Analysis of Capillary Pressure Modeling for Two-Fluid-Phase Porous Medium Systems

Abstract:

Standard two-fluid-phase porous medium flow models include a closure relation describing what is generally called capillary pressure as a function of fluid saturation. This relation is well known to be both empirical and hysteretic. Recent advances have shown that a hysteresis-free state equation can be derived from integral topology for these systems. We used lattice Boltzmann simulations to replicate standard experimental methods for parameterizing so-called capillary pressure closure relations and to explore system states outside of these bounds. We show the fidelity of typical capillary pressure closure relations in comparison to the hysteresis-free state equation and we identify conditions for which the typical closure relations deviate most significantly from the true system state.