Analysis Of Spar Platform Response Due To Waves And Current

Spar platform is one of the significant subjects in the oil and gas exploration in deep water, but there is few researches to study Spar platform with general FEM software at present. The static and kinematical response of Spar platform due to waves and current were analyzed by using the ANSYS software in the present thesis.The main contents and conclusions are summarized as follows:1. The development of Spar platform is introduced systematically as well as the structure characteristics, advantage and disadvantage, economical efficiency and the future of Spar platform.2. Based on the method of Williams and Demirbilek which is used to calculate the wave load on floating cylinder, a Fortran program was developed to compute the first-order wave force on a Spar platform. Simultaneously, the influence of truncated order on the wave force was also discussed. It is indicated that when the truncated order is about 20, the truncated error is less than 0.004%.3. A coupled ANSYS model for a Spar platform and its mooring system is established. The inner force of mooring system under the static condition is evaluated, as well as the tension of mooring line with different mooring angle and the mooring stiffness of different direction. It is shown that the horizontal mooring stiffness of the Spar platform increases with the excursion. The coupling characteristics of Spar platform and its mooring system are simulated reasonably by the model.4. A model for the kinametical response of Spar platform due to waves and current is set up. The kinametical response of Spar platform and its mooring system due to the first-order wave force and steady current based on the condition of the South China Sea is simulated. Then the kinematical characteristics of the platform under different angles of waves and current are discussed. It is concluded that the Spar platform excurses with the current and oscillate with the wave. The drag force and inertial force should also be taken into consideration when analyzing the kinematic characteristics of Spar platform due to waves and current.