Critical Evaluation and Improvement of Methods for Determination of Matrix Permeability of Shale

Abstract

Abstract Previously available interpretation methods developed for determination of gas permeability from crushed samples are mostly applicable for conventional porous rocks of reasonably high permeability. This paper presents an improved formulation which honors the relevant physics of fluid, transport, and shale-rock conditions for determination of extremely-low nanodarcy gas permeability of shale by pressure-pulse transmission testing of crushed shale-rock particles. The new method is demonstrated by means of typical simulated test conditions. Assuming viscous, Darcy flow instead of the nonDarcy flow yields almost twice the actual value of the intrinsic permeability for this case.