Simulating the CO2 Interface in Hydraulically Communicating Water-Oil Zones

This work examines CO2 injection into hydraulically communicating water-oil zones using a CFD model based on the Volume of Fluid (VOF) method. Validation against analytical CO2-brine solutions confirms accurate pressure behavior in the viscous regime. Three-phase simulations show that the intermediate oil layer acts as a dynamic buffer, delaying CO2 -brine contact and modifying plume migration. A distinct outward-moving pressure inflection point is identified, providing a practical proxy for tracking the CO2 plume front in complex multi-fluid storage sites.