Abandoned energy

Researchers from Newcastle University and Calgary University in Canada think they may have found a way of extracting more energy from the world's oil reserves.

The team of geologists and biologists have been studying the little-understood process by which naturally-occurring bacteria deep below the ground convert oil and coal to natural gas over many millions of years.

They believe that the process could be speeded up, possibly by simply feeding the bacteria nutrients like vitamins and minerals down boreholes.

If the theory works in practice, oil and possibly coal reserves that are currently uneconomic to extract from the ground could be converted to sources of natural gas, otherwise known as methane.

The research was led by Prof Ian Head and Dr Martin Jones, of Newcastle University, and Prof Steve Larter, who works at both Newcastle University and Calgary University in Canada.

It was already known that most of the world's oil reserves are affected by the bacteria, to some extent. This reduces the value of the oil by making it thicker and more costly to extract. Some reserves have been left in the ground because it would be uneconomic to work them.

However, little was known about the process by which the bacteria 'biodegraded' the oil. By studying the actions of bacteria in laboratory tests over a two year period, the team of researchers found that it was an anaerobic (taking place in the absence of oxygen) fermentation process that produced methane gas.

They now hope that the discovery can be applied commercially to oilfields, such as the huge tar sand deposits in Canada - and possibly coalfields, like the former mining areas around Newcastle, in North East England.

'There are potentially major economic implications to these findings, since a proportion of the trillions of barrels of oil, currently regarded as unworkable, could in theory be converted into methane, or natural gas,' Prof Head said.

Prof Head, of the School of Civil Engineering and Geosciences at Newcastle University, points out that burning methane as a fuel, for example in power stations, produces about ten per cent less greenhouse gases, such as carbon dioxide, than burning coal or oil.

'In North East England, similar processes may occur in abandoned coal mines, opening the door to a possible means for recovery of the region's extensive abandoned energy resources as clean-burning methane.'