Author Wichers, J.E.W. and Chung Qun Ji
Title Behaviour of turret moored tanker in combined extreme metocean parameters
Conference/Journal Offshore Technology Conference (OTC), Houston
Paper no. OTC1997-8272
Month May
Year 1997

Abstract
At present the mooring technology of turret moored tankers is challenged as exploration activities for oil and gas move into deep and ultra-deep water and more hostile environments. The more hostile environment concerns the Atlantic Frontiers and the typhoon prone areas. For the field development in these water depths and under these weather conditions, the availability of a cost effective mooring system can be an important factor in determining economic success. The approach for developing fields in the mentioned areas has typically relied upon the adaption of mooring technology developed for shallower water depth applications.

To improve the understanding of and the insight in the reliability and integrity in the application in the deep water mooring systems, numerical design tools can be used. As the numerical design tool a by model tests validated computer' program based on the fully integrated dynamics of turret moored F(P)SO systems has been recently developed and applied to deep water. Further the computer program can be used to optimize the system and to enhance the safety of the design by applying numerous combinations of extreme weather conditions in order to discern the most severe weather condition.

In this paper the program has been described. The results of the validation with model tests on a tanker moored with a conventional mooring system in 350 m water depth are shown. The results of the computations agree well with the results of the model tests. Finally by means of computations with the tanker moored with a conventional system with and without spring buoys were investigated in 400 and 1200 m water depth applications. By varying extreme metocean parameters the understanding of and the insight in the reliability and integrity in the mooring system can be improved.

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