A Novel Permeability Model of Coal Considering Gas Slippage and Gas Sorption-Induced Strain

As an unconventional natural gas, coalbed methane (CBM) has been recognized as a significant fuel and chemical feedstock that should be recovered. Permeability is key factor controls CBM transport in coal. The slippage effect influential phenomenon occurs during gas penetration processes, especially low-permeable media. Apparent permeability may differ greatly from intrinsic due to slippage. However, the not considered most analytical models. Based on cubic law, new model suited for analysis of coal under different stress conditions derived, taking into consideration matrix shrinkage/swelling desorption/adsorption. To enhance its application, derived constant hydrostatic pore pressure. then compared with existing models, reliability verified by comparison between prediction experimental data conditions.