It’s one of thousands of sticky questions answered at the sparkling new Canada Science and Technology Museum. If you find yourself in Ottawa, check it out. In the meantime, get a taste of the museum by taking this little quiz and learning what its oil sands exhibit has to teach us.
The following excerpt from the exhibit tells you more about how oil is extracted. Like everything in the museum, it makes science and technology as easy to digest as soup and a sandwich.
If bitumen had feelings: steamed and pumped!
- Canada has some of the largest reserves of heavy oil or bitumen in the world. This oil is contained in sand which is trapped between layers of impenetrable rock. These reserves are called oil sands.
- 80% of oil sands deposits are deep underground and can only be accessed by drilling wells – a process called in-situ extraction. To remove the all overlying rock and soil would be expensive and cause considerable environmental impact.
- However, the oil in these deposits is too thick to flow easily to a well. In these conditions, bitumen has the consistency of a hockey puck and must be softened to move into a well.
- One method of extracting heavy oil from such deposits is “cyclic steam stimulation” or CSS.
- The basic principal of cyclic steam generation is to pump steam under high pressure down the well, heating and pressurizing the formation.
- The first step in this process is the steam phase, which involves pumping steam down the well.
- Next, some time is allowed for the steam to soak into the formation. At this point, the thick oil gradually becomes more fluid and flows more easily.
- The pressure within the formation drives the more fluid bitumen towards the well and surface. This is the flowback period.
- Next the oil must be pumped to the surface with pump jacks.
- The whole cycle -- the steam phase, soaking, the flowback period and pumping -- is repeated. The phases take longer and longer to access further and thicker deposits.
- Cyclical Steam Stimulation performed on a traditional well can only access a certain area around the well. However, new methods allow wells to be drilled horizontally in different directions.
- Now, 20 or more wells can be drilled vertically from one bore hole down to a reservoir, then radiating horizontally outwards. This increases access to the reservoir while minimizing the disturbance of land on the surface.
- On the surface, the bitumen and water recovered from multiple pads is pumped to a central processing plant. Over 95 per cent of the water is recovered and recycled for steam injection in further cycles. The other 5 per cent of the water stays in the formation or is exhausted as steam at the plant. Overall, one barrel of water is needed to produce one barrel of oil.
Recovering Bitumen from Oil Sands – a New Approach
NRCan scientists are investigating innovative approaches to separating bitumen from sand. Oil sands are mixed with a solvent and spun incredibly fast in a centrifuge. The force of this movement pushes the diluted bitumen out while the sand remains. This approach could lead to eliminating the use of water in oil sands extraction. Check it out!
Exhibit partners: Natural Resources Canada and Imperial Oil