PART FIVE

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• PART FIVE
• Off-shore Oil Formation and Reserves

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How Oil Is Formed

• Extreme pressure and heat and bacterial action
  converts the organic matter into oil gas.

• Millions of years ago plants and animals of the
  oceans died settled on the ocean floor.

• Sediments covered the dead organisms

• Oil reserves form when non-porous rock lies above
  
• porous rock underneath.
• Oil seeps up through the porous rock is
  trapped by the non-porous rock.

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Oil Reserves Pg. 183

• Fold Trap the up fold or anticline in the layers
  of the earth's crust form the reservoir.

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Oil Reserves

• Fault Trap the vertical movement of the earth's
  crust forms a pyramid or v-shaped reservoir.

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Oil Reserves

• Salt Dome Trap The salt dome forms an up-fold in
  the earth's crust not unlike the anticline caused
  by tectonic forces.

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Oil Reserves

• Stratigraphic trap has a former limestone reef
  as its porous rock feeding the reservoir.

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Techniques Used to Locate Reserves

• Before 1900s
• The search for oil was limited. Had to look along
  fault lines for oil seeping to the surface (EX
  Jed Granny Clampett and the Beverly
  Hillbillies).
• After early 1900s
• Geologists knew to drill in gentle anticlines or
  faulted sedimentary rock where reservoirs of oil
  might occur. (Not always successful).
• Hit and miss operations.

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Techniques Used to Locate Reserves
Modern oil exploration on the seas

• ships tow sound emitters hydrophones to send
  sound towards earths crust.
• different rock layers
• reflect sound differently.
• computers convert the sound data into 3D pictures
  of the oceans rock layers.

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Techniques Used to Locate Reserves

• Wild cat wells are drilled to test for oil
• if they strike oil then delineating wells are
  drilled to determine the size of the reservoir.
• If they miss oil then the core samples are
  examined for evidence of oil.

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Steps/stages in Oil Exploration What is the
SEQUENCE?????

• Recording sound waves using hydrophones
• Drilling wildcat wells, OIL or NO oil???
• Analyzing the seismic data
• If drilling produces a dry hole, core samples
  taken
• Directing sounds waves to ocean floor
• Additional wells used to determine size of reserve

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Steps/stages in Oil Exploration The SEQUENCE
is.

• Directing sounds waves to ocean floor
• Recording sound waves using hydrophones
• Analyzing the seismic data
• Drilling wildcat wells, OIL or NO oil???
• Additional wells used to determine size of
  reserve
• If drilling produces a dry hole, core samples
  taken

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Patterns of Offshore Oil Production

• FIGURE 11.2 PG. 184

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Patterns of Offshore Oil Production

• FIGURE 11.2 PG. 184
• Most oil regions of the world are on land.
• Oil regions under the ocean floor are
  concentrated in the North sea around the UK and
  in the Gulf of Mexico.

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• Gulf of Mexico North Sea West Africa
• (Ivory Coast)

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Patterns of Offshore Oil Production

• FIGURE 11.3 PG. 185
• It also reveals that OFFSHORE oil production is
  increasing faster than land production of oil.
• West Africa, especially around the Ivory Coast,
  seems to have high oil reserves and is increasing
  in oil production.

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Where are most of the worlds proven oil reserves
located?
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• PART SIX
• Systems Model and Offshore Oil

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Offshore Oil Decision to Recover

• The determination must be made whether cost of
  inputs and processing will be offset by the value
  of the output oil.

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Physical Factors Affecting Recovery

• Ocean related factors include
• Ocean Depth , Ocean currents, Icebergs pack ice
  
• Climate/weather related factors include
• Wind speeds, Storms, Monsoons, Hurricanes
• Oil Related factors include 
• Size of the reserve, Oil quality
• Environmental protection factors 
• Other resources like fish stocks, marine mammals,
  and spawning grounds would be affected in the
  event of an oil spill.

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Human Factors Affecting Recovery

• Worker Safety
• How safe can the drill rig and production
  platform be for the workers?
• Financial Factors include
• cost of inputs - building a rig to withstand
  icebergs, hurricane winds, or to drill at great
  depths.
• cost of processes - transporting the oil from
  off-shore to land, or maintaining equipment.
• price of oil which is set and then you determine
  if enough money is recovered from the oil to
  exceed the cost of production.

