An Introduction to Coalbed Methane (CBM) reservoirs:
The process by which plant material
is converted to coal generates large quantites of methane gas, which is often
trapped within the coal. The presence of this gas is very well known due to underground
coal mining, where it presents a serious safety risk. This is coalbed methane,
often refered to as CBM.
Coalbed methane differs from a typical sandstone natural gas reservoir in the following ways:
1) Methane is stored within the matrix (the coal) by a process called adsorption. The methane is in a nearly liquid state, lining the inside of the coal pores.