves to the left on sonic-density/neutrondensity geophysical well logs, and the mudstones typically read between 100 API to 150
API on the Gamma Ray logs.
The light coloured mudstones are interpreted to be the result of pedogenesis on a
floodplain, while organic-rich to coaly mudstone represents flooded marsh or oxbow lake
deposits. Siltstone grading to mudstone is interpreted to represent over-bank deposits
from flooding events and suspension sedimentation. The presence of both terrestrial
palynmorphs and marine microfossils suggests that despite a very strong evidence for
purely continental deposition a marginal marine influence on deposition is present.
3.2.8
Facies 8: Laminated Siltstone to Very Fine Sandstone
Facies 8 (F8) is comprised of light grey unconsolidated laminated siltstone inter-
bedded with very fine grained sandstone. The very fine grained sandstone is observed as
flasers within the siltstone. This facies has very fine laminated bedding with common
centimetre scale soft sediment deformation features such as convoluted bedding, load
casts and flame structures. Although no specific biogenic structures could be identified,
the overall appearance appears bioturbated (Table 3.1).
F8 is a relatively rare facies, since it has been only observed in four of the logged
drill cores. It ranges in thickness from 1.0 m to 2.2 m with an average thickness of 1.5 m.
F8 occurs within facies F3 and F4, and no bitumen staining was observed in this facies
(Figure 3.20).
77
Figure 3.20. Inter-laminated siltstone and very fine grained sandstone (Facies 8); well 05-3494-25W3, 231.80 m. Note potential burrows.
78
Figure 3.21. (A-C) Smectite in SEM image at varying magnification. (A) indicates X-ray
spectrum sample locations for determination of mineralogy. (D) Photomicrograph of a
Smectite mineral (red arrow indicates location) (E) X-Ray spectrum of Smectite from
points 1, 2 and 3 along with element percentages from point 1.
79
In thin section, F8 is comprised of ~50% very fine, angular to sub-rounded, well
sorted grains. Quartz grains exhibit undulose extinction. Minor amounts of muscovite
were also observed. An olive green clay mineral was also observed between quartz grains
and was identified through scanning electron microscope – energy dispersive
spectrometry (SEM-EDS) analysis as Smectite (Figure 3.21). The other ~ 50% is
represented by silty mudstone, again with rare muscovite. F8 is interpreted as being
deposited on a floodplain as over-bank deposits where seasonal avulsion events where
channel levees were bypassed and unchannelized floods occur.
3.3
Facies Associations and Depositional Environments
3.3.1
Facies Association 1: Braided Fluvial Channel
Facies Association 1 (FA1) is comprised of F3, F4a, b, F5 and F7 (Table 3.2).
FA1 is dominantly sandy and gravelly with variable amounts of structureless beds, trough
cross-beds and planar bed sets (Figure 3.22a). Planar cross-bed sets may be observed as
solitary decimetre to metre scale bed sets at various stratigraphic levels within FA1 and
the vertical stacking order is variable. There are very little overall vertical grain size
trends within FA1 other than a general fining upward within bed sets. The proportion of
each individual facies represented in FA1 is also quite variable as well. Common mud
clasts, woody and coally material is observed (up to tree trunk in size), while biogenic
structures are non-existent within FA1.
Facies Association 1 (FA1) is generally found in the basal part of the Dina
Member in the study area and typically found overlying the sub-cretaceous unconformity
(Figure 3.22a, 3.23 and 3.24). Correspondingly, FA1 tends to be within the lowest
relative paleo-geographic structural lows of the sub-Cretaceous unconformity (Figure
80
Table 3.2 Description, interpretation and sequence stratigraphic nomenclature of facies
associations in the study area. LST = Lowstand systems tract; TST = Transgressive
systems tract.
81
Figure 3.22a. Core litholog of well 16-32-94-25W3, illustrating vertical relationships of
FA1. Note Gamma Ray (GR) curve and Resistivity (Res) curves. The legends are shown
in Figure 3.22b
82
Figure 3.22b. Litholog legends for Figure 3.22a. The same legends applied to all lithologs
in this section.
83
Figure 3.23. Isopach map of Facies Association 1 (FA1) in the study area. Note the
confined morphology and irregular isopach thickness, with a slight thickening toward the
northeast.
84
Figure 3.24. Schematic diagram illustrating fluvial architecture in the study area as a
result of relative sea-level rise along with changes in accompanying vertical and lateral
accommodation space.
85
3.22a and 3.24). FA1 has been observed in 32 of the logged cores and ranges in
thickness from 2 m to 27 m with an average thickness of 14 m.
Where FA1 was observed to be thinnest, the Devonian was structurally high
and/or Quaternary down cutting was exceptionally deep. This often contributed to the
thin isopach of FA1, which rarely represent original thickness. FA1 was also observed in
outcrop along the Clearwater River in northwestern Saskatchewan (Kohlruss et al.,
2010a) (Figure 3.25).
The vertical profiles produced by geophysical well logs, in particular gamma ray
traces also give valuable information towards the interpretation of the FA1. The gamma
ray traces are typical of amalgamated braided channel deposits (Hamilton and Galloway,
1989). The gamma ray readings are generally very low, giving a blocky vertical profile,
indicating very little clays which is consistent with observations in cores (Figure 3.22).
The abundance of gravel and coarse grained sand and random stacking patterns of
F3, F4, F5 and F7 of FA1 is suggestive of a mixed sand and gravel braided non-marine
fluvial system.
Thick successions of F4 likely represent aggrading channels where no cross
channel bars were able to form and deposition was primarily from three dimensional
dunes (Cant, 1978), while planar cross beds tend to be thin and likely represent sand flats
and/or cross channel bars as described by Cant (1978) in the South Saskatchewan River
near Outlook in Saskatchewan (Figure 3.6). In mixed sand gravel braided fluvial systems,
bars, sand flats and mid-channel sediments are generally deposited upon each other in
very random order. Major sand and gravel deposition likely occurred during seasonal
86
Figure 3.25. Outcrop photo of FA1 located along the Clearwater River valley in
the extreme south of the general study area. Note complex and random stacking patterns
of the internal facies. Lens cap for scale.
87
flashy floods and would account for the occurrence of massive bedded sandstones, large
grain sizes and woody debris as large as tree trunks (Figure 3.26).
While rarely observed, the presence of rooted mudstones and coals of F7 are
generally cm scale and found at the top of FA1. This likely represents isolated
preservation of overbank deposits. The rare occurrence of overbank deposits is likely due
to the nature of braided systems, which tend to be wide and occupy the majority of a
fluvial plain or incised valley, and floodplain/overbank deposits do not have an
opportunity to be preserved (Miall, 2010). The preservation potential for fines within a
low accommodation setting is much lower in a braided system setting. Typical fluvial
fining-upward cycles are not as readily preserved since channel systems are likely
scouring back and forth, within the confinement of the incised valley, stripping the top
off of previous cycles. With higher lateral and/or vertical accommodation, complete
cycles may have been preserved.
3.3.2
Facies Association 2: Tidally Influenced Meander Channel Deposits
Facies Association 2 (FA2) successions are comprised of F1, F2, F3,F4, F5 and
F6 (Table 3.1). FA2 is composed mainly of fining upward sands (Figure 3.27). The
lowest portions of the vertical profile generally begin with trough cross-bed sets
truncating older braided channel deposits followed by stacked metre scale planar crossbed sets. This in turn is followed by inter-bedded, occasionally bioturbated sandstones
and siltstones/mudstones (Figure 3.27). Occasionally, FA2 can be seen truncating earlier
FA2 successions, creating stacked FA2 successions (Figure 3.28) identifiable by
vertically stacked fining-upward packages. The base of stacked successions can be
identified by an abrupt change to coarse sediments, including mud clasts or pebbly layers
88
Figure 3.26. Mummified tree trunk (Bitumen impregnated) found at the basal contact of
F5 within FA1 assemblage along Clearwater River Valley.
89
Figure 3.27. Core litholog of well 16-28-94-25W3, illustrating vertical relationships of
FA2. Note Gamma Ray (GR) curve and Resistivity (Res) curves. Blue infill on
Resistivity curve indicates water zone and/or lean zone (below 6% bitumen saturation by
weight). Green infill indicates bitumen saturated zones of greater than 6% by weight.
90
Figure 3.28. Gamma Ray trace of well 06-20-94-25W3, illustrating the channel stacking
patterns of FA2.
91
of F5. The inter-bedded sandstones and mudstones/siltstones tend to be predominantly
sand dominated but in some rare instances mudstone/siltstone dominates. F1 and F2 tend
to be observed at the base of F6, the top of F3 and/or inter-bedded within F6 muds/silts
(Table 3.1). Facies Association 2 (FA2) has been observed in 28 of the logged cores and
ranges in thickness from 6 m to 30 m with an average thickness of 18.5 m.
The vertical profiles produced by geophysical well log Gamma Ray profiles are
noticeably “clean”, reading very low to moderate at the base (<30 API) and gradually,
with the increase of inter-bedded silt and mud, have increased Gamma Ray log readings
(>90 API) (Figure 3.28). This produces a vertical Gamma Ray log profile that resembles
a “bell” shape (Figure 3.27) typical of a fining upward sequence.
The vertical stacking relationships of the observed facies within FA 2 are typical
of meandering channels (Figure 3.29). The channel deposits are comprised of both
laterally accreting point bars, fluvial and tidally influenced, as well as in-channel 3D
dunes (F4) and in some instances mid-channel bars. The 3D dunes (F4) and mid-channel
bars (F3) were deposited within the channel thalweg and are overlain by cross beds of
laterally accreting bars (F3, F6). These vertically grade into inter-bedded sandstones and
muds also produced by lateral accretion (F6) (Figure 3.29). The laterally accreted beds
are similar to structures defined by Thomas et al., (1987) as Inclined Stratification (IS)
and Inclined Heterolithic Stratification (IHS) respectively. For the most part, IS beds
and IHS beds of FA2 are composite sets where IHS sequences gradationally overlie IS
deposits. Mid-channel bars can be identified and differentiated from bank attached point
bars primarily by the presence of reactivation surfaces, co-flow and back flow ripple
cross laminations separating metre scale cross-bed sets (Nio and Yang, 1991).
92
Figure 3.29. Idealized point bar facies distribution model in a tidally influenced
meandering river channel system. Note the tidally influenced IHS beds of F6 and the IS
beds of F3 overlying F4 trough cross-bed sets. Mud rip-ups are commonly found at this
contact due to lateral accretion over trough cross-bedded sands of F4. Note channel
abandonment mud plug of facies association 3 (FA 3)
93
Deposition of mid-channel bars and laterally accreting point bars are primarily
found within meandering fluvial channels (Dalrymple and Choi 2007; Dalrymple,
2010). In many instances a tidal influence can be identified and is evidenced in several
ways. The ichnology of F3 and F6 within many of the observed FA2 successions is
typical of brackish water environments, displaying diminutive simple vertical burrows
and very low diversity (Pemberton et al., 1982; Beynon et al., 1988; Ranger and
Pemberton, 1992). These burrows predominantly populate the mudstone and siltstone
layers of the laterally accreting IHS beds of F6 but have also been observed within the
laterally accreting IS beds of F3. Additionally, the lack of bioturbation in the IHS beds
may be indicative of laterally accreted beds formed in a fully fluvial environment, or at
least deposited in a fully fresh water environment beyond the limits of the turbidity
maximum. Muds in these instances may represent extended periods of low flow due to
seasonal fluctuations or perhaps counter point-bar development. Also,
micropaleontological analysis undertaken in F6 identified both terrestrial Trilete spores
and marine dinoflagellate cysts (L. Bloom, pers. com. 2010). The co-existence of
terrestrial palynmorphs and marine dinoflagellate cysts supports the interpretation of FA2
being predominantly fluvial environment with a marine influence.
The introduction of mud deposition and bioturbation within the channel sands is
evidence of a change in depositional conditions and possibly water chemistry from a fully
fresh water fluvial environment to a brackish tidally influenced environment (Allen et al.,
1980; Allen, 1991; Dyer, 1995; Dalrymple and Choi, 2007). Deposition of mud beds
likely represents reduced influx of fluvial sediments and/or dominance and a closer
proximity to the Turbidity Maximum due to seasonal up stream migration caused by
94
lower fluvial water discharge. An increase in salinity promotes mud flocculation and
creates brackish water conditions favourable for opportunistic trace makers (Beynon et
al., 1988; Ranger and Pemberton, 1992). The paucity of burrows likely reflects that
brackish conditions were seasonal. Only at low fluvial out-put stages was marine water
able to migrate landward enough to influence the study area and create brackish
conditions. The low abundance of burrows populating the mud beds also reflects the
relative increase of salinity levels and subsequent tidal and/or fluvial influence, in that the
conditions were either short lived or just barely tolerable (Pemberton et al., 1982;
Beynon, 1988; Ranger and Pemberton, 1992).
FA2 successions are thickest in the most southern areas of the study area and
taper to zero to the north (Figure 3.30). This is a function of the transgressive nature of
FA2 deposition, as it is back stepping and on-lapping northward within the incised valley
and subsequently thinning of FA2. F6 IHS deposition and trace fossil populations are also
confined to the southern portion of the study area. The base of these deposits and the
northern limit mark the extent of landward incursion of saline water (Figure 3.31).
The onlapping and thinning of F6 IHS deposits are consistent with deposition
from north to south (as well as vertically from top to bottom) changing from a location
landward of the tidal limit to seaward towards the turbidity maximum. Fluvial processes
are primarily dominant, especially within the sand fraction, and likely reflect seasonally
high river flow. At these times, the tide limit and turbidity maximum are pushed furthest
seaward (Figure 3.32). When mud is able to accumulate, seasonally low river flow is
likely responsible. At these times the turbidity maximum is likely extended landward to
its farthest (Figure 3.32).
