# Study on Permeability Stress-Sensitivity in
## 5 Conclusions  
This study analyzed the permeability evolution of tight sandstone with effective stress through permeability stress-sensitivity experiments, and established the coupled seepage-geomechanical model for the target formation. Numerical simulations were conducted for fractured deep tight sandstone gas reservoirs, and the influence of permeability stress-sensitivity on gas reservoir development was analyzed on the basis of fitting with historical gas production data. The following conclusions can be drawn:  
1. When the effective stress increased from 0 to 65 MPa, the permeability of the natural sample with fractures decreased by 81.28%, and the permeability of the intact core sample decreased by 54.67%. The permeability stress-sensitivity of natural fractures is stronger than that of the matrix, which had a dominant influence on permeability;
2. The reservoir heterogeneity can have an impact on the permeability variation, which is manifested by different changes in three-dimensional permeability. The vertical permeability decreases are the most pronounced. The permeability of the fractured zone and the matrix decreased by about 40% and 16%, respectively;
3. When the pore pressure near the well decreased from 120 to 85 MPa, the effective stress increased by 5-10 MPa, 4-9 MPa and 11-19 MPa in the three dimensions of X, Y and vertical, respectively. Only elastic deformation occurs in natural fractures and faults, and the normal strain is greater than the shear strain;
4. The mean square error between the historical gas production results and the simulation results considering permeability stress-sensitivity was 2.22, while it was 4.01 without considering permeability stress-sensitivity. The coupled seepage-geomechanical model with permeability stress-sensitivity was more accurate in historical gas production fitting;
5. According to the numerical simulation and production conditions, three production optimization schemes were determined for the seven wells, including maintaining the state without adjustments, slight depressurization in the well and a combination of depressurization and observation.  
This study conducted a case study on the permeability stress-sensitivity in deep tight gas reservoirs using laboratory tests and numerical simulations, which can provide  
Figure 22: Daily gas production of seven wells.  
theoretical support for the historical matching and prediction of gas production in the fractured deep tight sandstone gas reservoirs.  
Conceptualization, J.L. and R.S.; Data curation, J.S. and Y.S.; Formal analysis, J.S., R.S. and Y.S.; Funding acquisition, R.S.; Investigation, J.L.; Methodology, J.S. and J.L.; Project administration, R.S.; Resources, J.S., R.S. and Y.S.; Software, J.S.; Supervision, R.S.; Validation, J.L.; Visualization, J.S., J.L. and R.S.; Writing--original draft, J.S.; Writing--review & editing, J.S. and Y.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by [Knowledge Innovation Program of Wuhan-Basic Research] grant number [2022010801010158]. The APC was funded by [Knowledge Innovation Program of Wuhan-Basic Research].  
Not applicable.  
All the data and materials used in this paper are available from the corresponding author upon request.  
This work was financially supported by Knowledge Innovation Program of Wuhan-Basic Research (2022010801010158).  
The authors declare no conflict of interest.