The price of crude oil has slumped to its lowest point in six years, and that has sent some major oil companies scrambling to get out of expensive tar-sands projects in Alberta, Canada. Shell has pulled out of one of its largest lease applications, and Petrochina is attempting to get rid of its tar-sands assets. Environmentalists have watched the slowdown with great hope.
Yet at the same time, some of those very same companies are positioning themselves to tap into an even more dirty and expensive kind of oil in Alberta: bitumen carbonates.
The little-known bitumen carbonates are a far more difficult-to-mine, more unconventional form of the molasses-like bitumen that’s already being extracted from the tar sands. In Alberta, the carbonates are in a deposit called the Grosmont formation, and most of it is underneath the tar sands themselves. The bitumen soaking the surface-level tar sands was once pushed up through the layers of limestone and dolomite that comprise the carbonates, and much of that bitumen is still trapped within the layer of porous rock. The carbonate rock resembles Swiss cheese, and in images of samples, black bitumen oozes from its holes. The Grosm... Read more
