A Simple Relation for Estimating Shale Permeability

Estimating matrix permeability from mercury injection capillary pressure measurements is one of the routine tasks in the petrophysical characterization of a formation. Performing this task is not yet possible for shale formations due to the absence of a realistic, convenient model, similar to those of Purcell (J Pet Technol 1(2):39-48, 1949) and Swanson (J Pet Technol 33(12):2498-2504, 1981). With this in mind, we present a simple relation, based on the acyclic pore model, for estimating shale permeability. We test the simple relation for seven samples extracted from three different formations. We discuss why other models, which are based on the random spatial distribution of the pore-throat sizes, are not applicable. The simple relation has major applications in the petroleum industry on a daily basis.