通过腐蚀浸泡试验与电化学性能测试，并结合扫描电镜（SEM）、能谱仪（EDS）与X射线衍射仪（XRD）对20钢和L245NS钢在CO₂驱油反排水中的腐蚀行为进行了研究。结果表明：20钢和L245NS钢的腐蚀速率随着温度和CO₂分压的提高而显著增大，分别在温度55℃、CO₂分压0.75 MPa时达到最大值；Cl^-的抑制腐蚀机制与促进腐蚀机制之间的竞争，使两种碳钢的腐蚀速率随着Cl^-含量的提高呈现先增大后减小再增大的规律；20钢和L245NS钢的腐蚀产物以FeCO₃为主，其结构疏松，对基体保护性较差；腐蚀前后的极化曲线与电化学阻抗谱分析结果显示，20钢和L245NS钢的腐蚀电流密度与容抗弧直径分别有较小程度的降低与增大，表明腐蚀产物膜对钢材的保护作用不够明显。

Corrosion behavior of carbon steel 20 and carbon steel L245NS in drainage of CO₂ enhanced oil recovery (CO₂-EOR) was studied by immersion tests and electrochemical measurements combined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the corrosion rates increased significantly with the increase of temperature and partial pressure of carbon dioxide. When the temperature was 55℃, or the partial pressure of carbon dioxide was 0.75 MPa, the corrosion rates of both carbon steels all reached a maximum. The competition between corrosion inhibition mechanism and corrosion promotion mechanism of Cl^- made the corrosion rates increased first, and then decreased and increased at last with Cl^- concentration increasing. The corrosion product film mainly consisted of FeCO₃ with a loose structure, and had bad protection to substrate. The results of polarization curves and electrochemical impedance spectroscopy showed after corrosion the corrosion current density decreased and the capacitive loop increased for carbon steel 20 and L245NS in comparison with before corrosion, which indicated that protective effect of corrosion product film was not obvious.