Recovering bitumen from oil sands is currently done in 2 different ways both requiring water. If the oil sand is not too deep in the ground it is dug out (oil sand mining), then mixed with water, after which the bitumen is recovered as a froth from the surface of the oil sand-water mixture. If the oil sand is deep, underground methods are used to extract the bitumen while leaving the sand in place (in situ extraction). The most common in situ technique is steam-assisted gravity drainage (SAGD). In SAGD, steam is pumped into a horizontal well to heat the bitumen which then flows to a second well that was drilled below the first well, from which the bitumen is pumped to the surface.
CanmetENERGY focus on 3 main areas regarding oil sands and water:
- Chemicals in Oil Sands Process Water — we determine the fate of water-borne chemicals
- Oil Sands Water Chemistry Modelling — we build computer models to predict the changing water chemistry of oil sands process water
- Oil Sands Water Treatment — we look at the effect of using water treatment on overall efficiency of oil sands operations
The Extraction Process
About 7 to 10 m3 of water per m3 of bitumen are needed in order to extract bitumen from mined oil sands. Almost 3/4 of that water is recovered from the waste (referred to as tailings) ponds and is recycled back to the bitumen extraction process. The remaining water is trapped in the solids in the tailings ponds so more water needs to be imported to make up for the trapped water.