低H2S/CO2分压比下油管钢腐蚀产物膜特征及形成机制研究

摘要

利用美国Cortest公司高温高压反应釜模拟低H2S/CO2分压比腐蚀环境，在流动高矿化度饱和H2S/CO2介质中进行试验，辅以SEM， XRD， XPS等表面分析技术，探讨了油管钢在低H2S/CO2分压比腐蚀环境下的腐蚀产物膜特征及形成机制。结果表明：在微量H2S条件下，当PH S/PCO为1/400时，试样表面在数秒内形成很薄的一层腐蚀产物膜FeS；随着时间的延长，形成具有3层结构的腐蚀产物膜，腐蚀产物膜由硫化物和FeCO3组成；当PH S/PCO增大到1/100时，腐蚀产物膜仅由硫化物组成。%Solution immersion environments containing H2S/CO2 were simulated in a high temperature and high pressure autoclave manufactured by USA Cortest Company, and test was conducted in flowing medium with high salinity. Characteristic and formed mechanism of corrosion film were analyzed and discussed by the following technologies, such as SEM, XRD, XPS and etc. The results showed that with small amounts of H2S, when H2S/CO2 partial pressure was 1/400, a very thin film (FeS) which has several nanometers thick can be formed within several seconds.With the increasing of corrosion time, the corrosion film with three layers structure was formed, corrosion film composed of FeS and FeCO3. When H2S/CO2 partial pressure increased to 1/100, corrosion film comprise of FeS only.