中文摘要：

为了研究天然裂缝性地层中天然裂缝网络对水力裂缝延伸的影响规律，采用室内大型试验模拟装置进行了物理模拟。根据实际地层条件和施工参数确定试件参数和试验条件，并采用高温加热自然空气冷却的方法使试件中产生随机裂缝。研究发现，天然裂缝显著影响水力裂缝的延伸，天然裂缝性地层中水力裂缝的延伸具有一定的随机性。裂缝性地层中的水力裂缝是由少数几条尺寸较大的主裂缝和大量尺寸较小的次裂缝组成的系统。压力曲线随时间波动幅度大，在实际压裂施工中表现为压裂液的大量滤失，容易造成过早砂堵，推荐采用高黏度压裂液。

英文摘要：

Large - scale physical simulations are carried out to investigate the influence of natural fracture networks on propagation of hydraulic fracture. Based on practical geological and treatment parameters, experimental samples are prepared to generate random fractures inside, by heating at for 3 hours then cooling in the air. The results indicate that natural fractures exert great effect on hydraulic fracture propagation, at random to some degrees. The hydraulic fracture is a fracture system consisting of several main fractures of big size, and many fractures of small size. There is pressure fluctuation in pressure records, with the magnitude of several MPa to 8 MPa, corresponding to large fluid loss in treatment. So, high viscosity is preferred in treatment, to prevent from premature screenout.