Coal Bed Methane : What
is Coal Bed Methane (CBM)?
 |
| Courtesy of Montana Department of
Environmental Quality |
Coal Bed Methane, which is a more pure gas than conventional
gas, is found within the carbon lattice of coal at a molecular
level. The less "sweet" natural gas, which is found
in more conventional fields, was generated by hydrocarbon source
rocks and is trapped in a porous and permeable reservoir rock,
such as carbonate reserve or sandstone. Water pressure holds
Coal Bed Methane in place, which required new drilling technology,
to efficiently extract.
To extract Coal Bed Methane, a company drills wells into the
coal seam, and then perforates and fractures the coal seams.
By increasing permeability through this process, water is able
to be pumped out of the coal seam. During this de-watering process,
pressure holding the gas in place is reduced. This pressure
differential vents the gas through the fracture systems into
the well.
|
