On Estimating the Water Content of CO2 in Equilibrium With Formation Brine

Abstract

Water content of carbon dioxide (CO2) is an important parameter in engineering applications, such as CO2 storage in deep saline aquifers and enhanced oil recovery processes. A large number of experimental data have been reported on solubility of CO2 in brine. However, experimental data on water content of CO2 in equilibrium with formation brine are not reported in the literature. Water content of natural gas is traditionally calculated by general water content charts; however, these charts are not available for CO2 in equilibrium with formation brine. Using an accurate fugacity and activity model available in the literature, the authors developed an efficient and simple procedure to estimate the water content of CO2 in equilibrium with formation brine. To validate the developed procedure, the predicted CO2-rich phase water content is compared with the reported experimental data in the literature and other predictive models for CO2-water system. A CO2 water content chart is presented that can be simply used to predict the water content of CO2 in equilibrium with formation brine. The procedure presented may be used for generating necessary input data for flow simulation of CO2 storage in deep saline aquifers.