95
Figure 3.30. Isopach of Facies Association 2 (FA2). Note FA2 is thickest in the southern
most portion of the study area, thinning towards the northeast. This is a function of FA2
deposition back-steping in a “landward” direction.
96
Figure 3.31. Isopach map of F6 (IHS) deposits (seasonally brackish-water deposits).
These deposits are characterized by inclined heterolithic strata and an assemblage of
brackish trace fossils. Like composite FA2 deposits, these deposits are thickest to the
southwest and taper to the northeast in a wedge geometry.
97
Figure 3.32. Illustration of estuarine circulation, sedimentation and salinity stresses
between times of high and low fluvial discharge. (A) At times of low fluvial discharge,
tidal currents dominate over fluvial density driven currents. At these times brackish water
conditions migrate significant distance up fluvial channels and seasonally deposits muds
and silts. (B) At times of high fluvial discharge, fluvial/density circulation dominates but
silts and mud deposition occurs much further seaward. The river dominated segment has
abundant sediment reworking (after Lettley, 2004).
98
3.3.3
Facies Association 3: Oxbow Lake Fill
Facies Association 3 (FA3) is comprised entirely of F7 (Table 3.2). Successions
of this facies association are consistently comprised of upward fining cycles beginning at
the base as a very thin, cm scale layer of siltstone, quickly transitioning to light grey and
white muds. Each repetition of silt to mud is, in turn, commonly capped by a weakly
rooted horizon (Figure 3.33). FA3 is generally void of recognizable sedimentary
structures and is unburrowed. Rarely, very fine sandstone marks the base of the fining
upward succession. Individual fining cycles range in thickness from 1 m to 5 m (Figure
3.33).
Gamma Ray logs typically have a vertical profile that is jagged with a zig-zag
appearance, reflecting multiple fining upward successions. The mud responses on
Gamma Ray logs read between ~100 API to ~150 API (Figure 3.33).
Facies Association 3 (FA3) is relatively rare, in that it has only been observed in
seven of the logged cores. FA3 ranges in thickness from ~2 m to 14 m with an average
thickness of 12 m (Figure 3.34).
FA3 likely represents vertically accreted abandoned channel deposits. In four
closely spaced logged cores, FA3 deposits form an isolated remnant plug. The plug
covers an area measuring ~1500m by ~500m. Sediments within the abandoned channel
were deposited as a result of suspension settling in quiescent setting, with the silts and
very fine sands settling first followed by clays and muds. The presence of silty and sandy
layers followed by successions of mud likely indicates that deposition took place when
adjacent active channels were breached during high flood events, spilling suspension rich
waters into the abandoned oxbow lake/channel. The presence of rooted horizons
99
Figure 3.33. Core litholog of FA3 deposits. A thick, amalgamated succession of FA3
oxbow lake deposits is present in 08-01-25W3.
100
Figure 3.34. Isopach map of facies association 3 deposits. Note that the areal distribution
is limited to discrete “bodies” of isolated mud filled oxbow lake deposits.
101
demarcating the tops of successive flooding events indicates prolonged desication periods
where plants were able to populate the tops of flood sequences. Micropaleontological
analysis indicates the presence of marine dinoflagelettes along with terrestrial triletes (L.
Bloom, pers. com. 2010), suggesting that the adjacent channels were more likely those of
FA2 rather than FA1 and the waters responsible for flooding the abandoned channels
were likely brackish. It has been speculated that the abandoned channel depositional
elements provide molds of the channel system and clues to the scale of the channels
(Nielsen, 2008; Hubbard et al., 2011). Therefore, the channels in the study area
potentially range from 2 m to 14 m deep.
3.3.4
Facies Association 4: Flood Plain Crevasse Splay
Facies Association 4 (FA 4) is entirely comprised of Facies 8 (Table 3.2). It occurs
between FA1 and FA2 successions (Figure 3.35). FA4 is a relatively rare succession in
the study area. It was only observed in four of the logged drill cores and ranges in
thickness from 1.0 m to 2.2 m with an average thickness of 1.5 m (Figure 3.36). The
areal extent of the FA 4 is ~500 m by ~250 m and is thickest (2.2 m) at its northern extent
of the study area and subsequently tapers to the south to 1.0 m and then to zero (Figure
3.36). The fine grained nature, laminated structure, presence of soft sediment
deformation, and the over-all dimensions are consistent with crevasse splay deposition
(Smith et al., 1989; Smith and Perez-Arlucea, 1994; Bristow et al 1999). Similar
depositional characteristics were observed along the rapidly aggrading braided Niobrara
River in Nebraska (Bristow et al, 1999) and also some of the depositional features of the
lower reaches of the Saskatchewan River (Smith et al., 1989; Smith and Perez-Arlucea,
1994). Based upon observed characteristics, this particular splay is likely a Stage I type as
102
Figure 3.35. Core litholog of Facies Association 4 deposits. The transgressive
surface/non-marine flooding surface is linked to the base of FA4 deposits in this
stratigraphic test hole core log.
103
Figure 3.36. Isopach map of FA4 deposits illustrating the limited extent of preserved
crevasse splay deposits. These were deposited during transgression as part of the
aggradation of the braided channel environment.
104
described by Smith et al. (1989), assuming preserved dimensions and thicknesses are
close to those originally deposited. Stage I splays are small, lobate in plan view and form
a wedge shape in cross section much like what is observed in the study area (Figure 3.35
and 3.37) (Smith et al., 1989).
The crevasse splay deposit was likely formed following aggradation of an
adjacent channel belt due to unchannelized overbank floods, possibly as a result of base
level rise, since preservation of splay deposits during non-aggradational or degradational
settings is highly unlikely (Bristow et al., 1999; Miall, 2010). However, the rarity of this
facies in the study area is also likely a function of the depositional environment.
Deposition likely occurred within a confined valley system where frequent lateral
reworking of sediments took place. In this environment, even in an aggradational setting,
preservation of splay deposits would still be a rare occurrence (Bristow et al., 1999).
3.3.5
Facies Association 5: Floodplain Deposits
Facies Association 5 (FA5) consists of leeched white mudstones and
carbonaceous silty mudstones that grade into a coal at its top and is comprised of F7
deposits (Table 3.1) (Figure 3.17). Bioturbation is absent except for a single continental
beetle burrow observed burrowing down into a coal bed (Naktodemasis) (Figure 3.18)
(Smith et al., 2008; Ranger et al., 2008; Kohlruss et al., 2010). Facies Association 5
(FA5) is an extremely rare facies and has been observed in only one logged drill core and
is ~6.0 m thick (Figure 3.38).
FA5 likely formed primarily from suspension fall-out in the inter-channel/
overbank areas. These areas may have been vegetated bogs or swamps laterally adjacent
105
Figure 3.37. Cross-section B-B’ illustrates the geometry of an active Stage I splay. This is
similar to the geometry of the crevasse splay deposits observed in the study area (after
Smith et al., 1989).
106
Figure 3.38. Isopach map of Facies Association 5 (FA5) deposits. The location of FA5
paleosol deposit is indicative of interfluves deposits.
107
to active channels. The vertical association of a leeched zone and rooted
horizon/organic-rich horizon is consistent with a paleosol interpretation as well.
Though rare, FA5 has the potential to be critical in further development of the
stratigraphic history (Ranger and Gingras, 2008). Alluvial paleosols can be easily
recognized and can offer ideal marker beds for correlating deposits and sedimentary
events (Bown and Kraus, 1987). Further identification of FA5 throughout the study area
would be beneficial.
108
4. STRATIGRAPHIC ARCHITECTURE AND DEPOSITIONAL MODEL
4.1
Introduction
In the previous chapter facies and facies associations were described in great
detail. Here the lateral and vertical distribution of the Dina/McMurray and its facies
associations will be determined through geological structure and isopach maps as well as
six structural well log and drill core cross-sections. Five cross-sections were orientated
perpendicular to the main channel thalweg and the sixth was orientated within the
thalweg of the main channel. An attempt to correlate the facies associations and
boundaries is made across all the cross-sections. This will in turn provide a framework
from which the depositional model and history can be inferred. Sequence stratigraphic
nomenclatures (Shanley and McCabe, 1994; Van Wagoner, 1995; Posamentier and Allen,
1999, Catuneanu et al., 2009) are used in stratigraphic correlations and depositional
history reconstruction, despite limitations caused by using a structural, rather than a
stratigraphic datum, as discussed earlier.
4.2
Structural and Isopach Maps
Utilizing drill core and geophysical well logs, a series of maps of the Dina
Member in the study area were constructed, including a structural map of the subCretaceous unconformity surface, the Dina Member/McMurray Formation isopach map,
and a structural map of the sub-Quaternary erosional surface. The well coverage for the
detailed study area is shown in Figure 4.1. These maps were developed in an effort to
109
Figure 4.1. A map of the study area showing the well coverage, locations of logged cores
(red dots) and structural cross-sections. Note black dashed line indicates outline of paleovalley.
110
identify the main paleo-topographic features of the depositional surfaces of the
Dina/McMurray, to identify thickness trends in the Dina/McMurray and to determine the
affects of, and degree of, Quaternary erosion upon the Dina/McMurray respectively.
Mapping of the sub-Cretaceous unconformity surface revealed some notable
features, not the least of which was a continuous, significant paleo-low running through
the study area (Figure 4.2). In many places the lows are in excess of 50 metres below the
surrounding areas (Figure 4.2). The axis of the paleo-low runs approximately northnortheast beginning approximately in section 9 township 94 range 25 west of the third
meridian up to section 13 township 95 range 25 west of the third meridian (Figure 4.2). A
second “arm” of the paleo-low extends in an easterly direction from approximately
section 36 township 94 range 25 west of the third meridian to section 21 township 94
range 24 west of the third meridian (Figure 4.2). The resulting paleo-low features are
likely enhanced by incision initiated by karsting and salt collapse. Several, smaller
“tributaries” can also be mapped rejoining with the main paleo-low (Figure 4.2).
The isopach map of the Dina Member/McMurray formations shows that the
thickest portions generally align with the main structural lows along the sub-Cretaceous
unconformity (Figure 4.3). The thickest of the accumulations occur in the most
southwestern portions of the study area reaching thicknesses of 45 metres (Figure 4.3).
These deposits thin quickly to zero outside of the paleo-lows defined by the subCretaceous unconformity. There are also anomalously thin or zero-thickness areas within
the isopach of the Dina/McMurray that coincide with paleo-topographic structural lows
(Figure 4.3). As shown in the sub-Quaternary unconformity structural map (Figure 4.4),
111
Figure 4.2. Structural map of the sub-Cretaceous unconformity surface. Structural lows
are interpreted to be incision initiated by salt dissolution in the middle Devonian Prairie
Evaporite Formation and karsting in the middle Devonian Winnipegosis Formation. 5
metre contours above mean sea-level.
112
Figure 4.3. Isopach map of the Dina Member/ McMurray Formation (Top of the subCreatceous unconformity to the base of the Quaternary (sub-Quaternary unconformity).
Note, the thickest areas of sediment accumulation generally coincide with structural lows
on the sub-Cretaceous unconformity. Note area of deep Quaternary erosion (between
dashed red lines). 5 metre contour interval.
113
Figure 4.4. Structural map of the base of the Quaternary glacial deposits (sub-Quaternary
unconformity). Note structural lows (blue) cutting across the study area as a deep
Quaternary erosional channel.
114
these are areas where Quaternary glaciation and/or glacial melt waters removed
significant thicknesses of the Mannville Group sediments.
In several parts of the study area the effects of Quaternary erosion can be seen. In
particular, a significant low cuts across the Mannville sediments, down through to the
underlying Devonian rocks and in some cases to the underlying Precambrian (Figure 4.4).
This “channel” is orientated in a northwesterly direction and begins in the northwest at
section 21 township 95 range 25 west of the third meridian and extends to section 34
township 94 range 25 west of the third meridian, approximately 1 km wide. Extending
beyond section 34 the channel widens to approximately 5 km wide and abruptly turns
south west and evidence of the anomalously deep channel terminates in section 16
township 94 range 25 west of the third meridian (Figure 4.4).
4.3
Facies Association Structural Cross-Sections
The stratigraphic architecture of the Dina Member/McMurray Formation in
northwestern Saskatchewan is presented in this section through a series of five structural
cross-sections orientated perpendicular to a prominent channel thalweg and one structural
cross section orientated parallel or near parallel to the channel thalweg running through
the western side of the study area (Figure 4.1). All stratigraphic test holes utilized within
the cross-sections make use of drill core for facies association correlation and sequence
stratigraphic interpretations. Geophysical well logs were also utilized to aid in drill core
interpretation.
All the Dina Member/McMurray Formation sediments occur between two
unconformities, the sub-Cretaceous unconformity and the sub-Quaternary unconformity.
115
The Dina/McMurray sediments were subsequently divided into systems tracts of either
lowstand, transgressive or highstand.
Although not ideal, a structural datum was chosen for cross-section construction
and stratigraphic interpretation due to the absence of a consistent stratigraphic datum
(major marine shale, extensive coal, etc). Because post-Mannville structural displacement
was likely limited, apart from an overall westward dip, correlation of the facies
associations with a structural datum is considered to be accurate.
The vertical measured depth is recorded on all geophysical well logs along with
the Kelly Bushing (KB) elevation. Gamma Ray log traces were used to illustrate rock
lithology (differences between mud and sand) and correlations on the cross-sections,
while facies contacts and sequence stratigraphic surfaces were verified by core analysis.
