Effect of organic acids on CO2-rock and water-rock interfacial tension: Implications for CO2 geo-storage

A small concentration of organic acid in carbon dioxide (CO2) storage formations and caprocks could significantly alter the wettability such into less water-wet conditions, decreasing CO2-storage potential containment security. Recent studies have attempted to infer influence on rock–CO2–brine systems by measuring advancing receding contact angles. However, no investigated contamination capacities from rock-fluid interfacial tension (IFT) data because solid-brine solid-CO2 IFT values cannot be experimentally measured. Equilibrium angles datasets were used evaluate viability CO2 rocks caprocks. First, rock brine-CO2 measured compute Young's equilibrium Subsequently, rock-brine rock-gas at geo-storage conditions computed via a modified form Neumann's equation state. For two storage-rock minerals (quartz calcite) one caprock mineral (mica), results demonstrated high CO2-brine pressure (0.1–25 MPa) increasing concentrations stearic (10?5 10?2 mol/L). Rock-brine increased with but remained constant pressure. In all order hydrophobicity surfaces is calcite > mica quartz. At 323 K, 25 MPa, mol/L, quartz became intermediate-wet angle 89.8°, whereas CO2-wet 117.5° 136.5°, respectively. This work provides insight effects acids inherent interactions.