用于川西气田CO2腐蚀控制的缓蚀剂性能的研究

Electrochemical Behavior and Inhibition Performance of an Inhibitor for Prevention of CO_2-Induced Corrosion at Gas Field in Western Sichuan

为解决川西气田的CO2腐蚀问题,利用极化曲线法和交流阻抗方法结合失重试验方法对缓蚀剂MC-1在常温常压和高温高压条件下CO2饱和的模拟气井产出水中的电化学行为和缓蚀性能进行了测试。电化学试验结果表明:在两种条件下,加入缓蚀剂后,体系的阳极电流密度都减小,自腐蚀电位都明显正移,缓蚀机理属于"负催化效应";常温常压下存在阳极脱附现象,而且阻抗值比高温高压条件下的大;常温常压下,缓蚀剂在浓度为100mg/L时其缓蚀效率达到极值,而在极值浓度下,浸泡时间越长缓蚀效果越好。失重试验结果表明,缓蚀剂在高温高压下的效果不如常温常压下理想。

In order to get rid of CO2-induced corrosion in western Sichuan gas fields,polarization curve measurement and electrochemical impedance spectroscopic(EIS)analysis combined with weight loss test were conducted to evaluate the electrochemical behavior and inhibition performance of MC-1 corrosion inhibitor in simulated water saturated with CO2 under normal temperature/pressure and high temperature/pressure conditions.It was found that under the two conditions,the addition of the corrosion inhibitor led to decrease in the anodic current density and positively shifting of the corrosion potential,where the corrosion was dominated by negative catalysis effect'.At the same time,anodic desorption was observed at normal temperature & pressure,and the impedance at normal temperature & pressure was bigger than that at high temperature & pressure.Under normal temperature & pressure,the inhibition efficiency reached an extremum at a concentration of 100 mg/L,while extended dipping in MC-1 at this extremum concentration led to better inhibition efficiency.However,the inhibition efficiency under high temperature & pressure condition was poorer as compared to that under normal temperature & pressure condition.