Hyundai Heavy Industries Co., Ltd. has developed a LNG-FPSO with production capacity of 2.5 MTPA to meet the demand of the offshore LNG well development in near future. This paper presents the experimental and the numerical study on the mooring and the offloading performances of the developed LNG-FPSO.
In the FEED design stage, the turret mooring system and the offloading mooring system with side-by-side arrangement were designed using the quasi-dynamic method and verified through the model tests using the truncation method in the basin. It is known that the quasi-dynamic method is very efficient to calculate many environmental combinations for the evaluation of the turret mooring system and the offloading availability. And the numerical parameters for the truncated system are calibrated with the model test results with the same truncated set-up and it is expanded into the full depth model.
In this study, it was verified that the safety of the station keeping system under the extreme environmental condition and the offloading performance satisfied the design requirement. Especially, the hydrodynamic and mechanical couplings between LNG-FPSO and LNG carrier were considered as the important parameters in the offloading availability with ship-to-ship arrangement. Finally, the design parameters such as the relative motion, line tension and fender load of offloading system were evaluated with considering the dynamic positioning system.