Today, the production of underground oil sands resources too deep to mine generally involves the use of steam to heat up the bitumen so it can flow back to the surface.
In recent years, oil sands producers have explored different ways to lower energy and greenhouse gas emission intensities, like injecting hydrocarbon solvents into the reservoir to reduce steam requirements. Now, a group of University of Calgary researchers is studying an alternative method that eliminates the need for steam entirely—instead using warm water in combination with additives.
“Instead of putting steam into the reservoir, we’re looking at the use of hot water and additives to get the same effect and mobilize the oil at a much lower energy intensity,” says Ian Gates, GRI director and lead researcher on the project, which is part of the university’s Global Research Initiative in Sustainable Low Carbon Unconventional Resources.
Steam and SAGD
One of the keys to recovering oil sands bitumen from underground reservoirs too deep to mine is heating up the reservoir so that the thick bitumen flows. This allows the oil-containing bitumen to be collected at the surface via a well.
Steam-assisted gravity drainage (SAGD) was a revolutionary technology that uses steam to make this happen. Developed by Roger Butler in 1978, it enabled the economic recovery of a vast supply of oil resources in northern Alberta, turning Canada into an international energy powerhouse.
Since 2017, Gates and his team have been examining the use of different additives—surfactants, wettability agents and surface-active particles—that can reduce the tension between oil, sand and water interfaces.
“These materials can assemble at these interfaces and essentially ‘tune’ them so oil is mobilized through the porous rock with minimum energy,” explains Hossein Hejazi, an associate professor in chemical and petroleum engineering who’s working on the project.
So far, the researchers have focused their experiments in the laboratory on finding the most effective surface agents. Some are studying the materials at a molecular level to understand how they can be designed for oil recovery. Others are applying laser microscopes and high-speed cameras to track the effect of additives on oil flow patterns in visual reservoir models.
“Each of us is looking at different sides of the project to solve this complex challenge,” Hejazi says.
Gates says, that once surface-active materials are selected, the next step for the group will be to test them, using scaled-up physical models. With this knowledge, the group ultimately hopes to develop recovery processes that, at most, combine hot water with additives. Preliminary tests in the lab show this approach could allow producers to recover bitumen at a quarter of the energy intensity of steam-assisted gravity drainage (SAGD) technology.
“Because this method only heats water to hot water, it doesn’t burn as much fuel. This combined use of hot water and additives could lead to new recovery processes where much of the injected energy and GHG emissions is reduced,” Gates says.