Experimental Study of Dynamic Capillary Pressure Effect in Two-phase Flow in Porous Media

There is strong evidence in the literature that traditional equations describing two-phase flow processes in porous media may be inadequate under non-equilibrium or dynamic conditions. There exist theories that propose that the capillary pressure depends not only on saturation but also on the time rate of change of saturation. In this work, the significance of dynamic effects in the capillary pressure-saturation relationship is investigated through experiments in a homogeneous porous medium. A series of laboratory experiments were performed involving flow of two immiscible fluids, water and Tetrachloroethylene (PCE), in a homogeneous column. The experiments consist of a continuous cycle of drainage, imbibition, and drainage, where a large pressure of 20 kPa is applied to the displacing fluid. Contrary to traditional procedure, no hydrophobic or hydrophilic membranes were used in this experimental set-up. In this paper, the experimental set-up is described and preliminary results are presented. Capillary pressure and saturation curves measured under dynamic and static conditions are shown. The data are analyzed and the value of the dynamic coefficient τ is calculated.