二酸化炭素貯留適地調査事業の概要と現況について

抄録

The project "Investigation of potential sites for CO₂ storage in Japan" has been carried out since 2014 as a joint project of the Ministry of Economy, Trade and Industry and the Ministry of the Environment with the aim of selecting multiple large-scale storage sites capable of storing more than 100 million tons of CO₂. Japan CCS Co., Ltd. has been entrusted with this project, and while developing a process for selecting suitable storage sites, has been conducting seismic survey, geological analysis, numerical simulation of geological CO₂ storage, etc. for candidate sites for storage offshore Japan. As a result of storage capacity evaluation using 3D seismic data until March 2020, the amount that can be stored in a total of seven sites was estimated to be about 9 billion tons. This storage capacity is evaluated by the volumetric method which evaluates the capacity of the pore space in reservoir rock, and does not take into account seal ability, injection well arrangement, injection properties, CO₂ movement, etc. In order to reduce uncertainty in assessing the amount of storage and to improve the accuracy of risk assessment, it is necessary to drill survey wells. The current goal is to select about three candidate sites for survey well drilling from a comprehensive perspective among prospective sites suitable for storage by around 2023.