Reliability Analysis of Subsea Riser System Based on Fuzzy Fault Tree Analysis Method

Abstract To deal with the complex structure of subsea riser system and the lack of failure statistics and insufficient information during operation, a fuzzy fault tree analysis (FFTA) method is applied to analyse the reliability of the subsea riser system, and a qualitative and quantitative analysis is carried out by establishing a fault tree model of the riser system to obtain the minimum set of cuts and the basic events. The fuzzy importance degree of each fundamental event is determined as well as the failure probability of the headline event of the fuzzy fault tree, “failure of subsea riser system,” using the triangular fuzzy number computation method. Finally, the “average value” method of comprehensive analysis of the fault tree model, the analysis results show that the bottom event riser check valve, riser buoyancy device, riser working medium isolation valve, riser line, riser gas lift device and other components of the failure of the subsea riser system is relatively the weak links, compared with the actual situation, the analysis results in line with the actual engineering situation, these five aspects should be regularly detected and focused on prevention. In conclusion, this research helps to comprehensively analyse the reliability of the riser system and take into account the uncertainty factors, and provides more accurate guidance on the reliability constraints for the localized design and production of subsea riser system.