Internal inspection of high-risk long-distance subsea pipelines using acoustic resonance technology

The complexity of subsea environment poses significant challenges for subsea pipeline internal inspection, making the integrity management difficult. Acoustic Resonance Technology (ART) has advantages such as superior passability and high detection accuracy for internal detection. However, there is currently no established ART based internal inspection methodology suitable for high-risk long-distance subsea pipelines, which is not conducive to improving the integrity management. This paper proposed an ART based internal inspection methodology for high-risk long-distance subsea pipeline, which includes six steps: confirm the applicability of the methodology, preparation for pipeline pigging experiment, preparation for pipeline internal inspection experiment, carry out pipeline pigging experiment, carry out internal inspection experiment and inspection data analysis and pipeline lifespan assessment. In order to verify the effectiveness of this methodology, the field experiments of a subsea pipeline were carried out, which were successfully completed. By analyzing the internal inspection data, the minimum safe working pressure of the target pipeline is calculated to be 13.14 MPa, significantly exceeding the design pressure of 9.9 MPa. The minimum remaining lifespan of the pipeline is greater than 20 years. Therefore, this methodology can provide valuable technical insights and references for the integrity management of high-risk long-distance subsea pipelines.