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

• Carbonated water injection (CWI) as an EOR and CO2 storage strategy is studied here.
• A new mathematical model is developed to capture the CO2 transfer kinetics during CWI.
• The mathematical model is used to simulate and study a real CWI coreflood experiment.

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.