Coal bed methane is methane gas (which is exactly the same as natural gas), which is produced conventionally by the petroleum industry from underground gas reservoirs. The only difference between conventional natural gas and coal bed methane is the way that the gas is actually trapped within the rock. In conventional reservoirs, it is contained in the pore spaces between the sand grains and in coal it is absorbed onto the surface of the rock - in other words, the gas is part of the coal and was produced when the organic matter was converted into coal. Coal bed methane is mainly known from mining accidents. As the coal is mined, periodically, you get catastrophic breakouts of this gas which is absorbed onto the coal surface and causes mining accidents. To exploit the coal bed methane, wells are drilled into coal seams.