Hydraulic fracturing has been proven to be an effective technique for stimulating petroleum reservoirs. During the hydraulic fracturing process, the effects of the natural fracture, perforation orientation, stress reorientation, etc. lead to the production of a non-planar, mixed-mode I/II hydraulic fracture. In this paper, a criterion for a mixed-mode I/II hydraulic fracture crossing a natural fracture was first proposed based on the stress field around the hydraulic and natural fractures. When the compound degree (KII/KI) approaches zero, this criterion can be simplified to identify a pure mode I hydraulic fracture crossing a natural fracture. A series of true triaxial fracturing tests were conducted to investigate the influences of natural fracture occurrence and in situ stress on hydraulic fracture propagation. These experimental results agree with the predictions of the proposed criterion.

中文翻译：

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识别穿越地下天然裂缝的混合模式 I/II 水力裂缝的标准

水力压裂已被证明是一种有效的油藏增产技术。在水力压裂过程中，受天然裂缝、射孔定向、应力重新定向等影响，产生非平面的I/II型混合型水力压裂裂缝。在本文中，首先基于水力和天然裂缝周围的应力场提出了穿越天然裂缝的混合模式I / II水力裂缝的判据。当复合度 (KII/KI) 接近零时，可以简化该标准以识别穿越天然裂缝的纯模式 I 水力裂缝。进行了一系列真三轴压裂试验，研究了天然裂缝产状和地应力对水力裂缝扩展的影响。