The hydraulic fracturing technique has been widely applied in many fields, such as the enhanced geothermal systems (EGS), the improvement of injection rates for geologic sequestration of CO₂, and for the stimulations of oil and gas reservoirs. The key points for the success of hydraulic fracturing operations in unconventional resources are to accurately estimate the redistribution of pore pressure and stresses around the induced fracture and predict the reactivations of preexisting natural fractures. The pore pressure and stress regime around hydraulic fracture are affected by poroelastic and thermoelastic phenomena as well as by fracture opening compression. In this work, a comprehensive semi‐analytical model is used to estimate the stress and pore pressure distribution around an injection‐induced fracture from a single well in an infinite reservoir. The model allows the leak‐off distribution in the formation to be three‐dimensional with the pressure transient moving ellipsoidically outward into the reservoir from the fracture surface. The pore pressure and the stress changes in three dimensions at any point around the fracture caused by poroelasticity, thermoelasticity, and fracture compression are investigated. With Mohr‐Coulomb failure criterion, we calculate the natural fracture reactivations in the reservoir. Then, two case studies of constant water injection into a hydraulic fracture are presented. This work is of interest in the interpretation of microseismicity in hydraulic fracturing and in the estimation of the fracture spacing for hydraulic fracturing operations. In addition, the results from this study can be very helpful for the selection of stimulated wells and further design of the refracturing operations.

中文翻译：

---

水力压裂增产过程中3D应力重新分布的半解析模型及其对自然裂缝再活化的影响

水力压裂技术已广泛应用于许多领域，例如增强的地热系统（EGS），提高地质封存CO ₂的注入速率等，用于增产油气藏。在非常规资源中水力压裂作业成功的关键是准确估算孔隙压力和应力在裂缝周围的重新分布，并预测先前存在的天然裂缝的再活化。水力裂缝周围的孔隙压力和应力状态受孔隙弹性和热弹性现象以及裂缝开口压缩的影响。在这项工作中，使用了一个综合的半分析模型来估算无限储层中单井的注入引起的裂缝周围的应力和孔隙压力分布。该模型允许地层中的泄漏分布是三维的，压力瞬变从裂缝表面椭圆形向外移动到油藏中。研究了由孔隙弹性，热弹性和裂缝压缩引起的裂缝周围任意点的三维压力变化。利用Mohr-Coulomb破坏准则，我们可以计算储层中的自然裂缝再活化。然后，介绍了将两个恒定水注入液压裂缝中的两个案例研究。这项工作对解释水力压裂中的微震性和水力压裂作业中裂缝间距的估算很有意义。此外，