低碳中铬钢在模拟CO_(2)-EOR环境下的腐蚀行为

Corrosion behavior of low carbon medium chromium steel under simulated CO_(2)-EOR environment

为了研究Cr5和Cr7(质量分数/%)钢在CO_(2)-EOR高温高压服役条件下的腐蚀机理,利用高温高压反应釜模拟其腐蚀行为,使用失重法测定了腐蚀速率,采用SEM、EDS、XRD和XPS等手段对腐蚀产物进行了观察与分析,探讨了试验钢在CO_(2)条件下的腐蚀机理,并提出了腐蚀模型。研究结果表明,Cr5钢的腐蚀速率为0.73475mm/a,Cr7钢的腐蚀速度为0.21732mm/a;腐蚀产物均由外层的FeCO_(3)晶体以及内层的非晶态FeCO_(3)和Cr(OH)_(3)组成;腐蚀初期,产物膜以原位形成和阳极溶解后逐渐沉积两种途径生成;产物完全覆盖基体后,离子在界面处的扩散后沉积成为产物膜生长的主要途径。

In order to study the corrosion mechanism of Cr5 and Cr7(wt.%)steel under CO_(2)-EOR high temperature and high pressure service condition,the corrosion behavior was simulated by using high temperature and high pressure reactor,and the corrosion rate was measured by weight loss method to compare the corrosion resistance of two test steels.Corrosion products were observed and analyzed by SEM,EDS,XRD and XPS.The corrosion mechanism of test steels under CO_(2) corrosion conditions was discussed,and an intuitive corrosion mechanism model during the entire corrosion process was constructed.The research results show that the corrosion rate of Cr5 steel is 0.73475 mm/a,and that of Cr7 steel is 0.21732 mm/a.Corrosion products are composed of FeCO_(3) crystals in the outer layer and amorphous FeCO_(3) and Cr(OH)_(3) in the inner layer.In the initial stage of corrosion,the product film is formed by in-situ generation and gradually deposited after anodic dissolution.After the product completely covers the substrate,the diffusion and deposition of ions at the interface becomes the main way for product film growth.