Time-Dependent Reliability Analysis of Well Barrier Elements

Resumo

The exploration and production of hydrocarbons in pre-salt ultra-deepwater environments demand robust integrity assessment methodologies due to extreme operational conditions and high intervention costs. This work proposes a time-dependent reliability framework to evaluate the structural performance of well barrier elements (WBEs) throughout the well lifecycle. The approach integrates Monte Carlo simulation, corrosion modeling, and fault logic via cut sets. Historical failure rates were combined with simulated casing corrosion to assess two critical failure modes: internal burst under formation fluid pressure (Klever-Stewart model) and collapse under full evacuation (Klever-Tamano model). Results show that accounting for time-dependent corrosion increases system failure rates and cumulative probabilities, with the KT model yielding more conservative outcomes. These findings highlight the importance of incorporating temporal degradation mechanisms into offshore well integrity management, particularly for long-life assets. The methodology allows for the estimation of remaining useful life (RUL), identification of critical degradation paths, and quantification of system reliability at any point in time.