A review on geological storage of marine carbon dioxide: Challenges and prospects

Abstract

Carbon capture, utilization, and storage (CCUS) is believed to be the most promising technology to mitigate climate change and global temperature rise. As an effective method for reducing carbon emissions, carbon dioxide (CO2) storage on the seabed can be achieved by injecting captured CO2 from offshore platforms into subsea storage sites, such as the sediment layers, depleted oil and gas reservoirs and deep saline aquifers, thereby permanently removing it from the atmosphere. Additionally, hundreds to thousands of meters of seawater above seabed storage layers provide naturally high seawater pressure and abundant barrier settings that can reduce leakage risk. Consequently, this has become an ideal storage location for long-term CO2 storage. In order to thoroughly investigate the mechanism and potential of marine CO2 storage and promote further development of CCUS, this paper provides a comprehensive description of theoretical research of marine CO2 geological storage, including storage mechanisms, storage capacity, wellbore flow, CO2 migration, cap rocks integrity and CO2 leakage monitoring. The implementation status of global engineering projects is summarized. Currently, there are relatively few successful marine storage projects globally, with the majority of others still in the research and testing stages. Finally, the challenges and prospects of marine CO2 storage are also discussed. This review demonstrates the enormous potential and promising future of marine CO2 storage, but there are also leakage risks. It can be avoided through in-depth theoretical research to clarify the entire process of storage mechanisms and take corresponding technological measures. Ultimately, a new technology for large-scale efficient injection and enhanced storage of marine CO2 storage will be formed.