Brief History of Upheaval Buckling Studies for Subsea Buried Pipeline

Abstract

Since the early seventies, pipelines have become one of the main means of transporting oil and gas offshore in many parts of the world. In-service hydrocarbons must be transported at high temperature and pressure to ease the flow and prevent solidification of the wax fraction. The buckling of subsea pipelines occur because of the introduction of axial compressive forces caused by the constrained expansions set up by thermal and internal pressure actions. Such compressive forces can lead to either lateral buckling in the plane of the seabed or buckling in a vertical plane. To ensure minimal interference with other marine activities, the pipelines can be buried in a trench. In such cases, the lateral soil restraint exceeds the vertical uplift restraint created by the pipe’s submerged weight. Therefore, vertical buckling is of particular interest with respect to entrenched subsea pipelines. The possibility of upheaval buckling in subsea pipelines has been appreciated in the pipeline industry for over 30 years. The recent growth in interest in high-temperature pipelines in China is stimulated because of the frequent failures in Bohai Gulf. This paper describes the history of the theoretical and experimental studies on the subsea buried pipeline vertical buckling, as well as the authors’ experiences with this problem. Engineers could benefit from the literature reviews and summaries in this area. The paper also highlights the design of protective covers for the pipelines, and finally identifies areas for further development.