On critical parameters of squall associated with the mooring design of a turret-moored FPSO

Abstract

ABSTRACTSqualls bring a unique challenge for the design and analysis of Floating Production Storage and Offloading Unit's (FPSO's) turret mooring systems in offshore West African and South Asia. This paper focuses on the characterisation of the squalls. The synthetic squall equations are introduced to simplify the actual squall time series. In addition, Monte Carlo method is used to calculate the response-based categorised estimates of maximum offsets and mooring line tensions. The hydrodynamic coefficients are calculated from ANSYS-AQWA and exported to ARIANE software in which the time-domain squall events can be considered as inputs. The system's responses, including turret offsets and mooring line tensions, are initially considered as the consequence of various critical parameters and instantaneous environmental parameters. Furthermore, a sensitivity check of critical parameters affecting the results has been carried out and discussed. Finally, the safety evaluation procedure required in the turret mooring system has also been presented.