Numerical pore-scale modeling of three-phase fluid flow: Comparison between simulation and experiment

It has been recently shown experimentally by Øren and Pinczewski [SPE Form. Eval. 7, 70 (1992); 9, 149 (1994)] that on the pore scale the presence of continuous wetting and spreading films is vitally important in describing the mobility of the various fluid phases in three-phase fluid flow. In this paper we put in place a numerical, pore-scale model to describe three-phase drainage dominated flow. Our model incorporates all the mechanisms observed in glass micromodel experiments. The pressures of all phases are calculated explicitly so that no ad hoc rules need be introduced to describe fluid flow. In doing this we are able to reproduce many of the experimentally observed characteristics of three-phase flow, i.e., multiple, simultaneous displacements, flow through thin wetting and spreading films, and double drainage events. The numerical simulations are carried out for a variety of wetting and spreading conditions, i.e., oil-wet, water-wet, positive spreading, and negative spreading, and in all cases we see good agreement with micromodel experiments.