An Enhanced Geothermal System (EGS) can be thought of as an underground heat exchanger designed to extract geothermal energy. The performance of these systems can be improved by increasing permeability with hydraulic fracturing, following the same technique used for hydrocarbon reservoirs. To understand hydraulic fracturing, whether it is implemented in an EGS or in a hydrocarbon reservoir, it is important to know the fracture parameters of the rock at stake, e.g., the fracture energy. We report here the use of a method based on an energy balance during hydraulic fracture tests. Specimens were prepared and they have been mechanically and hydromechanically characterized at 20 ºC and 100 ºC, a temperature representative of actual reservoir conditions. The fracture energy is obtained from a balance of kinetic, potential and pressure energies involved in the hydraulic fracture tests. The method provides fracture energies that are consistent with the literature data on similar materials. It is also found that the fracture energy increases upon heating.

可以将增强型地热系统（EGS）视为旨在提取地热能的地下热交换器。遵循与碳氢化合物储层相同的技术，通过水力压裂增加渗透率可以改善这些系统的性能。为了理解水力压裂，无论是在EGS还是在碳氢化合物储层中进行，重要的是要了解所涉岩石的压裂参数，例如压裂能量。我们在这里报告在水力压裂试验期间基于能量平衡的方法的使用。样品已经准备好，并已在20ºC和100ºC（代表实际储层条件的温度）下进行了机械和流体力学表征。断裂能是从动平衡中获得的，液压断裂试验中涉及的势能和压力能。该方法提供的断裂能与相似材料的文献数据一致。还发现，断裂能在加热时增加。