A THERMODYNAMIC MODEL FOR MUTUAL SOLUBILITY OF WATER AND CO_2 IN BRINES

摘要

Modeling of CO_2 disposal into saline formations requires accurate formulation for the PVT properties and mutual solubility of CO_2 and water as a function of temperature, pressure and salinity. We have previously developed a numerically efficient thermodynamic model for phase partitioning in the CO_2-H_2O system without salinity. Our formulation included provisions to deal with the non-ideality of CO_2 at near-critical conditions and was shown to provide an excellent match to experimental data in the range 12-100°C and up to 600 bar. The present paper reports some results obtained by extending this formulation to account for dissolved salts in the aqueous phase. Our main focus is on the partitioning of CO_2 and H_2O components between the different fluid phases.