Analytical Solution of a Pressure Transmission Experiment on Shale Using Electrochemomechanical Theory

Abstract

Analytical solutions are derived for a pressure transmission experiment of a saturated charged compressible porous medium. The governing equations describe infinitesimal deformations of charged porous media saturated with a monovalent ionic solution. From the governing equations a coupled diffusion equation is derived for the three electrochemical potentials, which is decoupled introducing a set of normal parameters. The magnitude of the eigenvalues of the diffusivity matrix corresponds to the time scales for Darcy flow, diffusion of ionic constituents, and diffusion of electrical potential. The radial strain is very sensitive to the ionization.