Primary Resource Activities Offshore Oil And Gas Geography 3202 Unit 4 S.C.O. 4.3 & 4.5 Primary Resource Activities Offshore Oil And Gas

4.3.1 Factors Affecting The Decision To Recover Offshore Oil And Gas Physical Factors Ocean Related Factors which include; 1.Ocean depth, 2. Ocean currents, 3.Icebergs and 4.Pack Ice. Climate/Weather Factors including; 1.Wind Speeds, 2.Storms. Oil Related Factors including; 1.Size of Reserve, 2.Oil Quality. Environmental Protection 1.What are the chances of an oil spill? 2. State of fish stocks, marine mammals, spawning grounds. What are the impacts on humans?

4.3.2 Factors Affecting The Decision To Recover Offshore Oil And Gas Human Factors Worker Safety including; 1.How safe can the drill rig and production platform be for the workers? Financial including; 1.Cost of building a rig to withstand icebergs or drill at great depths. 2. Cost of processes like transporting the oil to land, or maintaining the platforms equipment. 3. Price of oil.

Offshore Oil Oil Rig Oil Tanker

4.3.3 Relate the Recovery Technology to Environmental Conditions There are four different types of oil rigs: 1. Submersible 2. Jack-Up 3. Anchored Semi-Submersible 4. Dynamically Positioned Semi-Submersible

Modern Drill Rigs

Oil Rigs 1. Submersible Rests on columns attached to pontoons. Once towed to site pontoons flooded until platform rests on ocean bottom. Restricted by depth to (20m). No storage capability.

Oil Rigs 2. Jack-Up Supported by legs resting on sea floor Built to replace drill ships Access to deeper water restricted to 100m More open to elements To relocate, “legs” must be lifted (time consuming under hazardous conditions) No storage capability

Jack-Up Oil Rig

Oil Rigs 3. Semi-Submersible Allows to get into deeper water (200m) & heavy seas Partial submergence to keep it stable To maintain stability water pumped in or out of pontoons Oil stored in pontoons

Oil Rigs 4. Dynamically Positioned Semi-Submersible Can reach depths up to 2000m In unstable conditions can detach quickly Easy to relocate Partially submerged to keep it stable Stores oil in pontoons To maintain stability water is pumped in or out of pontoons

4.3.4 Elements of an Offshore Oil Recovery Operation 1. Well or reserve 2. Pipelines: feeder and export (oil and gas) 3. Platform: processing systems for oil & water, living quarters 4. Tankers: Supply and storage

5. Crews: 24 hour operation 2 crews. Day and night shifts 2 week shift rotations Engineers, crane operators, scaffolders, nurses, control room, catering (cooking and laundry), maintenance (mechanical, electrical.

4.3.5 Economic Importance of Off-Shore Oil and Gas Operations Our lifestyle is very dependent on oil energy (oil and gas being dominant in our economy) Oil is valued as a fuel because: 1) it produces large amounts of heat and power per unit of mass. 2) It is relatively easy to store, move, and convenient as a source of energy for transportation. Oil is a raw material that can be processed into refined products.

Economic Importance Of Off-Shore Oil And Gas Operations

4.3.6 Factors Affecting Viability of Off-Shore Oil Industry World oil prices: High prices, encourage companies to develop oil production Low prices discourage companies due to reduced profit. Ex. 1984-1990 Hibernia did not begin due to low oil prices. Government policy: Tax breaks encourage companies to develop oil production Tax increases discourage companies due to reduced profit

4.5.1 The Formation (Process) of Oil and Gas 1. Millions of years ago plants and animals of the oceans died & settled on the ocean floor. 2. Sediments piled up and pressed the remains into layers of sedimentary rock. 3. This caused extreme pressure, heat, and bacterial action. 4. Over millions of years, these natural processes then converted the organic material into oil and gas.

4.5.1 Four Types Of Oil And Gas Reserves (Traps) Fig 11.1

1. Fold (Anticline) Trap 1 Cap Rock 2 Reservoir Rock 3 Source Rock Ground Water Natural Gas Oil Fold Trap: The up fold or anticline in the layers of the earth's crust form the reservoir.

2. Fault Trap 1 Cap Rock 2 Reservoir Rock 3 Source Rock Ground Water Natural Gas Oil Fault Trap: The vertical movement of the earth's crust forms a v-shaped reservoir.

3. Salt Dome Trap 1 Cap Rock 2 Reservoir Rock 3 Source Rock Ground Water Natural Gas Oil Salt Dome Trap: The salt dome forms an up-fold in the earth's crust (like the anticline caused by tectonic forces).

4. Stratigraphic Trap 1 Cap Rock 2 Reservoir Rock 3 Source Rock Ground Water Natural Gas Oil Stratigraphic Trap: has a former limestone reef as its porous rock feeding the reservoir.

4.5.2 Techniques Used To Locate Offshore Oil And Gas Reserves Before 1900’s Search was limited to the search for oil seeping to the surface along fault lines. After 1900’s Geologists knew to drill in gentle anticlines or faulted sedimentary rock where reservoirs of oil might occur.

4.5.2 Techniques Used To Locate Offshore Oil And Gas Reserves Modern oil exploration on the seas Ships tow sound emitters and hydrophones. Different rock layers reflect sound differently. Computers convert the sound data into 3D pictures of the ocean’s rock layers “Wild cat” wells are drilled to test for oil. If they…. * strike oil : then they drill delineating wells * miss oil : then they examine core samples for evidence

4.5.3 Distribution Of Proven Oil And Gas Reserves (Fig 11.2)

4.5.3 Distribution Of Proven Oil And Gas Reserves Refer to Fig 11.2 in your text (Also shown on previous slide) Most oil regions of the world are located on-land. The ones that are located under the ocean floor are concentrated in the North Sea around the United Kingdom and in the Gulf of Mexico.

4.5.3 Patterns Of Offshore Oil Production

Offshore Oil Usually occurs in the shallow waters on the continental shelf (20 to 200m in depth) Can occur in water as deep as 2000 meters deep. Once an oil reserve is found and the oil rig is developed, they can start extracting the oil. Extraction of oil is done through an offshore oil rig. Oil is then transferred to land on oil tankers or pumped through pipes.

4.5.3 Pattern of Offshore Oil Production Figure 11.3 (on previous slide) show the oil production by non- OPEC countries. North Sea and Gulf of Mexico are regions of high offshore oil production. Offshore oil production is increasing faster than land production of oil. West Africa, around the Ivory Coast seem to have high oil reserves and is also increasing in production.

Off-Shore Oil Production This move to offshore oil production has occurred for three reasons 1. Reduced exploration costs due to improved three-dimensional imaging and other exploratory techniques 2. Improved design of rigs, storage facilities, and offloading systems

Off-Shore Oil Production 3. Most importantly, directional drilling (see fig. 11.5 p. 187) which allows rigs to reach deposits several km away from the rig.

Characteristics that determine Oil Quality Oil quality varies with viscosity Heavy, viscous (thick slow running) oil is used for asphalt and electric generating stations Light less viscous oil is easier and cheaper to refine. It is used for gasoline, jet fuel, and petroleum products.