Study On The Installation Method Of Single Ship Based On Multi-body Hydrodynamic Performance And Motion Response

The floating ship heave motion will occur inevitably because of the impact of the waves during the deepwater installation of subsea tree.By analyzing the existing installation successful projects,combined with China’s existing water production facilities installed capacity,puts forward the Vertical Dipping Installation Method of single ship of dipping of subsea tree installation system coupled motion analysis,the main contents of this thesis are as follows:To summarize installation method commonly used in China and abroad deepwater production facilities,installation method of comparing several advantages and disadvantages,according to the installed capacity of Liwan 3-1 gas field of the marine environment and China’s existing installation of marine resources,carries research on Vertical Dipping Installation Method of "offshore oil 708" single ship.A spring model of the steel wire rope is established,and the dynamic analysis of its is taken as the research object,and the dynamic response and without dynamic response are considered respectively.Two main installation stages are considered: overboarding and the lower stage,the environmental load of the hoisting system is simplified reasonably,and the basic model of the installation process system is presented,the equivalent model is analyzed,and the expression of the model is obtained.Based on the theory of time domain computation of multi body nonlinear coupling,the coupling time domain motion analysis of the ship,the steel wire rope and the subsea tree is carried out,the time domain equations of motion of the ship are obtained,and the time domain equations of motion are solved by using the Newmark-beta method.In the time domain coupling analysis of the ship,the cable and the volume coupling system,the whole system is simplified to a spring mass system with dampers.The dipping system modeling using SESAM software,and overboarding and the lower stage of two phases dynamic time domain simulation.To analyze the dynamic response of the installation of the three coupling action of the ship-steel wire rope-subsea tree,and the dynamic time history of the installation vessel,the tension variation of the steel wire rope,the movement of the subsea tree are obtained.By control variables that water depth,water drag force,and wave height to influence of dipping system,time history curve of the parameters such as the tension of the wire rope,the displacement of the transverse displacement and the motion response of the ship were obtained,and then verified the Vertical Dipping Installation Method of single ship for the installation of the feasibility of the subsea tree.