Blocks offered in Sri Lanka`s Second Licensing

Blocks offered in Sri Lanka’s Second Licensing Round
Sri Lankan Main Basins
Cauvery
Basin
Cauvery Deep Water
sub-basin
Mannar
Basin
2
Structural Framework – Sri Lanka Basins
•
Cauvery & Mannar Basins were
initiated as rifted basins in
Gondwanaland, producing NE –
SW structural grain
• Two thermal events have
controlled basin development &
burial history:
• Gondwana breakup & start
of sea floor spreading (~99
My)
• Breakup of India &
Madagascar & sea floor
spreading from Central
Indian Ridge (~64 My)
• Seismic data confirms that NE-SW
structural grain extends into
Mannar Basin
• Up to 5500 m of Upper Jurassic to
Recent sedimentary section,
possibly underlain by Triassic
(Karoo) Coal Measures , providing
gas source potential
•
Mannar Basin has Late
Cretaceous to Tertiary objectives,
with deeper potential in Late
Jurassic – Early Cretaceous syn-rift
section.
Tectonostratigraphic Framework
(Cauvery & Mannar Basins)
4
•
Stratigraphic columns and tectonic
framework interpretations of Cauvery &
Mannar Basins
•
Note that the Tertiary section in Mannar
Basin is more complete than in Cauvery
Basin
•
Two episodes of basaltic extrusion in the
Mannar Basin during the Cretaceous
•
An early interpretation of Mannar Basin
suggested that Turonian igneous unit
(the BHF in Pearl 1) well represented
Cretaceous oceanic crust which was
overlain by Tertiary section
•
This interpretation led to Mannar Basin
being written off as non-prospective
•
Cairn Energy’s 2011 discoveries have
proved that there is a working petroleum
system in Mannar Basin and that it is
highly prospective
Cairn India’s View
prospect
prospect
prospect
prospect
prospect
prospect
5
Line SL01-1 through
Dorado North well
Available data in Cauvery Basin: Well data
• Six wells have been drilled in the Sri Lankan sector of
the Cauvery Basin, three onshore Mannar Island and
three offshore.
• Basic details of the wells are provided in the following
table:
Adam’s Bridge
archipelago
Well Name
Onshore
Terrain Latitude
Offshore
Longitude
Water
Depth
Meter
Water
Depth
Feet
Ground Ground
Elevation Elevation
Meter
Feet
Operator
Name
Spud
Date
Init Drill Well
End Date Status
Content
Td
Feet
Td
Meter
Pesalai 1
Onshore
Land
N 09`04'07.960" E 079`48'10.420"
9
29.5
Ceylon
07/02/74 ?/12/1974
Petroleum Corp
P&A
Pesalai 2
Onshore
Land
N 09`04'25.380" E 079`49'01.300"
2
6
Ceylon
27/04/75 16/08/75
Petroleum Corp
P&A
oil & gas
shows
8639
2633
Pesalai 3
Onshore
Land
N 09`05'03.790" E 079`48'29.900"
3
10
Ceylon
10/01/76 24/04/76
Petroleum Corp
P&A
dry
9571
2917
Palk Bay 1 Offshore
Shelf
N 09`19'03.840" E 079`43'21.540"
15
50
19/06/76 06/08/76
P&A
dry
7829
2386
08/08/76 09/09/76
P&A
dry
5855
1785
Citco Sri Lanka
20/11/81 21/12/81
Petroleum Corp
P&A
dry
6600
2012
Delft 1
Offshore
Shelf
N 09`40'01.236" E 079`33'27.216"
13
43
Pedro 1
Offshore
Shelf
N 09`53'05.360" E 079`36'25.910"
13
43
•
Well summaries for all wells are
7 available in the data room..
Marathon
Petroleum
Marathon
Petroleum
gas shows 8507
2593
Seismic Data in Mannar Basin
2350 km2 3D in
Block SL2007-01-001.
All seismic
Mannar Basin only
15471
2350
3056
6321.02 km
2D
2
2350 km
3D
2673
NB. Old Block 11 included Palk Straight (Cauvery Basin) and the
northern part of Mannar Basin. Data acquired in Block 11 have not
been included, so that total seismic in the Mannar Basin may be
greater than shown.
8
Well data in Mannar Basin: Pearl 1
Pearl-1 was the only well drilled in the Sri Lankan sector of the Mannar Basin prior to Cairn’s wells in Block SL2007-01-001 (in 2011-12)
• Pearl 1 was drilled by Cities Service in 1981 to test a Late Cretaceous structural
(fault) trap. Tertiary drape provided a secondary objective
•
The well penetrated thick Late Cretaceous sandstones (between 2,194.6 m &
2886.5 m) and a ‘Basal Cretaceous sandstone’ (between 2926 m & 2937.5 m)
• There were no shows in either sandstone
•
The well TD’d in what was described as igneous (olivine diabase) rocks which was
interpreted as basement
• Similar rocks were encountered in Mannar-1, -1A, located 68 km to NW, in the
Indian sector of Mannar Basin, leading to the misconception that Mannar Basin
was underlain by oceanic crust
•
Pearl 1 failed to test the syn-rift section now interpreted to lie below the well TD
• Cities cited ‘lack of charge’ as reason for failure but NewSouth Global suggest
that lack of top seal or fault breaching are more likely causes of failure.
? Fault cut
9
Ceylon Basin: Location, seismic & well data
• Ceylon Basin is located to south & south-west of Sri Lanka
• No wells have been drilled in the Ceylon Basin
• There are no interpretation reports available for the Ceylon Basin
• There are very few seismic lines available in the Ceylon Basin; the only
data were acquired in 1976, as part of Western’s Circum Island spec
survey
• Western’s Line 17, a NW – SE line off the southern coast of Sri Lanka, is
illustrated (as reprocessed by CGL in 2012).
Western
Geophysical’s
Circum Island spec
survey, 1976
10
Data Pack Contents
•
•
•
•
•
Block Summary Sheets
Interpretation Reports
Expanded Basin Descriptions
Gravity Maps
Well Reports for:
• Delft
• Palk Bay
• Pearl 1
• Pedro
• Pasalai 1
• Pasalai 2
• Pasalai 3