Despite significant effects on macroscopic migration and distribution of CO
2 injected during geological sequestration, only limited information is available on wettability in microscopic scCO
2-brine-mineral systems due to difficulties in pore-scale observation. In this study, a micromodel had been developed to improve our understanding of how scCO
2 flooding and residual characteristics of porewater are affected by the wettability in scCO
2-water-glass bead systems. The micromodel (a transparent pore structure made of glass beads and glass plates) in a pressurized chamber provided the opportunity to visualize scCO
2 spreading and porewater displacement. CO
2 flooding followed by fingering migration and dewatering followed by formation of residual water were observed through an imaging system. Measurement of contact angles of residual porewater in micromodels were conducted to estimate wettability in a scCO
2-water-glass bead system. The measurement revealed that the brine-3M NaCl solution-is a wetting fluid and the surface of glass beads is water-wet. It is also found that the contact angle at equilibrium decreases as the pressure decreases, whereas it increases as the salinity increases. Such changes in wettability may significantly affect the patterns of scCO
2 migration and porewater residence during the process of CO
2 injection into a saline aquifer at high pressures.
Keywords: Micromodel;Supercritical $CO_2$;Visualization;Residual phase;Contact angle;