Selection and application of assessment methods for residual strength of corroded pipelines

Reliability-based design and assessment method is the development direction of natural gas pipeline assessment technology and it is of great importance to analyzing the applicability of assessment methods for residual strength of pipelines. The empirical formulas for residual strength of corroded pipelines, i.e. ASME B31G standard, revised ASME B31 G/RSTRENG 0.85 Ld method, C-Fer method, DNV-RP-F101 specification, and PCORRC method developed by the US Battle Lab, were introduced, and the adaptability analysis was conducted on these five standards with the collected test data of pipelines. Based on Monte Carlo simulation method, the influence rules of multi-parameters were calculated, and the reliability assessment and residual life prediction of in-service corroded gathering and transportation pipelines were carried out with the measured data. The research shows that these five assessment methods are conservative to some extent for the same assessment objects. DNV-RP-F101 method is more accurate in the residual strength assessment of medium and low grade defective steel pipelines. The method is characterized by convenient operation, high reliability and high engineering application value.