Reliability analysis of gas pipelines considering spatial and temporal corrosion variability

Abstract

The accelerating deterioration rate, notably due to corrosion in buried gas pipelines, has prompted the development of a systematic methodology for assessing structural integrity. This study introduces a methodology to evaluate the system reliability of a corroded gas pipeline, incorporating the spatial and temporal variability in corrosion growth. To capture the spatial variability of the corrosion process, random field theory is applied, which illustrates the correlation between defect depth and length growth, while a stochastic process is utilized to model the temporal evolution of these defects. The methodology considers two primary failure modes, i.e., small leaks and bursts, and investigates how the length scale in random fields, and the correlation strength between these fields influence the failure probability of the pipelines. System reliability is ultimately assessed based on the analysis of individual pipeline segments. The findings underscore the importance of considering spatial variability in estimating the reliability of gas pipelines. The proposed methodology offers a practical and more accurate approach to account for the spatial and temporal dynamics of corrosion, thereby enhancing the accuracy of reliability assessments for corroded gas pipelines.