摘要
Abstract
H2S/CO2 corrosion environments in oil and gas field containing rich S were simulated in a high temperature and high pressure autoclave manufactured by USA Cortest Company,and tests were conducted in flowing medium with high salinity. Second corrosion behavior of oil tube steel in high temperature and high pressure H2S/CO2 corrosion environments was analyzed and discussed by the following technologies,such as SEM,XRD,dynamic potential scanning,AC impedance and electrochemical techniques. The results showed that corrosion rate of N80 oil tube steel was very high,up to 1.89 mm/a. when solution immersion environment contain only CO2. If H2S corrosion was conducted after CO2 corrosion, the corrosion rate reduced to 1.38 mm/a. The corrosion type showed distinct characteristic of local corrosion. FeCO3 corrosion film formed firstly would be transformed to FeS film,in this process,aberration of crystal lattice happened,which would result in delamination and loosen of film. If CO2 corrosion was conducted after H2S corrosion, the corrosion rate decreased a lot,up to 0.27 mm/a, FeS film formed firstly would not transformed. Through electrochemical test and analysis ,the corrosion product film FeS has a good protect to substrate,while FeCO3 film is poor.关键词
油管钢/高温高压/H2S/CO2腐蚀/二次腐蚀/点蚀Key words
oil tube steel/high temperature and high pressure/H2S/CO2 corrosion/second corrosion/pitting分类
矿业与冶金
