Simultaneous measurement of hysteresis in capillary pressure and electric permittivity for multiphase flow through porous media

Abstract

We present a tool that simultaneously measures the complex permittivity and the capillary pressure characteristics for multiphase flow. The sample holder is a parallel plate capacitor. A precision component analyzer is used to measure the impedance amplitude and phase angle as a function of frequency ([Formula: see text] to [Formula: see text]). The complex impedance of the (partially) saturated sample is directly related to the effective complex permittivity. We have conducted main drainage and main imbibition cycles for unconsolidated sand-water-gas [Formula: see text] systems at 8-bar pressure and at temperatures between [Formula: see text] and [Formula: see text]. Hysteresis in capillary pressure and electric permittivity, as a result of phase distribution, is found between drainage and imbibition for [Formula: see text] and becomes more pronounced at higher water saturations. Good agreement of the measured electric permittivity with the complex refractive index model indicates that induced polarization is not observed for [Formula: see text] and the water saturation is reasonably predicted. The experiments have been performed to study the capillary pressure behavior during [Formula: see text] sequestration.