| The South China Sea is one of the world's four major marine oil and gas accumulation sites.However,there is a certain gap between the technology reserves of China's oil and gas development and the developed countries,and Vietnam and the Philippines have taken the lead in oil exploration in the disputed areas of the South China Sea.So it is extremely urgent to accelerate the exploitation of oil and gas resources in the South China Sea.The exploitation of offshore oil requires a positioning device to fix the platform at a certain position,and the mooring positioning is a traditional positioning method.The study of its composition and arrangement is an important part that cannot be ignored.In order to study the optimal mooring system of semi-submersible platform under the depth of 120 m,the mathematical model of the multi-component mooring line and static model of semi-submersible platform is established by MATLAB.The model considers the influence of the flow force on the mooring line and its own elastic elongation.By analyzing the performance difference of the mooring system under different structural components,the optimal composition of the multi-component mooring line and the mooring installation method are determined,and the tension response of the semi-submersible platform under different disturbances is given.The article first introduces the development of the semi-submersible platform and the material type and performance parameters of the mooring line,and determines the parameters of the mooring line according to the diameter of the material.The relationship between tension and movement of multi-component mooring line is deduced by mechanical analysis,and the mathematical model is built by Simulink library.Under the fixed tension,the mathematical model of the mooring line is used to study the influence of the different material composition of the mooring line on the overhang length,the horizontal tension and the anti-interference ability of the mooring line.Through normalization and dimensionless the simulation data,the evaluation curve is obtained,and the best mooring line material composition is determined.Paralleling buoy in mooring lines to improve the performance of the mooring system.And taking into account the impact of the scale of the buoy.The influence of different buoy position and buoyancy size on the mooring system is compared by the method of normalization and dimensionless.Finally the optimum buoy position and buoyancy size is obtained.The tensiondisplacement curve of the single mooring line is calculated by simulation,and the initial pretension force of the mooring system is determined according to the safety coefficient and the working radius of the semi-submersible platform.Two stress calculation methods of semi-submersible platform remittance and non-remittance system are deduced.The difference of static restoring force between them is studied emphatically.The method of non-remittance system is used to analyze the static restoring force response and the tension response of each mooring line under different disturbances.Finally,the centralized mooring installation method is selected.The whole simulation design can provide reference for the design of shallow water mooring positioning system. |
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