## 4 Conclusions  
1. The gas production characteristics of commingled multilayer production can be categorized into three stages, i.e., the production stage with stable interference from each interlayer, stable production from commingled layers, and the production decline stage from commingled layers. During the production stage with stable interference from each interlayer, there is a gas backflow occurring from a high-pressure layer to a low-pressure layer. Subsequently, in the stable production stage with commingled layers, all layers produce gas continuously. During the production decline stage, there is a gradual reduction observed in the commingled production rate.
2. The greater the difference in interlayer pressure, the more pronounced the disparities in backflow time, the ratio of backflow time to gas production time, and the ratio of backflow gas discharge time to gas production time. The experiments demonstrated a range of backflow time to gas production time ratios, spanning from 0.14% to 9.84%. The ratio between the duration of backflow gas discharge and the duration of gas production in the experiments spans from 0.29% to 53.22%, and the volumetric ratio of backflow volume to the original gas volume is varied from 0.12% to 86.15%.
3. Under conditions where the pressure differentials between commingled layers are similar, as the number of commingled layers increases from two to four, there is an escalation in the interference index for the gas production coefficient and a corresponding rise in the gas loss ratio from 10.95% to 13.36%, intensifying the interlayer interference and ultimately resulting in an overall reduction in gas production, with a more pronounced decrease observed in low-pressure layers. Therefore, it is imperative to minimize the number of interfered layers during commingled multilayer production.
4. The H8, S1, S2, and TY layers exhibit a minimal interlayer pressure difference, negligible interference index, and suitable compatibility for commingled production. Since the initial pressure of the layer Q5 is lower and the layer BX is characterized by its high permeability, high original pressure, and limited original reserves, both layers are unsuitable for commingled production with other layers.  
Conceptualization, Y.L., J.W., J.L. and D.Y.; methodology, Y.L., W.H., J.L., H.S. and D.Y.; validation, W.H., J.W. and J.L.; formal analysis, Y.L., W.H., J.W., J.L., H.S. and D.Y.; investigation, Y.L., J.W. and D.Y.; resources, Y.L., J.W., J.L. and D.Y.; data curation, Y.L., W.H., J.W., J.L. and H.S.; writing--original draft preparation, Y.L. and W.H.; writing--review and editing, Y.L., W.H., J.W., J.L., H.S. and D.Y.; funding acquisition, Y.L. and D.Y. All authors have read and agreed to the published version of the manuscript.  
National Natural Science Foundation of China (Grant No.: 52274049) and Natural Sciences and Engineering Research Council of Canada (NSERC) (Discovery Grant and Collaborative Research and Development (CRD) Grant).  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
Authors [PERSON] and [PERSON] were employed by Changqing Oilfield 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.