Contribuição à análise de integridade em sistemas de revestimento via confiabilidade estrutural

Abstract

Uncertainties will always be present in the development of any structural Project and should be mitigated if possible. Knowledge of the mechanical behavior of the structure in this scenario is extremely important and necessary for the evaluation of the associated safety levels. Most normative codes are based on deterministic analyses, which basically employ partial safety factors, which reduce resistance and increase loadings. On the other hand, the reliability analysis applied to the structural design allows the probability of failure of the structure to be predicted, still in design stage.The reliability-based model can be constructed based on the evaluation of the uncertainties associated to the design variables, which are statistically described.The structural well integrity corresponds to its characteristic of adequately supporting all the expected loadings, from the drilling operations, and throughout the life in service. It is clear, then, the relationship between the well integrity and its structural safety, which is significantly dependent on the casing system.This work applies structural reliability theory to the estimating of safety levels in well casing tubulars, considering both resistance and loading uncertainties. It aims to analyze the well integrity by means of successive failure events in di.erent casing sections by using system reliability concepts.The evaluation of the probability of failure is performed using the FORM transformation method and the Monte Carlo simulation.