Capability Analysis Of Position System Of J-lay Vessel

Marine oil and gas exploration and exploitation is inevitably the critical way to solve energy problems.The transportation of oil and gas from oil field to the land requires long-distance pipe.J-lay vessels are not subject to water depth restriction,having extensive use in deep water and ultra-deep water pipe laying.High positioning accuracy can secure the operation of J-lay vessel,which calls for high attention in the preliminary design.Based on the research on key technologies of a deep-sea light J-lay system of the Ministry of Industry and Information Technology(MIIT [2012]No.539),the performance of the position system for the light J-lay vessel was studied in this paper.Based on the vessel motion analysis,the optimization of the layout for the dynamic positioning propulsion system was studied.The dynamic positioning capability of the optimized scheme was analyzed considering the influence of pipe laying process.Besides,the comparative analysis of dynamic positioning,mooring positioning and thruster assisted mooring system was carried out.The main contents for this paper are:(1)Research on the kinematic performance of J-lay vessel was carried out concentrating on the hydrodynamic calculation and environmental load calculation,as the basis research for the study of position capability.(2)Optimization design of J-lay vessel dynamic positioning propulsion system: based on differential evolution algorithm,the layout of propulsion system was given.The scheme was improved after dynamic capability and thruster failure analysis.The differential evolution was applied to optimize the parameters of the new scheme.(3)The time domain simulation of J-lay vessel was conducted under 1500-meter water depth,the vessel motion and power assumption was studied.In addition,the influence of pipe laying operation on the dynamic position capability was studied,proving the feasibility of the optimized dynamic positioning scheme.(4)Comparative analysis of dynamic positioning,mooring positioning and thruster assisted mooring system was conducted studying the features of three position methods in 500 m water depth.The failure mode effect analysis was carried out for the thruster assisted mooring system.