Research and Design on Internal Turret Mooring System of FPSO in South China Sea

This paper mainly introduced the research and design procedure, method and conclusion for internal turret mooring system of FPSO in South China Sea. According to the environmental condition characteristic and operating experience of FPSO in South China Sea and other reasons, the permanent internal turret mooring system with disconnected function is recommended as the final scenario after comparison with the other internal turret systems including disconnected system in typhoon condition and permanent system without disconnected function. For the gradually bad environmental conditions such as wind, wave and current in South China Sea, 500-year return typhoon condition is required as the extreme design condition of mooring system. According to the environmental condition distribution and classification requirement, the design standards, rules and corresponding design parameters for 500-year return condition are determined as the basis of mooring system design. The mooring system is very difficult to design because of very shallow water for catenary system and 500-year return typhoon environmental condition in South China Sea. For the problems appeared because of 500-year return extreme design condition and other parameters, a reliable solution was proposed from the aspect of wave characteristics research and got approval from classification society. The new design criteria for mooring system of FPSO in South China Sea is updated and the mooring system design is completed based on the updated design criteria. The research and design procedure and method for internal turret mooring system of FPSO in South China Sea are summarized too. This paper can be helpful to the similar projects in South China Sea.