Module 1 - Hydrocarbon Industry Overview
Transcription
Module 1 - Hydrocarbon Industry Overview
OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org OIL AND GAS OPERATIONS MODULE 1 HYDROCARBON INDUSTRY OVERVIEW 1 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org TABLE OF CONTENTS 1. Module Objectives 4 2. The Origins of Crude Oil and Natural Gas 5 3. Oil Traps 7 4. Searching For Formations That Might Contain Hydrocarbons 9 5. Drilling For Oil and Gas 10 6. The Hoisting Equipment 10 7. The Rotating Equipment 10 8. The Circulating Equipment 10 9. Types of Drilling Rigs 11 10. Down Hole Tubulars 11 11. Surface Casing 12 12. Intermediate Casing 12 13. Production Casing 13 14. Production Tubing 14 15. The Wellhead 15 16. Surface Casing Head 16 17. Intermediate Casing Head 16 18. Production Casing Head 16 19. Production Tubing Head 16 20. Christmas Tree 17 21. Directional Drilling 18 22. Horizontal Drilling 18 23. Crude Oil Recovery 19 24. Reservoir Pressure Maintenance 20 25. Well Stimulation 21 26. Acid Stimulation 21 27. Hydraulic Fracturing 21 28. Movement of Crude Oil to Processing Plants 22 29. Oil Production Degassing Plants 23 30. Production Degassing Separator 23 31. Gas Processing 24 32. Refining of Crude Oil 25 33. Petroleum Products 28 2 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org TABLE OF FIGURES Figure 1 - Precambrian Period .................................................................................... 5 Figure 2 - Physics of Typical Oil Bearing Rock ........................................................... 6 Figure 3 - Typical Anticline Trap ................................................................................. 7 Figure 4 - Fault Trap ................................................................................................... 8 Figure 5 - Statigraphic Trap ........................................................................................ 8 Figure 6 - Types of Traps ............................................................................................ 8 Figure 7 - Seismic Survey ........................................................................................... 9 Figure 8 - Different Types of Drilling Rigs ................................................................. 11 Figure 9 - Surface Casing ......................................................................................... 12 Figure 10 - Production Casing .................................................................................. 13 Figure 11 - Casing, Tubing and Production Packer .................................................. 14 Figure 12 - Stages of Shaped Charge Perforations .................................................. 15 Figure 13 - Single String Wellhead and Xmas Tree .................................................. 17 Figure 14 - Typical Onshore Wellhead and Xmas Tree ............................................ 18 Figure 15 - Combination of Gas Cap and Water Drive ............................................. 19 Figure 16 - Water Injection ........................................................................................ 20 Figure 17 - Propogation of Acid Stimulation .............................................................. 21 Figure 18 - Simplified Production Flow ..................................................................... 22 Figure 19 - Production Inlet Manifold ........................................................................ 22 Figure 20 - Distribution of Various Oil and Gas Deposits and Associated Wells ...... 23 Figure 21 - Horizontal Production 2 Phase Separator .............................................. 24 Figure 22 - Typical Onshore Crude Oil Refinery ....................................................... 25 Figure 23 - Distribution of Light End Hydrocarbons .................................................. 26 Figure 24 - Simplified Crude Fractionating Tower ..................................................... 27 Figure 25 - Refinery Petroleum Products .................................................................. 28 3 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 1. MODULE OBJECTIVES Any process operator should have a general knowledge and understanding of how companies operate their hydrocarbon industry. This module will teach you the following: • How crude oil and natural gas were formed • How underground locations for oil and gas are found. • How we drill into those underground formations. • How we bring the oil and gas to the surface. • How the crude oil and gas move from the well head to different processing plants. • What happens to the crude oil and gas in the processing plants. • This unit is your introduction to the orgins of oil and gas and is generic in its approach. Detailed modules will follow taking you from reservoir to point of delivery. • To achieve the module certificate you must complete the online course and pass the final test with 80% or more. • Take the online course and gain your certificate of achievement here: http://oilguru.org/oil-guru-academy/ 4 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 2. THE ORIGINS OF CRUDE OIL AND NATURAL GAS Millions of years ago many plants and animals died and became deposited in various locations, predominately in the sea. The remains of these plants and animals built up upon each other together with dust, sand and debris. This dust and sand covered the remains of the plants and animals. (See Figure 1). Figure 1 - Precambrian Period This process continued for many, many, years. The weight of the thick layers of dust and sand increased with time and squeezed the remains of the plants and animals. The pressure changed the remains of the plants and animals to hydrocarbons. (Oil and Gas) The pressure also changed the dust and sand to rock. Solids that fall to the bottom of a liquid are called sediments so the rock that formed from the dust and sand is called sedimentary rock. Because sedimentary rock was formed under the sea all the gaps and holes in the rock are filled with water. These gaps and holes in the sedimentary rock are called “pores” so sedimentary rock is “porous” rock. Porosity means how many gaps and holes the rock contains. 