The ability of pure CO₂ injection into an oil reservoir to bring about CO₂ storage is hindered by the fact that CO₂ is more mobile than oil. Most “mobility control” methods (such as foam injection) work only at low temperatures. This study investigates whether water-saturated CO₂ injection can provide mobility control at high pressures and temperatures. In this study, CO₂ and water-saturated CO₂ are injected into a Bentheimer sandstone core. Experimental runs are performed at 70 ℃ to simulate a low-temperature reservoir and 116 ℃ to simulate a high-temperature reservoir. The selected pressure ranges from 10.3 to 18.6 MPa. Results show that water-saturated CO₂ consistently exhibits lower mobility than pure CO₂. Hence, water-saturated CO₂ injection provides effective mobility control for both low- and high-temperature reservoirs, especially at higher pressure. The effectiveness of water-saturated CO₂ in reducing mobility compared to pure CO₂ increases exponentially with pressure. Despite the improved mobility control provided by water-saturated CO₂ injection, experimental observation finds net CO₂ stored and oil recovery to be similar to that of pure CO₂ injection, as CO₂ sweep efficiency is already high in experimental runs. However, at field-scale sweep efficiency is low. Therefore, field-scale simulations reveal a 19%-47% increase in net CO₂ stored during water-saturated CO₂ injection compared to pure CO₂ injection.