Energy & Fuels, Vol.33, No.3, 1990-1997, 2019
Estimation of Shale Apparent Permeability for Multimechanistic, Multicomponent Gas Production Using Rate Transient Analysis
Gas-producing shale and ultratight reservoirs are playing a key role in the energy industry and the global gas market. Compositional simulation of gas production from shale media in the presence of different mechanisms such as viscous flow, slip flow (Klinkenberg effect), Knudsen diffusion, sorption, pore radius variation, and real gas effect is a computational challenge. In this work, we present a model that takes into account all of the noted mechanisms of gas transport in shale media. It is shown that the compositional effect of gas in shale media can be lumped into a single component by introducing an apparent gas permeability, which can be estimated from the conventional rate transient analysis. The main contribution of this study is a workflow incorporating the relevant physics into a single term (apparent permeability) that will substitute the Darcy permeability. This procedure reduces the simulation runtime substantially and will find applications in reservoir characterization and simulation of production from shale gas reservoirs.