Post Buckling Analysis with Different Configurations of Snaked Laid Pipelines

A common solution for oil and gas transportation in offshore fields is long distance pipelines. Flowing of High Pressure/ High Temperature (HP/HT) fluid may cause uncontrolled buckling because of material or geometry defects. In order to reduce damages and avoid buckling in unpredictable places, the controlled buckling concept is introduced. In order to trigger buckling in predetermined location, pipeline can be placed in snaked lay configuration. In this article, it is aimed to investigate the effect of geometrical parameters, i.e., laying wavelength, laying radius and offset angle of snaked lay configuration on the displacement of offshore pipelines, axial force and bending moment in post buckling stage under HP/HT condition. Then, these results are used to evaluate the global buckling failure. This work is performed by using nonlinear finite element analysis and pipe-soil interaction of as-laid pipelines is modeled by employing spring elements. The results of investigation show that different ranges of the mentioned parameters may cause the maximum difference in displacement, bending moment and axial force about 133.6%, 155%, and 30%, respectively. Investigation of global buckling failure determine the most critical section of pipelines and it is observed that as the curved section of pipeline shrinks, the possibility of global buckling failure will increase but the effect of laying wavelength is contrary and the failure will be decreased about 8.3%.