About Coal Seam Gas in Queensland

Coal seam gas (also called coal bed methane and coal seam methane) is an important energy resource in Queensland and production of this gas now makes up an increasing proportion of Queensland gas demand.

Queensland is highly prospective for coal seam gas due to a combination of favourable geology and extensive coal resources. Coal seams are thick and multiple seams are present in many basins, with vast resources shallower than 1000 m.

Interest in CSG as an energy source has increased significantly in recent years and exploration has steadily grown, encouraged by the Queensland Government’s 2002 Queensland Energy Policy – a Cleaner Energy Strategy. This policy required 13% of Queensland’s electricity to be generated from gas (including CSG) by 2005.

Queensland CSG production is growing rapidly. The first production of CSG in Queensland was in 1996. By 2004 total CSG production had increased to approximately 27 Petajoules (PJ) equating to about 25% of Queensland’s current gas demand - a dramatic increase from around 2 PJ in 1998 and about 11 PJ in 2001.

What is Coal Seam Gas?

Methane gas (CH4) is formed as part of the burial of peat to form coal. The gas remains attached (adsorbed) to the coal by burial pressure and water. Because of natural fractures called cleats, coal has a large internal surface area and is capable of holding larger volumes of gas than conventional sandstone reservoirs. The amount of gas present in a coal seam depends on the depth of the seam, the thickness and the extent to which the fracture system is interconnected.

When water is pumped from holes drilled into the coal seam the pressure is reduced and gas is released from the coal. As pumping progresses water production declines and gas production increases.

At the surface, the methane, other gases and water are separated.

For further information visit the Queensland Government Department of Natural Resources and Water web site (http://www.nrw.qld.gov.au/mines/petroleum_gas/csg/index.html)