Structural Reliability Analysis Of Deep-water Risers And Mooring Systems In Catastrophic Ocean Environment

The South China Sea region is an important area of deep-sea oil and gas resources development, but also a multiple region that extreme sea conditions happens frequently. In this paper, for the potential of the disastrous marine environment, the time-domain coupled analysis of deep-sea floating systems technology and structural reliability technology was combined to develop a process for security assessment applicable to riser and mooring system of deep-water floating system to protect the security of oil and gas resource development.Firstly,based on the advanced time domain couple analysis for deep-sea platforms and finite element dynamic response analysis for risers, the random time-domain dynamic response of the structure was obtained. Based on extreme value theory, statistical processing and numerical simulation to the results of the non-linear response was carried to study the load probability model approach.Secondly, the limit states of the risers and mooring systems was analyzed, the limit state equation was solved by using FORM/SORM methods. And system reliability analysis was carried out according to the component connection type risers and mooring systems. At the same time, sensitivity analysis was carried out for the riser that contain many uncertainties.This methodology takes coupling effect of deep-sea platforms fully into account, which can provide a useful method for reliability assessment of deep-water risers and mooring systems in catastrophic sea state.