Comparative Study On Hydrodynamics And Motion Performance Of An Oblong FPSO

As the global economy grows, energy consumption continues to grow. Oil and energy as an important part of the global energy structure, the demand for oil and energy is increasing year by year. In the present stage, the oil and gas field production is difficult to increase,which can not meet the economic demand. The offshore oil and gas field has abundant reserves, which has a very broad prospect for development.In this paper, based on the advantages of the new concept FPSOs, a new design of a oblong FPSO is presented according to the South China Sea Environment, which has a innovation in the shape. This paper is concered with the investigation and comparison on hydrodynamics and motion performance of the oblong FPSO and the ship type and the cylinder type FPSO. The control methods of the oblong FPSO response are discussed in this paper.First, the hydrodynamic information of the three kinds of FPSO is acquired based on the three-dimensional potential flow theory. Then the added mass coefficients, radiation damping coefficients and the first-order Response Amplitude Operators (RAO) of the three kinds of FPSO are calculated and compared in frequency domain.And according to the JONSWAP wave spectrum of three kinds of FPSO motion to predict short term.Secondly, time domain analysis method is applied to calculate the time domain response of floating body motion with coupling effect between mooring system and the floating body considered. Then, the results of the three kinds of FPSO are compared and analyzed.Finally, some methods to improve the motion of the oblong FPSO are discussed,such as the height of center of gravity, draft depth, bilge keel length and width which could impact the motion performance to some extent.