Stimulation gas production from a coal seam

摘要

A method for stimulating gas production from a coal seam involves contacting the seam 11 with a permeability modifier which swells the seam to close cleats 111 and thereby reduce its permeability. Following this, a fracturing operation occurs which is said to be more controllable as a result of the cleats 111 being closed. Various permeability modifiers are claimed including carbon dioxide.