Regional CO₂ solubility trapping potential of a deep saline aquifer in Pohang basin, Korea

This paper presents regional CO₂ solubility trapping potential for stable CO₂ storage as immobile phase and decomposed form while CO₂ migrates through flow pathways characterized by the geological structure of an aquifer in Pohang basin, SE offshore Korea. The saline aquifer in Pohang basin has been selected as a target formation for geologic carbon storage due to favorable geologic structures and sedimentary strata defined through seismic survey. The aquifer is confined by southeast and northwest faults, and structure is unconfined and sloping toward the northeast direction. The main target within the aquifer to store CO₂ contains west plunging anticlines. In order to enlarge contact area of CO₂ with brine and improve injectivity, the CO₂ injector is located on marginal anticlines or small synclines. This structure may significantly affect CO₂ flow dynamics through upward migration pathways within the aquifer. We, in this area, provide estimates for CO₂ solubility trapping affected by dynamic CO₂ migration pathways and present different types of CO₂ trapping potentials. The numerical results based on thermodynamic equilibrium equation provide regional CO₂ solubility trapping potential which has a linear relationship with brine salinity. We suggest that dynamic migration pathways resulting from geological structure are significantly important to increase CO₂ solubility trapping potential in geological storage of CO₂.