CO2 geological storage represents a critical step in achieving carbon neutrality, with immense potential in saline aquifer sequestration. This study focuses on the Weyburn oilfield, utilizing the transition state theory of geochemical reactions and wettability hysteresis theory to establish a numerical model for CO2 sequestration in saline aquifers, encompassing structural, residual, dissolution, and mineralization sequestration mechanisms. The model is complemented by a geophysical interpretation of 4D seismic data from the field site, exploring the evolution of CO2 geological storage in saline aquifers and the impact of plume flow migration. Simulation results indicate that during the injection phase, CO2 migrates vertically due to buoyancy forces and laterally driven by injection pressure in the horizontal direction. In the sequestration phase, vertical migration dominates, with slow horizontal migration. Additionally, CO2 accumulates at the top, forming a reverse cone-shaped gas accumulation zone. This results in a gradual increase in the molar mass fraction and saturation of CO2 within the sequestration body, aligning with the geophysical interpretation of 4D seismic data. This study provides valuable insights into understanding CO2 migration patterns following injection and informing the safe monitoring of CO2 sequestration in saline aquifers.