【摘要】 水力压裂是青海共和盆地干热岩地热资源开发的难点技术问题之一。本文基于升级改造的大尺寸真三轴水力压裂物理模拟实验系统模拟干热岩储层高温高压环境,利用青海共和盆地露头岩心进行水力压裂物理模拟实验,揭示干热岩储层水力裂缝的起裂和扩展规律。通过物理模拟实验发现:干热岩储层裂缝起裂可以通过文中提出的起裂模型判断起裂方式和预测起裂压力;水力裂缝在岩石基质中的扩展形态简单,仅沿最大主应力方向延伸;但是水力裂缝会受到岩石中弱面的影响,发生转向沿弱面延伸,形成较复杂的裂缝形态。因此,建议在干热岩储层实际施工中,在天然裂缝发育较丰富的层段开展水力压裂,以实现复杂裂缝网络提取地热能。更多还原

【Abstract】 Hydraulic fracturing is one of the most important technical challenges in the development of hot dry rock geothermal reservoirs in Gonghe basin, Qinghai. Based on the advanced large-scale true triaxial hydraulic fracturing simulation experimental system, the authors studied the hydraulic fracture initiation and propagation in hot dry rock geothermal formations with high temperature and high pressure. The samples were from the outcrop core of Gonghe basin. According to the experimental result, the hydraulic fracture initiation and pressure could be predicted by the crack initiation model proposed in this paper. The propagation in the hot dry rock matrix has a simple extension along only with the direction of the maximum horizontal stress. The hydraulic fractures, however, are affected by natural fractures to achieve larger stimulation reservoir volume. Therefore, it is suggested that in the field, the hydraulic fracturing treatment should be in the formations rich in natural fractures so as to get a complex fracture network for geothermal energy extracting.更多还原