CO₂ Storage in Saline Aquifers: Design of a Demonstration Project to Dispose CO₂ Associated with Natural Gas Fields in South China Sea Available to Purchase

DF1-1 gas field in the west of the South China Sea is associated with high concentration of CO₂. Many options have been assessed by the operator (CNOOC) in recent years in order to dispose the CO₂ separated from the gas stream. In this study, geological storage of CO₂ into offshore saline aquifers near the gas separation plant on the Hainan Island is considered, and a demonstration project is proposed and designed in terms of aquifer selection and assessment, CO₂ transportation and injection, and project economics. Several aquifer structures around the gas field and near the Hainan Island were investigated and assessed with respect to geological structure, reservoir and trap features, fluid properties, storage capacity and site location. A saline aquifer (namely LT13-1), 60 km offshore the Hainan Island, was chosen as the storage site. CO₂ will be transported by a long-distance subsea pipeline at high pressure and injected into the aquifer via a subsea well-head and through a horizontal well. Reservoir simulation and injectivity analysis have been conducted to estimate the injection rate and pressure, and also to predict the movement of CO₂ after injection. A scoping economic analysis of the project was also conducted and presented in the paper.