The seal failure of tubing and casing connections compromises underground gas storage well safety. This work proposes a systematic uncertainty analysis framework for connection sealability assessment. The framework covers reliability analysis and reliability sensitivity analysis and attempts to provide more effective support for the reliability design of connection seals. The reliability analysis introduces an adaptive Kriging with stopping criterion P-Monte Carlo simulation (AKP-MCS) method, which can provide a satisfactory estimate of failure probability with a small number of performance function evaluations. This metamodeling technology can effectively reduce the numerical efforts required for the reliability assessment of connection sealability. In the reliability sensitivity analysis, the refined metamodel obtained from the reliability analysis is coupled into a single-loop Monte Carlo simulation (MCS) method. The classifier attribute of this metamodel can meet the requirement of the single-loop MCS method to classify the signs of sampling points. This attribute enables sample matrices to be evaluated on this metamodel instead of the performance function, making the reliability sensitivity assessment more feasible. The proposed method is first demonstrated with four academic examples with promising results. Next, an illustrative tubular connection case is provided. The proposed scheme gives estimates of the failure probability and reliability sensitivity close to the classical model but requires less computational cost. The results of the analysis can provide useful information for the scheme decision-making and reliability optimization of connection seal design.

油管和套管连接的密封失效会危及地下储气井的安全。这项工作为连接密封性评估提出了一个系统的不确定性分析框架。该框架涵盖了可靠性分析和可靠性敏感性分析，试图为连接密封件的可靠性设计提供更有效的支持。可靠性分析引入了具有停止准则的自适应克里金法 P-蒙特卡罗模拟 (AKP-MCS) 方法，该方法可以通过少量的性能函数评估提供令人满意的故障概率估计。这种元建模技术可以有效减少连接密封性可靠性评估所需的数值工作。在可靠性敏感性分析中，从可靠性分析中获得的精炼元模型被耦合到单循环蒙特卡罗模拟 (MCS) 方法中。该元模型的分类器属性可以满足单循环MCS方法对采样点符号进行分类的要求。此属性使样本矩阵能够在此元模型上而不是性能函数上进行评估，从而使可靠性敏感性评估更加可行。所提出的方法首先用四个学术例子进行了证明，结果很有希望。接下来，提供说明性的管状连接箱。所提出的方案给出了接近经典模型的故障概率和可靠性敏感性的估计，但需要较少的计算成本。