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为了研究煤储层中水力压裂产生的裂缝扩展延伸机理,借助大尺寸的真三轴试验设备,以相似材料成型的试件为研究对象,进行了水力压裂模拟试验。试验结果表明:水力压裂裂缝总的扩展方向为最大、最小主应力合力的矢量方向,即沿着力最大的方向扩展。天然裂缝的存在会影响水力压裂裂缝的扩展路径,部分裂缝穿过天然裂缝弱面继续沿着最大主应力方向扩展、部分裂缝扩展至天然裂缝面尖端后继续沿着最大主应力方向扩展、部分裂缝在天然裂缝面之前发生分层、转向。
In order to study the mechanism of crack propagation and extension caused by hydraulic fracturing in coal reservoirs, a hydraulic fracturing simulation test was carried out on a large-scale true triaxial test equipment with specimens made of similar materials. The experimental results show that the general direction of hydraulic fracturing is the direction of maximum and minimum force of principal stress, that is, the direction of maximum force expansion. The existence of natural fractures will affect the expansion path of hydraulic fracturing. Some of the fractures continue to extend along the maximum principal stress through the weak fractures of natural fractures. Some fractures extend to the tip of natural fractures and continue to expand along the direction of maximum principal stress. Cracks in the natural fracture surface stratification, steering.