Unconventional oil such as heavy oil and bitumen found in Alberta’s oilsands is more difficult to coax from the ground because it is has a thick consistency—and sometimes even forms rock. Oil companies in Alberta and around the world are trying to get the most out of these challenging reservoirs.
The steam-assisted gravity drainage (SAGD) method commonly employed to pump this oil from the ground involves injecting steam or solvents into the ground, causing heavy oil to flow more freely and making it easier to bring to the surface. Tayfun Babadagli, who holds the NSERC Industrial Research Chair in Unconventional Oil Recovery, is researching ways to improve this technique, enabling oil companies to recover as much oil in as efficient a manner as possible.
SAGD can be “a very difficult technology,” says Babadagli. Heat (in the form of steam, air or electrical heating) or solvents are used to get the thick, heavy oil to flow more freely.
“Our job is to optimize these techniques to minimize the costs and maximize recovery,” says Babadagli, a professor in the U of A Department of Civil and Environmental Engineering’s School of Mining and Petroleum Engineering. “You want to find ways to use the least amount of steam or the least amount of solvents. Our main goal is to find ways to reduce the reservoir oil that gets left behind.”
Another challenge for the industry is the fact that up to 25 per cent of Alberta’s heavy oil is trapped in carbonate minerals—no one has yet devised a way to flush the oil from these tightly packed rock formations. It’s another challenge Babadagli and his team are investigating.
Babadagli has patented a recovery technique that alternates the use of steam and solvents to make bitumen more easily accessible. Variables, such as the temperatures and length of time spent heating the oil and the strength of a solvent, can be experimented with.
“Injection times and waiting times and the strength of the solvent are all critical elements. Sometimes you might be heating for two weeks but maybe one week is enough.”