Dynamic Response And Anti-recoil Control Of Tensioner System Under Second-order Waves And Freak Waves

Drilling vessels and various floating platforms play an important role in offshore oil and gas exploration.The research object of this paper is the tension leg platform in the floating platform.The riser system is a channel for transporting drilling mud,oil and gas from the seabed to the platform.The platform and riser need to be connected by a hydraulic pneumatic tensioner system.In order to reduce the impact of platform movement on the riser system and make the riser run safely and reliably,which requires the study of the dynamic response of the hydraulic pneumatic tensioner.When the platform encounters harsh environment or loses dynamic positioning control,in order to prevent the riser from being damaged,the LMRP and BOP need to be disconnected urgently.Anti-recoil control of the riser tensioner system is required to prevent collision or bending of the riser that may occur after disconnection.In this paper,the dynamic response and anti-recoil control of hydro-pneumatic tensioner will be studied by combining the construction of coupled model,numerical simulation and experimental verification.Firstly,the coupled model of riser-tensioner-platform is constructed.Secondly,the influence of second-order wave forces,the freak wave forces and different accumulator pressures on the dynamic response of the hydro-pneumatic tensioner is explored,and the dynamic response of the tensioner under the condition of one cylinder failure is analyzed.Then,the experimental model of tensioner is built,and the experimental model is obtained by reducing the original tensioner size.The accuracy and adaptability of theoretical coupled model and simulation model are verified by experimental data.Finally,on the basis of verifying the correctness of the model,the anti-recoil control of tensioner is designed and verified,and the method of synchronous control of displacement and tension of hydraulic cylinder is proposed.The second-order wave forces and the freak wave forces have different characteristics on the displacement and tension of the tensioner,mainly in the range and frequency of numerical variation.The influence of accumulator pressure on the displacement and tension of the tensioner is mainly shown in the range of numerical variation.The greater the pressure,the smaller the range.In the study of failure characteristics,the state changes of the other three cylinders are mainly reflected in the tension.By comparing the test data with the simulation data,the accuracy and effectiveness of the theoretical model and the simulation model are verified.The designed co-control method can control both the retraction speed of hydraulic cylinder and the tension of hydraulic cylinder.In the control process,the relationship curve between the opening of the main valve and the displacement of the hydraulic cylinder mainly affects the retraction speed of the hydraulic cylinder,and the maximum opening pressure of the proportional overflow valve mainly affects the tension of the hydraulic cylinder.