Numerical Simulation of Behavior of Carbon Dioxide Injected into Target Geologic Formations in the Bukpyeong Basin, Korea

A series of thermo-hydrological numerical simulations was performed to predict and analyze behavior of carbon dioxide injected into target geologic formations in the Bukpyeong Basin, which is one of the prospective offshore basins for geologic carbon dioxide storage in Korea. The results of the numerical simulations for the two areas in the basin show that the spatial distribution, structure (layered structure), and hydrological properties (anisotropy of intrinsic permeability) of the target geologic formations have significant impacts on three-dimensional behavior of carbon dioxide injected. The horizontal movement of carbon dioxide along the spatial distribution of a target geologic formation (Unit C-4) is more dominant than the vertical movement. As the injection amount of carbon dioxide increases, carbon dioxide plume expands furthermore and reaches to the shallower depth region from the mean sea level. Even in case of the maximum injection amount of carbon dioxide, carbon dioxide does not leak through the top boundary (sea floor) of the modeling domain for both areas. It indicates that carbon dioxide can be stored in the two areas up to their effective storage capacities of free fluid phase carbon dioxide, which was estimated in authors' previous study. As time progresses, carbon dioxide stored by hydrodynamic trapping decreases, while carbon dioxide stored by solubility trapping increases. The total mass of carbon dioxide stored by solubility trapping evaluated in this study is significantly greater than that estimated in authors' previous study. It indicates that the storage efficiency of aqueous phase carbon dioxide is greater than that of free fluid phase carbon dioxide. Therefore, this difference in the storage efficiencies of the free fluid and aqueous phases of carbon dioxide must be properly considered when more rigorous effective storage capacities of carbon dioxide are to be estimated on basin and even site scales. This work was supported by the Energy Efficiency and Resources Program funded by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), Ministry of Trade, Industry and Energy, Republic of Korea.