Multi-Physics Modeling of Above-Ground Electromagnetic Inspection on Underground Pipeline

This study explores the effectiveness of electromagnetic-based non-destructive evaluation (NDE) for above-ground inspection of underground pipelines to detect corrosion defects. The above-ground electromagnetic inspection method involves measuring the magnetic field induced by an alternating current (AC) passed through the buried pipeline and analyzing the resulting electromagnetic field perturbations under various frequencies to identify defects. Finite Element Analysis (FEA) simulations using ANSYS Electronics Desktop were conducted to model the electromagnetic field around pipelines induced by a given AC signal with various frequencies through the pipeline with and without defects. The numerical simulations indicate the capability of detecting magnetic field perturbations caused by wall defects from above-ground sensors, even at a distance of one meter above the pipeline. However, sensing ability at the nano-Tesla level is required. The thresholds for such perturbations to indicate a pipeline defect were also numerically studied. The study also evaluated the impact of sensor movement and its sensitivity effect on the electromagnetic field and then the Low-High Frequency Method was introduced to mitigate potential false positives due to sensor displacement. The results highlight the potential of electromagnetic NDE for reliable and efficient pipeline monitoring, contributing to enhanced safety and operational efficiency in the oil and gas sector. Future experimental validation will be performed to validate the numerical solutions, quantify the effectiveness and optimize defect detection.