Concept Design And Research On Hydrodynamics Of A New Type Spar Platform

Spar platform is be known as a most developing foreground ultra-deep water offshore oil platform because of excellent motion stability,safety and economic performance in deep water environment.This title firstly introduces the three generation Spar platforms based on the investigation at home and abroad,and then raises a new concept Spar-geometry truss Spar(GT-Spar)with a major shape design based on G-Spar and CT-Spar conceptual design types.The main structure shape,mooring system and main size are designed as per oil and gas developing demand for South China Sea and the input parameters of a regional environment.The modeling and meshing work for this new Spar platform are done by ANSYS software,these work include structural analysis,main structure strength analysis,structure stress key points and weak points analysis which provide a reference for the future detail design.A hydrodynamic calculation model for GT-Spar platform is built with AQWA hydrodynamic calculation software which did a frequency domain analysis based on the three-dimensional potential flow theory,obtained the added mass coefficient of platform,radiation damping coefficient and motion response amplitude operator(RAO)and other hydrodynamic parameters.Analysis results for this new Spar show a normal frequency response result and a better performance compared with the second generation Truss Spar platform.Based on analysis of frequency domain,a time domain coupling calculation model is built with AQWA-Drift tool which simulate the movement of target Spar in the actual marine environment and give a calculation results for wave stream time history and response spectrum with 0°incident direction conditions.Finally we research the influence of the changing numbers and shapes of heave plate to platform movement and the influence of changing the gravity center to platform movement performances.The conclusion shows that the design of new GT-Spar platform can get a very good movement performance and meet the design requirement for exploitation of oil and gas on deep water area.GT-Spar gets much more optimized design performance compared with second generation truss Spar platform.During the analysis of structural strength and the hydrodynamic performance for GT-Spar platform,we summarize some skills about modeling and meshing and some analysis conclusions which have a positive reference for further study on the Spar platform.