Because of the gas compressive storage effect, permeability as a
critical parameter describing the flow efficiency for liquid might not
apply to gas, but gas pressure diffusivity that takes into account of
gas compressive effect might do. In this study, pulse-decay experiments
were performed on one shale core under different pore pressures with
different pressure pulse magnitudes. A novel approach was put forward to
determining the intrinsic permeability and gas slippage factor through a
single pulse-decay experiment, which is significantly more efficient
than the conventional method that requires multiple operations. We
verify that gas pressure diffusivity instead of the permeability is the
appropriate measure of the efficiency of gas flow, given the fact that
the ratio of pulse size over diffusivity is roughly proportional to the
experiment duration. We obtain consistent results using different
empirical models to capture the intrinsic permeability, gas slippage
factor, and pressure-dependent apparent gas permeability simultaneously.