Influences of temperature and pressure on CO2 solubility in saline solutions in simulated oil and gas well environments

Abstract The phase equilibria of H 2 O CO 2 NaCl systems is of general interest to many scientific disciplines and technical fields. One aspect is the CO 2 -mediated corrosion of oil country tubular goods in deep saline aquifers. In this study, CO 2 solubility experiments were conducted in simulated oil and gas well environments using a novel experimental apparatus and method. The solubility of CO 2 in deionised water and NaCl solutions was measured at temperatures of 303.15–363.15 K and pressures of 50–250 bar. The impacts of temperature, pressure and salinity on CO 2 solubility are analysed quantitatively and qualitatively and are consistent with published data. CO 2 solubility increases with pressure in all cases, and pressure inhibits the effect of temperature on CO 2 solubility to some extent. An interesting phenomenon is that CO 2 solubility increases with pressure much faster at low pressures than at high ones. A transition pressure of 150 bar was determined at medium-low temperature and low salinity.