Remote inspection by the magnetic tomography method (MTM) to prevent the risks imposed by exploitation of Arctic offshore pipelines

Cold climate areas that provide opportunities for the remote inspection of pipelines include the Barents Sea, the Russian Arctic, the Alaskan Chukchi Sea, the Beaufort Sea and the Canadian Arctic offshore. First, an analysis of several actual projects of contactless diagnostics using the magnetic tomography method of pipelines in Arctic conditions is done. Second, the Risk-Based Inspection methodology for Arctic offshore pipelines is discussed. It involves ensuring pipeline reliability on the basis of data on the technical condition of the metal in actual operating conditions. The magnetic tomography method allows not only to remotely identify areas of anomalies with metal defects, but also to register mechanical stress levels taking into account actual loads. This reduces the risk for the structure to come to the critical state in terms of exceeding local loads. Finally, magnetic tomography technology allows managing risks in cases of local corrosion, stress cracking or loss of stability of underwater pipelines in areas with free spanning. The qualitative indicators of the inspection include the probabilities of identifying, interpreting the degree of danger, missing a dangerous defect. The pipeline diagnostics report provides the parameters of reliability forecasting: the period of incident-free operation, safe working pressure, and pressure coefficient. (paper)