**6. Conclusions**

(1) Pore networks in tight gas reservoirs can be divided into intergranular-dominant and intragranular-dominant pore networks, based on surface fractal theory and mercury intrusion features. Intergranular-dominant pore networks correspond to the conventional pore-throat structure model that large pores are connected by wide throats, while intragranular-dominant pore networks are characterized by a tree-like pore structure that the narrower throats are connected to the upper-level wider throats like tree branches, and there is no significant difference between pores and throats.


**Author Contributions:** Conceptualization, D.X.; funding acquisition, D.X., S.L., and G.C.; investigation, L.Z.; methodology, L.Z. and Y.Q.; project administration, S.L.; resources, S.L.; software, L.Z. and R.Z.; supervision, D.X., S.L. and S.J.; writing—original draft, L.Z.; writing—review and editing, S.J. and Y.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (No.: 41802157, 41972139, 41902127 and 42072174), the National Science and Technology Major Project Foundation of China (No.: 2016ZX05061), the Fundamental Research Funds for the Central Universities (No.: 18CX02069A), the Initiative Postdocs Supporting Program (No.: BX20190303), the Postdoctoral Innovative Research Position of Hubei Province (No.: 247419), the Research Project of Guangxi Investment Group Co., LTD. (No.: NYHT2020-016), the Open Fund of Key Laboratory of Tectonics and Petroleum Resources (No.: TPR-2020-12), and the Project of Excellent Young Talents in Heilongjiang Province (No.: 140119002).

**Conflicts of Interest:** The authors declare no conflict of interest.
