Topic 2 Off-shore Oil

Sedimentary Basins of Canada (Locations of Oil and Gas) 1. Western Canada Sedimentary Basin 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.

How Oil Is Formed in the Ocean Millions of years ago plants and animals of the oceans died & settled on the ocean floor. Bacterial action and extreme pressure from layers of sediment converted the organic matter to oil & gas. Oil reserves form when non-porous rock lies above porous rock. Oil seeps up through the porous rock & is trapped by the non-porous rock.

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

Oil Reserves Fault Trap: the vertical movement of the earth's crust forms a v-shaped reservoir.

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.

Oil Reserves Stratigraphic trap: has a former limestone reef as its porous rock feeding the reservoir.

Off-shore Oil Rigs Modern Drill Rigs  Submersible Rigs  Jack-up Rigs  Semi-submersible Anchored rigs  Semi-submersible Dynamically Positioned

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.

Submersible Rigs

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.

Jack-Up Rigs

Semi-Submersible Anchored Rigs Float BUT are anchored above the drill site.  Llimited 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.

Semi-Submersible Anchored Rigs

Semi-submersible Dynamically Positioned Use thrusters to keep position above the drill site.  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.

Semi-submersible Dynamically Positioned