Hydrofracturing technology has become successful in enhancing the permeability of shale gas reservoirs. However, given the geological complexity in the subsurface, considerable challenges remain in quantitatively analyzing the hydrofracture geometry and understanding the anisotropic fracture process. To investigate, we conducted hydrofracturing tests through a horizontal borehole in shale core samples to simulate a horizontal fracturing stimulation. Based on the X-ray computed tomography scanning and fracture geometry reconstruction results, a new quantification method was established to evaluate the effect of bedding inclination and stress contrast on hydrofracturing efficiency. We concluded that the complex fracture network with higher stimulation index could be created at bedding inclinations of 0°–30° and stress contrast of 10 MPa. In this scenario, the fracturing process presented distinctive stages of fracture initiation, propagation, thoroughgoing failure, and stable seepage. The main fracture propagation in arrester mode would require higher fluid pressure, generate a complex fracture pathway, and a larger amount of acoustic emission amplitude, energy, and events. Also, the time from fracture initiation to physical breakdown was relatively long due to the branching of the main fracture into the weak beddings. With the increase in bedding inclination, the fracturing mode gradually changed from arrester to short transverse. The fracturing process was becoming instant, which was accompanied by a lower breakdown pressure, short acoustic emission response, and simple fracture geometry. The understanding of anisotropic fracture process and evaluation method are of interest in shale reservoir fracturing engineering and academic applications.

水力压裂技术在提高页岩气储层渗透率方面取得了成功。然而，鉴于地下地质的复杂性，在定量分析水力压裂几何形状和理解各向异性压裂过程方面仍然存在相当大的挑战。为了进行调查，我们通过页岩岩心样品中的水平钻孔进行了水力压裂测试，以模拟水平压裂增产。基于X射线计算机断层扫描和裂缝几何重建结果，建立了一种新的量化方法来评估层理倾角和应力对比对水力压裂效率的影响。我们得出结论，在0°~30°的层理倾角和10 MPa的应力对比下，可以形成具有更高增产指数的复杂裂缝网络。在这种情况下，压裂过程呈现出裂缝起裂、扩展、彻底破坏和稳定渗流的独特阶段。阻火器模式下的主要裂缝传播需要更高的流体压力，产生复杂的裂缝路径，以及更大量的声发射幅度、能量和事件。此外，由于主裂缝分支到弱层理，从裂缝开始到物理破裂的时间相对较长。随着层理倾角的增大，压裂方式逐渐由避雷器向短横向转变。压裂过程变得即时，伴随着较低的击穿压力、短的声发射响应和简单的裂缝几何形状。