Abstract:

CO₂ enhanced oil recovery（EOR） with carbon capture and storage（CCS） projects offer dual benefits of increasing oil recovery and CO₂ storage, making it one of the most economically viable carbon sequestration methods nowadays. However, EOR-CCS projects typically involve multiple well sites, and the high risk of CO₂ leakage from wellbores poses significant safety and environmental challenges over large areas. To address the limitations of previous atmospheric diffusion studies based on point-source leakage at well sites, a new method for studying surface CO₂ leakage and atmospheric diffusion in EOR-CCS projects based on area-source flux monitoring at well sites was developed. A case study of an oilfield in East China, based on scenario analysis, demonstrated that CO₂ leakage flux monitoring using the eddy covariance method could provide accurate data on area-source leakage fluxes for entire well sites, enabling large-scale computational fluid dynamics（CFD） simulations. Multi-well-site CFD diffusion simulations effectively captured the impact of complex regional topography and multiple well sites on CO₂ leakage, supporting regional safety and environmental risk management for well site leakage.

Key words: CO₂ EOR-CCS, CO₂ leakage, eddy covariance, numerical simulation, atmospheric diffusion