4.3.1
Cross-section A-A’
Cross-section A to A’ is the most southerly cross-section and runs east-west,
perpendicular to the inferred thalweg and is comprised of eight cored stratigraphic test
holes (Figure 4.1 and 4.5). The cross-section shows mainly Facies Association 2 (FA 2),
but in the deepest portions of the valley, an approximately 20m succession of braided
channel deposits of Facies Association 1 (FA1), has been preserved. Overlying these
deposits are the tidally influenced meander deposits of FA2 (Figure 4.5). The FA2
deposits are comprised of amalgamated, stacked laterally accreting deposits, fining
upwards successions from trough cross beds of Facies 4a (F4a) and IS deposits of Facies
3 (F3), into inter-bedded sandstones and mudstones of Facies 6 (F6). The inter-bedded
sandstones and mudstones found near the top of the successions are inclined heterolithic
116
6-20-94-25W3
KB 568.82m
GR
API
0
Dina Member
Lower Cretaceous
Quaternary
Measured Depth
150
180m
A
Sub-Quaternary
Unconformity
8-20-94-25W3
190
KB 557.1m
0
0
7-20-94-25W3
GR
API
GR
API
150
KB 544.47m
200m
200
190m
0
GR
API
0
GR
API
KB 545m
150
0
0
0
GR
API
150
3
180m
190m
220m
220
180
180
220
190
Winnipegosis
Fm.
Devonian
210
Prairie
Evaporite
Breccia
200
230
230
190
190
TD
200
220
TD
210
240
Sub-Cretaceous
Unconformity
150
150
170m
170m
210
200
GR
API
GR
API
KB 537.5m
5-21-94-25W3
150
210
KB 532.95m
6-21-94-25W3
4-21-94-25W3
KB 574.5m
150
A’
7-21-94-25W3
KB 572.6m
5-20-94-25W3
S
1
240
200
200
1
210
220
250
Datum=Subsea
250
210
TD
S
Depths MD
220
TD
TD
TD
TD
220
~400m
TD
F
T95
FA 1
FA 2
FA 3
3
-SB 2 /Sub-Quaternary Unconformity
2
-Surface of Maximum Brackish Incursion
1
FA 4
S
-TS/NMFS
-SB 1/ LST Unconformity/Sub-Cretaceous Unconformity
FA 5
E
E'
D'
D
C
B
T94 A
C'
B'
A'
F'
Figure 4.5. Structural cross-section A-A’. See text for discussion.
R25
R24W3
117
0
1
2
3
4
Kilometres
5
stratification (IHS) (Thomas et al., 1987). The mudstone beds contain low diversity,
diminutive trace fossils and represent deposition during seasonal brackish water
conditions. On the east side of the cross-section, in well 7-21-94-25w3, two abandoned,
mud filled oxbow lake deposits of Facies Association 3 (FA3) were observed (Figure
4.5).
The lower contact is the Sub-Cretaceous Unconformity defining the bottom of the
channel and represents a major sequence boundary (SB1), separating Devonian and
Jurassic sediments from overlying Cretaceous sediments of the Mannville Group
(Christopher, 1974, 1997, 2003; Jackson, 1984; Hayes et al., 1984; Cant 1996). The
sequence boundary represents a minimum hiatus of 10-20 My and is considered a
second-order sequence boundary representing a major reorganization of the Cordillera
and the adjacent foreland basin (Cant and Stockmal, 1989). The upper contact is
represented by the sub-Quaternary unconformity and represents the second sequence
boundary (SB2).
The lower sequence boundary (SB1) is coincident with a lowstand unconformity,
since some valley cut occurred by fluvial action during the lowstand and it is also
expected that braided sediments of FA1 began to accumulate during the lowstand as well,
although a portion of the transgressive deposits may have also been assigned to FA1,
especially upstream, to the east as the base level rose and braided channel deposits begin
to aggrade within the incised valley. A transgressive surface (TS) or Non-Marine
Flooding Surface (NMFS) marks the beginning of back-stepping and a landward on-lap
of an overall transgressive systems tract (TST) initiated by a relative sea-level rise. This
118
is truncated at the top by SB2. In cross-section A-A’, the TS/NMFS is marked by the
transition from FA1 deposits to FA2 deposits.
4.3.2
Cross-section B-B’
Cross-section B-B’ is also orientated perpendicular to the inferred channel
thalweg and is comprised of seven cored stratigraphic test holes (Figure 4.1 and 4.6).
Again, the base of the channel is marked by SB1, which is also coincident with the
lowstand unconformity. Directly on top of SB1, within the lowest portions of the valley
are FA1 sediments located in 15-20, 16-20, and 13-21-94-25w3 stratigraphic test holes.
The FA1 sediments are relatively thin and represent a veneer of lowstand system tract
(LST) deposition. Overlying FA2 sediments have eroded down into FA1 sediments
producing a morphology where FA1 sediments lap out against the valley flanks. This is
typical of LST sediments within an incised valley fill (Figure 4.6) (Blum, 1990; Shanley
and McCabe, 1994; Zaitlin et al., 1995). Within cross-section B-B’, the contact between
FA1 and FA2 sediments marks the TS/NMFS.
Sedimentation from laterally accreting point bars of FA2 are represented in all the
stratigraphic test holes of cross-section B-B’, except in the most eastern hole where
Quaternary glacial processes have cut away all Mannville group sediments and SB1 and
SB2 are coincident (Figure 4.6). Much like in cross-section A-A’, the FA2 deposits are
comprised of amalgamated, stacked laterally accreting deposits, fining upwards from F4a
and F3, into F6 and sit directly on top of FA1 sediments in the centre of the channel and
directly on top of SB1 on the flanks. Again, the mud beds are populated by low diversity,
diminutive trace fossils and represent deposition during seasonal brackish water
conditions. In stratigraphic test holes 15-20 and 14-21-94-25w3, mud filled oxbow lake
119
14-21-94-25W3
KB 563.3m
0
GR
API
150
Quaternary
Dina Member
Lower Cretaceous
B
13-20-94-25W3
KB 540m
0
GR
API
Measured Depth
14-20-94-25W3
Sub-Quaternary
Unconformity
KB 540.68m
0
GR
API
180
150
GR
API
CD
210
KB 537m
210
190
0
150
200m
GR
API
150
3
210
CSG
210
220
220
220
200m
200
220
S
TD
0
GR
API
200m
16-20-94-25W3
150
1
TD
230
1
230
210
230
TD
TD
Winnipegosis
Fm.
Devonian
200
KB 563.4m
0
200
KB 562.8m
150
15-20-94-25W3
180m
190
0
GR
API
B’
15-21-94-25W3
KB 558.6m
170m
Prairie
Evaporite
Breccia
190
13-21-94-25W3
150
Datum=Subsea
240
1
220
Sub-Cretaceous
Unconformity
Depths MD
240
S
250
230
TD
TD
250
240
~400m
250
TD
F
T95
FA 1
FA 2
FA 3
FA 4
FA 5
3
2
1
S
-TS/NMFS
E
E'
D'
D
C
B
T94 A
C'
B'
A'
F'
Figure 4.6. Structural cross-section B-B’. See text for discussion.
R25
R24W3
0
120
1
2
3
4
Kilometres
5
FA3 deposits are observed, further supporting the meander channel and oxbow
channel abandonment model for FA2 and FA3.
The upper sub-quaternary unconformity surface within cross-section B-B’ is very
irregular and cuts preferentially deeper coincident with the underlying channel thalweg
and, as mentioned previously, it cuts and removes all Mannville valley fill sediments in
the 15-21-94-25w3 stratigraphic test hole.
4.3.3
Cross-section C-C’
Cross-section C-C’ is orientated perpendicular to the inferred channel thalweg and
is comprised of ten cored stratigraphic test holes (Figure 4.1 and 4.7). This cross-section
represents the widest representation of the inferred Valley system and is nearly 5 km
wide. The base of the valley in cross-section C-C’ has less relief compared to crosssections A-A’ and B-B’. Consequently, there is increased lateral preservation of FA1
sediments observed, although still thin and confined to the lowest portions of the valley.
FA1 sediments comprise the LST and sit directly on top of SB1/lowstand unconformity
surface (Figure 4.7).
FA2 sediments sit directly on top of FA1 sediments in almost all the stratigraphic
test holes, except in 13-29, 14-29, and 13-28 where FA2 sits directly on top of SB1.
Again, the contact between FA1 and FA2 represents the TS/NMFS. FA2 sediments
comprise the majority of the strata in cross-section C-C’. FA2 is predominantly
comprised of F4a and F3 with a noticeably thinner succession of F6 deposits overlying
the stacked meander channel successions. Despite the much larger channel width, only
one intersection of oxbow lake deposits of FA3 were encountered in the far east
121
Quaternary
14-28-94-25W3
C 13-29-94-25W3
Dina Member
Lower Cretaceous
KB 560.71m
14-29-94-25W3
KB 562.0m
0
GR
API
0
KB 564.2m
0
GR
API
GR
API
150
16-28-94-25W3
150
KB 549.9m
190m
150
15-28-94-25W3
Sub-Quaternary
Unconformity
190m
16-29-94-25W3
13-28-94-25W3
KB 555.7m
200
200
0
GR
API
KB 553.6m
190m
150
190m
0
GR
API
0
3
KB 558.6m
GR
API
KB 568.6m
0
150
Prairie
Evaporite
Breccia
210m
Winnipegosis
Fm.
210
220
230
220
220
1
230
220
S
Sub-Cretaceous
Unconformity
220
230
TD
230
240
TD
TD
230
TD
230
240
TD
TD
~400m
E
FA 1
2
S
-TS/NMFS
E'
D'
D
C
B
T94 A
C'
B'
A'
F'
FA 5
Figure 4.7. Structural cross-section C-C’. See text for discussion.
R25
R24W3
0
122
1
S
220
Depths MD
3
190
210
240
230
TD
1
180
210
210
150
200
S
TD
GR
API
3
1
220
KB 535.8m
170m
150
220
210
C’
13-26-94-25W3
0
200
220
Datum=Subsea
Measured Depth
150
210m
F
FA 4
GR
API
GR
API
190m
200
200m
0
13-27-94-25W3
150
T95
FA 3
KB 575m
210
200
FA 2
14-27-94-25W3
150
190m
210
Devonian
GR
API
0
1
2
3
4
Kilometres
5
TD
200
TD
stratigraphic test hole, 13-26-94-25w3. This reflects the nature of lateral
reworking and poor preservation potential of oxbow lake mud fills within a confined
incised valley fill system.
The SB2 surface of the sub-Quaternary unconformity of cross-section C-C’ has
less relief compared with cross-section B-B’ and much more of the underlying deposits
have been preserved as a result of less down-cutting of the Quaternary unconformity.
4.3.4
Cross-section D-D’
Cross-section D-D’ is comprised of ten cored stratigraphic test holes and is
orientated primarily perpendicular to the thalweg of the inferred channel form but due to
stratigraphic test hole density and orientation of the channel form, test holes 15-34 and
13-35-94-25w3 are orientated askew from a perpendicular alignment with the thalweg
(Figure 4.1 and 4.8). Regardless of the orientation of the cross-section to the thalweg,
these two test holes were also chosen to illustrate the effects of glacial processes in the
study area and will be discussed in further detail further below.
Much like cross-section C-C’, cross-section D-D’ shows a relatively wide incised
valley with a similar, relative low relief base. Again, the valley base is coincident with
SB1 (Figure 4.7). FA1 deposits directly overly the SB1 surface and are generally thin and
confined to the lowest portions of the valley form. As was observed in cross-section BB’, in test hole 16-20-94-25w3, erosion of FA1 deposits and compound fill of FA2
sediments on top of FA1 deposits at well 5-33-94-25w3, leaves FA1 deposits restricted
and lapped out against the valley flanks. In test holes, 8-33, 5-34 and 6-34-94-25w3, rare
preserved crevasse splay deposits of FA4 is observed overlying FA1 deposits. The FA4
123
D
Quaternary
GR
API
Measured Depth
KB 549.77m
KB 546.3m
150
GR
API
0
170m
0
150
KB 562.1m
0
GR
API
180
Sub-Quaternary
Unconformity
150
190m
5-33-94-25W3
GR
API
KB 532.42m
190
150
170m
0
3
GR
API
0
3
180
1
0
150
210m
150
3
200
190m
5-34-94-25W3
KB 577.75m
200
200
190
0
GR
API
220
150
15-34-94-25W3
0
230
1
210
200
190
GR
API
150
210m
220
TD
230
TD
190
1
S
220
210
200
TD
210
KB 559.65m
220m
180
S
Datum=Subsea
GR
API
150
180
TD
220
Winnipegosis
Fm.
Devonian
Prairie
Evaporite
Breccia
GR
API
170m
FA 2
210
KB 580.27m
KB 558.1m
KB 535.9m
190m
6-34-94-25W3
8-33-94-25W3
7-32-94-25W3
0
200
170
Sub-Cretaceous
Unconformity
220
1
240
S
250
TD
TD
230
210
Depths MD
240
200
250
TD
230
3
210
TD
240
~400m
240
TD
TD
220
F
FA 1
FA 4
150
5-32-94-25W3
T95
FA 3
GR
API
160m
210
FA 2
D’
13-35-94-25W3
6-33-94-25W3
KB 558.56m
0
Dina Member
Lower Cretaceous
8-32-94-25W3
E
3
2
1
-TS/NMFS
S
E'
D'
D
C
B
T94 A
C'
B'
A'
F'
FA 5
Figure 4.8. Structural cross-section D-D’. See text for discussion.
R25
R24W3
0
124
1
2
3
4
Kilometres
5
S
deposits have been placed within the TST since crevasse splay preservation in a
degradational stage is extremely rare and are more likely to be preserved during
aggradation. The TS/NMFS has been placed within FA1 deposits and coincided with the
base of the FA4 deposits in 5 and 6-34-94-25w3 (Figure 4.8).
