某海上注水井N80油管腐蚀穿孔失效分析

Failure Analysis on the Corrosion Perforation of N80 Oil Pipe in an Offshore Water Injection Well

通过宏观分析、理化性能分析、金相分析、XRD分析、扫描电镜微观形貌分析和能谱分析、水质和细菌测试、有限元分析等方法,并结合实际现场工况,对海上某注水管柱在底部配水器下方发生局部腐蚀穿孔的原因和机理进行分析。结果表明:该油管是垢下细菌腐蚀导致的内腐蚀穿孔,酸化作业后残酸中的高Cl-加速了局部腐蚀穿孔,据此提出采用定期投加药剂和采用耐蚀管以防止油管早期腐蚀穿孔失效的建议。

In this paper,the cause and mechanism of local corrosion perforation under the bottom water regulator of an offshore water injection pipe string were analyzed by means of macro analysis,physical and chemical properties analysis,metallographic analysis,XRD analysis,SEM micro morphology analysis,energy spectrum analysis,water content and bacteria test,and finite element analysis and other methods,combined with the actual site conditions.Results showed that the internal corrosion perforation of the oil pipe was caused by bacterial corrosion under the scale,and the high Cl-in the residual acid after acidizing operation accelerated the local corrosion perforation.Based on this,it was suggested to regularly add chemicals and use corrosion-resistant pipes to prevent early corrosion perforation failure of oil pipes.