December 14th, 2007
Oil-eating microbes produce green energy
It is estimated that oil sands — or bituminous sands — represent two thirds of the world’s oil reserves. Still, it’s expensive and difficult to extract oil from these sands. Even with today’s crude oil prices, the industry is still looking for cheaper ways to produce energy from the so-called ‘tar’ sands. Now, according to the University of Calgary, an international team of researchers has found a way for using microbes to extract methane from oil sands. With its enormous reserves, Canada could become one of the major oil producer in the 21st century. Field tests of this new technology should start in 2009.
The largest heavy oil reserves are located in the Canada province of Alberta. You can see on the left a map showing the three major oil sand deposits in the area, the Athabasca Oil Sands, the Cold Lake Oil Sands, and the Peace River Oil Sands. (Credit: Norman Einstein, May 10, 2006, link to a larger version. Please also read two Wikipedia pages about
Tar sands and the
Athabasca Oil Sands.
This discovery has been done at the University of Calgary by Steve Larter, Canada Research Chair in Petroleum Geology, helped by Jennifer Adams, one of his PhD students. You can see a picture of them on this page.
They were not alone. Ian Head, Professor of Environmental Microbiology, and Dr Martin Jones of Newcastle University, UK, were also members of the team. In fact, Newcastle University published its own news release, “Energy from abandoned oil reserves” (December 12, 2007).
How will the industry benefit from these findings? “The oil sands industry would no longer have to use costly and polluting thermal, or heat-based, processes (such as injecting steam into reservoirs) to loosen the tar-like bitumen so it flows into wells and can be pumped to the surface. ‘The main thing is you’d be recovering a much cleaner fuel,’ says Larter. ‘Methane is, per energy unit, a much lower carbon dioxide emitter than bitumen. Also, you wouldn’t need all the upgrading facilities and piping on the surface.’”
The online edition of Nature provides additional details. “‘To get heavy oil out you’ve basically got to melt it,’ says Larter. This means using energy to produce steam to extract the gunk, he says. ‘It’s like turning gold into lead.’ Only 17% of the oil can usually be recovered. Methane gas, on the other hand, simply rises to the surface. But it has been unclear how methane is produced by microbes in heavy-oil fields.”
Nature also details the process used by the researchers. “The first type of bacteria to attack crude oil can break down the long-chain hydrocarbons into acetic acid, carbon dioxide and hydrogen. In the second step of biodegradation, one set of microbes can turn acetic acid to methane, and another set acts on carbon dioxide and hydrogen to produce methane. To work out which process dominates in an oil field, Larter and his colleagues, recreated methanogenesis in the lab. [...] They analysed the isotopic ratios of the methane produced and compared that to the methane produced by the actual oil field, and discovered that in the field the hydrogen route dominates. They think this to be true of all heavy oil fields.”
For more information, this research work has been published in Nature under the title “Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs” (Volume 450, Number 7172, December 12, 2007). Here is a link to the abstract.
Sources: University of Calgary news release, December 12, 2007; Katharine Sanderson, Nature, December 12, 2007; and various websites
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