A review on defect assessment of pipelines: Principles, numerical solutions, and applications

Abstract

Defect assessment is critical to fitness-for-service determination and failure pressure prediction for pipelines. This work develops a comprehensive review of the principles, numerical solutions, and applications of Levels 1, 2 and 3 defect assessment methods developed in the past four decades. Commentary remarks were given on each method regarding the potential problems and suggested improvements. Pipeline defect assessment has evolved in significant developments of modelling method, geometrical definition, computational solutions and predictive accuracy and reliability. Specifically, the introduction of finite element analysis in Level 3 assessment method enables modelling of defects with a more complex geometry. The integration of a mechano-electrochemical interaction at corrosion defect results in development of multi-physics field coupling models, making the defect assessment and pipeline failure prediction at a more mechanistic and accurate level. New criteria are proposed to identify interaction rules for adjacent corrosion defects to further improve the modelling accuracy. Nowadays, Levels 1 and 2 defect assessment methods have been commonly used in industry. However, the use of Level-3 method requires sound background knowledge in multiple academic majors, limiting its use in practice. Further efforts should be made to develop a convenient operating platform for industry to directly use Level-3 defect assessment. Moreover, defect assessment on pipeline welds should be paid particular attention in the future work.