Interaction between upheaval/lateral and propagation buckling in subsea pipelines

Due to high service temperatures and internal pressures in oil and gas pipelines, axial compression forces are induced in the pipe due to seabed friction. Slender trenched pipelines can experience global buckling in the vertical plane (upheaval buckling) while untrenched pipelines buckle in the horizontal plane (lateral buckling). Furthermore, deep subsea pipelines subjected to high external hydrostatics pressures can undergo catastrophic propagation buckling. In this study, the possible interaction between upheaval/lateral buckling and propagation buckling is numerically investigated using finite element analysis. A new concept is proposed for subsea pipelines design that gives higher capacity than conventional pipelines.