目的 研究超临界CO2/原油/盐水环境下J55碳钢的腐蚀机制。方法 利用高温高压反应釜模拟CO2压力为9 MPa、温度为65 ℃的超临界CO2/原油/盐水腐蚀环境，分别测定不同含水率下J55碳钢的平均腐蚀速率，通过扫描电镜和能谱仪观察分析腐蚀产物膜的微观形貌及元素组成，并测量最大腐蚀深度和计算点蚀系数。建立超临界CO2/原油/盐水环境中J55碳钢腐蚀模型，并阐述其腐蚀机制。结果 J55碳钢在超临界CO2/原油/盐水环境中的平均腐蚀速率随着含水率的升高而增大，含水率<50%时，腐蚀产物较少，最大腐蚀深度和点蚀系数较小，腐蚀形态为均匀腐蚀。随着含水率的增加，腐蚀产物增加，最大腐蚀深度和点蚀系数迅速增加，腐蚀形态变为局部腐蚀。结论 J55碳钢在超临界CO2/原油/盐水环境中的腐蚀速率远低于在超临界CO2/盐水环境中，原油的缓蚀作用明显。原油的存在改变了J55碳钢的腐蚀形态。

In order to study the corrosion mechanism of J55 carbon steel in supercritical CO2/crude oil/brine environment. An autoclave was used to simulate supercritical CO2/crude oil/brine corrosion environment with CO2 pressure of 9 MPa and temperature of 65 ℃. The average corrosion rate of J55 carbon steel with different water cut was measured. The micro morphology and element composition of corrosion product layer were observed and analyzed by SEM and EDS, and the maximum corrosion depth and pitting coefficient were measured. The corrosion model of J55 carbon steel in supercritical CO2/crude oil/brine environment was established and its corrosion mechanism was described. The results show that the average corrosion rate of J55 carbon steel in supercritical CO2/crude oil/brine system increases with the increase of water cut. When water content is less than 50%, the corrosion products are less, the maximum corrosion depth and pitting coefficient are small, and the corrosion morphology is uniform corrosion; with the increase of water content, the corrosion products increase, the maximum corrosion depth and pitting coefficient increase rapidly, and the corrosion morphology becomes local corrosion. The corrosion rate of J55 carbon steel in supercritical CO2/crude oil/brine system is much lower than that in supercritical CO2/brine system, and the inhibition effect of crude oil is obvious. The existence of crude oil changes the corrosion morphology.