Gas slippage in anisotropically-stressed shale: An experimental study

Abstract Due to the extensive presence of nanopores, the slippage effect is frequently invoked in shale to enhance gas transport, therefore, causing the more than expected gas production. We conducted laboratory experiments on cubic shale samples (drilled from the Longmaxi Formation in southwestern China) to study the gas slippage effect with respect to anisotropic stresses and low pore pressures. The pore size distribution (PSD) of Longmaxi shale demonstrates that pore sizes mostly lie in the range of 8–400 nm and that gas transport in shale generally exists within the slip flow regime (0.001