Still, FA2 deposits are dominant in the cross section, but vertical channel
amalgamation is tighter and IHS deposits of F6 are only observed in test holes 8-32 and
6-33-94-25w3 and are significantly thinner than those observed in the more southerly
cross-sections. This suggests that cross-section D-D’ is near the upstream limits of the
seasonal incursion of salt water for the preserved deposits.
In 13-35-94-25w3, the most eastern test hole of the cross-section, a large deposit
of FA3 is observed. This particular deposit of FA3 is comprised of three fining upward
cycles and likely represents the amalgamation of oxbow lake deposits. In all of the
discussed cross-section, a pattern of mud filled abandoned oxbow lakes, at the margins of
the valley has developed, particularly at the eastern margin. This is likely a result of the
Paleozoic Dolostone bedrock valley wall acting as an erosion-resistant barrier. The river
meanders respond to confinement through down-valley migration or translation (Smith et
al., 2009; Fustic et al., 2012). The result is not only a concentration of counter point bars
along the margins (Figure 3.16), but when a meander lobe is abandoned the oxbow lake
fills tend to be confined to the valley margins as well. These can then also act as erosion
resistant barriers to subsequent meanders.
SB2 is at the base of the Quaternary and is highly irregular through cross-section
D-D’ and in many places has removed much of the underlying Dina Member deposits. In
particular, in test hole15-34-94-25w3, the unconformity cuts all the way down to the Pre-
125
Cambrian, with no Phanerozoic deposits preserved (Figure 4.8). This cut extends from
section 21 township 95 range 25 west of the third meridian and cuts completely across
the valley to depths of at least the underlying Paleozoic rocks.
4.3.5
Cross-section E-E’
Cross-section E-E’ is the most northerly cross-section orientated perpendicular to
the inferred channel thalweg and is comprised of six cored stratigraphic test holes (Figure
4.9). The amalgamated lowstand unconformity and SB1 is noticeably flat lying through
cross-section E-E’ with very little relief. This is due to the cross-sections orientation and
positioning. The cross-section is orientated perpendicular to the thalweg, but it is near a
bend in the valley-form, which turns from an orientation of north-northeast to northwest
(Figure 4.1 and 4.3). Although orientated perpendicular to the north-northeast thalweg the
alignment with the northwest orientated thalweg likely contributes to the low relief
character of SB1.
FA1 deposits lie directly above the SB1 surface and represent a significantly
higher percentage of the Dina Member in the cross-section than what has been observed
in the more southerly cross-sections. This is likely due to amalgamation of lowstand and
transgressive FA1 deposits in response to relative sea level rise. The placement of the
TS/NMFS is therefore located within the FA1 deposits. This surface has been assigned to
a minor paleosol development in 12-12-95-25w3 and a distinctive erosional contact with
abundant mud rip-ups in 3-12-95-25w3.
126
E
Dina Member
Lower Cretaceous
Quaternary
0
GR
API
KB 545.3m
KB 545m
KB 542.8m
Measured Depth
12-12-95-25W3
150
KB 537.24m
170m
Sub-Quaternary
Unconformity
0
GR
API
11-1-95-25W3
3-12-95-25W3
150
0
0
150
GR
API
150
GR
3
180
180
180
3
190
190
180
190
190
190
190
200
200
200
1
200
TD
Datum=Subsea
220
~400m
F
E
E'
D'
D
C
FA 4
210
210
Depths Measured Depth
3
2
1
-TS/NMFS
S
FA 5
B
T94 A
C'
B'
A'
F'
R25
R24W3
0
Figure 4.9. Structural cross-section E-E’. See text for discussion.
127
S
TD
TD
FA 1
1
210
TD
S
TD
Sub-Cretaceous
Unconformity
210
210
210
Winnipegosis
Fm.
Devonian
Prairie
Evaporite
Breccia
200
1
T95
FA 3
150
170m
170m
200
FA 2
GR
API
0
150
180m
180m
170m
GR
API
KB 548.1m
KB 547.2m
GR
API
0
E’
8-1-95-25W3
7-1-95-25W3
6-11-95-25W3
1
2
3
4
Kilometres
5
220
TD
355mSS
A thick succession of FA3 deposits are located in 7-1 and 8-1-95-25w3 and can
be correlated to the FA3 deposits found in the test hole 13-35-94-25w3 of cross-section
D-D’. These deposits sit directly on top of SB1. This is not likely the result of a single
abandoned oxbow, but rather a consolidation of several in a location of high preservation
potential.
FA2 deposits directly overly both FA1 and FA3 deposits and comprise a much
lower percentage of the section in the cross-section than in the previous more southerly
cross-sections. The FA2 deposits are primarily comprised of tightly stacked channels of
F4a deposits capped by F3 grain striped planar cross-bedded sandstones. No IHS deposits
of F6 were observed in any of the test holes in cross-section E-E’, likely indicating the
deposits preserved in the cross-section are located upstream of the seasonal salt water
incursion limit.
The SB2 surface is relatively flat lying throughout cross section E-E’ with no
preferentially deep incisions, as observed in cross section D-D’.
4.3.6
Cross-section F-F’
Cross-section F-F’ is orientated along the axis of the main valley’s inferred
thalweg in an effort to determine the longitudinal variations of the facies associations and
to tie together all the perpendicular-to-strike cross-sections previously described (Figure
4.1 and 4.10). Cross-section F-F’ has a general north-south orientation and is comprised
of six stratigraphic test holes.
The major sub-Cretaceous unconformity surface which comprises SB1 is
characterized by relatively low relief, with some of the minor fluctuation along its length
128
F
Dina Member
Lower Cretaceous
Quaternary
13-21-95-24W3
KB 558.60m
0
KB 563.20m
KB 546.3m
150
170m
0
GR
API
14-28-94-25W3
0
KB 560.71m
150
160m
0
GR
API
GR
API
150
7-21-94-25W3
180
KB 532.95m
2
1
3
12-12-95-25W3
KB 537.24m
S
0
GR
API
2
190m
180
3
150
200
170m
210
180
200
200
TD
180
2
190
210
1
2
Winnipegosis
Fm.
190
200
1
S
220
S
190
220
1
1
200
200
210
S
S
TD
230
TD
210
TD
TD
TD
F
T95
FA 1
FA 4
GR
API
3
~400m
FA 3
0
150
170m
Prairie
Evaporite
Breccia
3
190
170
240
FA 2
F’
150
3
190
Devonian
14-21-94-25W3
6-33-94-25W3
GR
API
E
3
2
1
-TS/NMFS
E'
S
D'
D
C
B
T94 A
C'
B'
A'
F'
FA 5
Figure 4.10. Structural cross-section F-F’. See text for discussion.
R25
R24W3
0
129
1
2
3
4
Kilometres
5
likely due to test hole location within the channel, since not all test holes in the crosssection are exactly in the centre of the thalweg. The interfluve area rises above the valley
in the northern most portion of the cross-section, beginning approximately at section 13
township 95 range 25 west of the third meridian and extending towards test hole 13-2195-24w3 (Figure 4.10).
FA1 deposits directly overlie the SB1 surface throughout the inter-channel area,
except within test holes 14-21 and 7-21-94-25w3. FA1 sediments are only absent in the
cross section since the cross section is slightly off-centre of the deepest portions of the
valley. This highlights the restricted nature of the FA1 deposits in the southern reaches.
FA1 deposits thicken slightly towards the north, and as mentioned earlier, this is likely
due to aggradation of the FA1 deposits due to onset of trangession. The TS/NMFS is
inferred to be at the thin paleosol located in 12-12-95-25w3. The FA1 deposits below the
paleosol and in the other more southerly wells are designated to be within the LST
(Figure 4.10). FA1 deposits on-lap the edges of the valley and do not extend onto the
interfluves regions.
FA2 deposits predominantly lie directly on top of FA1 deposits, especially within
the main thalweg valley. FA2 deposits are thickest in the southern part of the crosssection and gradually thin northward. This is likely a result of both depositional thinning
northward along with the effects of down cutting caused by glacial erosion. FA2
sediments thin significantly, but do extend over the valley edge into the interfluve area. In
test hole 13-21-95-24w3, FA2 sediments lie directly on top of a well-developed FA5
marsh paleosol deposit produced when relative sea level rise outpaced sediment supply.
130
This marks the beginning of the transgressive systems tract and can be correlated to the
south with the TS/NMFS.
Within FA2, the longitudinal distribution of F6 IHS deposits is of significant
importance and illustrates the back-stepping /transgressive depositional nature of the
succession (Figure 4.10). All FA2 sediments are tidally influenced fluvial deposits, but
those of F6 are not only tidally influenced, but are seasonally (during low river flow
periods) brackish and subject to the influences of the turbidity maximum. A wedge of
seasonally brackish-water mud deposits is observed starting in almost all the FA2
deposits of test hole 7-21-94-25w3 and gradually pinches out at 6-33-94-25w3 (Figure
4.10). Below this wedge, laterally accreting FA2 deposits occur as Inclined Stratification
(IS) deposits rather than Inclined Heterolithic stratification (IHS) deposits (Figure 4.10)
FA3 deposits occur in test holes 7-21 and 14-21-94-25w3. The thickness of FA3
deposits is higher in the southern portion of the cross-section, but this is biased due to the
off-centre location of the cross-section in the southern portion. The sub-Quaternary
unconformity of SB2 is relatively flat lying with only minor undulations, including over
the sub-Cretaceous unconformity valley edge, with the exception of the deep, preferential
erosional “cut” located between test hole 12-12-95-25w3 and 6-33-94-25w3. This
channel cut is inferred from the isopach and structure maps, as well as other logged core
intervals, since there is no test hole utilized in the cross-section that intersects the
Quaternary channel.
4.4
Depositional Model
The following depositional history/model utilizes a simplified base level curve
interpretation due to the correlation challenges of fluvial deposits along with the
131
challenges of using a structural datum. Thus, the depositional history/model does not take
into account higher frequency base level fluctuations that occurred within the duration of
each systems tract, as described, and does not account for anomalous facies stacking
patterns that resulted from higher frequency base level changes. Although the author
recognizes the presence of these higher frequency base level fluctuations, the
stratigraphic correlations are simplified due to the limitations encountered in the study
area.
The depositional history of the Dina Member in the study area is illustrated by a
series of plan view sketches showing the morphology and depositional environments. The
system tracts and corresponding relative base level changes are also indicated (Figure
4.11).
Initial down-cutting was in response to a base level fall during lowstand
conditions. The down-cutting likely enhanced and exploited karst features upon the subCretaceous unconformity and created incised valleys (Figure 4.10). Facies Association 1
(FA1) is interpreted as a lowstand systems tract (LST) of braided-fluvial channels
developed and largely preserved within the lowest paleo-topographic lows upon the subCretaceous unconformity (Figures 3.26, 4.2, 4.5, 4.11A and B). This fluvial system
flowed southwest, towards Alberta, where it joined with the Firebag tributary system as
described by Ranger (2006) and Hein et al. (2007) (Figure 2.6). This tributary system is
orientated approximately east-west and generally follows the township 95 grid, until it
reaches and empties into the Assiniboia paleo-valley (McMurray main trunk valley) at
approximately township 95 range 8 west of the fourth meridian (Figure 2.6).
132
A
T95
T95
T95
D
T95
Tidally Influenced
Fluvial Meander
Braided Channel
Braided Channel
Tidally Influenced
Fluvial Meander
Tidally Influenced
Fluvial Meander
Tidally Influenced/
Seasonal Brackish
Influence
Incised Valley
Trench
T94
R25
R24W3
1
2
3
4
Kilometres
R25
5
0
1
2
3
4
Kilometres
R24W3
5
0
1
High
Low
High
Low
Lowstand
Systems Tract
R25
R24W3
High
0
T94
Lowstand (wedge)
Systems Tract
2
3
4
Kilometres
R24W3
5
0
High
R25
T94
Low
T94
133
C
Low
Figure 4.11. Plan view sketches of incised-valley system in the study area, showing its
evolution over its depositional cycle from sea-level fall to subsequent late transgression.
(A) Lowstand time showing the incised valley system. (B) Lowstand (wedge) time
showing the beginning of braided fluvial deposition throughout the incised valley system,
including overbank crevasse splay deposits. (C) Transgessive systems tract time showing
development of tidally influenced meander channels as part of the “meander” of a
straight-meander-straight system, as well as the aggradation of braided fluvial system,
within the landward “straight” segment. (D) Late transgressive time showing further
migration landward of the meander fluvial system with “distal” tidally influenced
seasonally brackish portion transitioning beyond the influences of seasonal salt incursion
to a tidally influenced meander system (modified from Zaitlin et al., 1995).
B
Transgressive
Systems Tract
(Early)
Transgressive
Systems Tract
(Late)
1
2
3
4
Kilometres
5
In the study area, the most landward expression of the tributary system runs through
townships 94 and 95, ranges 24 and 25 west of the third meridian, but the thickest
preserved sediments are within townships 94 and 95 range 25 west of the third meridian
and is orientated north-northwest (Figure 4.3).
Following the LST, a relative sea level rise marks the beginning of the
transgressive systems tract (TST). Within the study area’s valley system, this can be
recognized by the vertical transition from the braided channel deposit of FA1, to laterally
accreting tidally influenced point bar deposits of FA2, or in some cases by a minor
paleosol observed within FA1 deposits in the northern areas of the paleo-valley (Figure
4.10 and 4.11 C and D).
