Study On Comfort And Nonlinear Coupled Dynamics Of Deep-water Semi-submersible Support Unit

With the rapid development of the global economy,energy consumption has increased significantly,and economic development is increasingly dependent on oil and gas energy,which is the key to economic security and sustainable development.At present,the exploitation of marine oil and gas resources gradually extends to deep-sea,Because of the long distance and extreme condition,it is difficult for material supply,storage and transshipment and the working ability of the operators is seriously affected.Therefore,it is of great significance to study the deep-water support unit for offshore oil and gas resources development to improve the production efficiency of offshore oil and gas,ensure the healthy life of operators and sustainable development.Semi-submersible support unit began to attract attention with relatively low cost in construction,large deck space and variable load,strong storm resistance and other advantages.Based on the investigation and analysis of the development trend and research status of semi-submersible support platforms at home and abroad,this paper studies comfort and nonlinear coupled dynamics of deep-water semi-submersible support unit.(1)Numerical simulation in frequency-domain consists of on the hydrodynamic characteristics of semi-submersible support platform at the center of gravity,living building and GANGWAY is carried out based on potential flow theory and short-term prediction theory.(2)Sensitivity analysis of various crucial parameters in the mooring system are conducted by comparison of corresponding numerical simulation results.The effects of the length of line,mooring radius and number of anchor of mooring system on unit motion under the combined action of wind,wave and current are studied.(3)The motion resonance features of semi-submersible platform are investigated,based on a nonlinear coupling mathematical model,considering the effects of pontoons and bracings and the coupling of heave,roll and pitch motions on the buoyancy and restoring force.The effect of irregular wave parameters is also investigated.