Comparative Study between Two Corrosion Growth Assessment Methods

Abstract Pipelines are susceptible to corrosion, which can weaken their structural integrity and pose significant operational, environmental, and safety risks. Corrosion Growth Assessments (CGAs) are essential for ensuring the integrity of pipeline systems by identifying and quantifying historical corrosion activity. The results from CGAs are critical inputs for Fitness-for-Purpose (FFP) assessments that predicts when corrosion anomalies may require repair / investigation. This paper presents a comparative analysis of two common deterministic CGA methodologies using repeat Axial Magnetic Flux Leakage (Axial MFL) In-Line-Inspection (ILI) data. The two CGA methods are box-to-box matching and signal-to-signal matching comparisons. In summary, this paper highlights the comparative strengths and limitations of two common deterministic CGA methodologies used to support pipeline integrity management. The differences between box-to-box matching and signal-to-signal matching and their subsequent impacts on the predicted future integrity of a pipeline will be explored. For multiple case studies, using two (2) sets of Axial MFL ILI data acquired from the same pipeline, quantitative comparisons between estimated depth changes and corrosion growth rates (CGRs), number of anomalies predicted for repair over a set time interval, among other topics will be further explored.