5 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org There is sometimes a mixture of salt water and hydrocarbons in the pores of the sedimentary rock. The hydrocarbons are lighter than water (oil floats on top of water) so the hydrocarbons will try to rise up through the water. If the pores in the rock are joined together the rock is permeable and the hydrocarbons can move through it. The ability of a rock to let liquids move through it is called “permeability”. A rock that is porous and permeable will let liquids pass through it. (See Figure 2). Figure 2 - Physics of Typical Oil Bearing Rock Hydrocarbons in sedimentary rock move upwards through the rock until they are above the water. They can rise all the way to the surface where they can be lost into the air or form lakes of heavy hydrocarbons. 6 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 3. OIL TRAPS In may situations hydrocarbons formed in sedimentary rock can not rise all the way to the surface if there is something to stop them. They are trapped. If the porous sedimentary rock is covered by a non porous rock the hydrocarbons stop moving when they meet the non-porous rock. This is because non-porous rock is “impermeable”, which means fluid cannot pass through it. (See Figure 3). Because the impermeable rock is on top of the trap it is called a “cap rock”. Figure 3 - Typical Anticline Trap There are many different types of oil traps. The type depends on how the trap was formed. Anticline traps are formed by the movement of the earth’s crust. 7 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org The other types of traps found are fault traps and stratigraphic traps. (See Figures 4 and 5). Figure 4 - Fault Trap Figure 5 - Statigraphic Trap Figure 6 - Types of Traps The sedimentary rock where the hydrocarbons have been trapped is called the “reservoir rock”. The trap itself is also called a “formation”. The trap is formed by the shape of different rocks. 8 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 4. SEARCHING FOR FORMATIONS THAT MIGHT CONTAIN HYDROCARBONS We cannot see under the ground. We cannot know if there are oil traps 4 to 5 kilometres below the surface of the earth. We have to use scientific methods in our search for oil and gas formations. The main method used is the “seismic survey”. In simple terms, vibrations are made at the surface of the earth. This is done with a number of explosions or a heavy vibrator on a truck. The vibrations travel down through the layers of rock under the ground. Some of the vibrations bounce off the layers of rock and others continue through the layers of rock. We are able to measure the speed and strength of the vibrations as they return to the surface. Computers take all these measurements and draw a picture of the shape of the rocks under the ground. When we know the shape of the rocks we can see if there are any formations that might be oil traps. (See Figure 7). Figure 7 - Seismic Survey 9 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 5. DRILLING FOR OIL AND GAS When the survey team find a place where they think there might be oil they have to drill a hole down into that formation. The method for drilling holes is called “Rotary Drilling”. The drilling rig equipment is powered by diesel electric. This means that very large diesel engines turn electric generators to produce direct electric current. The direct current is then used to power pumps, hoists, compressors and other equipment. The mechanical equipment used on a rotary drilling rig is grouped into three areas. • The hoisting equipment • The rotating equipment • The circulating equipment 6. THE HOISTING EQUIPMENT The hoisting equipment lifts the drilling column in and out of the hole. 7. THE ROTATING EQUIPMENT The rotating equipment turns the drilling column so that the drill bit can make a hole. 8. THE CIRCULATING EQUIPMENT The circulating equipment pumps liquid down the hollow drilling column. It comes back up to the surface through the space between the drilling column and the walls of the hole which is called the annulus. The main job of this liquid is to remove the small pieces of broken rock made by the drill bit. It also lubricates and cools the drill bit and drill pipe. It prevents blow outs and supports the walls of the hole. A blow out is when the well flows out of control. 10 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 9. TYPES OF DRILLING RIGS Different types of drilling rigs are used for different areas (see figure 8). Even though the drilling rigs are different they all operate the same way. Figure 8 - Different Types of Drilling Rigs 10. DOWN HOLE TUBULARS Different sizes of steel pipe are installed in the well as it is drilled deeper. The hole is wide at the surface, 75cm and narrow when it reaches the depth were the oil is, 24cm, or 18cm. 11 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 11. SURFACE CASING The earth has soft sandy and sticky layers near to the surface. There is also good fresh water near the surface. A large size hole is drilled through these layers and a large steel pipe is inserted. This steel pipe is called “casing”. Because it is at the surface of the well it is called surface casing. This surface casing is cemented in place. It seals off the water zones and supports the walls of the hole. (See Figure 9). Figure 9 - Surface Casing 12. INTERMEDIATE CASING As the well is drilled deeper and deeper into the ground problems can occur. These problems could make it difficult to continue to drill. A second string of casing is then put into the well and cemented in place. This casing string is called intermediate casing. (Intermediate means between two points). There can be more than one intermediate casing. 