## 3 Results and Analysis
### Effect of Fracturing Cluster Number
Figure 3: Results of conventional quantitative metrics under different cluster configurations ((**a**) number of damaged interface elements versus time; (**b**) fracture area versus time; (**c**) fracture aperture at injection point versus time; (**d**) maximum fracture aperture versus time; (**e**) fracture volume versus time; and (**f**) ratio of tensile failure versus time) (C1, C3, C6, C9, and C12 refer to fracturing scenarios involving 1 cluster, 3 clusters, 6 clusters, 9 clusters, and 12 clusters, respectively). Figure 5 presents a comparative analysis of the final morphology of artificial fractures generated under varying cluster configurations, including different numbers of clusters and cluster spacing. In single-cluster fracturing, a single dominant fracture is mainly formed, with limited fracture initiation and propagation in the near-wellbore region. However, as the number of clusters is increased to three, three primary fractures are observed to develop, exhibiting both single-wing and double-wing propagation. This suggests that increasing the number of clusters can stimulate the formation of fractures near the wellbore and facilitate the development of multiple main fractures, enhancing the overall fracture complexity. When using six clusters of fracturing, multiple fractures appeared near the wellbore. When the number of clusters increases to nine, more fractures initiate simultaneously. It is worth noting that the fracture morphology was magnified 10 times in the simulation results to observe most of the artificial fractures. However, the main path of the fractures in cluster 6 fracturing is more obvious, while cluster 9 fracturing shows a discontinuous main path, indicating the presence of many locally small opening fractures, which is not conducive to the transportation of proppants and subsequent mining. More than 12 artificial fractures have sprouted in the near-wellbore area of 12-cluster fracturing. As the fracturing process progresses, competition expands, causing some of the newly formed fractures to not open further, ultimately leading to the expansion of 10 main fractures. The above results indicate that the more fracturing clusters there are, the smaller the cluster spacing, which usually significantly increases the volume of artificial fractures, thereby improving the effectiveness of reservoir transformation. Similar conclusions can also be observed in some studies on on-site earthquake monitoring methods [37; 38; 39; 40; 41]. For example, [PERSON] et al. found through micro seismic monitoring of shale gas reservoirs in the southwestern region that an increase in the number of fracturing clusters can promote the occurrence of more micro seismic events, and micro seismic event points near the wellbore gradually gather to form multiple bands, indicating the possibility of producing more artificial fractures. At the same time, they also found that under the influence of natural fractures and other factors, many micro seismic events may occur in areas far from the wellbore, which is significant in the expansion results of the fracturing of a single cluster in Figure 5. It is worth mentioning that compared to the 3D view, only a portion of the main seam shape is observed in the top view. This is obviously due to some fractures opening too little. Therefore, increasing