Research On Mooring System Design And Optimization For FDPSO

With the increasing demand for global energy, and the gradually exhausting resources and energy on land, oil and gas exploration and development is turning to the ocean. At present, offshore oil and gas exploitation has reached a certain scale. Deep sea oil field hasn't to be developed. The next hot spots has been transforming from shallow water,semi-shallow water to deep water. The breakthrough of deep sea oil exploration technology is the key factor in long-term strategic of deep sea exploration. In summary, Floating Drilling Production Storage and Offloading(FDPSO) multi-point system under South China Sea operation has been surveyed. Through the numerical and physical models, it also sets up the completely theoretical foundation and the support for the engineering and technology development.FDPSO is the ocean platform that can be used to produce oil, drill oil, store the crude oil and transport. It is advanced from drilling equipment based on Floating Production Storage and Offloading(FPSO). Hence, FDPSO, a technology intensive and danger intensive concentrated production equipment, which can generate power, drill, store and discharge simultaneously.Considering the FDPSO hydrodynamic coefficient obtained by frequency, and Cummings impulse theory and circumstance and mooring loadings, the coupling motion equations of FDPSO multi-point mooring system have been established. Thus, the hydrodynamic performance under time domain have been accomplished in this way. In South China Sea with waves and wind flow in the same direction, the characteristics of six DOFs of FDPSO mooring system has been calculated under survival condition and operational condition.In this dissertation, 3D potential flow theory, has been applied to research the coupling behavior in time domain when the vessel is moored. Six DOFs of decaying motion in static water and response of the floating body under regular waves have been analyzed. Then,natural frequencies, decaying curve and RAOs of two scenarios(quartering and oblique wave) of six DOFs have been researched. According to optimizing the mooring materials,mooring line arrangement and the axial stiffness of mooring line, verify the accuracy of mooring system design and precision of the numerical simulation.At the same time, FDPSO mooring system hydrodynamic test has been exploited,which improve the general design, moolpool, production system, drilling system and themooring system. Besides, the numerical test also validates the numerical one. The numerical test includes free decaying test in static water and under mooring scenario and multipoint model mooring under wave and wind interaction. Free decaying test shows the free rolling and pitching of FDPSO. It also shows the natural frequency and damping of the surging and swaying motion. The wind and wave model is helpful to obtain the FDPSO vessel motion property and dynamic characteristics of mooring wire. Also, the research of FDPSO's location ability is relatively complete. Then through the comparison between the physical and the numerical model, the validity and the reliability of the method have been verified.