Flow Induced Vibration in Subsea Jumper Subject to Downstream Slug and Ocean Current

Abstract

This paper presents a multiphysics approach for characterizing flowinduced vibrations (FIVs) in a subsea jumper subject to internal production flow, downstream slug, and ocean current. In the present study, the physical properties of production fluids and associated slugging behavior were characterized by pvtsim and olga programs under real subsea condition. Outcomes of the flow assurance studies were then taken as inputs of a fullscale twoway fluid–structure interaction (FSI) analysis to quantify the vibration response. To prevent onset of resonant risk, a detailed modal analysis has also be carried out to determine the modal shapes and natural frequencies. Such a multiphysics approach actually integrated the best practices currently available in flow assurance (olga and pvtsim), computational fluid dynamics (CFD), finite element analysis (FEA), and modal analysis, and hence provided a comprehensive solution to the FSI involved in a subsea jumper. The corresponding results indicate that both the internal production flow, downstream slugs, and the ocean current would induce vibration response in the subsea jumper. Compared to the vortexinduced vibration (VIV) due to the ocean current and the FIV due to the internal production flow, pressure fluctuation due to the downstream slug plays a dominant role in generating excessive vibration response and potential fatigue failure in the subsea jumper. Although the present study was mainly focused on the subsea jumper, the same approach can be applied to other subsea components, like subsea flowline, subsea riser, and other subsea production equipment.