Development of simulation model for virtual testing and design of a riser tensioner system

Abstract

This project contains a study of a wireline riser tensioner system provided by TTS Energy. A mathematical model is derived for both the pneumatic-, hydraulic and the mechanical system. The main motivation for this work is the development of a multibody mechanics model in simulationX, together with 1D mechanics and fluid power systems in the shape of both hydraulics and pneumatics. After the models are verified as sound, several simulations are ran and a number of parameters are varied in order to investigate the response of the system under different load-cases. The investigation of the system is done for several operation modes. In all of them a vertical total load from the marine riser string together with a constant horizontal load are acting on the tensioner units, while the rig is following a sinus motion with amplitude of 4,8 meter and time of period 18 seconds. The first scenario is normal operation. The second one is when one or two wires in diametrally opposite positioned cylinders rupture at the same time. The third one is system performance if the marine riser must be decoupled from the BOP, and the anti recoil system have to ensure that the cylinder positions are moved in a controlled way to maximum stroke. Different values for key parameters of the system will be investigated and the results are summarized on the last pages of these thesis.