Practical Application of Inline Inspection Tool With Combination of Eddy Current and Deformation Technology

Abstract

In the actual process of magnetic flux leakage inline inspection, the following four problems are often encountered: 1) There are many impurities in pipelines, which seriously interfere with the results of magnetic flux leakage inline inspection; 2) Girth weld misalignment cannot be accurately detected by magnetic flux leakage inline inspection because MFL signals are complex in girth welds; 3) The minimum passage of magnetic flux leakage inline inspection tool is poor when negotiating with pipeline geometry restrictions, so in practice geometry inline inspection normally perform prior to magnetic flux leakage inline inspection to validate the tool passage risk and avoid tool stuck incident, this will lead to tremendous extra efforts, as well as expenses; 4) The magnetic flux leakage inline inspection tool is normally heavier due to mechanical design and strong magnetic attraction force with metal surface, which lead to a much higher driving/pulling force. To solve these problems above, this paper propose the inline inspection tool with combination of eddy current and deformation technology. This inline inspection tool has the advantage of light weight and lower friction force, which lead to a comparative lower driving/pulling force. It can detect the metal loss on the inner wall of pipelines and weld misalignment of girth welds while realizing geometry inspection. By comparing the inspection results with the high-resolution magnetic flux leakage inline inspection results, it is concluded that the inspection tool combined with the eddy current and deformation technology inline inspection technology can replace the high-resolution magnetic flux leakage inline inspection tool when focusing on the inner metal loss of pipe wall.