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在对裂缝性储层进行水力压裂过程中,天然裂缝的存在会对水力裂缝的扩展产生十分重要的影响。通过建立水力裂缝遭遇天然裂缝的二维平面应变计算模型,采用数值模拟的计算方法,对裂缝性储层中水力裂缝的扩展规律进行研究。结果表明,在水力裂缝扩展过程中,水力裂缝的入射角、远场主应力比以及天然裂缝的胶结强度是影响水力裂缝扩展的主要因素。在低入射角,低远场主应力比的情况下,水力裂缝更易于转入天然裂缝并在缝内延伸;在高入射角,高远场主应力比的情况下,水力裂缝更易于直接穿过天然裂缝;天然裂缝胶结强度越低时,水力裂缝越容易转入天然裂缝并在天然裂缝内延伸。
During the hydraulic fracturing of fractured reservoirs, the existence of natural fractures will have a very important influence on the expansion of hydraulic fractures. Through the establishment of two-dimensional plane strain calculation model of natural fractures encountered by hydraulic fractures, the numerical simulation method is used to study the propagation of hydraulic fractures in fractured reservoirs. The results show that the incidence angle of hydraulic fractures, the ratio of principal stress in far field and the cementation strength of natural fractures are the main factors affecting the hydraulic fracture propagation. Hydraulic fractures are easier to transfer into natural fractures and extend within fractures at low incident angles and at low and far field principal stress ratios. Hydraulic fractures tend to directly pass through at high incident angles and at high and far field principal stress ratios Natural cracks; natural fracture bond strength is lower, the hydraulic fractures more easily into the natural fracture and extension within the natural cracks.