Modeling WAG Experiments with Three-phase Hysteretic Fractal Model

Water Alternating Gas (WAG) processes promise optimized results in applications such as CO2 storage in reservoir rocks, enhanced oil recovery or soil remediation. In this kind of processes, hysteretic phenomena take place due to imbibition/drainage processes or to varying wettability affecting the three-phase relative permeabilities. The optimization of WAG process requires improving the predictive capabilities of current three-phase relative permeability models. In order to emphasize the impact of relative permeability hysteresis on the numerical simulation of WAG injection a series of experiments were performed : injection of nitrogen at residual oil saturation, WAG experiment at ambient conditions, WAG experiment at reservoir conditions. The experiments were then simulated with three available methods : Carlson's hysteretic model and Stone2, Killough's hysteretic model and Stone1 and the three-phase hysteretic fractal model (SPE 65127). The three models were applied and compared with the experimental results and the three-phase fractal hysteretic model which solely applies to both WAG ambient and WAG reservoir conditions was successfully used.