Estimation of Geologic Storage Capacity of Carbon Dioxide in the Bukpyeong Basin, Korea Using Integrated Three-Dimensional Geologic Formation Modeling and Thermo-Hydrological Numerical Modeling

A conventional method, which was suggested by NETL (2007), has been widely used for estimating the geologic storage capacity of carbon dioxide in sedimentary basins. Because of its simple procedure, it has been straightforwardly applied to even spatially very complicate sedimentary basins. Thus, the results from the conventional method are often not accurate and reliable because it can not consider spatial distributions of fluid conditions and carbon dioxide properties, which are not uniform but variable within sedimentary basins. To overcome this limit of the conventional method, a new method, which can consider such spatially variable distributions of fluid conditions and carbon dioxide properties within sedimentary basins, is suggested and applied in this study. In this new method, a three-dimensional geologic formation model of a target sedimentary basin is first established and discretized into volume elements. The fluid conditions (i.e., pressure, temperature, and salt concentration) within each element are then obtained by performing thermo-hydrological numerical modeling. The carbon dioxide properties (i.e., phase, density, dynamic viscosity, and solubility to groundwater) within each element are then calculated from thermodynamic database under corresponding fluid conditions. Finally, the geologic storage capacity of carbon dioxide with in each element is estimated using the corresponding carbon dioxide properties as well as porosity and element volume, and that within the whole sedimentary basin is determined by summation over all elements. This new method is applied to the Bukpyeong Basin, which is one of the prospective offshore sedimentary basins for geologic storage of carbon dioxide in Korea. A three-dimensional geologic formation model of the Bukpyeong Basin is first established considering the elevation data of the boundaries between the geologic formations obtained from seismic survey and geologic maps at the sea floor surface. This geologic formation model is discretized into 170,808 hexahedral elements. Thermo-hydrological numerical modeling is then performed for the geologic formation model using TOUGH2 (Pruess et al., 1999). Finally, the geologic storage capacity of carbon dioxide in the Bukpyeong Basin is estimated to be about 345 Mton in the supercritical carbon dioxide region and about 1,883 Mton in both supercritical and liquid carbon dioxide regions. It is expected that the new method, which is suggested and applied in this study, can be utilized as reasonable and practical guidelines when more quantitative estimation of the geologic storage capacity of carbon dioxide in a sedimentary basin is required. This work was supported by the Energy Efficiency and Resources Program grant (No. 2010201020001A) funded by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), Ministry of Knowledge Economy, Republic of Korea.