Modeling the Frequency?Dependent Effective Excess Charge Density in Partially Saturated Porous Media

In the context of seismoelectric and self-potential surveying, effective excess charge density electrokinetic coupling coefficient are key parameters relating measured electrical potential hydraulic characteristics explored porous media. this work, we present a novel flux averaging approach that permits to estimate frequency-dependent in partially saturated For this, conceptualize medium as bundle capillary tubes under oscillatory conditions. We account for pore size distribution (PSD) determine capillary-pressure saturation relationship corresponding medium, which, turn, scale saturation. then solve Navier-Stokes equations within capillaries and, by means flux-averaging procedure, obtain upscaled expressions for: (a) density, (b) permeability, (c) coefficient, which functions probing frequency. analyze explain these three different PSDs: fractal, lognormal, double lognormal. It is shown PSD have strong effect on response. The proposed has an excellent capability reproducing experimental measurements models literature, otherwise based well-known empirical relationships. results work constitute useful framework interpretation signals