Investigation of the Criticality of Flux Leakage of a Magnetizer Assembly of a MFL Tool for Oil and Gas Pipelines Inspection

Almost all pipelines need constant monitoring and frequent inspections. This paper presents the design of a magnetizer assembly and experimental simulation investigation of flux leakage. The simulations carried out in a well known multiphysics software to get insights for the designed magnetizer assembly based MFL tool. Defects of different size and depth are modeled and simulated so that a better design aspect of the magnetizer assembly can be conceived. Several simulations were carried out, and magnetic field density plots of the pipe cross-section were obtained. It was observed that as the thickness of the pipe is decreasing the magnetic flux density in that region increases. The center of the pipe, where the metal erosion is maximum, the flux density was also found to be increased and gradually decreases as we move toward the edges of the metal erosion. These findings helped in selecting the second chamber of the tool consisting of a magnetic section and optimal magnets arrangement for a given material of pipeline. The findings will help in selecting the chamber of the tool consisting of a magnetic section having magnets that are arranged in a crisscross pattern to provide stability to the tool.