| The world offshore oil resources accounted for34%of total global oil resources, marine will become the main development battlefield. The semi-submersible unit is widely used because of its special characteristics:the great performance of stability, the capacious deck area, the preferably payload, the strong ability of drilling and multi-functioned. Hai Yang Shi You981constructed by China in2011is a6th-generation deepwater semi-submersible unit and is designed to serve the multiple functions of exploration, well drilling, completion and workover in the sea areas of the South China Sea, Southeast Asia and West Africa, which represents the most advanced level of semi-submersible platform. With an operating water depth of3,000meters and the largest drilling depth at10,000meters. It can cope with typhoon of200year frequency and its service life is30years.Hai Yang Shi You981moves at the six free degrees resulting from the wind, wave and current force. Therefore, Hai Yang Shi You981must have stationkeeping system to ensure its movement in the allowable range above the well location. Hai Yang Shi You981is equipped with a DP3system as well as a12-point conventional mooring system designed for stationkeeping system. When the water level is below1,500Hai Yang Shi You981adopts mooring system, while the water level is above1,500Hai Yang Shi You981adopts DP3system. Mooring system is one of the key technologies.Hai Yang Shi You981is research object in this paper. The composition of the mooring system for deepwater semi-submersible unit is first introduced and the composition of the mooring line is mainly studied. Then calculation method of wind, wave and current force for ddeepwater semi-submersible unit is discussed and based on catenary method static analysis of single single-component and multi-component mooring line is studied. According to the design criteria and analysis condition of the mooring system for deepwater semi-submersible unit, the three-dimensional potential flow theory is adopted to calculate wave force, the hydrodynamic analysis of Hai Yang Shi You981adopts hydrodynamic software AQWA, AQWA can get the hydrodynamic parameter of Hai Yang Shi You981, including the added mass, added damping, exercise and stress response and transfer function. According to API RP2SK under the conditions of the water depth of1500m, finally12-point multi-component mooring system for Hai Yang Shi You981is analyzed in time domain and the effect of the mooring system is assessed from the strength and positioning ability. According to the horizontal offset of Hai Yang Shi You981and mooring line tension, positioning ability and safety of the12-point mooring system meet the demand of API RP2SK.(1) Analysis of hydrodynamic characteristics of Hai Yang Shi You981 semi-submersible unitAccording to3-D potential flow theory, the first step is frequency-domain calculation of the semi-submersible in different conditions, to obtain the added mass and damping coefficients, as well as response amplitude operators (RAO) of motions in various frequency and wave directions. Then, a database of frequency-domain hydrodynamic parameters is built up.(2) Time-domain analysis of12point mooring system for Hai Yang Shi You981semi-submersible unitTime-domain coupled analyses of mooring system for Hai Yang Shi You981semi-submersible unit is carried out in operating sea conditions to obtain motion responses in horizontal direction and tensions of mooring line. |
PDF Full Text Request