The effects of SO2 contamination, brine salinity, pressure, and temperature on dynamic contact angles and interfacial tension of supercritical CO2/brine/quartz systems

The successful implementation of geologic CO2 sequestration schemes in deep saline aquifers requires storage sites with minimum risk of CO2 leakage through the caprock and maximum storage capacity in the reservoir rock. Some of the essential parameters that affect the effectiveness of a storage scheme are the density of CO2, the interfacial tension between CO2-rich and aqueous phases, and the wettability of reservoir rock and caprock in contact with these fluids at reservoir conditions (Tokunaga and Wan, 2013). In this study, densities, interfacial tensions, and dynamic contact angles of CO2/brine/quartz systems at high temperatures and pressures were simultaneously measured using the Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method. Measurements were performed at pressures (2000-4000 psig), temperatures (50-100 °C), and brine salinities (0.2-5 M) relevant to carbon sequestration in deep saline aquifers. These experimental conditions had not been investigated in the past. Additionally, the effect of SO2 as a co-contaminant (0-6 wt%) was investigated on these parameters for the first time. Contact angle hysteresis was also examined and the possible implications of the results on different CO2 trapping mechanisms were discussed.