Offshore Oil Formation

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Offshore Oil Formation

• The formation of oil takes a tremendously long
  time.  Millions of years ago plants and animals
  of the oceans died settled on the ocean floor. 
  While large organisms contributed to the oil it
  was often the mass of small and microscopic
  organisms that contributed the bulk of the carbon
  for OIL.

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• Over many thousands of years bacterial action and
  extreme pressure from layers of sediment
  converted the organic matter to oil gas.  The
  extreme pressure came form the continuous build
  up of sediment.  The pressure created tremendous
  amounts of heat which helped the process along.

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• The oil moved within the soil and oil reserves
  formed when non-porous rock lay above porous
  rock. Oil seeps up through the porous rock is
  trapped by the non-porous rock.

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Sedimentary Basins of Canada
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• Western Canada Sedimentary Basin
• (our primary source of oil)
• 2. Hudson Bay Basin
• 3. Mackenzie and Banks Basins
• 4. Canadian Arctic Basin
• 5. Baffin Bay
• 6. Labrador Sea Shelves
• 7. Scotian Shelf
• 8. Grand Banks
• 9. Anticosti
• 10. Maritimes Basins.

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Atlantic Sedimentary Basins
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Hibernia Cross Section
Oil (light-green lines and blobs) and gas (red
lines) in the Hibernia Formation (yellow) in
the Carson Basin, mainly in stratigraphic traps.
The brick colour underlying the oil and gas
stream lines represents the Egret type source
rock.
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Oil and Gas Traps

• All oil and gas traps have
• a nonporous rock cap and
• a porous rock source. 
• The porous rock allows the oil to seep into the
  cavity and the nonporous rock prevents the oil
  from leaving.

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Oil Reserves

• 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 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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Submersible Oil Rig

• Supported primarily on large pontoon-like
  structures submerged below the surface. The
  operating decks are elevated 100 or more feet 30
  m above the pontoons on large steel columns.
• Once on the desired location, this type of
  structure is slowly flooded until it rests on the
  seafloor. After the well is completed, the water
  is pumped out of the buoyancy tanks, the vessel
  refloated and towed to the next location.
• Submersible rigs are normally limited to ocean
  depths of 20 m.

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Semi Submersible

• Float on the ocean
• This floating drilling unit has pontoons and
  columns that, when flooded with seawater, cause
  the pontoons to submerge to a predetermined
  depth. Although it is moved by wave action, it
  sits low with a large part of its structure under
  water. This, combined with eight huge mooring
  anchors, make it a very stable installation
• 200 m for anchored and 2000 m for dynamically
  positioned

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Ocean Ranger (semi submersible)

• Valentine's Day, 1982 a terrible storm rages off
  the coast of Newfoundland. On the Grand Banks,
  the Ocean Ranger, the world's mightiest drilling
  rig, is pounded by waves more than 20 metres
  high. At the height of the storm, the
  "indestructible" rig begins to tip over, then
  capsizes. All 84 men on board 56 of them from
  Newfoundland perish.
• http//archives.cbc.ca/environment/extreme_weather
  /topics/349/
• http//archives.cbc.ca/environment/extreme_weather
  /topics/349-1874/
• http//www.thecanadianencyclopedia.com/index.cfm?P
  gNmTCEParamsA1ARTA0005876

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Jack-up Oil Rig

• Instead of floating over its drilling location
  the Jackup has long leg structures, which it
  lowers to and into the sea bed raising the rig
  out of the water. (100 m)

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Gravity Based Oil Rigs

• The Hibernia GBS sits on the ocean floor
  approximately 200 metres in depth with its
  topsides extending approximately 50 metres out of
  the water. The platform acts as a small concrete
  island with serrated outer edges designed to
  counter ice bergs.
• http//www.hibernia.ca
• http//www.thecanadianencyclopedia.com/index.cfm?P
  gNmTCEParamsM1ARTM0011173

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FPSO

• A Floating Production, Storage and Offloading
  Vessel

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Once the field is depleted, the FPSO can be moved
to a new location. In areas of the world subject
to cyclones (NW Australia) or icebergs (Canada),
some FPSOs are able to release their
mooring/riser turret and steam away to safety in
an emergency.