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Offshore Oil Decision to Recover

• The main determinate is
• whether the cost of overcoming all other
  factors will be offset by the price oil can be
  sold for and make the venture financially viable!

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A Brief History of Oil Recovery

• Keeping the Connection to Land
• In the 1860s wharves were built extending
  365m out into the ocean to facilitate ocean
  drilling off California.

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A Brief History of Oil Recovery

• Letting go of Shore
• In the 1920s a drill rig was built on wooden
  pilings in lake Maracaibo, Venezuela.

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A Brief History of Oil Recovery
Moving to Steel In the 1930s a drill rig was
built on steel structures in the Gulf of Mexico
but it was limited to 7m of water or less.
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A Brief History of Oil Recovery

• Letting go of the Ocean Floor
• In 1956, the first drill ship was built allowing
  drilling in deeper water.
• These types of drill ships allowed exploration
  off the shores of Newfoundland.

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Drill Ships
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Off-shore Oil Rigs

• Modern Drill Rigs
• (Pg. 186 - Figure 11.4)
• Submersible Rigs
• Jack-up Rigs
• Semi-submersible Anchored rigs
• Semi-submersible Dynamically Positioned

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Submersible Rigs

• Fixed columns ground them on the ocean floor!

• Usually limited to ocean depths of 20 m. For
  this reason they are limited to continental
  shelves, relatively close to shore.
• The rigs are floated as they are towed to drill
  site. Once in position ballast tanks are flooded
  until columns rest on ocean floor.

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Submersible Rigs
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Jack-Up Rigs

• Extendable legs ground them on the ocean floor.

• Are limited to a maximum ocean depth of 100 m.
• The jack-up is similar to the submersible in
  that it rests on the ocean floor.
• However its steel legs (Not columns) rest on
  ocean floor.

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Jack-Up Rigs
http//www.youtube.com/watch?vzLLqXaWL1Vkfeature
related
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Semi-Submersible Anchored Rigs

• Limited to a max. ocean depth of 200 m.
• Built on land, then flooded and towed to the
  drill site.
• Water is pumped in and out of ballast tanks to
  keep stability along with anchor lines.
• Oil is stored in pontoons until shipped on-shore.

• Float BUT are anchored above the drill site.

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Semi-Submersible Anchored Rigs
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Semi-submersible Dynamically Positioned

• Able to drill outside the continental shelf.
  Still limited to a max. ocean depth of 2000 m.
• Like other rigs they are towed to the drill site.
• Water is pumped in and out of ballast tanks to
  help stability (NO anchor lines).
• Like the Anchored rigs oil is stored in
  pontoons until shipped on-shore.
• Note dynamic means changing or moving.

• Use thrusters to keep position above the drill
  site.

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Semi-submersible Dynamically Positioned

• thrusters

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Semi-submersible Dynamically Positioned
Eirik Raude - The Worlds largest self-propelled,
semi-submersible, all weather oil drilling rig. 
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Gravity Based Structure - GBS

• Submersible - sits on ocean floor.
• Made of 4 ft thick concrete walls.
• Teeth to break apart ice and icebergs
• 80 m of ocean water
• Hiberniathe worlds first of this type.
• The largest in the world!

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Directional drilling

• Newest technology!!!
• Flexible shaft used to drill in different
  directions.
• Dont have to relocate a drill rig when a deposit
  dries up.
• Saves a LOT of money time

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• Offshore Work (6 min 7 sec)
• Jack-up Oil Rig (14 sec)
• Jack-up rig towage (23 sec)
• Deepwater Offshore Drilling Rigs.(2 min 38 sec)
• Geology formation basin trap oil (34 sec)
• Norwegian Oil Rigs .(1 min 52 sec)
• Offshore Drilling Fight - CBS News .(3 min 05
  sec)
• Jack-up Rig Launch .(3 min 21 sec)
• Oil Drill Animation (42 sec)
• A look at Life on an offshore Oil Rig .(5 min 24
  sec)

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Hibernia Case Study

• Pg. 187-191