Effects of Injection Temperature and Pressure on CO<sub>2</sub> Storage Capacity and Safety in a Sloping Formation
Jing Jing, Yanlin Yang, Jianmei Cheng, Xianwen Jing, Z. L. Ding
Abstract
Injection capacity and storage safety of carbon dioxide (CO 2 ) are two key issues that should be considered in the CO 2 geological storage (CGS) projects. Temperature and pressure of injected CO 2 may be artificially controlled, constraining the CO 2 injection amount. Faults provide a pathway to CO 2 leakage, threatening its storage safety. Formation dip angle causes an asymmetric distribution of the CO 2 plume and accelerates its upward migration rate. Thus, it is necessary to reveal the influence of the injection temperature and pressure on the CO 2 storage. However, the multifactors’ (pressure and temperature of injected CO 2 combined with formation dip angle and fault) effects on CO 2 storage remain unclear. A three-dimensional (3D) numerical model of the Shiqianfeng Formation of Shenhua-Carbon Capture and storage (CCS) in the Ordos Basin was established in this study. The simulation results showed that the injection temperature and pressure significantly affected the injection and migration of injected CO 2 in a sloping formation with faulting. The larger injection pressure and higher injection temperature caused an earlier time of the CO 2 leakage. Results indicated that injection pressure was more favorable than injection temperature for CO 2 injection increased the injection temperature and pressure decreased the storage safety of CO 2 . CO 2 migrated into the fault after 280 years at an injection pressure of 1.5P and an injection temperature 31 °C in a 3° sloping formation. The impact of injection pressure on the CO 2 storage capacity was significantly greater than that of the injection temperature. The injection amounts of CO 2 can increase with different injection pressures and temperatures. In addition, part of the gas-phase CO 2 transformed to the dissolved-phase during storage, reflecting the storage capacity of CO 2 . This study provided a theoretical basis for the site selection and injection capacity control of subsequent CGS.