An oilfield infrastructure company wants to use deep-well injection to sequester billions of barrels of oil sands mine water in underground reservoirs.
The project could dramatically reduce the volume of fluid tailings being managed in surface ponds, but some worry it would create its own environmental hazards and make it easier for the oil sands industry to get out of cleaning up its waste.
As of 2023, bitumen extraction and processing has produced more than 1.4 trillion litres of tailings, and millions of litres of effluent are added to tailings ponds in northern Alberta each year.
While researchers search for effective ways to reclaim oil sands tailings, the estimated 300 square kilometres of man-made lakes now storing the toxic mining by-product present massive environmental and health liabilities and have proven difficult for companies to manage.
Aqua Solutions Inc. (ASI), an Alberta-based corporation, is proposing the contaminated fluid not being reclaimed instead be removed from the landscape entirely by injecting it in wells deep underground.
Deep well sequestration has been used extensively by mining and oil and gas industries for liquid waste disposal but hasn’t yet been applied to oil sands mine water. ASI says by pairing existing industry practices and technologies with its novel process, they could be moving 630,000 barrels of tailing fluid per day into a reservoir in northeast Alberta as early as 2028.
ASI is currently lobbying the government of Alberta for disposal lease certainties, stating that it has identified a “high quality disposal zone” but the “infrastructure required must be matched to the volumes and the disposal certainty from government.”
ASI’s website says there are more than 7 billion barrels of oil sands mine water in Alberta’s tailings ponds, and that large volumes of this highly contaminated water can be “safely and permanently” disposed of to advance reclamation strategies.
Mine water is a waste fluid which contains less solid material than denser tailings slurry. In this case, a spokesperson for ASI clarified their estimate for mine water “is a combination of the total volume of mine water plus a portion of the fluid tailings volume.”
Alberta’s energy regulator estimates the volume of mine water in tailings ponds to be about 2.3 billion barrels, and the total amount of fluid tailings to be approximately 9.3 billion barrels. The amount of water in tailings ponds fluctuates each year depending on precipitation, new waste being added, and how much water is being recycled back into oil sands mining processes.
Phillip Meintzer, a conservation specialist with Alberta Wilderness Association, said oil sands companies are supposed to have an obligation to clean up their waste products, and the deep well disposal would only move the problem “out of sight and out of mind.”
“Injecting tailings effluent underground is not actually a cleanup solution. It just moves the problem elsewhere,” Meintzer said.
“It makes it easier for operators who are producing the tailings waste to hide that waste underground beyond scrutiny.”
Meintzer also raised two concerns about water. By injecting liquid waste products into underground reservoirs, “you’re eliminating water from the water cycle” and storing it elsewhere. Depending on the depth of the sequestration wells, there is also the risk of groundwater contamination, he said.
Pat Ward, president and CEO of ASI, said the project is being developed to meet or exceed industry standards.
“Reservoir geological mapping, hydrogeological mapping and computer reservoir simulation have been completed as well as injection testing. This work confirms that appropriate subsurface containment seals are in place for groundwater protection,” Ward said.
