14 May 2008
A greener way to recover methane
Oil reservoirs could have an environmental make-over with the help of bacteria.
A report in Nature has shown how crude oil in deposits around the world is naturally broken down by microbes to methane.
Scientists say that increasing microbe activity would produce a more energy-efficient method of methane recovery.
It is likely field tests will start by 2009.
The ability to recover methane directly from deeply buried oil reserves means energy-intensive and thermal polluting processes are removed.
But methods like injecting steam into the reservoirs to heat and loosen the heavy viscous oil, so it can be pumped to the surface, are no longer needed say the authors of the Nature report.
"The main thing is you'd be recovering a much cleaner fuel," says co-author Steve Larter, a petroleum geologist from the University of Calgary.
"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."
Co-author Martin Jones, from the University of Newcastle, told the BBC News website that recovering methane from microbe biodegradation could also be used in exhausted oil fields: "Typically more then half of the oil that is in the reservoir is left there after the field is exhausted. In cases where they can't get the oil out economically, then they could convert it to gas."