Casing collapse is a costly phenomenon in drilling industry that occurred in different geological environment with different geomechanical property. Geomechanical and numerical analysis of casing collapse in Sirri-E, one of the offshore Iranian oilfield in Persian Gulf has been investigated in this work. In this study we tried to model several collapse loading of rock-cement-casing system under real condition of in-situ stress and geomechanical property of different lithology, cement and casing, to decrease simplified modeling assumption. A mechanical earth model is built to determine the accurate amount of in-situ stresses and different mechanical property of rock. This geomechanical data extracted from 1D geomechanical earth model and entered to numerical model involved formation, cement and casing. Furthermore the interactions between the casing and surrounding formation are simulated by applied elastic-plastic behavior for rock and cement. Also Joint property between different media considered to increase the accuracy of model to real condition of borehole at the collapsing depth. The result show that over pressured marl and salt have high potential for casing collapse and the maximum external load applied to the casing is very more than maximum mud weight that usually considered in API standard for design of casing. So it is necessary to use coupled data from mechanical earth modeling and numerical analysis to determine maximum lithostatic pressure applied to the casing.

套管塌陷是钻井行业中一种代价高昂的现象，发生在具有不同地质力学特性的不同地质环境中。在这项工作中，对Sirri-E（位于波斯湾的伊朗海上油田之一）的套管塌陷进行了地质力学和数值分析。在这项研究中，我们试图对在真实地应力和不同岩性，水泥和套管的地质力学特性的真实条件下的岩石-水泥-套管系统的多个倒塌载荷进行建模，以减少简化的建模假设。建立机械地球模型可以确定准确的原地应力量和岩石的不同机械特性。该地质力学数据是从一维地质力学地球模型中提取并输入到涉及地层，水泥和套管的数值模型中的。此外，通过应用岩石和水泥的弹塑性行为来模拟套管与周围地层之间的相互作用。此外，还考虑了不同介质之间的联合特性，以提高模型在塌陷深度下对井眼实际状况的准确性。结果表明，压力过大的泥灰和盐很可能导致套管塌陷，施加到套管上的最大外部载荷远远超过API标准中套管设计通常考虑的最大泥浆重量。因此，有必要使用来自机械地球建模和数值分析的耦合数据来确定施加到套管的最大岩石静压力。此外，还考虑了不同介质之间的联合特性，以提高模型在塌陷深度下对井眼实际状况的准确性。结果表明，压力过大的泥灰和盐很可能导致套管塌陷，施加到套管上的最大外部载荷远远超过API标准中套管设计通常考虑的最大泥浆重量。因此，有必要使用来自机械地球建模和数值分析的耦合数据来确定施加到套管的最大岩石静压力。此外，还考虑了不同介质之间的联合特性，以提高模型在塌陷深度下对井眼实际状况的准确性。结果表明，压力过大的泥灰和盐很可能导致套管塌陷，施加到套管上的最大外部载荷远远超过API标准中套管设计通常考虑的最大泥浆重量。因此，有必要使用来自机械地球建模和数值分析的耦合数据来确定施加到套管的最大岩石静压力。