天然气管道间接检测技术及应用

Application of Natural Gas Pipeline Indirect Detection Technique

为了预防天然气管道发生腐蚀后引发泄漏等一系列安全事故,对管道开展周期性检测工作可以及时发现缺陷并采取修复、补强等措施。对比了目前常见的几种管道间接检测技术原理及其优缺点,并分别采用多频管中电流检测(PCM)、交流地电位梯度检测(ACVG)、直流地电位梯度法(DCVG)对一条Φ273 mm埋地钢制管道进行检测和开挖验证。结果表明,DCVG和ACVG检测法对管道外防腐层破损点定位的精确性和准确度最高,因此在对埋地钢制管道进行外腐蚀检测过程中,建议优先选用这两种方法对管道外防腐层进行破损点检测,同时尽可能缩小测试间距,减少大缺陷产生的电位梯度的影响,提高检测精度。

In order to prevent a series of safety accidents such as leakage and even explosion caused by corrosion of natural gas pipelines,periodic inspection of pipelines can be carried out to find defects in time and take measures such as repair and reinforcement.The principles of indirect detection technologies of PCM,ACVG and DCVG and the application in a gas field are compared,and three detection methods are used to detect and verify the excavation ofΦ273 mm buried steel pipeline.The results show that DCVG and ACVG detection methods have the highest accuracy in locating the damaged points of the external coating of the pipeline.Therefore,in the process of external corrosion detection of buried steel pipelines,it is recommended to give priority to these two methods to detect the damaged points of the external anti⁃corrosion coating of the pipeline,while reducing the test spacing,and the effect of potential gradient generated by large defects,improve the detection accuracy.