FDPSO Drilling Riser Dynamic Response And Fatigue Analysis

Drilling riser system is the important equipment for the deep sea oil and gas exploration and development. Because the drilling riser is slender and lack of effective support, it is easy to failure. So the dynamic response of the drilling riser and cumulative fatigue damage research is particularly important. FDPSO's drilling riser is the main research object of this paper. This paper is mainly focused on the drilling riser's dynamic response and fatigue performance under the combined action of wave and current. The main contents of this paper includes the following aspectses:1) According to API standard to design drilling riser length, buoyancy block configuration, determine the top tension, etc;2) Under the combined action of wave and current, using the Orcaflex software to analysis the drilling riser's dynamic characteristic;3) Using deterministic irregular wave method to calculate the wave induced fatigue damage of the drilling riser;4) Analysis vortex-induced vibration of the drilling riser under the current;5) Shear7 software is used for calculation and analysis of the drilling riser's fatigue damage caused by vortex-induced vibration;6) By means of the criterion of Miner on drilling riser to process the cumulative fatigue damage calculation.Results indicate that:Under the combined action of wave and current, the 2000 m depth of the drilling riser's flexible joint angle and the equivalent stress meet the specification checking requirements. Through wave causes fatigue damage, vortex-induced vibration cause fatigue damage and cumulative fatigue damage analysis and research, found that fatigue damage caused by vortex-induced vibration dominated riser total damage,and this direct control of the drilling riser fatigue damage of the system.