Development of anisotropic permeability during coalbed methane production

Although coal–gas interactions have been comprehensively investigated, prior studies have focused on one or more component processes of effective stress in driving only isotropic changes in coal permeability. In our previous work (Wu et al., 2009) a general porosity and permeability model was developed to represent the behavior of both the primary medium (coal matrix) and the secondary medium (fractures) under conditions of variable stress. In...