Motion Response Analysis Of Deepwater Single Point Mooring FPSO Based On Tank Sloshing Coupling

Since entering the 21 st century,oil and gas resources have become an important strategic resource for the economic and social development of various countries.China has found abundant oil and gas reserves in the deep sea,and the development of deepsea oil has become an important energy strategy.Therefore,the independent research and development of deep water offshore oil and gas development equipment has become a major scientific and technological development plan in China.The deep-sea oil storage FPSO with internal turret single point mooring is the key facility for the development of deep-sea oil and gas.The research on the dynamic response of deep water FPSO mooring system is a frontier scientific and technological issue in the field of ship and ocean engineering.Under the action of wind,wave and current,single point mooring FPSO will produce a large range of motion,especially in the deep sea area,where the mooring line is several kilometers long and the marine environmental load is far greater than that in the shallow water area,the control of FPSO operation and viability is a great challenge.The crude oil in the tank sloshing during the violent movement of FPSO,and the sloshing will in turn affect the motion response of the ship.Therefore,considering the coupling of tank sloshing and hull,the motion response of FPSO in the mooring state,the mooring system tension,the inner turret displacement and other mooring responses are analyzed to ensure the safety of FPSO operation and resist the adverse sea conditions has important research significance and engineering value.In view of the above problems,this paper takes the Deepwater Widely Adaptability FPSO with 1800 m operation depth as the research object,and carries out the research work.(1)Establish the FPSO hydrodynamic calculation by the three-dimensional potential flow theory of the frequency domain response of FPSO under the action of unit regular wave,calculate the amplitude frequency response function of considering tank sloshing and not considering tank sloshing under different loading conditions,and analyze the influence of tank sloshing on the ship motion response.At the same time,the Rao,added mass and radiation damping of FPSO at different water depths are calculated,and the influence of water depth on the hydrodynamic performance of FPSO is analyzed.(2)Based on the time domain coupling method,the motion response and mooring system response considering coupled with tank sloshing are calculated under various loading conditions and sea conditions.The FPSO motion response is predicted under100 years return period sea conditions,and the FPSO motion response,inner turret displacement and mooring system response under different loading conditions and sea conditions are compared The dangerous loading rate under various conditions is analyzed,and the mooring arrangement is analyzed combined with the environmental conditions,which provides guidance for the mooring arrangement and motion control of FPSO.(3)The influence of tank sloshing on the coupled motion of FPSO and mooring system under 50% loading condition is calculated;the influence of mooring line length on the motion response of FPSO is studied,and the reasonable design length of mooring line is determined.(4)By changing the parameters of environmental conditions and mooring system,the motion response and mooring response of FPSO under different parameters are analyzed.The sensitivity of FPSO mooring system is analyzed.The influence mechanism and corresponding laws of different environmental parameters and mooring system parameters on the response of FPSO are studied.Based on a large number of analysis and research work,the characteristics of the response of liquid tank sloshing to the FPSO motion of single point mooring of the inner turret are obtained.The influence of tank sloshing on the single point mooring FPSO movement is revealed.The liquid storage rate of the tank is an important parameter affecting the FPSO movement,and the liquid storage rate of the tank which has a significant influence on the FPSO movement is determined.The motion response of FPSO and mooring system considering the coupling of liquid tank sloshing is obtained,and the mechanism of the influence of sensitivity parameters on the dynamic response of mooring system is revealed.The research work in this paper has guiding significance for the design and optimization of Deepwater Widely Adaptability FPSO in China,and has been applied in the research and development of FPSO.