Simulation studies of effect of flow rate and small scale heterogeneity on multiphase flow of CO2 and brine

A series of steady state core-scale multiphase flow experiments at a wide range of fractional flows of CO2 (95%, 79%, 61%, 34%, 26%) and different total flow rates have been simulated by using TOUGH2 MP with ECO2N simulator. CO2 and brine were co-injected into the brine saturated core at reservoir conditions (P=12.4MPa and T=50 degrees C), average carbon dioxide saturations and sliced average saturation along the core were measured after steady state. Moreover, carbon dioxide saturation distributions can also be observed in the simulations to study the heterogeneous effect on displacement efficiency. To investigate the heterogeneity and gravity effect on brine displacement efficiency, 95% fractional flow of CO2 and 5% brine were injecting into homogeneous and heterogeneous cores in the absence of gravity and including gravity at specific flow rates. When injection rates are large enough (viscous-dominated regime) and low enough (capillary-dominated regime), gravity effect can be neglected. These high resolution simulations can help us to understand the interplay of three physical forces on brine displacement efficiency. (C) 2010 Published by Elsevier Ltd.