Hydrodynamic Response of A Fully Coupled TLP Hull-TTR System with Detailed Modeling of A Hydraulic Pneumatic Tensioner and Riser Joints

Tension Leg Platform(TLP) in deepwater oil and gas field development usually consists of a hull, tendons, and top tension risers(TTRs). To maintain its top tension, each TTR is connected with a tensioner system to the hull. Owing to the complicated configuration of the tensioners, the hull and TTRs form a strong coupled system. Traditionally,some simplified tensioner models are applied to analyze the TLP structures. There is a large discrepancy between their analysis results and the actual mechanism behaviors of a tensioner. It is very necessary to develop a more detailed tensioner model to consider the coupling effects between TLP and TTRs. In the present study, a fully coupled TLP hull-TTR system for hydrodynamic numerical simulation is established. A specific hydraulic pneumatic tensioner is modeled by considering 4 cylinders. The production TTR model is stacked up by specific riser joints. The simulation is also extended to analyze an array of TTRs. Different regular and irregular waves are considered. The behaviors of different cylinders are presented. The results show that it is important to consider the specific configurations of the tensioner and TTRs, which may lead to obviously different response behaviors, compared with those from a simplified model.