Group Maintenance Strategy for FPSO Offloading System Based on Reliability Analysis

Floating Production Storage and Offloading (FPSO) is being widely used in offshore petroleum production. As a key subsystem, the offloading system often fails and causes marine disaster. The aim of this study was to investigate the failure events and failure rate to determine the efficient maintenance strategy, in particular maintenance interval and overhaul cycle. Failure Mode and Effects Analysis (FMEA) method was applied for the reliability analysis of the main failure events and their interrelations. In order to guarantee the accuracy, the analysis is based on four primary subsystem of offloading system: platform safety system, offloading hose system, center control system and auxiliary system. The logic structure of the main failure events was demonstrated by dynamic fault tree analysis (DFTA) in order to obtain the minimal cut sets, mean time between failure (MTBF) and failure probability by numerical analysis method. At last, group maintenances theory is applied to obtain the maintenance interval and overhaul cycle for the FPSO to achieve global optimum and feasibility. The result suggested the overhaul cycle is 4.8 years. After the comparison with actual engineering data, it is proved to be precise and this method is stable to be applied for engineering practice.