Estimation of CO2 storage capacity in saline aquifers in west of South China Sea

Many natural gas fields discovered in the west of South China Sea, such as DF1-1, YC13-1 and Ledong, are associated with high concentration of CO2. Considerable amounts of CO2 has to be separated from natural gas stream during the development of these gas fields each year. In order to reduce the emission of CO2 into the atmosphere, geological storage of CO2 in deep saline aquifers has been considered. This study is aimed at selecting saline aquifers in the Yinggehai region, intending to carry out a CO2 storage demonstration project. Five candidate aquifers are selected and their capacities of CO2 storage are estimated based on an accurate method which considers various mechanisms of CO2 storage in aquifers as well as the influence of aquifer structural features on CO2 migration and distribution. The assessment results show that all five aquifers are good candidates for CO2 storage with high storage potential to store all the CO2 expected during the demonstration project, and also can provide storage sites for the man-made CO2 in Hainan and Guangdong provinces in the near future.