Exploring carbon-negative CO2-enhanced natural gas recovery

Carbon capture, utilization, and storage (CCUS) operating alongside petroleum recovery presents an option for achieving petroleum resource production with zero or negative emissions. The properties of supercritical CO 2 may benefit enhanced natural gas recovery. In this study, we investigate the potential application of CO 2 -Enhanced Gas Recovery (CO 2 -EGR) in an offshore natural gas field situated in the Yinggehai Basin of the South China Sea, which has been producing gas for approximately 20 years. The geological setting is complex, featuring anticlines and extensive faults. Here, we analyze the performance of the CO 2 -EGR process from the perspectives of injection rate, production rate, and well placement. The results demonstrate that CO 2 -EGR yields enhanced natural gas production alongside CO 2 sequestration and that the extraction process could be carbon neutral or negative regarding the total natural gas produced if it were combusted as fuel. Also, depending on the placement and number of wells, the incremental recovery of methane beyond the no-CO 2 -EGR base case ranges from 23% to 127%. The placement of the wells, particularly considering the geological complexity, is crucial for achieving optimal process performance.