Transcript Slides 4.3 and 4.5 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 SemiSubmersible
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 SemiSubmersible
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 OffShore Oil And Gas Operations
4.3.6 Factors Affecting Viability of OffShore Oil Industry
World oil prices:
1.
High prices, encourage companies to
develop oil production
2.
Low prices discourage companies due to
reduced profit. Ex. 1984-1990 Hibernia did
not begin due to low oil prices.
Government policy:
1.
Tax breaks encourage companies to develop
oil production
2.
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
1.
Ships tow sound emitters and
hydrophones. Different rock
layers reflect sound differently.
2.
Computers convert the sound
data into 3D pictures of the
ocean’s rock layers
3.
“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.