The Investigation into Sand Production Under Supercritical Carbon Dioxide (SC-CO₂) Flooding in Sandstone Reservoirs Using the Resolved CFD-DEM Method

Supercritical carbon dioxide (SC-CO₂) flooding technology can significantly enhance the oil recovery but the impact on sandstone reservoirs remains unclear. In this study, the mechanisms of sand production during SC-CO₂ flooding are systematically studied via the coupled resolved computational fluid dynamics (CFD) and the discrete element method (DEM), with models of water flooding, liquid CO₂ flooding, and no flooding explored for comparison. The macro and microscopic mechanisms of particles migration during flooding are monitored and analyzed. The simulation results indicate that SC-CO₂ flooding proves to be an effective method for mitigating sand production in reservoirs due to its low viscosity. In the water flooding model, the drag force increases due to the higher density, and the stability of the flow field decreases during flooding caused by the mixture of two-phase flow, resulting in the increased sand production. In the case of liquid CO₂ flooding, the amount of produced sand is almost the same as the model without flooding. The parameter analysis shows that the sand production increases with the increase of the viscosity and density of SC-CO₂, while the sand production decreases first and then increases with the increase of interfacial tension. These findings offer a valuable theoretical foundation that endorses the utilization of SC-CO₂ flooding techniques for enhancing oil recovery in sandstone reservoirs.