Discloses a three step process to stimulate well production of
methane from
coal seams, wherein step one provides for injection of a treating gas into a well bore intersecting a
coal seam, step two includes a shut-in period and step three comprises the placement of a propped
fracture treatment. In step one, the injection of the treating gas physically opens pre-existing paths of
weakness in the
coal. As the treating gas travels along these planes of
weakness, it preferentially adsorbs onto the coal and displaces the
methane. This displacement process induces shrinkage of the
coal matrix, which further increases the size of the intervening existing fractures. The second step, or shut-in period, allows time for this
gas exchange process to substantially complete, thereby maximizing the effect of matrix shrinkage and enhancement of the intervening fractures. The third step provides for placement of a propped
fracture treatment into this enhanced fracture
system. Propping of the enhanced fractures ensures that they remain open, even as removal of water and
methane work to close the fractures by increasing
effective stress within the coals. The result is a stimulated coal seam that maintains enhanced permeability during production operations.