On the effect of long corrosion defect and axial tension on the burst pressure of subsea pipelines

Abstract

Due to water, sediment and chemical contaminants etc., the internal corrosion of subsea pipelines is inevitable. The internal corrosion is usually at or near the bottom of the subsea pipeline where the water and sediment can settle out of the transport medium. After some time, narrow and long defects occur in pipelines. Besides, as the temperature changes, the pipe is often stretched. Pipelines with long corrosion defect and axial tension subjected to high internal pressure have potential failure risk in service. In this paper, the effect of long corrosion defect and axial tension on the burst pressure of subsea pipelines are studied. Firstly, the pipelines with narrow and long corrosion defects are simplified as the Apollonius model. Then, a semi-empirical burst pressure equation of corroded pipelines subjected to internal pressure and axial tension is presented. Next, the accuracy of the burst pressure equation is verified by given experimental data. In the end, the effects of long corrosion defect and axial tension on burst pressure are analyzed. The results reveal that both axial tension and long corrosion defects can greatly reduce the burst pressure of pipelines. It is beneficial to assess the integrity of pipelines subjected high internal pressure and deepen the understanding of pipeline failure behavior.