Turns out that when you inject high-pressure steam into heavy oil reservoirs underground, you can’t always predict which way the oil will go.
Oil spills at a major oil sands operation in Alberta have been ongoing for at least six weeks and have cast doubts on the safety of underground extraction methods, according to documents obtained by the Star and a government scientist who has been on site.
Canadian Natural Resources Ltd. has been unable to stop an underground oil blowout that has killed numerous animals and contaminated a lake, forest, and muskeg at its operations in Cold Lake, Alta.
The documents indicate that, since cleanup started in May, some 26,000 barrels of bitumen mixed with surface water have been removed, including more than 4,500 barrels of bitumen…
The company says it is effectively managing and cleaning up the spills.
The company’s operations use an “in situ” or underground extraction technology called “cyclic steam stimulation,” which involves injecting thousands of gallons of superhot, high-pressure steam into deep underground reservoirs. This heats and liquefies the hard bitumen and creates cracks through which the bitumen flows and is then pumped to the surface…
“We don’t understand what happened. Nobody really understands how to stop it from leaking, or if they do they haven’t put the measures into place.”
This might explain why Maracaibo has had so many mysterious oil slicks in recent years, when state oil company PDVSA has insisted that its pipelines aren’t leaking. (Here’s one from 2012.) There is a lot of steam injection into fields under the lake.
Also, heavy oil fields in the Colombian llanos (wet plains) are slated for “enhanced recovery” that may at some point include steam injection. I hope this situation in Alberta is taken as a lesson.