Field-Validated Results of the Non-contact Magnetic Gradient Tomography Method (MTM-G) for Enhancement in Pipeline Integrity

Abstract The non-contact magnetic gradient tomography method (MTM-G) is a potential tool for the assessment of non-piggable pipelines. This technology uses magnetic sensors from aboveground to identify stress concentration zones on buried metallic pipelines. MTM-G does not require direct contact with the pipeline, making it suitable for inspecting buried pipelines without the need for excavation or costly interventions. This non-intrusiveness allows pipeline operators to evaluate the condition of unpiggable pipelines without disrupting operations or requiring extensive preparation. MTM-G can detect external anomalies, such as external metal loss, third-party damage, or ground movement, that pose a significant risk to buried pipelines. By identifying these external threats early on, operators can take proactive measures to prevent pipeline failures, such as repairing damaged coatings or reinforcing vulnerable sections of the pipeline. Recent findings have shown that this technology can identify areas of corrosion external metal loss, cracks, mechanical defects and geohazard impacts from aboveground. The paper presents recent findings and correlations of defects identified by inline inspection and MTM-G. A successful outcome of recent validations would supplement existing technologies for condition assessment in critical and sensitive locations and be good news for pipeline operators looking for a proven solution to address buried unpiggable pipelines.