Development of risk assessment tool for CO₂ geological storage

In this paper, the authors review state of the arts of risk assessment about CO₂ geological storage. Then, the authors introduce our risk assessment tool under development, which aims to assist decision-making for safety and risk management legislations around CO₂ geological storage by way of optimum level of risk quantification. It is expected that our tool will contribute for evaluation of CO₂ injection, especially to shallower aquifers. The authors show example calculations of surface propagation of 0.1 to 10^-3 % of CO₂ release from 1-million ton/year injection. Calculated results are evaluated comparing with known CO₂ impact value. The most results of example air propagation analysis prove risks are negligible level. Exceptions are some special geometry like craters. We are thinking it is important to present rational reasons to distinguish issues whether to be negligible or not. The authors are expecting to accomplish the first prototype of our tool by the end of this fiscal year.