Mathematical modeling of carbonated water injection for EOR and CO₂ storage with a focus on mass transfer kinetics

Mathematical modeling of carbonated water injection (CWI) as an EOR and CO₂ storage technique is studied in this paper. When carbonated water (CO₂ saturated water) contacts oil during injection into oil reservoirs, CO₂ will migrate from water into the oil phase as it has higher solubility in hydrocarbons. Consequently, oil mobility, and in turn oil recovery, will increase. In addition, CO₂ can also be stored securely in the reservoir during CWI. The simulation study of CWI coreflood experiments presented in the literature show that during CWI, the CO₂ transfer between water and oil phases is slow and equilibrium state is not reached instantaneously. Hence, in this paper, a new compositional simulator is developed by including the kinetics of CO₂ transfer and a set of CWI coreflood experiment from the literature is simulated and studied in detail. A genetic algorithm based optimizer is applied to obtain the unknown parameters during simulation through a history matching experiment. The performance of the developed simulator is also compared with ECLIPSE300 commercial compositional simulator. The CO₂ storage profile is also studied using the simulation results. Generally, the developed simulator can be used to better understand the physics of CWI process for practical field applications and also as a solid foundation for kinetic based study of transport phenomena in porous media where the mass transfer is important and not instantaneous.