Revolutionizing Unpiggable Pipeline Assessment: The Power of Holistic Inspection (C2026-00292)

Chukwuma Onuoha, DIVINE NNAMDI, Marc Blouin, Richard Buksa, Maekaren Panganiban, Dion Rennie

Contactless Magnetic Inspection Technology (CMIT) represents a major advancement in aboveground pipeline inspection, offering a non-intrusive method to assess the integrity of steel, cast iron, and ductile iron pipelines. By deploying highly sensitive magnetic sensors along the pipeline right-of-way, CMIT detects subtle variations in the ambient magnetic field that signal subsurface anomalies such as metal loss, cracks, or stress-induced damage—defects often missed by conventional aboveground inspection techniques. Recent innovations have also transformed indirect inspection methods for External Corrosion Direct Assessment (ECDA) and Stress Corrosion Cracking Direct Assessment (SCCDA). Techniques such as Cathodic Protection Close Interval Survey (CP CIPS), Direct Current Voltage Gradient (DCVG), Alternating Current Voltage Gradient (ACVG), Alternating Current Current Attenuation (ACCA), and depth of cover surveys can now be performed in a single pass, significantly improving data quality and efficiency.
To achieve comprehensive integrity assessments, pipeline operators are increasingly integrating CMIT with these indirect inspection tools. This multi-layered approach enables precise anomaly detection, verification of cathodic protection system effectiveness, and improved prioritization of high-risk areas—particularly on buried, unpiggable pipelines. This paper presents a holistic integrity assessment framework using this integrated methodology, supported by successful case studies demonstrating its value in maintaining safe, reliable pipeline operations.