Measurements of relative permeability, absolute permeability and fracture geometry in coal

Adequate permeability is vital to the coalbed methane industry. We report here on tfuee issues of importqnce to the subject of coal permeability. Laboratory measurements of relati\€ penneabiiity in Australian coal have been made in our laboratory. These eryeriments were conducted to provide data for numerical simulation and e'raluation of coalbed methane reserroirs. Transient flow was used to determine drainage relative permeability, this having the most relera.nce to the primary depletion of a reservoir. Many of the Australiqn coals we harac tested have displayed minerrlisation of the cleats and fractures. Acid leaching of these coal cores in the laboratory has led to an increase in permeability of up to two orders of magnitude.