A New Numerical Method to Investigate Capillary End Effects in Coreflooding

Summary Capillary pressure imbibes wetting phase fluid into rock, which tends to prevent the wetting phase from leaving end of a core plug during non-wetting phase displacing wetting phase. Starting from the definition of capillary pressure, this work explicitly introduces capillary pressure into the pressures of oil phase and water phase. For the simulation of the CEE, we apply the sudden change in the capillary pressure at the entrance or exit of the core plug in the model. The experimental setting is imitated in the numerical simulation. The inlet is a flux boundary, and the velocity is equal to the injection rate, while the outlet is a constant pressure boundary, and the pressure is equal to the experimental backup pressure. Using the tailored simulator, we systematically simulated the imbibition and drainage processes for water-wet and oil-wet cores. Taking the case of ignoring capillary pressure as a reference, the impact of CEEs on the production and pressure drop during displacement were analyzed and evaluated.