Data for: CHARACTERIZATION OF TWO-PHASE FLOW PATTERNS IN POROUS MEDIA BY CAPILLARY AND VISCOUS FORCES ESTIMATION

This paper proposes a method for characterization of the two-phase flow patterns (viscous fingering, capillary fingering, stable front, and crossover) in porous media. The approach is based on separate estimation of the capillary and viscous forces and subsequent calculation of the ratio between them (designated as W). The value W determines the dominance of capillary force and is essentially the inverse capillary number. The advantage of this approach consists in taking to account the scale of the samples and predicting the flow patterns using parameters measured in laboratory conditions. The balance between viscous and capillary forces is controlled by surface tension and fluid viscosities. For flow simulation, the lattice Boltzmann equations and the color-gradient model are applied. The values of W equal to 0.5 and 2, which define the boundary of the crossover zone and separate it from the flow patterns, were determined and the proposed method was successfully validated on three two-dimensional samples of porous media with different permeability coefficients. It was revealed a directly proportional effect of permeability on W. As a result, the surface tensions, which determine the boundaries of patterns, are shifted towards smaller values with increasing permeability. Also, the effect of the permeability and flow patterns on the displacement efficiencies before, after and at quasi-steady regimes was investigated. The tendency to efficiency decrease with increasing surface tension and decrease in viscosity ratio was revealed for quasi-steady regime. The absent of the mobile wetting fluid after breakthrough is detected for crossover and capillary fingering patterns. The no-displacement regime after breakthrough and, consequently, effectiveness drop to minimal values in quasi-steady regime occurs at lower surface tensions with increasing permeability.