Experimental and Numerical Study to Investigate Dynamic Capillary Pressure Effect in Two-Phase Flow in Porous Media

Abstract

Experimental and Numerical Study to Investigate Dynamic Capillary Pressure Effect in Two-Phase Flow in Porous Media Simona Bottero, Majid Hassanizadeh Department of Earth Sciences, Utrecht University, P.O.Box 80021, 3508 TA Utrecht, The Netherlands It is known from literature that traditional equations describing two-phase flow processes in porous media may be inadequate in case of non-equilibrium or dynamic condition. In the latest theory an additional dynamic term is proposed such that capillary pressure may depends on both the rate of change of saturation in time and on saturation. In this work we investigate the dynamic effects on capillary pressure-saturation relationship in a homogeneous porous medium. A series of laboratory experiments are performed using water and Tetrachloroetylene (PCE). The experiments consist of a continuous cycle of drainage and imbibition where boundary pressures of 20, 30, 40 kPa are applied. Homogeneous sand is uniformly distributed in a column of 10 cm diameter and 22 cm high. Initially the sand is fully water saturated. A large pressure is then applied at the bottom of the column. As the pressure of PCE is much higher than the entry pressure of the porous media, PCE flows vertically upward in the sand replacing water. The water replaced by PCE and the PCE that flows out of the sample during the experiment are collected in an overflow reservoir. The cumulative flow of both phases is measured throughout the experiment. Pressure of both water and PCE phases and water saturation are monitored locally inside the sand sample at three different depths by means of six pore pressure transducers (PPT) and three tetra probe’s (TP) respectively. Beside laboratory experiments a series of numerical experiments are performed. In one set of experiments the traditional flow equations for two-phase flow are used. In another set of experiments the effect of the additional dynamic term are studied. Measured and simulated capillary pressure-saturation curves are compared and discussed in this presentation.