Coal Bed Methane "Primer"
Coalbed methane, or CBM, is a natural gas produced from coal seams or adjacent sandstones.
The amount of methane in a coal deposit depends on the quality and depth of the deposit. In general, the higher the energy value of the coal and the deeper the coal bed, the more methane in the deposit.
Methane is loosely bound to coal -- held in place by the water in the coal deposits. The water contributes pressure that keeps methane gas attached to the coal. In CBM development, water is removed from the coal bed (by pumping), which decreases the pressure on the gas and allows it to detach from the coal and flow up the well.
Figure I-24 below is a typical Coalbed Methane Well.
Source: Ecos Consulting
Coal Bed Methane & Natural Gas Measurements
Mcf: one thousand cubic feet of natural gas
Mmcf: one million cubic feet of natural gas
Bcf: one billion cubic feet of natural gas
Tcf: one trillion cubic feet of natural gas
Mmcf/d: millions of cubic feet of gas per day
Boe: barrel of oil equivalent (one barrel of oil equals 6,000 cubic feet of natural gas)
Mboe: one thousand barrels of oil equivalent
Mmboe: one million barrels of oil equivalent
Mmcfe: one million cubic feet of natural gas equivalent
Bcfe: one billion cubic feet of natural gas equivalent
Tcfe: one trillion cubic feet of natural gas equivalent