## 6 Conclusions  
Based on selected seismic attributes, an accurate geological model was established. Similarly, 3D geomechanical models were constructed in accordance with the geological model by integrating various data, such as mechanical experiments, logging, and acoustic impedance. Along with determining the orientation of horizontal principal stress, a quantitative analysis was conducted on the 3D in situ stress of the Fengcheng Formation in the Mahu Sag.  
The influencing factors of the in situ stress field are complex, with the magnitude affected to some degree by Young's modulus and Poisson's ratio. However, the magnitude of horizontal principal stress is more affected by burial depth than by mechanical parameters. The deeper the burial depth, the higher the magnitude of horizontal principal stress. Additionally, the orientation of horizontal principal stress is mainly correlated with faults. Regardless of the fault strike, the dip azimuth of in situ stress will increase if a fault is nearby.  
The horizontal stress difference and horizontal stress difference coefficient impact the fracture network system, controlling the patterns and development of fractures. As the burial depth increases, the horizontal stress difference also increases. However, the horizontal stress difference coefficient, mainly influenced by geomechanical parameters, is not significantly affected by burial depth. In the vicinity of faults, both the stress difference and the stress difference coefficient may vary to some extent.  
To thoroughly understand the stress regime of the research area, A\({}_{\varphi}\) is introduced to quantitatively describe the stress regime. According to the research results, most of the stress regimes in the study area are of the reverse faulting type, with a small number of SS to RF types mainly distributed near the SE-NW-oriented faults.  
The fault slip potential analysis was conducted from a 3D perspective. By comparing the values of k and K\({}_{\mu}\), it was found that most faults display high stability throughout the  
Figure 26: The stability analysis on F1 fault and F2 fault (the location is shown in Figure 10). **(A)** The stability analysis on F1 fault; **(B)** The stability analysis on F2 fault.  
region with nearly no risk of slippage. However, in the lower part of certain faults, fault slippage is still possible.  
**Author Contributions:** PC. Conceptualization, methodology, visualization, formal analysis, writing--original draft, writing--review and editing; H.Q. visualization, conceptualization, writing--review and editing; C.S. project administration, visualization, conceptualization, writing--review and editing; X.C. visualization, conceptualization, data curation, formal analysis. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author on reasonable request.  
**Acknowledgments:** Many thanks to the PetroChina Company Limited for the supplement of the data.  
**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.