温度对注气井P110油管钢耐蚀性能的影响

Effect of Temperature on Corrosion Resistance of Tubular Steel in Gas Injection Wells

目前,对于注气工况下井筒存在的氧腐蚀问题及其影响因素研究较少。利用高温高压反应釜进行腐蚀模拟试验,辅以失重法、SEM、EDS、XRD等测试手段,研究含氧工况下温度对P110油管钢耐蚀性能的影响。结果表明:温度通过改变溶液中的氧含量、电化学反应速率、溶解氧的扩散作用以及表面产物层而影响P110钢耐蚀性能。温度升高,电化学反应加速,溶解氧扩散加快,CaCO_3垢层脱落,腐蚀速率增大;溶解氧含量下降,又会导致腐蚀速率下降。温度的双重作用导致P110腐蚀速率先增大后减小,100℃时最大,且会发生局部腐蚀。

The effect of temperature on the corrosion resistance of P110 tubular steel under operation conditions including O2 was studied by autoclave test for simulating corrosion tests, together with other analysis methods such as weigh loss method, SEM, EDS and XRD. Results showed that temperature influenced the corrosion resistance of P110 steel by changing the content of oxygen, rate of electrochemical reactions, oxygen diffusion and film product. Increasing temperatures would increase the rate of electrochemical reactions, quicken the oxygen diffusion, and peel off the film of CaCO3, and these increased the corrosion rate. Meanwhile, the content of dissolved oxygen decreased, and it led to decreased corrosion rate. In general,the increase of temperature with dual functions caused that the corrosion rate of P110 increased and then declined. When the temperature was 100℃ ,the corrosion rate was the largest, and localized corrosion occurred.