Evaluation and monitoring of offshore CO₂ storage using marine electromagnetic sounding

Abstract The storage of offshore carbon dioxide (CO 2 ) is seen as an effective way to reduce greenhouse gas emissions. Submarine sediments offer a large volume and adequate permeability for the long-term injection of CO 2 at high pressure and low temperature. The selection and monitoring of offshore CO 2 storage sites have a significant impact on their stability and safety. Therefore, accurately identifying the distribution of offshore CO 2 storage is crucial for monitoring. This study utilizes marine controllable source electromagnetic sounding (CSEM) to investigate the sensitivity of identifying plume transport distributions in offshore CO 2 storage monitoring. The results show that CSEM is effective in monitoring the distribution of CO 2 plumes during offshore storage processes. The changes in electromagnetic field response can reflect the distribution of CO 2 plumes, providing important basis for the stability and safety of offshore CO 2 storage site selection and monitoring.