Large-scale numerical simulation of CO_2 geologic storage and its impact on regional groundwater flow: A hypothetical case study at Tokyo Bay, Japan

摘要

With the help of massively parallelized computing techniques, a comprehensive, large-scale numerical simulation of CO_2 geologic storage that predicts not only CO_2 migration but also its impact on regional groundwater flow was performed. As a case study, a hypothetical industrial-scale injection of CO_2 at the Tokyo Bay, surrounded by the most industrialized area in Japan, was considered. In the simulation, CO_2 is injected into a storage aquifer at about 1km depths under the Tokyo Bay from 10 wells with a total rate of 10 million tons/year for 100 years. A regional hydrogeological model with an area of about 60km × 70km around the Tokyo Bay was discretized into approximately 10 million gridblocks. To solve the high-resolution model efficiently, we used a parallelized multiphase flow simulator TOUGH2-MP/ECO2N on a highest performance supercomputer in Japan, the Earth Simulator (5120 CPUs). The results suggest that even if containment of CO_2 plume is ensured, pressure buildup in the order of tens of meters can occur in shallow confined layers of extensive regions including urban inlands.