CO2 geological storage is the primary means of achieving large-scale, low-cost emission reductions. Compared with onshore basins, storage in offshore basins has the advantages of larger storage volume and less impact on people and the environment. At the same time, there are also challenges such as high cost and technical difficulty for storage. At present, there are many researches on the selection and suitability evaluation of CCS in China, and there are also very successful demonstration applications, while the research on CO2 geological storage in sea areas is relatively few. Taking Zhuyi Depression of Pearl River mouth Basin in the South China Sea as an example in this paper, with the goal of meeting the storage capacity of one million tons per year. Making statistics on the factors affecting the suitability of CO2 storage of oil and gas-bearing structures in the depression from three aspects: geological characteristics, storage economy and storage safety, and constructs a screening index system of CO2 geological storage field, which includes 3 levels and 18 evaluation factors. The index weight of each evaluation factor is calculated by AHP. The suitability of CO2 sealing of selected oil and gas-bearing structures is quantitatively evaluated by multi-source information overlap analysis. The results show that the Xijiang 23 and other oil-bearing structures in the west of Huizhou Sag have priority as the storage field. The results of this study can provide reference for the implementation and management decision of CO2 saline aquifers storage in this area.
Keywords CO2 geological storage, saline aquifers, index weight, Zhuyi Depression