Continued relative sea-level rise increased accommodation space within the
incised valley, resulting in preservation of amalgamated, aggraded multistory, tidally
influenced meander channel deposits (Figures 3.27, 3.28, 4.2, and 4.5). The lowest
portions of these deposits were initially confined by steeper valley walls formed along the
sub-Cretaceous unconformity. The lateral accommodation space available during early
transgression was limited and abundant sediment cannibalism was occurring. Interchannel deposits were very rarely preserved at this level and occur as mud-clasts within
the lower FA2 deposits (F3 and F4). FA2 deposits consist of at least three stacked
meander channel belt deposits (Figures 3.28 and 4.5).
Continued relative sea-level rise and an increase in lateral accommodation space
combined with infilled irregular paleotopography resulted in a continued vertical and
landward shift in facies. A facies transition from tidally influenced IS deposits to not only
tidally influenced deposits, but also a seasonal deposition of brackish deposits occurs as a
134
seasonal salt-water incursion migrates farther inland. The brackish deposits are
characterized by impoverished, diminutive, simple vertical burrows in thin mud beds.
The mud beds and trace makers occur inter-bedded with sandstone and together comprise
the IHS component of point bar deposits. As a result of increased lateral and vertical
accommodation, the IHS deposits become thicker. In turn a more complete point-bar
succession is preserved.
A distinct wedge of seasonal brackish deposits is evident in the study area,
thickest in the southern portions of the paleo-valley system and thinning towards the
north (Figures 3.31 and 4.9). These deposits are confined within the uppermost portions
of F3 inclined stratification (IS) deposits and the muddy layers of the inclined heterolithic
stratification (IHS) deposits. During seasonal, low fluvial discharge, salt water migrated
up-channels and during seasonal high fluvial discharge, the salt incursion was pushed
downstream. Within the zone of mixing, salinity induced density stratification occurred,
resulting in density currents (Figure 2.11). As fine grained sediment enters the brackish
area it begins to flocculate and deposition of mud and silt occurs. This area is coincident
with the turbidity maximum, where elevated suspended sediment is concentrated.
During times of low fluvial discharge, mud accumulates on underlying sand beds
and a brackish water assemblage of trace fossils opportunistically populates the mud.
When fluvial fresh water discharge is high, trace makers die and sand is deposited on top
of the mud layers. The mud beds generally have erosive tops because of this. The base of
the brackish water deposits can trace the incursion of the brackish water conditions
landward (Figure 4.9)
135
Eventually, sedimentation overstepped the valley walls and deposition of tidally
influenced sediments occurred over interfluve regions. FA2 deposits subsequently overlie
FA5 deposits in the interfluves. The ultimate extent of the marine transgression is not
recorded in the study area due to the ultimate removal of the uppermost deposits by
Quaternary glaciation.
136
5.
5.1
BITUMEN DISTRIBUTION
Introduction
A series of four maps illustrating net “pay”, net water/ “lean” zones and bitumen
saturation were constructed along with two oil-water-contact cross-sections to determine
the extent of the bitumen resource within the study area . Trapping and controls on
bitumen distribution will also be discussed in this chapter.
5.2
Bitumen Distribution
Bitumen distribution throughout the study area is influenced by many
complicating factors and determining the most desirable development targets is not
straight forward.
The first step performed to assess the bitumen resource potential for the study
area was constructing a Dina/McMurray isopach map of the area to determine where the
thickest succesions were located (Figure 4.3). Then, utilizing dean stark analysis
performed on Oilsands Quest Inc’s drill core, by Norwest Corporation, net bitumen “pay”
isopach maps were also developed. For these, all bitumen saturation values >6 wt% were
accumulated, regardless of bottom water or perched water zones between bitumen zones,
and a 10 metre net thickness was used as minimum cut-off (Figure 5.1 and 5.2). Notably,
the thickest bitumen “pay” does not always correlate with the thickest Dina/McMurray
successions. Also, the “pay” is restricted to the western flank of the southern reaches of
the channel, but coincides with the thickest successions in the northern valley limit area
(Figure 5.2).
137
Bitumen Zone
Bitumen Zone
Top
Bottom
Figure 5.1. Core photograph of “perched” water-saturated zone between an upper and a
lower bitumen saturated zone; drill core 16-28-94-25W3, 182.55-219.40 m.
138
Figure 5.2.Map of total net bitumen pay (>6 wt%) more than 10 m in thickness; data
based on core analyses. 5 metre contour interval.
139
The average bitumen saturation for each stratigraphic test hole’s drill core was
also calculated and mapped. This was done regardless of thickness and two maps were
constructed, one showing average saturation values regardless of water and the other
excluding water (Figures 5.3 and 5.4). This again revealed the highest average bitumen
saturations were not always coincident with the thickest successions of Dina/McMurray.
Again, the highest saturation averages coincided with the western flank of the southern
portions of the valley and coincided with the successions in the most northern portions
and easterly portions of the valley (Figure 5.3 and 5.4).
A problematic reservoir condition involves the presence of low saturation zones
and water. A common observation in the study area is the presence of water saturated
zones, both observed as bottom water and perched water zones overlying and between oil
saturated zones (Figures 5.1, 5.5, 5.6 and 3.33). The southern portion of the channel fill is
especially prone to this problem (Figure 5.3, 5.4, 5.5 and 5.6). Unfortunately, these zones
degrade the resources and can be detrimental to in-situ recovery techniques such as
Steam Assisted Gravity Drainage (SAGD).
For the purposes of development, the best areas would be those where net
bitumen pay exceeds 10m, the average saturations are greatest and there is little water
(Figure 5.7, 5.8, 5.9 and 5.10). From a development perspective, the areas located in the
northern portions of the channel exhibit the most favourable conditions. The average
saturation values exceed 16%, the net pay is greater than 18 metres and there is very little
water or lean zones.
140
Figure 5.3.Map of weighted average bitumen saturations including water zones,
regardless of net bitumen pay thickness.
141
Figure 5.4. Map of weighted average bitumen saturations excluding water zones,
regardless of net bitumen pay thickness. Note, this will increase the average bitumen
saturation percentage values for individual drill cores where bottom water or “perched”
water zones are present.
142
6-20-94-25W3
KB 568.82m
0
Dina Member
Lower Cretaceous
Quaternary
GR
API
Measured Depth
150
180m
Sub-Quaternary
Unconformity
8-20-94-25W3
190
KB 557.1m
0
GR
API
7-21-94-25W3
KB 572.6m
5-20-94-25W3
0
7-20-94-25W3
GR
API
150
KB 544.47m
200m
KB 574.5m
150
190m
200
0
GR
API
0
KB 537.5m
5-21-94-25W3
KB 545m
150
0
150
210
200
GR
API
GR
API
0
210
3
220
Winnipegosis
Fm.
Devonian
150
150
180m
180
180
190
200
230
230
190
190
TD
200
220
210
240
S
1
240
200
200
1
210
220
250
Datum=Subsea
250
210
TD
S
220
TD
TD
TD
220
Sub-Cretaceous
Unconformity
~400m
TD
3
2
1
-TS/NMFS
Water Saturated Sandstone
Poor to Fair Bitumen Staining
Good to Excellent Bitumen Staining
Figure 5.5. Structural cross-section A-A’, illustrating the oil-water contacts. Note
multiple oil-water contacts through the cross-section, increasing from west to east. See
also text for further discussion.
143
GR
API
190m
210
S
0
150
220
TD
GR
API
170m
170m
220m
Prairie
Evaporite
Breccia
KB 532.95m
6-21-94-25W3
4-21-94-25W3
TD
Lower Cretaceous
Dina Member
Quaternary
F
13-21-95-24W3
KB 558.60m
0
GR
API
KB 563.20m
KB 546.3m
170m
0
GR
API
14-28-94-25W3
0
KB 560.71m
150
160m
0
GR
API
GR
API
F’
150
150
7-21-94-25W3
3
KB 532.95m
180
Prairie
Evaporite
Breccia
3
12-12-95-25W3
1
3
190
170
0
GR
API
150
KB 537.24m
S
190
Devonian
14-21-94-25W3
6-33-94-25W3
150
0
3
GR
API
190m
3
150
170m
180
200
170m
210
180
220
190
200
200
TD
180
190
210
Winnipegosis
Fm.
190
200
S
220
S
S
200
200
210
TD
230
210
S
TD
TD
TD
240
~400m
3
2
1
-TS/NMFS
S
1
F
T95
Water Saturated Sandstone
E
Poor to Fair Bitumen Staining
E'
Good to Excellent Bitumen Staining
Figure 5.6. Structural cross-section F-F’, illustrating the oil-water contacts from north to
south. Note multiple oil-water contacts in the southern wells, increasing in water content
from north to south. See text for further discussion.
D'
D
C
B
T94 A
C'
B'
A'
F'
R25
R24W3
0
144
1
2
3
4
Kilometres
5
Figure 5.7. Map of net thickness of water and low-saturation zones. Note the increased
thickness in the southern portion of the paleo-channel system.
145
Figure 5.8. Overlay of total net bitumen pay map (red cross-hatch indicates >10m net
pay) with weighted average bitumen saturation map (green contours). Areas of overlap
are the most desirable as production targets.
146
Figure 5.9. Overlay of total net bitumen pay map (red cross-hatch indicates >10m net
pay) with weighted average bitumen saturation map (green contours), regardless of
bottom or ‘perched” water zones. Areas of overlap are the most desirable as production
targets, but caution must be taken to consider the possible detrimental effects of water
zones (especially “perched”) on in situ recovery techniques.
147
Figure 5.10. Map overlay of the total net bitumen pay (red cross-hatch indicates >10m net
pay) and net thickness of water and low-saturation zones (blue contours). Note net
bitumen pay tends to overlap areas of thinner water-low saturation zones.
148
5.3
Trapping and Bitumen Distribution Controls
There is much controversy surrounding the source rocks for the gigantic
Athabasca bitumen deposit, but there is consensus that all potential source rocks occur
southwest and down-dip of the Athabasca Bitumen deposit in the foreland basin region
(Figure 5.11) (Vigrass, 1968; Moshier and Wapples, 1985; Higley et al., 2009). Within
the foreland basin, source rocks were buried deeply, to the point where temperatures and
pressures were sufficient enough to initiate primary migration of oil into adjacent porous
and permeable beds. Oil subsequently migrated up-dip approximately 600km, out of the
foredeep part of the foreland basin, towards the shallower areas in the northeast,
eventually becoming trapped in Dina Member and McMurray Formation deposits within
migration focal points and subtle structures.
There are currently two accepted models in the literature for the trapping
mechanisms for the Athabasca bitumen deposit: 1) the Prairie Evaporite salt solution
edge formed a significant structural trap restricting most of the oil of the southern portion
of the Athabasca bitumen deposit from migrating further up-dip to the north and east into
Saskatchewan (Figure 5.11) (Vigrass, 1968; Ranger, 2006) and 2) a stratigraphic trapping
mechanism for the northern portion of the Athabasca deposit. The bitumen in the study
area is part of the northern stratigraphic trap.
Trapping in the study area is strongly controlled by facies pinch-out. Oil migrated
into the sandstones of FA1 and FA2 and were trapped laterally where these facies
associations pinch-out against the impermeable paleo-valley walls of the sub-Cretaceous
unconformity surface.
149
0
100
200
km
Figure 5.11. Map of the Athabasca oil sands deposit. Note the proximity of the Prairie
Evaporite salt-solution edge and the edge of the Athabasca bitumen deposit (shaded
grey). The salt edge likely formed the trap that limited the eastward migration of oil
further east, up-dip, into Saskatchewan. The northern portion, including the study area
has a bitumen resource not structurally limited by the salt-solution edge and is trapped
stratigraphically. (modified after Ranger and Gingras, 2006 and Kohlruss et al., 2010a)
150
Vertically thick Cummings/Clearwater shales overlapped and sealed the Dina
Member/McMurray Formation reservoir against the rising Sub-Cretaceous Unconformity
surface (Ranger, 2006). Unfortunately there is no preserved confirmation of the later
component since all evidence has been completely removed by Quaternary erosion.
Internal relationships of facies and facies associations also exhibits controls on
bitumen distribution and trapping. A significant correlation can be made with facies
exhibiting controls on bitumen distribution in the southern portion of the paleo-valley
(sections 16, 17, 20, 21, 22, 27, 28, 29, 32 and 33-94-25w3) where the thickest
successions of Dina/McMurray reside. Here, oxbow lake mud filled channel deposits
comprised of at least three stacked meander-belt deposits, where F6, IHS deposits and
FA3 deposits produce a mosaic of barriers and baffles which inhibit bitumen migration.
In this area, the presence of multiple oil-water contacts is commonly observed and is a
result of complex lateral stratigraphic traps (Figure 5.12). This has been observed by
authors in the McMurray Formation and Elleslie Member (Edie and Andrichuk, 2005;
Fustic et al., 2011; Fustic et al., in press). Fustic et al. (in press) describes in detail, the
emplacement of bitumen through fill and spill concepts of Gussow (1954) and differential
entrapment (Schowalter, 1979). Since there are many lateral, up-dip traps created by IHS
and mud filled channels, individual traps become saturated by migrating oil (fills), and
subsequent arriving oil displaces existing oil and consequently is expelled from the trap
(spills) and fills laterally adjacent up-dip traps (Gussow, 1954; Fustic et al., in press).
This concept also lends itself to areas being isolated from oil emplacement, leading to
low saturation zones and water wet zones laterally and vertically adjacent to highly
saturated zones (Figure 5.5, 5.6, 5.10 and 5.12).
151
Figure 5.12. 3-dimensional schematic block diagram of lateral up-dip spill and fill
trapping. IHS and mud filled oxbow lake fills (grey) act as lateral barriers and baffles
restricting oil flow (green) into otherwise thick succession of reservoir quality sandstones
(beige). Note arrows indicate oil flow and spill points. Complex lateral and vertical
barriers creates mosaic of pathways creating multiple oil water contacts (modified after
Fustic et al., in press).
