M13井采出水腐蚀与缓蚀机理的研究

CORROSION AND CORROSION INHIBITION OF CARBON STEEL IN WATERS PRODUCED FROM A DRILLING WELL M13 AT JIANGSU OIL FIELD

用SEM、EDS法分析手段、动电位扫描极化曲线和滞后环实验等电化学方法研究了A3钢在M13井采出液水相中的腐蚀机理.结果表明,M13井采出液引起局部腐蚀的原因是形成CaCO3垢的垢下腐蚀而不是点蚀,腐蚀的速度受腐蚀反应的阳极过程控制.用旋转挂片仪筛选出的WJF-6缓蚀剂用量为50 mg/L、在M13井采出液中使用时,实验室中测出的缓蚀率超过90%,其根本原因是抑制了电极反应的阳极过程.

Corrosion tests were carried out for carbon steel samples by potentiodynamic polarization curves and hysteresis loop tests in waters produced from the M13 drilling well at Jiangsu oil field. Then the surface morphology and chemical composition of the corroded samples from laboratory test and that taken from oil field were examined by EDS and XRD. The results showed that the corrosion of carbon steel in the field was a kind of under-scale corrosion, and the corrosion rate was controlled by anodic process. A proper inhibitor WJF-6 was then selected by weight loss tests in the waters from drilling well M13, and inhibition efficiency was over 90% when the dosage of corrosion inhibitor was 50mg/L. The main function of the corrosion inhibitor WJF-6 is that the cathode process of electrode reaction can be restrained.