某油田ERW钢管管体泄漏失效分析

Leakage Failure Analysis of the ERW Steel Pipeline in an Oilfield

为分析东北某油田ERW钢管在输送油气过程中管体泄漏失效原因,对ERW钢管失效样品进行宏观形貌检验、理化检验、金相组织及扫描电镜分析等试验。结果表明,该ERW钢管管体泄漏失效的主要原因是管道底部残留积液和空气试压中的O2和CO2导致的腐蚀,腐蚀介质为大体积的O2和CO2在小体积的残留积液中形成持续饱和的腐蚀性水溶液,腐蚀类型为腐蚀产物膜的膜下腐蚀。建议对后续再建管线,试压前对管线进行热风吹扫;如果管线不及时投用,建议采用氮气保压。

This paper gives a thorough investigation on the leakage reason of the ERW steel pipeline in an oil field.Through appearance inspection,physical and chemical inspection,metallographic inspection and scanning electron microscope(SEM),it is shown that the main reason is corrosion caused by residual liquid at the bottom of the pipeline and O2 and CO2 during air pressure test.The corrosion medium is large volume of O2 and CO2 forming continuously saturated corrosive aqueous solution in small volume of residual liquid,and the corrosion type is under-deposit corrosion.It is recommended to conduct hot air purging before pressure test for future pipelines.If the pipeline is not put into use in time,it is recommended to use nitrogen to maintain pressure.