152
In general, areas coincident with FA1 deposits and the sand rich portions of FA2
(F3, F4) result in higher oil saturation and less water (Figure 3.27 and 3.36) while those
areas coincident with F6, IHS deposits and FA3 mud filled channel deposits tend to
complicate the bitumen trapping model and produce areas with multiple oil-water
contacts (Figure 5.6, 5.7, 5.12, 5.13 and 5.14).
153
Figure 5.13. Map of total net pay more than 10m thickness (red cross-hatch), the inferred
valley wall of the incised valley system created by the sub-Cretaceous unconformity
(black line) and the outline of the areal distribution of F6 IHS deposits and FA3 mud
filled oxbow lake deposits (blue cross-hatch). The combination of F6 and FA3 deposits
produces an intricate mosaic of baffles and barriers restricting oil flow to the east. In the
north, Dina/McMurray sediments pinch-out against the valley wall produced by the subCretaceous unconformity. The sub-Cretaceous unconformity and the underlying low
permeability rocks provide a lateral seal for trapping. Due to Quaternary erosion, the
vertical trap has not been preserved.
154
Figure 5.14. Overlay map of net water and low-saturation zones (blue contours) and
F6/FA3 distribution (red cross-hatch). Note, thickest water zones are coincident with
F6/FA3 distribution. 5 metre contour interval.
155
6.
CONCLUSIONS
The main purpose of this study was to characterize the Dina Member/McMurray
Formation and its resource potential in northwest Saskatchewan. This was accomplished
by integrating facies and facies association descriptions with mapping and sequence
stratigraphy, which lead to the development of a depositional model. Also, this study has
produced a stratigraphic framework that can now be linked to Alberta’s oil sand areas, in
particular, the Firebag-Sunrise developments. This study has greatly improved the
understanding of the Dina Member/ McMurray Formation in northwest Saskatchewan, as
well as the bitumen sands resource and the controls on bitumen distribution. The main
conclusions of this study are summarized as follows.
1) Dina Member/ McMurray Formation sediments within the study area have
accumulated within a paleo-valley system created by the sub-Cretaceous
unconformity.
2) The Dina Member/ McMurray Formation was deposited in a tidally
influenced fluvial system, that at times was seasonally influenced by brackish
conditions.
3) Deposition of the Dina Member/ McMurray Formation within the study area
was initiated as part of a relative sea level fall and early rise induced lowstand
systems tract and then followed by a subsequent sea level rise induced
transgressive systems tract that back filled the valley with tidally influenced
fluvial deposits.
156
4) The Dina Member/ McMurray Formation is bound by two major sequence
boundaries: the sub-Cretaceous unconformity/lowstand unconformity at the
base and the sub-Quaternary unconformity at the top.
5) Bitumen distribution is strongly controlled by facies and facies association,
with the best bitumen resource being hosted within FA1 and F3 deposit;
deposits of F6 and FA3 restrict initial oil emplacement due to baffles and
barrier to flow.
6) The overall bitumen trap is stratigraphic related to facies pinch-out. Bitumen
is trapped where facies on-lap against impermeable valley walls and are
sealed above by the Mannville Group, Clearwater/Cummings shales.
157
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24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
540.26
537.13
534.6
531.39
551.2
545.4
562.87
556.19
556.6
558.4
539.6
556.54
543.85
565.3
546.5
532.43
540.84
544.9
557.54
551.32
562.2
564.71
556.1
555.66
552.69
558.89
572.61
542.92
559.28
556.75
536.98
541.09
549.36
555.03
KB (m)
153.5
172.5
191
186
180.5
185
185.5
178.5
170.5
188
158.5
170.89
181
181
192
178
168
171
178
Dina
TVD
(m)
3.5
0
0
0
0
15
8.2
19
5
8.5
10.75
8.5
8.7
16.5
0
10.5
0
8.11
14
5.5
0
4
0
9
0
0
0
0
0
0
0
5.5
8.5
2.5
Dina
iso
(m)
157
163.5
170
147
181
187.5
199.2
205
185.5
193.5
196.25
187
179.2
204.5
229.75
169
202.8
179
195
186.5
190
196
176
187
181.5
200
194
172
188.3
187.5
168
173.5
179.5
180.5
SCU
TVD
(m)
157
163.5
170
147
181
187.5
199.2
205
185.5
193.5
196.25
187
179.2
204.5
229.75
202.8
197
195
186.5
198
211.5
202.5
187
192
200
194
172
188.3
187.5
186
173.5
179.5
198.4
DEV
TVD
(m)
166.7
180.7
184.6
165.1
191.1
198.7
215.1
219.7
213.6
209.9
194.75
195
219.3
237.9
184.83
212.7
206
207.2
195.13
208.71
222.7
211
197.8
206.7
210.9
206.6
183
198.2
198
198.7
182.5
190.1
218
TD
TVD
(m)
FA1
TVD
(m)
0
ISO
FA1
(m)
178
FA2
TVD
(m)
2.5
ISO
FA2
(m)
FA3
TVD
(m)
0
ISO
FA3
(m)
FA4
TVD
(m)
0
ISO
FA4
(m)
FA5
TVD
(m)
0
ISO
FA5
(m)
ISO
F6
(m)
170
27
28
28
28
29
29
30
30
30
30
31
31
31
31
32
32
04
15
05
13
15
07
15
05
07
13
15
05
07
13
15
05
07
05
05
05
05
06
06
06
06
06
06
07
07
07
08
08
08
09
15
13
15
05
06
07
11
14
15
08
13
15
06
08
13
14
10
05
Sec
LSD
Twp
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
535.7
526.61
553.75
554.78
553.5
546.21
538.25
553.2
561.75
565.74
552.6
563.38
570.3
541.14
543.5
535.72
547.6
556.9
537.25
573.1
559.47
562.3
554.5
562.7
567.8
539.6
544.06
536.56
538.6
540.51
531.6
KB (m)
163.5
157
179
185.5
192.4
198
192.2
181.5
189
209
173
166.5
180
189.99
173.5
203
191
180
186
192
194
175
174
165
164.5
168
Dina
TVD
(m)
5.5
9
0
11.5
8.5
0
0
7.6
19
15.8
23
4.5
11
13
0
5.5
11
1.01
8.5
11
14
31
22
14
16.5
7
18
5.5
8.5
13.5
0
Dina
iso
(m)
169
166
206.5
190.5
194
191
199
200
217
208
204.5
193.5
220
186
189
172
191
191
182
214
205
211
208
206
210.5
182
192
170.5
173
181.5
167.5
SCU
TVD
(m)
191
172
191
191
182
214
205
205.5
208
206
210.5
182
192
170.5
173
181.5
167.5
DEV
TVD
(m)
176.5
183.1
224.1
205.4
209.4
207.1
213.2
210
234.1
223
216.7
208.3
231.3
200.4
204.3
183
206.7
200.7
196
231.2
218.9
227.2
222.5
228.5
227.2
198
207
178.3
188.6
194.6
182.4
TD
TVD
(m)
191.85
FA1
TVD
(m)
0
0
8.45
0
ISO
FA1
(m)
187.5
FA2
TVD
(m)
0
0
0
19
ISO
FA2
(m)
FA3
TVD
(m)
0
0
0
0
0
0
0
0
0
0
ISO
FA3
(m)
FA4
TVD
(m)
0
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
ISO
FA5
(m)
ISO
F6
(m)
171
17
17
17
20
20
20
20
20
14
15
16
05
06
07
08
12
14
17
14
12
15
16
13
15
13
13
13
15
09
14
16
36
03
14
28
04
16
28
01
13
27
04
16
27
02
16
22
04
11
21
13
06
20
15
15
20
13
15
19
15
15
094
19
13
13
094
19
05
Twp
18
15
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
095
095
095
095
095
095
095
095
095
095
095
095
095
Sec
LSD
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
24
24
24
24
24
24
24
24
24
24
24
24
24
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
540
572.6
574.5
568.82
557.1
536.6
533.3
531.75
549.5
541.9
544.95
529.6
530.49
536.7
552.4
544.1
536.8
556.5
556.8
552.9
544.6
537.6
525.68
536.23
559.7
533.2
548.6
540.42
540.294
546.6
549.69
541.556
544.65
KB (m)
177
205
208
186
188
170
173
172.5
184
196
214
162
180.25
201.5
182
201
176
186.5
189
187.5
179.5
154.2
146
146.5
188
159
173.5
184
Dina
TVD
(m)
12
35.5
37
29.25
19
36
11.5
9.75
24
21
5.5
50
26.25
6.5
25
0
11
15.5
12.5
10.5
23.5
6.3
0
13.5
15.5
5
7.5
12.5
0
0
0
17.5
0
0
Dina
iso
(m)
189
240.5
245
215.25
207
206
184.5
182.25
208
217
219.5
212
206.5
208
207
201
187
202
201.5
198
203
160.5
159.5
162
193
166.5
186
180
191.5
200.5
201.5
174
173.5
SCU
TVD
(m)
240.5
215.25
206
182.5
219.5
206.5
159.5
162
180
191.5
200.5
174
173.5
DEV
TVD
(m)
205.12
255.1
260.02
231.1
222.9
221.2
192.4
197.8
224.1
230
235.2
223.7
222.2
222.21
219.4
219
204.4
217.9
215.4
208.6
212.2
177
175
176.8
208
181.3
200.2
191.7
205.3
219.6
223.9
189.8
192.4
TD
TVD
(m)
194.5
FA1
TVD
(m)
0
0
0
0
0
0
0
17.15
0
0
0
0
ISO
FA1
(m)
233.5
212.8
190.8
190.87
165
185
177.44
FA2
TVD
(m)
33.79
31.6
14.96
17.03
2.5
0
11
0
3.03
ISO
FA2
(m)
FA3
TVD
(m)
0
0
0
0
0
0
0
0
0
ISO
FA3
(m)
FA4
TVD
(m)
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
180.5
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
8.45
ISO
FA5
(m)
9
5
11
3.5
ISO
F6
(m)
172
26
27
27
27
27
28
28
28
28
13
14
15
03
05
07
09
23
05
23
13
15
13
23
07
26
23
05
26
22
13
07
22
07
05
22
05
25
21
15
25
21
14
15
21
13
13
21
12
24
21
07
13
21
06
24
21
05
24
21
04
07
094
20
16
05
094
20
15
Twp
20
14
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
Sec
LSD
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
560.5
551.62
565.7
566.62
570.2
568.6
543.27
535.8
565.75
559.1
553.53
550.29
565.25
548.88
534.7
565.87
533.9
545.15
562.8
563.2
558.6
559.46
532.95
537.5
545
544.47
537
563.4
540.68
KB (m)
191
175.5
192
224
209
185
176
180.5
177.5
167.5
184.5
176
219.9
187
192
185.5
163
171
188
171
201.5
217
186.5
Dina
TVD
(m)
27
30
39
0
8.5
24
6
18.5
13.11
0
0
0
0
21.5
0
0
14
11
0
0
17.5
0
32.5
40
41
32
40.5
30.5
43
33.5
21
6.25
Dina
iso
(m)
218
205.5
231
220
232.5
233
191
194.5
205
205
202
190.5
220
191.5
178.5
220
190
193.5
221.5
219.5
232
226.5
195
211.5
218.5
214
235
238
192.75
SCU
TVD
(m)
202
190.5
220
191.5
178.5
220
193.5
219.5
211.5
DEV
TVD
(m)
232.1
216.2
247.4
235.2
241.7
247.3
207.1
201.2
220.4
228.5
216.4
206.1
201
194.1
232.5
204.7
208.9
237.2
235.9
236
241.9
209.9
225.4
232.8
230.76
251.6
253.2
208.7
TD
TVD
(m)
241.5
234.5
222.9
215.63
200.65
230.25
233..98
FA1
TVD
(m)
0
9
8
0
0
0
0
0
0
0
0
0
10.2
0
0
1.7
13.61
4.84
4.58
0
ISO
FA1
(m)
218.34
210.98
176.43
187.85
196.45
159.97
171.42
186.13
170.05
201.39
219
186.74
FA2
TVD
(m)
0
23.5
22.52
15.78
0
0
0
0
0
0
0
31.59
26.45
35.33
36.98
29.2
30.6
28.86
11.65
6.1
ISO
FA2
(m)
192.21
219.44
170
230.65
FA3
TVD
(m)
0
0
0
1
0
0
0
0
0
0
0
4.73
0
5
0
0
0
0
3.33
ISO
FA3
(m)
233.5
FA4
TVD
(m)
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA5
(m)
6
10
18
29
6
6
11
ISO
F6
(m)
173
33
33
33