12 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 13. PRODUCTION CASING The well is drilled down through the formation that contains the oil. Then the final casing string is put into the well and cemented in place. This string of casing is called production casing. The production casing goes all the way to the surface (see fig. 10). If the production casing does not go all the way to the surface, which can happen due to high cost, it is called a production liner. Figure 10 - Production Casing 13 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 14. PRODUCTION TUBING This the final string of steel pipe put into the well. It is NOT cemented in place. The bottom of the production tubing is held in place and sealed inside the production casing by a device called a packer. The top of the production tubing is hung and sealed at the surface. All gas and oil produced from the well flows up the inside of the production tubing. When the production tubing gets old and worn it can be pulled out of the well and replaced. That is why it is not cemented in place (see fig. 11). Figure 11 - Casing, Tubing and Production Packer a Typical Single String Well Completion Recall that the production casing is cemented in the well through the formation that contains the oil. 14 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org There is no way for the oil or gas to enter the well through the sides of the bore. (The bore is the hole made by the drill). Holes have to be made through the production casing and through the cement into the oil bearing rocks. This is done by using special explosive charges. The process is called perforating and the holes are called perforations. (See Figure 12). Figure 12 - Stages of Shaped Charge Perforations 15. THE WELLHEAD The wellhead is the equipment at the top of the well. It is used to keep control of the well. It forms a seal to prevent well fluids blowing or leaking at the surface. How strong the well head is depends on how high the pressure is in the well. The wellhead is made up of casing and tubing heads, the christmas tree and pressure gauges. 15 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 16. SURFACE CASING HEAD This is attached to the surface casing which is the first and largest diameter casing put into the well. 17. INTERMEDIATE CASING HEAD This is attached to the casing that was run into the well to overcome problems when drilling. This casing covers formations that may cause blow outs or fall in and fill the hole. This casing head is put on top of the surface casing head. 18. PRODUCTION CASING HEAD This is attached to the production casing that goes all the way to the bottom of the well. This casing head is put on top of the intermediate casing head. 19. PRODUCTION TUBING HEAD The tubing head is attached to the production tubing. Because the production tubing is not cemented into the well the tubing head also supports the weight of the production tubing. 16 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 20. CHRISTMAS TREE This is the collection of valves that goes on the top of the well head. The well is controlled at the surface, and serviced by using these valves. Figure 13 - Single String Wellhead and Xmas Tree 17 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org Figure 14 - Typical Onshore Wellhead and Xmas Tree 21. DIRECTIONAL DRILLING Normally wells are drilled straight down vertically. Sometimes it is necessary or better to drill at an angle, especially offshore on a platform. Drilling at an angle is called directional drilling. Some offshore reservoirs need many wells. With directional drilling more than one well can be drilled from offshore platforms and towers. 22. HORIZONTAL DRILLING This is a relatively new technique which some companies use a lot. Some oil producing formations are not very thick and the rocks have low permeability. It is difficult for the crude oil to flow into the well bore. By drilling horizontally through the oil bearing formation much more rock is in contact with the well bore. Then it is easier for the oil to flow into the well bore. 18 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 23. CRUDE OIL RECOVERY The word “recovery” refers to the movement of crude oil from an underground reservoir, up a well, to the surface of the earth. Oil recovery depends on the principle that: A FLUID WILL MOVE FROM A PLACE WHERE PRESSURE IS HIGHER TO A PLACE WHERE PRESSURE IS LOWER. In oil production, oil moves from the reservoir, where the pressure is relatively high, up the well to the surface of the earth, where the pressure is relatively low. PRIMARY RECOVERY uses pressures that exist naturally in a reservoir to push oil up to the surface. The source of this natural pressure is called a DRIVE. Some oil fields have a combination drive, with a gas cap above the oil and water below it. Both the gas cap and the water push the oil into the well and up to the surface. (See Figure 15). Figure 15 - Combination of Gas Cap and Water Drive 19 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 24. RESERVOIR PRESSURE MAINTENANCE Recall that a fluid will move from a place where pressure is higher to a place where pressure is lower. The bigger the difference in pressure the more force there is to move the fluid. As the oil flows out of a reservoir the pressure in that reservoir drops. There is less force available to move the fluid. One method used to overcome this problem is to inject water into the water zone underneath the oil. (See Figure 16). Figure 16 - Water Injection Water is injected by pumping treated water down water wells to raise the level of the water under the oil. Oil and water do not mix. The water lifts the oil which is squeezed between the water and the gas cap. This makes more pressure. More pressure, more flow of oil. Companies also use gas injection to keep up the pressure. Gas produced with the oil is removed from the crude oil, compressed, and injected down wells into the gas cap. 20 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 25. WELL STIMULATION To make oil flow more easily and quickly to the well bore we can stimulate a well. To stimulate the well, new or bigger channels are cut in the rock. 26. ACID STIMULATION This is done by pumping acid down the well at high pressure. The acid dissolves the limestone rocks making the cracks and channels in the rock larger. (See Figure 17). Figure 17 - Propogation of Acid Stimulation Special chemicals are added to the acid to help it do its job better, and to protect the downhole equipment. 