Effect of interfacial forces on two‐phase capillary pressure—saturation relationships

Abstract

Quantitative descriptions of two‐phase flow in the subsurface require knowledge of the capillary pressure‐saturation relationships. The effect of interfacial forces on the drainage capillary pressure‐saturation relationship for organic liquid‐water systems is usually expressed by the ratio of the liquid‐liquid interfacial tensions as given by Leverett's (1941) function. To assess the appropriateness of this approach for primary drainage of organic liquid‐water systems typical of hazardous waste sites and to evaluate its extendability to spontaneous imbibition, measurements were made of these relationships for various immiscible liquid systems in unconsolidated sand. The results showed increasing deviations with decreasing interfacial forces between the measured values and those predicted by a ratio of interfacial tensions. To improve the predictive capability of Leverett's function, forms including the intrinsic contact angle and roughness were examined. Scaling of the capillary pressure relationships was best achieved by including a correction for both interface curvature and roughness. These corrections became significant for drainage for contact angles larger than 35°–55°, and for imbibition for contact angles larger than 15°–25°. None of the forms of Leverett's function examined predicted the increased residual saturation with decreasing interfacial forces observed in this study. Consequently, their ability to scale the measured data was predicated on posing the saturation of the wetting phase in terms of the variable effective saturation.

Wetting front instabilities: a three-dimensional experimental investigation

“…The finger diameters increased with decreasing surface tension. If the effects of contact angle on capillarity were considered (see Demond and Roberts 1991), the effect of a contact angle greater than zero would result in a decrease in capillary pressure. This decrease in capillarity should result in a decrease in finger diameter, which is opposite to what was observed.…”

An Analytical Model for Capillary Pressure–Saturation Relation for Gas–Liquid System in a Packed-Bed of Spherical Particles

“…Several authors have performed experiments on capillary porous media using various packing materials (Leverett 1941;Dombrowski and Brownell 1954;El-Genk et al 1983;Dullien et al 1989;Demond and Roberts 1991;Bradford and Leij 1995;Kramer 1998;Lago and Araujo 2001;Ishakoglu and Baytas 2005;Dodds and Srivastava 2006). Results from these experiments are not unambiguous and several differing theories prevail.…”

Folyadék-visszatartás, folyadékvezetés és porozitás összefüggései vízzel és/vagy szerves folyadékkal telített talajokban I. Folyadék-visszatartó képesség — Szemle

“…a folyadékok sűrűségéből képzett hányadossal, a határfelületi feszültségek ismeretében, a nedvesedési szög és a porozitás, illetve differenciált porozitás figyelembevételével (pl. DEMOND & ROBERTS, 1991;DANE et al, 1992;BRADFORD & LEIJ, 1995;MOSELEY & DHIR, 1996;İSHAKOGLU & BAYTAŞ, 2005). A módosított verziók elméleti alapja azonban azonos, a Leverett-egyenlet hibáit nem küszöbölték ki (MAKÓ & HERNÁDI, 2012).…”