SAGD

Steam is injected into the top (red) pipe, heating up the surrounding oil sands. Bitumen becomes less viscous, and drains into the lower pipe (green), where it is pumped to the surface to be refined.
Image copyright to the Heritage Community Foundation

Steam assisted gravity drainage (SAGD) was introduced in the early 1980s as a process for extracting bitumen from the oilsands. Two horizontal pipes are drilled into the reservoir parallel to each other. Steam is injected into the top pipe, and it heats the bitumen so that it becomes less viscous and drains into the lower pipe where it is pumped to the surface to be refined.

SAGD proved to be an effective way of extracting oil, but the method requires large amounts of energy and water and can be a major source of greenhouse emissions. Recently, companies have been forced to look for ways to improve their efficiency. 

Dr. Tawfik Nasr of the Alberta Research Council (ARC) holds several patents for inventions that are designed to reduce SAGD’s energy and water consumption by means of adding a solvent to the steam injection. The steam-solvent combination causes more bitumen to drain into the well and uses up to half as much water, reducing both energy requirements and greenhouse emissions. The use of the steam-solvent combination has yielded a 19 percent increase in oil production over the standard SAGD, and the product is less viscous and easier to transport.