钢质套管穿越段管道的完整性检测与评价

Integrity inspection and evaluation on the pipe with steel casing in the crossing section

输油气管道采用钢质套管穿越公路或铁路,通过基于电流电位的常规外检测方法,无法获得套管穿越段管道防腐层和管体的缺陷信息,为ECDA检测的盲点。以中沧输气管道恩城-平原公路穿越段和京沪铁路穿越段为对象,采用CIPS、PCM、ACVG、ON/OFF电位测试及超声导波等技术检测评价了套管与主管道的绝缘性、主管道的腐蚀情况及套管穿越段两侧管道的阴极保护状况,并对套管两端的密封情况进行开挖检查。结果表明:两处穿越套管与主管道均无电性接触或电通道,主管道无腐蚀,阴极保护状况良好;检测方法有效,可用于钢质套管穿越段管道的完整性检测与评价。

When oil or gas pipeline crosses the highway or railway with steel casing,the information in coating and pipe defects is hard to know by conventional potential method. Therefore,it is a blackspot in ECDA detection method. Taking the pipeline crossing Encheng-Pingyuan Highway in Zhongyuan-Cangzhou Gas Pipeline and Beijing-Shanghai Railway as examples,the method of CIPS,PCM,ACVG,On/Off potential and ultrasonic guided wave were employed to test and evaluate the insulativity between pipe and steel casing,corrosion of pipe and cathodic protection of pipeline at the both sides of the crossing section. In addition, the situation of sealing at the ends of steel casing was inspected with excavation method. The results showed that the electric connection or electric channel between the pipe and steel casing was not existed,and the condition of pipeline’s cathodic protection was well,and no any corrosion of the pipes in crossing section could be seen. It is considered that the inspecting methods above are effective and can be used to test and evaluate the integrity of the pipeline with steel casing crossing.