## 4 Conclusions  
Based on the FDEM and on-site data from a certain well block in Southwest China, multiple cluster fracturing simulation models were established considering the natural fractures and geological mechanical parameters of the target block. The changes in artificial fracture area, fracture aperture, fracture volume, fluid pressure, and fracture morphology in the simulation results are extracted, and the impact of the number of fracturing clusters and the number of natural fractures in the target block on the formation of artificial fractures was analyzed. The main conclusions are as follows:  
1. As the number of fracturing clusters increases, the number of artificial main fractures formed in the target block shows a significant increasing trend. However, when affected by the distribution of natural fractures, geo-stress, and other factors, it may also be difficult to form multiple main fractures through multi-cluster fracturing in the target block (Figure 9). Therefore, obtaining data on the spatial location and orientation of natural fractures may be more helpful in accurately estimating the fracturing effect of the target block.
2. Due to the influence of the original random fracturing path and natural fractures of the reservoir, shear stimulation phenomena are prone to occur. Under these conditions, artificial fractures in the reservoir are prone to bending, branching, and other phenomena. When further affected by multiple construction methods, the artificial main fracture will be more prone to single-wing expansion rather than double-wing expansion.
3. Multi-cluster fracturing construction may promote an increase in artificial fracture networks, but under the same injection amount, the aperture of artificial fractures will decrease. Therefore, increasing the injection rate appropriately during multi-cluster construction will be more conducive to the pumping of proppants and other materials.
4. The increase in the number of natural fractures in the target block will help to obtain a more complex artificial fracture network. When the number of natural fractures reaches a certain threshold, even using a single-cluster fracturing construction process may form an artificial fracture network connected by multiple main fractures.  
Conceptualization, Y.L. and Y.G.; data curation, Y.G.; funding acquisition, J.L.; investigation, Y.L., M.W., H.H., Y.G., Y.W. and J.L.; methodology, M.W.; project administration, Y.L., H.H., and Y.G.; resources, H.H. and J.G.; supervision, Y.L., H.H., Y.W. and J.G.; writing--original draft, M.W.; writing--review and editing, Y.L. and H.H. All authors have read and agreed to the published version of the manuscript.  
The authors gratefully acknowledge the financial support given by the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering, the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Grant NO SKLGME022020. Meanwhile, this article is funded by the science and technology special project of PetroChina Co., Ltd., titled \"Research on Large-scale Reservoir Increase, Production Increase, and Exploration & Development Technologies for Shale Gas\" (NO. 2023 ZZ14).  
Not Applicable.  
The raw data and code supporting the conclusions of this article will be made available by the authors on request.  
Author [PERSON] was employed by the Chongqing Shale Gas Exploration and Development Co., Ltd., author [PERSON] and [PERSON] were employed by the Shale Gas Research Institute of PetroChina Southwest Oil & Gas Field Company, author [PERSON] was employed by the PetroChina Southwest Oil and Gas Field Company. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.