33
33
33
33
34
34
08
09
13
15
16
05
06
32
07
29
16
05
06
29
15
33
29
14
32
29
13
05
29
12
16
29
11
32
29
09
32
29
08
15
29
07
14
29
06
32
29
05
13
29
04
32
28
16
08
28
15
32
094
28
14
07
094
28
13
Twp
28
10
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
Sec
LSD
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
580.27
577.75
566.1
547.5
568.5
572
548.8
546.3
532.42
564.9
556.8
560.46
537.72
558.56
535.9
562.1
551.7
562.65
564.2
562.07
568.93
547.61
546.98
579.86
574.2
571.46
536.18
549.9
553.6
560.71
558.6
557.85
KB (m)
224
218
199
184
195
204
176
169
166
196.5
193.5
188
184
173
198
195
201.5
200.25
196
198.5
186
175
217
213
203.5
175
184
185
192.1
194.5
193
Dina
TVD
(m)
16
25
12.5
19
31
28.5
35.5
33
34
21.5
20.5
17.5
0
29.5
18.5
5
20.76
15.5
16.25
11
18.5
14.5
37
23.3
22.5
22
24
34
29.5
39
27
14
Dina
iso
(m)
240
243
211.5
203
226
232.5
211.5
202
200
218
214
205.5
178
213.5
191.5
203
215.76
217
216.5
207
217
200.5
212
240.3
235.5
225.5
199
218
214.5
231.1
221.5
207
SCU
TVD
(m)
232.5
215.76
216.25
217
200.5
212
199
231.1
DEV
TVD
(m)
251.7
251.4
221.2
234.6
241.96
235.6
224.65
218.6
219.2
228.4
230.7
219
194
213.5
206.86
218.1
230.4
232.1
223.45
231.4
214.9
227.5
240.3
242.71
238.2
212.9
228.2
229.1
231.02
223.5
TD
TVD
(m)
230.8
220.75
198.35
195.8
191
188.2
212.28
211.02
211.95
208.13
217.9
FA1
TVD
(m)
13.21
17.65
22.75
6.86
9
0
0
0
3.74
0
3.48
0
0
12.4
0
6.15
6.05
13.2
0
ISO
FA1
(m)
169.03
179.16
196.7
184.14
176.5
198.73
196.26
199.26
198.93
193.36
216.8
182.55
188.55
192.91
207
FA2
TVD
(m)
0
0
0
26.77
12.84
20.3
0
26.84
11.7
3.87
16.02
6.14
8.53
17.66
7.51
29.44
19.58
25.63
14.5
ISO
FA2
(m)
FA3
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA3
(m)
238.85
231.8
FA4
TVD
(m)
1.6
2.2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA5
(m)
0
0
0
9
8
6
7
11
8.5
5
ISO
F6
(m)
174
02
02
02
02
03
03
03
03
10
13
15
16
01
03
05
06
01
02
01
07
08
08
01
06
02
36
15
06
36
07
02
36
05
02
35
16
05
35
15
03
35
14
01
35
13
16
35
07
01
35
05
15
35
04
01
35
01
13
34
15
01
095
34
14
11
095
34
13
Twp
34
11
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
Sec
LSD
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
547.7
533.7
553.41
547.84
556.1
544.6
543.06
543.66
563
560.67
571.17
557.3
551
548.1
545.3
545
552.3
534.1
536.14
553.1
546.6
561.28
548.1
549.77
540.77
542.25
543.27
563
559.65
566.67
568.1
547.67
KB (m)
196
164
175
195
177
177.2
222.5
196
186.5
200
191.5
180.5
179
176
175.7
186
171
170
171
193
180.5
185
223
181
221
192.5
203.5
183
Dina
TVD
(m)
11.16
15.5
18.5
0
8
19
11.3
0
13.5
13.5
18
14
27
28.36
27.75
29
16.3
26
6.5
0
35
7
13.5
21
26
0
0
17
0
0
22.5
15.5
32.5
Dina
iso
(m)
207.16
179.5
193.5
203
196
188.5
222.5
209.5
200
218
205.5
207.5
206.75
205
192
212
177.5
186.5
205
178
206.5
201.5
211
223
185
198
244
237
215
219
215.5
SCU
TVD
(m)
179.5
193.5
222.5
218
207.5
206.75
205
205
223
215
215.5
DEV
TVD
(m)
224.8
194.9
227.4
208.9
217.71
211
207.1
237.3
224.1
214.1
232.9
219
222.1
222.2
221.1
217
222
195.3
196.5
212.7
194.5
221.8
212
221.05
233.2
218.1
218.7
251.5
245.6
224
232
224.1
TD
TVD
(m)
193.8
204
198
193.6
FA1
TVD
(m)
0
0
13.05
4
8
0
0
0
0
0
0
0
18.35
ISO
FA1
(m)
182.73
187.14
182.35
177.09
175.7
186.45
FA2
TVD
(m)
0
0
11.1
19
13.15
17.86
16.2
0
10.55
0
0
0
0
ISO
FA2
(m)
208
195.5
194.95
191.9
197
FA3
TVD
(m)
0
0
0
8.5
2.5
11.81
9.7
0
0
0
0
0
14
0
0
0
0
ISO
FA3
(m)
FA4
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
0
0
0
0
ISO
FA5
(m)
0
0
0
0
0
0
0
ISO
F6
(m)
175
Sec
03
03
03
03
03
04
04
04
04
04
04
07
09
09
09
09
10
10
10
10
10
11
11
11
11
11
11
11
11
12
12
12
12
12
LSD
07
08
11
12
16
06
07
08
09
10
14
06
06
08
15
16
06
09
10
13
16
02
05
07
09
10
13
14
15
03
04
05
08
09
Twp
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
560.34
551.5
549.27
549.86
547.2
544.3
547.6
546.48
539.6
539.6
530.62
544.1
557.62
553.62
552.36
557.9
558.66
529.65
552.4
532.9
530.07
535.3
555.35
549.33
544.9
543.3
536.54
557.04
548.9
KB (m)
184.5
188
188
180.5
181
169.5
202.5
173.5
188
170.5
187
179.5
186
170
176
156.5
158
165
186
175.5
175
169.7
187.5
193
173.5
Dina
TVD
(m)
0
9.5
26.5
26
28.5
13.5
0
0
0
23.25
13.5
15.5
4
0
10.5
0
10
18.5
12.5
10.46
0
3.5
16.5
13.5
10
18
19
13.5
22.8
7.5
14.48
8.5
21.5
Dina
iso
(m)
198
194
214.5
214
209
194.5
219
192.75
216
189
192
181
198
197
198
198.5
204
173.5
173
171.5
175
204
194.5
188.5
192.5
195
201.5
195
SCU
TVD
(m)
198
214
209
192.75
181
197
171.5
194.5
195
195
DEV
TVD
(m)
206.15
208.1
229
223.9
212
210.1
223
207.89
225.7
205
204
196.9
210.1
213.2
213.1
215
218.5
189.1
196
186.5
187
189.3
216.5
209.8
204.5
206.9
210.1
217.5
210.8
TD
TVD
(m)
191.7
198.26
FA1
TVD
(m)
12.6
10.56
0
0
0
0
0
0
0
0
ISO
FA1
(m)
185.05
182.85
184.37
178.6
FA2
TVD
(m)
16.63
13.46
0
0
0
0
0
0
9.52
9.7
ISO
FA2
(m)
FA3
TVD
(m)
0
0
0
0
0
0
0
0
0
0
ISO
FA3
(m)
FA4
TVD
(m)
0
0
0
0
0
0
0
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
0
0
0
0
0
0
0
ISO
FA5
(m)
1
0
0
0
0
ISO
F6
(m)
176
Sec
12
12
12
12
13
13
13
14
16
21
21
22
22
23
24
33
33
LSD
11
12
14
15
03
05
15
03
10
01
15
02
06
11
11
08
15
Twp
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Rg
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
M
522.8
506.75
543.7
533.77
533.5
553.6
531
553.85
530.4
538.2
554.1
576.25
560.6
544.51
543.87
537.24
544.9
KB (m)
160
146.5
175.7
192
165.7
176
220
195
176
173
171.5
181
Dina
TVD
(m)
13
6.3
0
0
0.14
2.5
0
7.3
18
0
11
17.8
12.5
29
26.5
21
Dina
iso
(m)
173
152.8
189.8
173
175.84
194.5
171.5
214
173
194
194
231
212.8
188.5
202
198
202
SCU
TVD
(m)
171.5
188.5
202
198
DEV
TVD
(m)
195.3
168.3
194.1
203.7
186.7
209.2
187.6
221
186.2
208.8
207.3
239.7
226
202.7
215.5
204
217
TD
TVD
(m)
192
176.84
FA1
TVD
(m)
0
2.5
11.66
ISO
FA1
(m)
FA2
TVD
(m)
0
0
0
ISO
FA2
(m)
FA3
TVD
(m)
0
0
0
ISO
FA3
(m)
FA4
TVD
(m)
0
0
0
ISO
FA4
(m)
FA5
TVD
(m)
0
0
0
ISO
FA5
(m)
0
0
0
ISO
F6
(m)
APPENDIX II
BITUMEN SATURATION CALCULATIONS
177
LSD
Sec
Twp
Rg
M
13
09
15
07
09
13
15
05
05
01
05
09
13
15
05
13
15
07
13
15
05
07
15
05
07
13
15
15
01
05
07
09
13
15
13
13
13
13
15
13
15
01
05
07
13
02
04
07
09
09
09
10
11
15
16
16
16
16
16
17
17
17
18
18
18
19
19
19
20
20
20
20
20
21
21
21
21
21
21
22
23
25
26
26
27
27
28
28
28
28
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
555.03
549.36
541.09
536.98
556.75
559.28
542.92
572.61
558.89
552.69
555.66
556.1
564.71
562.2
551.32
557.54
544.9
540.84
532.43
546.5
565.3
543.85
Ground Elev
(m)
553.49
547.73
539.44
535.36
555.16
557.59
541.26
570.92
557.29
551.04
554.09
554.50
563.05
560.60
549.72
555.90
543.30
539.24
530.80
545
563.7
542.30
534.6
556.54
539.6
555
538
558.4
556.6
556.19
562.87
545.4
551.2
531.39
534.6
537.13
540.26
531.6
557
555
554.59
561.27
543.8
549.7
529.79
533.05
535.63
538.7
530
540.51
538.9
538.6
537
178
Net
pay
iso(m)
4.61
7.27
5.39
2.72
0
0
0
0
0
Lean/H2O
iso (m)
2.5
8.5
5.5
0
0
0
0
0
0
0
9
0
4
0
5.5
14
8.11
0
5.89
0
9.23
3.31
0
0
8.5
10.75
0
0
0
8.5
5
19
8.2
15
0
0
0
0
3.5
0
0
13.5
0
8.5
Avg
Sat%(h2o)
Avg sat
%
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
11.4
0
13.2
11
17
16
11
17
16
LSD
Sec
Twp
Rg
M
15
05
07
15
05
07
13
15
05
07
13
15
05
07
05
05
13
15
03
05
06
07
11
14
15
08
13
15
06
08
13
15
14
10
15
05
07
13
15
13
15
13
04
02
04
28
29
29
29
30
30
30
30
31
31
31
31
32
32
04
05
05
05
06
06
06
06
06
06
06
07
07
07
08
08
08
08
09
15
18
19
19
19
19
20
20
21
22
27
27
094
094
094
094
094
094
094
094
094
094
094
094
094
094
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
Ground Elev
(m)
Net
pay
iso(m)
536.56
535
544.06
539.6
567.8
562.7
554.5
562.3
559.47
573.1
537.25
556.9
547.6
535.72
543.5
541.14
570.3
563.38
542.44
538
566.2
561.20
552.90
560.7
557.80
571.60
535.75
555.3
546
534.14
542.00
539.60
568.80
561.88
552.6
551.00
561
564.20
10.01
15.29
9.88
8.79
14.57
7.31
0
526.61
535.7
544.65
541.556
548.1
560.25
551.70
536.75
544.65
552.00
553.13
552.13
525
525.11
534.10
543
539.956
549.69
546.6
540.294
540.42
548.6
533.2
559.7
536.23
548
545
538.704
538.891
547.00
531.60
558.10
534.6
2.76
0
0
0
1.03
6.37
1.99
11.71
565.74
561.75
553.2
538.25
546.21
553.5
554.78
553.75
179
13.4
10.89
14.83
16.14
12.49
5.1
8.96
0.93
0
1.56
9.75
3.1
4.39
2.58
0
7.25
4.02
0.3
0
0
Lean/H2O
iso (m)
5.5
0
18
7
3.1
3.11
7.17
14.86
1.51
5.9
0.08
11
5.5
0
11.44
1.25
1.4
0
12.99
Avg
Sat%(h2o)
15.8
10.89
10
14.35
16.05
14.52
12.39
14.37
15.8
12.15
14.3
14.35
16.05
14.52
12.39
3.4
14.43
8.3
14.86
10.37
11.4
13.97
12.85
5.92
0
4.43
0.29
0
0
4.11
8.92
0
4.98
5.2
0
0
0
14.74
0
0
0
11.47
1.13
3.01
3.79
Avg sat
%
8.9
13.94
12.9
11.84
0
0
13.95
6.2
0
13.3
4.86
12.32
5.9
7.28
3.3
15.1
10.2
14.7
5.57
15.95
12.9
10.88
0
0
15.4
LSD
Sec
Twp
Rg
M
01
02
03
04
03
03
14
13
15
12
15
13
15
06
11
13
14
15
13
14
15
16
05
06
07
08
12
14
15
16
04
05
06
07
12
13
14
15
05
07
13
15
05
07
13
28
28
28
28
36
36
09
13
13
14
14
15
15
16
16
16
16
16
17
17
17
17
20
20
20
20
20
20
20
20
21
21
21
21
21
21
21
21
22
22
22
22
23
23
23
095
095
095
095
095
095
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
24
24
24
24
24
24
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
525.68
537.6
544.6
552.9
556.8
556.5
536.8
544.1
552.4
536.7
530.49
529.6
544.95
541.9
549.5
531.75
533.3
536.6
557.1
568.82
574.5
572.6
540
540.68
563.4
537
544.47
545
537.5
532.95
559.46
558.6
563.2
562.8
545.15
533.9
565.87
534.7
548.88
565.25
Ground Elev
(m)
524
530
543
534
536.00
536
543.10
551.40
555.30
555.00
535.30
542.60
550.90
535.10
528.9
528.10
543.3
540.40
548.00
530.25
531.80
535
555.60
567.2
572.90
571
538.50
539
561.60
535.5
542.77
543.40
536
531.25
557.80
557.00
561.6
561.30
543.5
532.25
564.15
0
533.1
547.25
563.75
180
Net
pay
iso(m)
10.16
5.24
2.22
0
0
0
4.4
12.06
