Feasibility of eddy current inline inspection for crack-like defects of oil and gas pipelines

The crack-like defects of oil and gas pipelines, especially the crack-like defects on the inner surface, are the main factors leading to pipeline failure. However, due to the limitation of the existing inline inspection technology, the cracklike defects are difficult to detect through inline inspection. Herein, various eddy current inline inspection tests of crack-like defects were performed by setting up an eddy current high-speed automatic testing device to detect the crack-like defects in the pipe body and girth weld at different defect depths based on the electromagnetic eddy current technology. In addition, the eddy current signal characteristics of crack-like defects were analyzed, and the feasibility of applying electromagnetic eddy current technology to the inline inspection of crack-like defects was verified. The test results show that the crack-like defects of oil and gas pipelines at different locations can be distinguished by the impedance signal of defects at a higher inspection speed. Meanwhile, the signal characteristics become more obvious with the increase of defect depth, but attenuate with the increasing of the liftoff value of defects. In addition, the greater signal-to-noise ratio of defect signal can satisfy the requirements for accurately identifying the crack-like defects.