This paper presents an assumed enhanced strain finite element framework for simulating hydraulic fracture propagation in saturated thermoporoelastic media, considering the influence of thermal effects. The proposed approach combines classical thermoporoelasticity theory with a cohesive fracture model to describe the coupled behaviors of fluid flow, rock deformation and fracture propagation. Within this framework, fractures are represented using constant strain triangular elements enriched with constant displacement jumps. The mechanical response of fractures is governed by a trilinear cohesive law, and fracture initiation and propagation are both determined by using standard Newton’s method while maintaining global equilibrium. The numerical framework is verified through a series of examples, including cases without fractures, cases with rigid and deformable fractures, and hydraulic fracture propagation with thermal effects. The results show that thermal stress primarily affects the region near the injection point but has limited impact on fracture length evolution and fluid pressure distribution within the fracture. In contrast, temperature-dependent viscosity can significantly influence hydraulic fracture propagation. This work can be beneficial to our understanding of hydraulic fracture modeling in thermoporoelastic media and provide a potential useful numerical tool for simulating hydraulic fracturing processes with consideration of thermal effects.

中文翻译：

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用于模拟热多孔弹性介质中水力裂缝增长的假设增强应变有限元公式


考虑到热效应的影响，本文提出了一个假设的增强应变有限元框架，用于模拟饱和热多孔弹性介质中的水力裂缝扩展。所提出的方法将经典的热多孔弹性理论与内聚裂隙模型相结合，以描述流体流动、岩石变形和裂缝扩展的耦合行为。在这个框架内，断裂使用富含恒定位移跳跃的恒定应变三角单元来表示。裂缝的机械响应受三线性内聚律控制，裂缝的起始和扩展都是通过使用标准牛顿法确定的，同时保持全局平衡。通过一系列示例验证了数值框架，包括无裂缝的情况、具有刚性和可变形裂缝的情况以及具有热效应的水力裂缝扩展。结果表明，热应力主要影响注入点附近的区域，但对裂缝长度演变和裂缝内流体压力分布的影响有限。相比之下，与温度相关的粘度会显著影响水力裂缝的扩展。这项工作有利于我们理解热多孔弹性介质中的水力裂缝建模，并为在考虑热效应的情况下模拟水力压裂过程提供潜在的有用数值工具。