0
0
8.11
0.96
0
16.73
0
0
18
10.01
0.37
13.9
15.69
10.82
17.95
9.27
10.92
5.5
13.27
8.52
5.47
7.77
14.62
7.25
4.16
7.37
8.44
0
7.2
0
0
0
0
0
0
Lean/H2O
iso (m)
3.34
0
6.3
0
23.5
6.1
0.44
15.5
11
0
16.89
5.54
26.25
33.27
5.5
21
6
11.13
22.1
3.31
18.43
19.05
26.23
1.08
0.75
7.73
24.98
37.53
22.73
25.88
24.75
36.84
32.63
24.06
0
10.3
0
0
0
11
14
0
Avg
Sat%(h2o)
Avg sat
%
12.01
5.4
3.9
0.86
9.5
13.2
12.8
0
6.37
3.4
0.64
4.93
0
10.4
11.5
13.2
13.34
11.34
7
4.59
9.5
13.35
12.8
3.65
0
8.47
8.1
1.8
8.87
0
6.6
11.5
6.8
8.1
5.2
10.6
11.5
15.14
8.5
11.5
6.8
8.1
7.8
10
8
4.6
3.7
5.31
8.1
4
3.7
3.81
3.1
10
10.7
6.3
11.6
6.33
9.5
12.3
7.1
9.58
8.8
6
0
0
0
0
0
0
10
0
0
0
0
0
0
LSD
Sec
Twp
Rg
M
15
05
07
13
15
07
13
15
05
07
13
15
05
07
13
14
15
03
05
07
09
10
13
14
15
16
03
04
05
06
07
08
09
11
12
13
14
15
16
05
06
07
08
13
14
23
24
24
24
24
25
25
25
26
26
26
26
27
27
27
27
27
28
28
28
28
28
28
28
28
28
29
29
29
29
29
29
29
29
29
29
29
29
29
32
32
32
32
32
32
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
550.29
553.53
559.1
565.75
Ground Elev
(m)
548.7
552
557.60
564.10
553.1
0
551
543.27
539.9
534.30
544.5
541.77
568.6
567.10
570.2
566.62
565.7
551.62
560.5
557.85
558.6
560.71
553.6
549.9
574.2
579.86
546.98
547.61
568.93
562.07
564.2
562.65
551.7
562.1
568.50
565.00
564.00
550.00
559.00
556.35
557.00
559.00
552.10
548.20
560
534.68
569.90
567.6
572.60
578.3
545.35
546
567.2
560.57
562.6
561.00
550.10
560.60
535.9
558.56
537.72
560.46
534.30
556.9
536.22
558.80
535.8
536.18
571.46
181
Net
pay
iso(m)
0
5.83
0
0.32
6.61
0
0
0
0
12.91
11.84
6.39
1.39
2.15
2.6
11.69
0.71
0
0.52
14.01
0.88
4.78
9.66
13.04
5.13
9.45
14.63
6.53
20.44
9.06
5.58
12.52
6.32
11.59
7.07
9.42
4.2
13.2
7.76
0
14.64
Lean/H2O
iso (m)
0
15.67
0
0
0
0
0
0.2
6.66
Avg
Sat%(h2o)
Avg sat
%
6.7
0
2.7
12
0.1
0
8.4
0
12
12
0.2
0
1.3
12
6.6
4.61
6.88
21.4
2.76
7.64
9.29
1.9
13
13.1
13.4
8.86
13.8
3.73
10.34
9.29
0.82
11.65
4.97
13.19
10.55
7.2
6.2
6
7.35
10.52
12.16
8.39
13.41
10.78
7.8
7
7.1
7.38
9.78
8.2
8.3
11.83
10
11.09
8.04
11.33
11.69
8.4
8.57
10.4
16.1
8.59
11.78
11.81
9.6
9.47
11.1
16.1
10.38
3.5
0
11.6
10.58
4.9
0
16.3
7.79
0
38.48
15.99
26.12
9.22
17.34
25.96
24.37
24.55
24
15.47
13.44
23.3
37
8.92
5.98
4.68
4.66
8.43
11.34
0.8
0
5.3
21.74
0
2.86
LSD
Sec
Twp
Rg
M
15
16
05
06
06
07
08
09
13
14
15
16
05
06
11
13
14
15
01
04
05
07
13
14
15
16
05
07
13
15
01
06
07
08
09
11
13
15
16
03
05
06
08
10
13
32
32
33
33
33
33
33
33
33
33
33
33
34
34
34
34
34
34
35
35
35
35
35
35
35
35
36
36
36
36
01
01
01
01
01
01
01
01
01
02
02
02
02
02
02
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
094
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
556.8
564.9
532.42
546.3
548.8
572
568.5
Ground Elev
(m)
555.20
566.50
530.90
544.70
544.7
547.30
Net
pay
iso(m)
18.02
10.38
18.58
10.89
17.04
17.58
534.1
570.5
567.00
576.5
546.00
564.40
576.20
578.62
546
566.60
565
558.20
561.30
541.67
540.75
539.2
548.20
546.50
559.70
545.00
551.5
534.50
539.4
532.70
552.3
545
545.3
550.80
543.30
543.7
11.26
14.98
16.91
548.1
546.50
551
557.3
571.17
560.67
563
543.66
543.06
544.6
549.3
555.70
569.5
559.00
561.40
542
542.00
543.00
21.34
22.53
23.47
11.7
547.5
566.1
577.75
580.27
547.67
568.1
566.67
559.65
563
543.27
542.25
540.77
549.77
548.1
561.28
546.6
553.1
536.14
182
13.43
6.24
17.59
11.04
9.67
17.04
11.52
10.29
14.05
0
0
7.32
0
0
13.45
15.6
8.41
6.02
19.96
0
4.91
7.82
10.88
0
8.76
11.87
Lean/H2O
iso (m)
2.48
11.12
15.42
22.11
0
18.46
28.5
17.57
1.41
1.46
15.33
20.98
5.21
8.45
0
0
9.68
0
0
12.55
5.4
5.09
0.98
15.04
0
0
1.59
0
14.74
1.32
12.09
0
6.41
5.83
3.53
2.3
18
5.68
2.62
0
2.54
7.13
Avg
Sat%(h2o)
Avg sat
%
11.39
6.4
11.58
11.57
8.4
11.76
10.28
11.66
11.09
12.99
9.39
10.9
12.54
9.4
7.45
8.74
10.19
11.5
12.54
9.7
8.67
8.8
12.23
10.4
0
0.02
8.31
0
12.23
10.4
0
0.02
8.69
0
6.57
9.3
13.03
15.49
11.55
0
12.35
11.2
14.51
15.49
12.95
0
11.53
11.76
8.3
14.7
11.3
11.4
15.4
14.5
13.14
11.34
13.29
12.82
15.73
15.42
15.42
11.75
0
12.81
6.42
13.08
15.02
0
13.78
15.17
LSD
Sec
Twp
Rg
M
15
16
01
03
05
06
07
08
11
12
15
16
06
07
08
09
10
14
06
06
08
15
16
06
09
10
13
15
16
02
05
07
09
10
13
14
15
16
01
02
03
04
05
08
09
02
02
03
03
03
03
03
03
03
03
03
03
04
04
04
04
04
04
07
09
09
09
09
10
10
10
10
10
10
11
11
11
11
11
11
11
11
11
12
12
12
12
12
12
12
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
Ground Elev
(m)
556.1
554.50
547.84
553.41
533.7
547.7
548.9
557.04
546.34
551.76
532
546.20
547.25
555.44
536.54
535
542
541.70
543.40
547.8
553.62
533.80
528.38
531.40
550.90
528.00
557.10
543.3
544.9
549.33
555.35
535.3
530.07
532.9
552.4
529.65
558.66
557.9
552.36
553.62
557.62
544.1
530.62
539.6
539.6
546.48
547.6
544.3
547.2
549.86
549.27
551.5
560.34
556.40
550.90
552
556.00
542.4
542.5
540
529.00
538.00
538.00
544.8
546.00
545.5
542.80
540
545.60
548.16
547.67
549.90
558.74
183
Net
pay
iso(m)
4.28
0
4.82
7.72
8.7
6.68
7.42
4.01
11.53
15.87
9.18
9.53
8.48
6.62
10.73
8.3
3.34
0
10.26
6.29
13.7
2.9
0
8.85
4.4
0
1.09
11.81
0
0
0
8.99
16.66
23.03
16.4
8.5
Lean/H2O
iso (m)
3.72
0
18.5
0
10.68
3.44
12.8
1.82
7.06
3.49
Avg
Sat%(h2o)
11.39
12.85
14.4
8.5
11.56
6.93
4.32
9.47
9.52
3.38
2.77
8.2
0.16
0
0.2
6.21
4.8
7.1
0
1.65
0
2.91
3.69
13.5
23.25
0
0
0
4.51
0
0
5.47
9.6
26.5
1
0
15.28
14
14.07
0
14.7
14.69
Avg sat
%
11.57
12.28
13.12
12.19
14.7
9.9
12.98
11.73
14.06
16.25
15.65
14
16.03
16.28
16.17
10.76
0
15.5
17
0
4.01
16.07
15.75
0
14.7
14.86
14.74
14.54
0
15.5
17
0
12.72
16.07
0
0
13.32
10.3
0
0
13.58
12.2
12.29
10.24
12.58
13.27
15.92
15.92
LSD
Sec
Twp
Rg
M
10
11
12
14
15
03
05
15
03
10
01
15
02
06
11
11
10
15
08
15
12
12
12
12
12
13
13
13
14
16
21
21
22
22
23
24
28
28
33
33
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
095
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
KB Elev
(m)
544.9
537.24
543.87
544.51
560.6
576.25
554.1
538.2
530.4
553.85
531
553.6
533.5
533.77
543.7
506.75
522.8
Ground Elev
(m)
543.30
535.6
542.2
542.9
559.00
573.75
552.60
536.60
528.90
552.35
529.50
552.10
532.00
532.20
542.20
523
518
505.25
521.30
184
Net
pay
iso(m)
16.9
11.51
9.34
5.45
0
19.47
2.97
0
0
1.85
0.14
0
0
0
5.08
5.64
0
Lean/H2O
iso (m)
0
4.1
26.5
29
0.99
8.46
5.55
0
Avg
Sat%(h2o)
Avg sat
%
15.52
14.85
0
4.33
0
0
0.65
15.52
15.01
15.12
13.63
0
15.28
13.51
12.57
0
0
0
7.3
0.66
13
0
13.1
14.14
0
APPENDIX III
PALYNOLGICAL REPORT
L. Bloom
Department of Geoscience
University of Calgary
185
Age of McMurray Formation
The Manville Group has been given a gross age of Early Cretaceous based on fauna and
floral evidence (Singh 1964). Early Cretaceous period occurred 99.6 to 145.5 million
years ago, spanning the Berriasian-Albian stages. Most of the palynomorphs encountered
in this study are long ranging and non age-diagnostic, but several indicate a Lower
Cretaceous age most notably, Cicatricosisporites, Appendicisporites and Trilobosporites
(Burden and Hills 1989).
The McMurray Formation is interpreted as being primarily early to late Aptian in age
(Demchuk et. al. 2007). Although the lowermost limit for the palynoflora in this study
might be as old as Barremian.
Singh (1964) divided the Mannville Group into three formational units. He considered
the lower boundary for the Ellersllie Member was at the Barremian-Aptian boundary
therefore, making the basal beds of the Deville Member Late Barremian. Singh (1964) as
well dated the marine Upper Mannville (Clearwater and Grand Rapids Formation) as
mid-Albian.
Vagvolgyi and Hills (1969, p.155) stated that “the microfauna obtained from the Upper
Member of the McMurray Formation are very similar to those found in the basal
Clearwater Formation. The latter strata have been dated as Middle Albian on the basis of
the ammonites Subarcthoplites and Beudanticeras.”
However, Demchuk et. al. (2007) stated “the top of the McMurray Formation can be no
younger than earliest Albian based on the presence of earliest Albian dinoflagellates in
the overlying Wabiskaw Formation.
Depositional Environment
The samples studied displayed a strong recovery of terrestrial palynomorphs, mainly
gymnosperm pollen (bisaccates) and trilete spores many of which are probably from
pteridophytes (ferns). This domination of terrestrial driven forms suggests that the
paleoenvironments were fluvially dominated perhaps draining a heterogeneous habitat.
However, the presence of marine dinoflagellates and scoledonts also occurred on
deposition suggesting at least some marine influence existed on the strata of the
186
McMurray Formation. The dinoflagellates in this study are very thin walled, poorly
preserved and very difficult to identify.
References
Burden, E.T., and Hills L.V.
1989 Illustrated Key to Genera of Lower Cretaceous Terrestrial Palynomorphs
(Excluding Megaspores) of Western Canada. American Association of Stratigraphic
Palynologists Contribution Series Number 21
Demchuk, D.T., Dolby, G., McIntyre, D.J.,and Suter J.R.
2007 The Utility of Palynofloral Assemblages for the Interpretation of Depositional
Paleoenvironments and Sequence Stratigraphic System Tracts in the McMurray
Formation at Surmont, Alberta, p.1-5.
Singh, C.
1964 Microflora of the Lower Cretaceous Mannville Group, East-Central Alberta.
Alberta Research Council, Bulletin, 15: 238 pgs.
Vagvolgyi, A., and Hills, L.V.
1969 Microflora of the Lower Cretaceous McMurray Formation, Northeast Alberta.
Bulletin of Canadian Pet. Geol., Vol. 17, No. 2. P. 154-181
187

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HOCKEY OpEN HOUSE

Geological models, heterogeneities and scale relations

“Holiday Home Tour”

May 2013 www .limestonefederal.com

UE-1 Upgrader Expansion Project