Summary As wells in modern operations are getting longer and more complex, assessing the effect of casing wear becomes ever more crucial. Degradation of the tubulars through mechanical wear reduces the pressure capacity significantly. In this paper, we use the finite element method (FEM) to analyze the stress distribution in degraded geometries and to assess reduction in collapse strength. A model for the collapse strength of the casing with a crescent-shaped wear groove is developed and its performance evaluated in relation to experimental data. The model was created by using the Buckingham Pi theorem to make generalized empirical expressions for yield and elastic collapse of tubulars. Finite element analysis (FEA) of 135 geometries was used in the development of the model. The results show that the generalized expressions capture the trends observed in the FEA accurately and match the experimental data from six tubular collapse tests with an average relative difference in collapse pressure of 5.2%.

中文翻译：

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使用应力集中因子的磨损管塌陷的广义经验表达式

总结 随着现代作业中的油井变得越来越长、越来越复杂，评估套管磨损的影响变得越来越重要。由于机械磨损造成的管材退化会显着降低压力容量。在本文中，我们使用有限元方法 (FEM) 来分析退化几何形状中的应力分布并评估坍塌强度的降低。开发了具有新月形磨损槽的套管的抗塌强度模型，并根据实验数据评估了其性能。该模型是通过使用白金汉 Pi 定理对管材的屈服和弹性塌陷进行广义经验表达式而创建的。模型开发中使用了 135 种几何形状的有限元分析 (FEA)。