Abstract: The influences of macro-parameters and micro-parameters on the strike of hydraulic fracture interacted by natural fracture were studied by a series of large-size tri-axial experiments.The curves of pump pressure were analyzed,and the boundary line of natural fracture failure was determined.The fracture geometries under the different in-situ stresses were discussed.The test results indicated that the differential stress and angle of intersection were the macro-parameters affecting the hydraulic fracture propagation in normal stress regime,and the interfacial friction coefficient and dimensionless net pressure were the micro-parameters for fracture propagation.The fracture propagation mechanism of hydraulic fracturing in naturally fractured reservoir was discussed.The influence of natural fracture on hydraulic fracture propagation in the tectonic stress regime is smaller than that in the normal stress regime.

Key words: hydraulic fracturing, hydraulic fracture, natural fracture, fracture interaction mechanism, fracture propagation mechanism, experimental study

摘要： 采用大尺寸真三轴实验系统,探讨了天然裂缝与水力裂缝干扰后水力裂缝走向的宏观和微观影响因素,分析了压力曲线,提出了天然裂缝破坏准则,分析了不同地应力状态下裂缝的形态。试验结果表明,在常规应力状态下,水平主应力差和逼近角是水平裂缝走向的宏观影响因素;天然裂缝界面摩擦系数和缝内净压力无因次量是微观影响因素。给出了确定天然裂缝破坏边界线的回归公式,揭示了裂缝性油气藏水力裂缝与天然裂缝的干扰机理。局部构造应力状态对水力裂缝扩展的影响大于对天然裂缝的影响。

关键词: 水力压裂, 水力裂缝, 天然裂缝, 裂缝干扰机理, 裂缝扩展机理, 试验研究