27. HYDRAULIC FRACTURING Fluids containing sand are pumped down the well very fast and at very high pressure. The force pushing on the rock is very strong. The rock splits, opening up large cracks. The sand enters the cracks in the rock. The sand grains keep the cracks open when the pumping is stopped. The cracks make it easier for the oil to flow from the reservoir into the well bore. 21 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 28. MOVEMENT OF CRUDE OIL TO PROCESSING PLANTS Oil that is produced from wells moves through a flow line, then trunk line system to the production degassing plants. Figure 18 shows such a system. Flow lines carry crude oil from individual wells. These flow lines can go direct to the plant or they can go into a trunk line which goes to the plant. It is like the small roads leading to the bigger roads in a town. Figure 18 - Simplified Production Flow The production manifold system at the entry to the plant is similar to the one seen in figure 19. Figure 19 - Production Inlet Manifold 22 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 29. OIL PRODUCTION DEGASSING PLANTS Degassing means removing the gas from the crude oil. This is the first step of the many steps that are needed to process the crude oil into the products that we want. The degassing of the crude oil takes place in separators in the oil field. (See Figure 20). Figure 20 - Distribution of Various Oil and Gas Deposits and Associated Wells 30. PRODUCTION DEGASSING SEPARATOR The production separator removes the gas that comes up with the crude oil. The separator is a large diameter cylinder closed at the ends. The oil and gas mixture enters this large cylinder. The speed or velocity of flow slows down and the pressure is reduced. The reduction in pressure causes the gas to escape (come out) from the crude oil. (It is just like when you remove the cap on a bottle of Pepsi. The gas bubbles appear from nowhere and float to the top because you have reduced the pressure). Because the flow has slowed down the gas has enough time to escape from the oil. The gas then goes out of the top of the separator and the oil goes out of the bottom. It is that simple (see figure 21). There is a lot of equipment inside and outside the separator to help this happen. 23 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org The principle is always the same. - light things go up heavy things go down Figure 21 - Horizontal Production 2 Phase Separator There are many different types of separator used in the process plants. You will learn about these in later modules. Included in these future modules are topics such as operational difficulties associated with separation, and how these may be resolved. 31. GAS PROCESSING All natural gas that was produced with the crude oil is called associated gas. Once the gas is separated from the crude oil it has any water vapour removed from it. The gas is then compressed by large compressors and sent through pipe lines to the gas processing plants. At the gas processing plants the components that make up natural gas are separated by distillation. These processes will be covered in detail in future modules. 24 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 32. REFINING OF CRUDE OIL The basic job of a refinery is to change crude oil into useful products. The crude oil must pass through a series of processes, one after the other. These processes change the crude oil into the finished products used in our homes and industries. (See Figure 22). The first and most important process is fractional distillation. Figure 22 - Typical Onshore Crude Oil Refinery 25 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org The crude oil is heated to 385ºC (725ºF) so that it boils. The hot vapours and liquids are then passed into a tall vertical steel cylinder called a fractionating tower. The lightest vapours go to the top of the tower, the heaviest go to the bottom of the tower. The vapours then condense (cool and become liquid) at different levels in the tower. This is because they have different boiling points (see figure 23). Figure 23 - Distribution of Light End Hydrocarbons There are trays in the tower to collect the condensed vapour. There are pipes from the trays so the liquids can flow out of the tower. Any vapours that come out with the liquids are sent back into the tower. (See Figure 24). 26 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org Figure 24 - Simplified Crude Fractionating Tower Remember that products from the crude distillation are only the first stage of refinery processing. Reduced crude is further processed to get asphalt, fuel oil, diesel oil and kerosene. Naphtha is separated into several fractions, which in turn are further processed. Temperature and pressure are very important in the distillation process. Specific temperatures must be maintained at each distillation point in the tower. This is so the fractions will condense correctly. You will learn how process temperature and pressure are controlled in later modules. You will also learn about refinery operations in much greater detail. 27 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OIL GURU ACADEMY & ARJ CONSULTANTS www.oilguru.org 33. PETROLEUM PRODUCTS Many more products come from crude oil. Refer to the following table for a detailed list. Figure 25 - Refinery Petroleum Products 28 MODULE 1 – HYDROCARBON INDUSTRY OVERVIEW OP09 224