| FPSO is widely used for exploiting oil and gas resources from the ocean in China.At the area where water depth is more than100m, turret mooring is the most widelyused mooring system. Analyzing the dynamic response of the system correctly andresearching the factors which can influence the response dramatically, is practicallyimportant for ensuring the safety, improving the performance and optimizing thesystem design.A turret moored FPSO operating at a water depth of100m is taken as theresearch object in this paper. Coupled time-domain method and semi-coupledtime-domain method are used to calculate the dynamic response and fatigue life ofthe mooring system respectively, and the results are compared. According to theenvironmental data, the heading analysis are performed, and the green water analysisin frequency domain is also performed. The sensitivity analysis is carried out bychanging the loading condition, environmental parameter and mooring systemparameter, and their impacts on the dynamic response of mooring system are studied.The main conclusions are:(1) At the given water depth, the results of thesemi-coupled analysis is more conservative compared with the coupled analysis;(2)The heading of the SPM moored FPSO is mainly controlled by the wave direction,and the green water phenomenon will take place in the high sea condition;(3) On thegiven environmental condition and water depth, the fatigue life calculated by rainflowcounting based on semi-coupled analysis is longer than the fatigue life based oncoupled analysis;(4) Compared with the fatigue life calculated by simple summationand combined spectrum, the fatigue life calculated by combined spectrum methodwith correction is more accurate;(5) The dynamic response of mooring systemstudied in this paper, is not sensitive to the loading condition of FPSO, but sensitive tothe Tp, sensitive to the weight of segment with clumps, and very sensitive to thelength of mooring line and the anchor position. |
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