An Experimental and Numerical Investigation of Crossflow Effects in Two-Phase Displacements

Abstract

Abstract In this paper we present flow visualization experiments and numerical simulations that demonstrate the combined effects of viscous and capillary forces and gravity segregation on crossflow that occurs in two-phase displacements in layered porous media. We report results of a series of immiscible flooding experiments in two-dimensional, two-layered glass bead models. Favorable mobility ratio imbibition and unfavorable mobility ratio drainage experiments were performed. We used preequilibrated immiscible phases from a ternary isooctaneisopropanol- water system, which allowed control of the interfacial tension (IFT) by varying the isopropanol concentration. The experiments performed had a wide range of capillary and gravity numbers. The experimental results illustrate the transitions from flow dominated by capillary pressure at high IFT to flow dominated by gravity and viscous forces at low IFT. The experiments also illustrate the complex interplay of capillary, gravity, and viscous forces that controls crossflow. The experimental results confirm that the transition ranges of scaling groups suggested by Zhou et al.7 are reasonable. We report also results of simulations of the displacement experiments by two different numerical techniques: finite difference and streamline methods. The numerical simulation results agreed well with experimental observations when gravity and viscous forces were most important and less well for capillary-dominated flows.