coal bed methane

        The primary energy source of natural gas is a substance called methane

      (CH4). Coal bed methane (CBM) is simply methane found in coal seams. It is

      produced by non-traditional means, and therefore, while it is sold and

      used the same as traditional natural gas, its production is very

      different. CBM is generated either from a biological process as a result

      of microbial action or from a thermal process as a result of increasing

      heat with depth of the coal. Often a coal seam is saturated with water,

      with methane is held in the coal by water pressure. Currently, natural gas

      from coal beds accounts for approximately 7% of total natural gas

      production in the United States.