Study on role of simulation of possible leakage from geological CO ₂ storage in sub-seabed for environmental impact assessment

This paper summarizes the selection of short-term leakage scenarios and the results of numerical simulations based on the scenarios in order to assess the impact of CO₂ on the ocean environment. Two leakage scenarios are considered: either CO₂ migrates from an aquifer to the seafloor through two discontinuous faults, or it migrates through an abandoned well. The distribution and leakage amount of CO₂ are estimated for each scenario by using the multi-phase flow simulator TOUGH2. Then, sensitivity analyses for parameters corresponding to the permeability of the leakage path are conducted. The results suggest that differences of permeability significantly affect the total amount and time at which CO₂ leakage starts.