Comprehensive evaluation of CO2 geological storage: Mechanisms, methods and project progress

The utilization and permanent storage of carbon dioxide (CO 2 ) through carbon capture and storage (CCS) technology helps reduce greenhouse gas emissions in the atmosphere and is one of the potential strategies to address global climate change. This study focuses on the field of geological storage within CCS technology, covering aspects such as CO 2 -enhanced oil recovery (CO 2 -EOR), permanent storage, and deep-sea storage. The research direction is consistent with the requirement of "taking urgent action to combat climate change and its impacts" in the United Nations Sustainable Development Goal of Climate Action. The main objective of this study is to comprehensively sort out the current research status, technical practices, and development potential in the field of CO 2 geological storage, clarify the challenges that need to be addressed and the directions for in-depth research, so as to promote the development of CCS technology. The study adopts a combination of review and analysis methods. By comprehensively evaluating global CO 2 storage demonstration projects, it systematically sorts out key information such as potential CO 2 sources, estimated storage capacity, relevant stratigraphic and fault structures, CO 2 transportation, and injection. At the same time, combined with global deep-sea storage technical practices, it analyzes the development trend of CO 2 ocean storage. The research results show that: at present, in global demonstration projects of CO 2 geological storage, a large number of research results have been accumulated in terms of CO 2 sources, storage capacity, stratigraphic structures, transportation and injection, and various strategies for geological storage using large-scale projects have been proposed; deep-sea and seabed-based CO 2 storage show good development potential, but they also face challenges such as complex formations, high costs, injection damage, and risks of migration and leakage. Meanwhile, in-depth research is still needed on aspects such as the self-containment effect of gas hydrates, monitoring technologies, and hazard mitigation strategies. In summary, CO 2 capture and storage technology is economically feasible in reducing greenhouse gas emissions. Certain research foundations and practical progress have been made in the fields of geological storage and deep-sea storage, but further research on existing challenges is still required to promote the improvement and application of CCS technology.