## 5 Conclusions  
This chapter involves cutting and processing the outcrop shale from the Changing area in Yibin City, Sichuan Province, to prepare core samples parallel and vertical to the bed  
Figure 24: Temporal variation in the hydraulic fracture area in Cases 4 and 5. Figure 23: Temporal variation in the bottom-hole pressure in Cases 1 and 5. Figure 22: Hydraulic fracture shape in Case 5. (**a**) \(t=200\) s (**b**) \(t=270\) s.  
ding planes. Uniaxial compression tests and Brazilian splitting tests were conducted to obtain the mechanical parameters of shale compression and tension. The anisotropic mechanical parameters of shale were systematically characterized in both bedding-perpendicular and bedding-parallel orientations. The elastic compressive modulus, Poisson's ratio, compressive strength, tensile modulus, and tensile strength of the shale with parallel and vertical bedding planes were calculated and compared. Experimental results demonstrated significant anisotropic behavior in the studied shale formations. The quantified anisotropy parameters were subsequently implemented in a finite element model for hydraulic fracturing simulation. A 3D multi-cluster fracturing model of a heterogeneous shale reservoir with natural fractures was established, and the complex 3D fracture morphologies after the interaction between any two fractures were revealed. The bottom-hole pressure, hydraulic fracture area volume, and hydraulic fracture propagation morphology at the corresponding time under different reservoir conditions were obtained. The effects of the reservoir conditions and fracture propagation conditions were studied and discussed. This computational framework enabled comprehensive investigation of fracture propagation patterns and three-dimensional morphology evolution under anisotropic geomechanical conditions, providing critical insights into hydraulic fracture-geological structure interactions in shale reservoirs. The results are summarized as follows:  
1. The shale samples exhibit distinct bedding planes, showing significant anisotropy. The elastic compressive modulus and Poisson's ratio of the parallel bedding shale samples are similar to those of the vertical bedding shale samples, while the compressive strength of the parallel bedding shale samples is significantly greater than that of the vertical bedding shale samples. The elastic compressive modulus of the parallel bedding shale samples ranges from 22.42 to 32.74 GPa with a Poisson's ratio between 0.11 and 0.15 and a compressive strength ranging from 127.82 to 223.21 MPa. The elastic compressive modulus of the vertical bedding shale samples ranges from 25.56 to 31.90 GPa with a Poisson's ratio between 0.13 and 0.18 and a compressive strength ranging from 83.53 to 158.22 MPa. 2. The anisotropy in the tensile performance of shale by Brazilian splitting test is significant. Both vertical and horizontal bedding shale curves from the tests show increasing load with more vertical displacement, then a sharp drop in load. The ultimate failure load and tensile strength of the parallel bedding shale samples are less than those of the vertical bedding shale samples. The ultimate failure load of the parallel bedding shale samples ranges from 2.20 to 4.51 kN with a tensile strength of 3.68 to 7.54 MPa. The ultimate failure load of the vertical bedding shale samples ranges from 7.91 to 8.98 kN with a tensile strength of 13.01 to 14.65 MPa. 3. The tensile modulus of the parallel bedding shale samples is greater than that of the vertical bedding shale samples. The tensile modulus of the parallel bedding shale samples ranges from 4.52 to 5.19 GPa, while the tensile modulus of the vertical bedding shale samples ranges from 3.52 to 3.75 GPa. The elastic compressive modulus of the shale is 6 to 10 times the tensile modulus. 4.