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

Abstract

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.

Characterization of Produced and Residual Oils in the CO2 Flooding Process

“…Carbon capture, utilization, and storage (CCUS) have been attracting more and more attention from the petroleum industry, as well as governments all over the world. − It is not only an effective means of reducing greenhouse gas emissions, but it is also a promising enhanced oil recovery (EOR) technique. , In 2012, 114 miscible and 9 immiscible ongoing CO 2 -EOR projects provided a total oil production of 284 193 barrels per day . In Canada, two commercial CO 2 -EOR projects are being operated, in Alberta and Saskatchewan .…”

A Review ofCO2Sequestration Projects and Application in China

“…Saline aquifer trap LT13-1, located in the east of DF1-1 gas field, 60 km away from the Dongfang gas terminal, has been selected as the target CO 2 storage site to sequestrate the CO 2 discharged from the DF1-1 gas terminal [ 67 ]. The reservoir is relatively good in homogeneousness and high in salinity, indicating a good trap feature.…”

“…The injected CO 2 will be trapped both in a supercritical state and in dissolved state in formation water. Sandbodies A and C of LT13-1 structure can provide a CO 2 storage capacity of approximately 0.1 × 10 9 t [ 67 ], as shown in Figures 6 and 7 . Zhang et al pointed out that the storage cost is about $33–37/t, slightly higher than abroad due to the high cost of offshore pipeline [ 68 ].…”