Pore scale visualization and simulation of miscible displacement process under gravity domination

Abstract

This paper presents both visualization and flow simulation of glass micromodel experiments which are performed to visualize the gravity dominated miscible gas displacement process. This approach enables to simulate the exact porous pattern on which the micromodel experiments are performed. At first, a porous pattern for experiments was constructed and then etched onto a glass plate. An experiment was performed at 45o dip angle at injection rate of 0.002 ml/min to visualize the displacement of two miscible fluids under gravity domination. Butanol and Iso-octane were selected as in situ and injected fluids respectively. The mobility and density ratio of these two fluids are comparable with medium API oil and CO2 at reservoir conditions. For simulation, the porous pattern was exported to the finite element analysis software, COMSOL Multiphysics, so that simulations of micromodel experiments were performed for the same porous pattern as used for experiments. To simulate miscible displacement, the Navier-Stokes and continuity equations were used to calculate pressure and velocity fields in the solute and solvent regions, while the convection-diffusion equation was used to calculate solute concentration in the mixture during the displacement. The experimental visual results were processed and compared with the simulation results indicating a good match between experiments and simulation. The validated model can be used to simulate and to find the optimized conditions and controlling parameters at different conditions for the gravity assisted miscible displacement process.