Dynamic Gas Permeability Investigations of Highly Stressed Coals (2006-2009)

Coalbed methane (CBM) is becoming a major source of energy supply within Australia. A large part of the CBM reserves are in coal seams subject to high compressive stress, either through depth or lateral tectonic movement. Compression generally reduces permeability and hence CBM productivity, but if the stresses in the different directions are significantly different in magnitude, then directional permeability may be improved. The aim of this project is to understand the interaction of the coal character, stress field and coal permeability. This will inform optimisation of well layouts for gas recovery and may lead to methods for inducing or managing stress fields in CBM reservoirs, to maximize productivity.