S/CO_2共存时温度对P110钢电化学腐蚀的影响

Effect of Temperature on Electrochemical Corrossion of API P110 Steel with Coexisteme of S/CO_2

针对当前S/CO2共存条件下的腐蚀研究不足,通过模拟油气田采出液腐蚀环境,采用电化学方法研究了温度对P110油套管腐蚀电化学行为的影响.利用电化学测试系统进行了开路电位、极化曲线和电化学交流阻抗谱测试.研究结果表明:随着温度的升高,P110钢在模拟介质中的开路电位降低了67mV,自腐蚀电流密度从3.68μA/cm2增加到56.4μA/cm2,阴极极化曲线Tafel斜率大于阳极极化曲线斜率,阴极过程由活化控制转变成由活化和扩散协同控制.腐蚀反应主要由阴极反应过程控制.90℃时,阴极反应控制减弱,交流阻抗谱曲线在低频区出现Warburg阻抗.

The current study of corrosion on conditions of S and CO2 coexistence is not sufficient .The effects of various temperatures on the electrochemical behavior of API P 110 steel in simulated oilfield liquid environment are investigated .Electrochemical test system is used to test the open circuit potential （OCP） ,polarization curves and electrochemical impedance spectroscopy （EIS） .The results show ：As the temperature increases from 25 ℃ to 90 ℃ ,the working electrode potential of API P110 carbon steel reduces 67 mV in the stimulant medium ,the corrosion current density increases from 3 .68 （μA/cm2 ） to 56 .4 （μA/cm2 ） ,and the slope of the cathodic polarization curve Tafel is greater than the slope of the anodic polarization curves ,cathodic process controlled by the activation into the cooperative control of activation and proliferation .T he corrosion process is controlled mainly by the cathode process .While it is 90 ℃ ,the catholic reaction control is weakened ,and its EIS appearances Warburg impedance in low frequency section .