CO₂地质埋存是温室气体资源化利用及减少大气温室气体排放的有效途径之一。在深部咸水层中实施CO₂地质埋存的减排处理，是减缓温室效应最有效的现实选择。针对CO₂在地下盐水层的埋存过程中，其超覆盐水层后存在渗漏和逃逸的风险，基于Buckley-Leverett驱油理论，研究并推导出CO₂对盐水层非活塞式驱动半径的计算公式，准确计算CO₂的扩散半径。计算结果表明，该计算式不仅可为CO₂盐水层封存的工程实践提供必要的理论依据，还为获得封存后存储介质中CO₂逸散风险的控制提供长期预测和数据的支持。

Storage of carbon dioxide is one of the effective methods for utilizing greenhouse gas and reducing greenhouse gas discharge. The storage of CO₂ into saline aquifers is the best way to mitigate the green house effect. However, there is a risk of leaking during the injecting of CO₂ into saline aquifers. So it is necessary to calculate the displace radius of CO₂ in saline aquifer. Based on the Buckley-Leverett equation, a new formula is derived to calculate the displace radius of CO₂ in saline aquifer. The research results can provide a theoretic support and a field guide for calculating CO₂ storage volume and risk control in saline aquifer.