BEHAVIOR EVALUATION OF SUBSEA JUMPERS EXPOSED TO CURRENT BY EXPERIMENT AND FEM

摘要

The oil and gas industry is headed toward deep water in recent years. Oil companies are seeking new technologies to meet the challenges of deep-water oil exploration and in the near future, this will bring new discoveries. The most difficulty of exploring oil in this region is the depth where the equipment is installed and the production lines must be safe for such activities. Full understanding of the dynamics of the behavior of this equipment is vital to the success of offshore production and operation due to environmental problems that can occur in an accident and a large amount of economic and human resources involved. The phenomenon of the vortex induced vibration (VIV) is complex and involves an interaction between hydrodynamic forces and the response of the structure. The force and displacement can be determined through experimental tests or the complete numerical simulation of the interaction between the structure and fluid. DNV-GL has recently published a guideline about the design of a subsea jumper [I], but it is still needed many studies and experiments to improve the evaluation of VIV in rigid subsea jumpers in the oil industry. The main objective of the present work is to investigate VIV phenomenon in a jumper exposed to uniform flow and verify its oscillation in the flow direction, which called inline VIV (VIVx). Throughout this study, the finite element method was used to perform the structural and modal analysis of the structure, in order to obtain the modes, frequencies and then validate the experimental result. Experimental analysis of jumpers was also performed in a current tank to evaluate the behavior of the jumper with the current flow.