Calculation Method for Failure Pressure of Oil and Gas Pipelines with Multiple Corrosion Defects

Abstract

In the structural integrity assessment of pipelines with multiple defects, conventional methods such as the DNV and MTI approaches demonstrate notable predictive biases. Specifically, the burst capacity estimated by the MTI model frequently exceeds experimental test values, whereas DNV calculations tend to be overly conservative, possibly resulting in unnecessary maintenance expenses. To address these challenges, this study employs nonlinear finite element analysis to reassess the failure pressure of pipelines with multiple corrosion defects. Initially, the interaction limit spacing between adjacent corrosion defects is computed to determine their potential for interaction. For adjacent corrosion defects exhibiting interaction, a merging limit criterion is introduced to evaluate their feasibility for merging. For those adjacent defects that satisfy the merging limit criterion, the DNV method is employed to merge them, followed by recalculating the failure pressure using the relevant formula. Finally, this study proposes a novel approach for assessing the failure pressure of pipelines with multiple corrosion defects. Through comparative analysis and validation, the proposed evaluation method exhibits enhanced accuracy in predicting the failure pressure of pipelines with multiple corrosion defects. The findings of this study provide a more precise methodology for assessing the residual strength of pipelines affected by multiple corrosion defects.