摘要
利用美国Cortest公司高温高压反应釜模拟高含硫油气田H2S/CO2及醋酸共存环境,在流动高矿化度饱和H2S/CO2介质中进行试验,辅以SEM、XRD、动电位扫描及交流阻抗等表面分析和电化学技术,探讨了高温高压及醋酸环境中H2S对油管钢CO2腐蚀行为的影响。结果表明:普通N80油管钢在单一CO2腐蚀速率较高,达到5.1mm/a,加入H2S后腐蚀速率明显受到抑制,降幅最大的点出现在H2S分压最小处,低至0.28mm/a,随着H2S分压的继续增大,腐蚀速率略有增加,但远低于单一CO2腐蚀速率。加入H2S后腐蚀产物以四方晶系的FeS(Mackinawite)为主,未出现FeCO3,腐蚀过程转变为H2S控制。试样的腐蚀形态以局部腐蚀为主,试样表面均出现了严重的点蚀,醋酸的存在增大了油管钢在H2S/CO2环境中产生局部腐蚀的倾向性。
Solution immersion environments containing HzS/CO2 and acetic acid were simulated in a high temperature and high pressure autoclave manufactured by UAS Cortest Company, and test was conducted in flowing H2S/CO2 medium with high salinity. The Effect of H2S on CO2 corrosion of oil tube steel were analyzed and discussed by the following electrochemistry technologies, such as SEM, XRD, dynamic potential scanning, AC impedance and etc. The results showed that the corrosion rate of N80 oil tube steel is very high, up to 5.1mm/a, when solution immersion environment contain only CO2 and acetic acid. However, with the addition of H2S, the corrosion rate is restrained obviously and the largest decreasing point is observed at the lowest partial pressure of l＇i2S, down to 0.28 mm/a. With H_,S partial pressure increasing, the corrosion rate slightly increased, but is far lower than simplex CO2 corrosion rate. With the presence of H2S, the corrosion products are mainly FeS （Mackinawite）, FeCO3 doesn＇t appear, and corrosion is controlled by H2S. The corrosion forms of samples are mainly localized corrosion, severe pitting presents on surface of samples, and exist of acetic acid promotes the tendency of pitting of oil tube steel in H2S/CO2 environment.
出处
《焊管》
2011年第10期9-15,共7页
Welded Pipe and Tube
关键词
油管钢
高温高压
H2S/CO2腐蚀
醋酸
点蚀
oil tube steel
high temperature and high pressure
HzS/CO2 corrosion
acetic acid
pitting
