Coal Bed Methane (CBM)

Coal bed methane (CBM) or coal seam gas (CSG) is the natural gas extracted from coal beds during underground coal mining. As coal is formed over millions of years, methane forms within the coal and is trapped by water in cracks in the coal molecules. The high methane content of the gas (over 90%) makes it an excellent fuel and a suitable alternative to natural gas.

CBM also results in environmental benefits, as methane is a potent greenhouse gas and its release into atmosphere during mining operations can have negative environmental consequences (coal mining accounts for around 10% of methane emissions in the US). Therefore recovery of of CBM mitigates these emissions, allowing for economic use of the resource.

CBM production has commenced over recent years in Canada, Australia, China and India. Indonesia has also shown untested potential, but as yet there has been no commercial CBM production. Russia has also shown an interest in developing CBM reserves and international companies have entered Colombia to drill for the gas.

Global Reserves
Estimates of worldwide CBM resources are difficult to make and vary considerably, however they should rise with new understanding and technology. However Halliburton petroleum engineer Joe Awny estimated global recoverable reserves to be around 1,200 trillion cubic feet in 2009.

Future Supply and Demand
According to oilfield services provider "Halliburton" the development of CBM is likely to accelerate as more is learned about coalbed behaviour, and as innovative drilling and completion techniques are applied. Demand is also likely to increase as global appetite for gas grows, in preference over oil and coal.

Oilfield services provider Halliburton claims that although the contribution of CBM to the total global energy mix was still modest as of 2009, it has impressive potential for the future. According to petroleum engineer Joe Awny, in some region CBM could eventually grow from a supplement to conventional natural gas supply to a main source of gas. In the long term, he said CBM is expected to be of great significance for the US, India, China, Poland, South Africa, Zimbabwe and elsewhere as a main source of gas supply.

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