Collapse Pressure Of Pipelines Research Articles

Collapse failure and capacity of subsea pipelines with complex corrosion defects

As one of the main deterioration causes of subsea pipeline, corrosion typically manifests itself as a loss of structural integrity. The accurate determination of collapse pressure for corroded pipelines is of practical importance in subsea oil & gas industry. Failure mode and collapse pressure of pipeline with complex corrosion i.e. constant-depth, elliptical and parabolic shaped corrosion are investigated. Parametrical study results indicate that corrosion shape has significant influence on the collapse failure mode as well as collapse pressure of pipelines. For practical purposes, the regression equations for predicting collapse pressure of subsea pipeline with complex corrosion defects are developed as well.

Effect of Steel Properties on Buckling Pressure of Corroded Pipelines

Due to the harsh environment for submarine pipelines, corrosion damage of the pipeline steels is inevitable. After the corrosion damage, pipelines are prone to failure and may cause serious consequences. The analysis of the effects of different steel properties on the collapse pressure of pipelines with corrosion defects is of importance for the option of appropriate pipeline and avoiding accidents. Based on the finite element method, the finite element model of the pipeline with defects under external pressure was built. Firstly, the accuracy of the numerical model was validated by comparing with previous experimental results. The effects of yield strength and strain hardening exponent on collapse pressure of pipelines with different sizes of defect were discussed in detail. Results showed that the yield strength and strain hardening exponent have different influences on collapse pressure: the collapse pressure increases with the increasing yield strength, and the collapse pressure decreases with the increasing strain hardening exponent.

On the effect of narrow and long corrosion defects on the collapse pressure of pipelines

Internal corrosion in pipelines is often caused by water, sediment, or chemical contaminants present in the multi-phase flow. This normally occurs at the bottom of the pipe and at low points in the pipeline where sediment and water can settle out of the product being transported, therefore creating narrow and long defects. The effect of corrosion defects on the collapse pressure of offshore pipelines was studied through combined small-scale experiments and nonlinear numerical analyses based on the finite element method. After calibrated in view of the experimental results, the model was used to determine the collapse pressure as a function of material and geometric parameters of different pipes and defects. An extensive parametric study using two and three-dimensional numerical models was carried out encompassing different defect geometries and their interaction with pipe ovalization. This paper reports these results which are subsequently used to develop a simple procedure for estimating the collapse pressure of pipes with narrow defects.

On the effect of corrosion defects on the collapse pressure of pipelines

The loss of metal in a pipeline due to corrosion usually results in localized pits with various depths and irregular shapes on its external and internal surfaces. The effect of corrosion defects on the collapse pressure of offshore pipelines was studied through the combination of small-scale experiments with nonlinear numerical analyses based on the finite element method. After calibrated based on the experimental results, the model was used to determine the collapse pressure as a function of material and geometric parameters of different pipes and defects. An extensive parametric study using 2-D and 3-D numerical models was carried out encompassing different defect geometries and their interaction with pipe ovalization.