A Compositional Model for CO2 Floods Including CO2 Solubility in Water

Abstract

Summary This paper presents a three-dimensional, three-phase compositional model for simulating CO2 flooding, including CO2 solubility in water. In this model, CO2 is allowed to dissolve in the aqueous phase, while all other components, except water, exist in the oil and gas phases. Oil- and gas-phase densities and fugacities are modeled by a cubic equation of state. The aqueous phase properties are functions of the amount of dissolved CO2.CO2 solubility is computed using a CO2 fugacity coefficient table that is converted internally from input CO2 solubility data as a function of pressure at reservoir temperature. Correlations for computing the solubility of CO2 in water and other properties of CO2-saturated water are presented. The results for simulation runs with and without CO2 solubility in water are shown for comparison.