Research On Motion Performance And Positioning Capacity Of Deep Sea Semi-submersible Drilling Platform

With the exploration to the deep water or even the extra deep water area all over the world,great challenges have been posed to the safety operation of the drilling platform under the extremely harsh environmental conditions.As one of the important deep sea equipment,the motion performance and DP capability are key performances of semi-submersible drilling platforms.Excellent motion response and DP capability are important guaranties for the safety operation of the drilling platforms.In this dissertation,we mainly focus on the research of the motion performance and DP capability analysis of the seventh generation semi-submersible drilling platform.Firstly,by adopting the commercial software,the calculation model of motion RAO is set up.According to the method of the short-term predication,the relevant programs and worksheets of the semi-submersible drilling platforms have been compiled,including the after-processing analytical program of the short-term predication and the calculation worksheet of the wave scatter and the analytical program of the work performance,it provides valid and proper analysis tools for analyzing the subsequent semi-submersible drilling platforms.Secondly,by adopting the quasi-static method,the analytical model of the dynamic positioning capacity for the semi-submersible drilling platforms has been established.With reference to ABS rules,the model of the thrust loss is established,and program of the thrust is compiled in order to get the accurate effect of the thruster arrangement on the thrust loss.Aiming at four different thruster arrangement,the research about effect of the thruster arrangement on the thrust loss has been implemented.Subsequently,based on the analytical result of 6-DOF motion RAOs for Blue Whale I,we adopt the operation performance analysis method to obtain the performance result of Blue Whale I in GOM,Brazil and South China SeaFinally,through the analysis and research on the motion performance and dynamic positioning capability of the Blue Whale I,scientific data is provided for the anti-Typhoon operation.And the continuous exploitation test of natural gas hydrate is eventually achieved during the typhoon "Merbok" in China South Sea,which is greatly beneficial to ensure the implementation of national crucial energy explorations.