The migration law of shale gas has a significant influence on the seepage characteristics of shale, and the flow of the gas is closely related to the pore structure. To explore the influence of shale pore parameters on permeability in different diffusion zones, the pore structure of the shale in the Niutitang Formation in Guizhou, China, was analysed based on liquid nitrogen adsorption experiments and nuclear magnetic resonance experiments. The relationship among fractal dimension, organic carbon content (TOC) and BET-specific surface area was analysed based on the fractal dimension of shale pores calculated using the Frenkel–Halsey–Hill model. Shale permeability was calculated using the Knudsen number (Kn) and permeability equation, and the influence of the fractal dimension and porosity in different diffusion zones on shale permeability was analysed. Previous studies have shown that: (i) the pores of shale in the Niutitang Formation, Guizhou are mainly distributed within 1–100 nm, with a small total pore volume per unit mass, average pore diameter, large BET specific surface area and porosity; (ii) fractal dimension has a negative correlation with average pore diameter and TOC content and a quadratic relationship with BET specific surface area; and (iii) permeability has a positive correlation with Kn, porosity and fractal dimension. In the transitional diffusion zone, fractal dimension and porosity have a significant impact on permeability. In the Knudsen diffusion zone, porosity has no obvious effect on permeability. The methodologies and results presented will enable more accurate characterization of the complexity of pore structures of porous media and allow further understanding of the seepage law of shale gas.

页岩气的运移规律对页岩的渗流特性有重要影响，其流动与孔隙结构密切相关。为探讨页岩孔隙参数对不同扩散区渗透率的影响，基于液氮吸附实验和核磁共振实验，对贵州牛头塘组页岩孔隙结构进行了分析。分形维数，有机碳含量（TOC）和BET比表面积之间的关系是根据使用Frenkel-Halsey-Hill模型计算出的页岩孔隙的分形维数进行分析的。页岩渗透率使用克努森数（Kn）和渗透率方程，分析了不同扩散区的分形维数和孔隙度对页岩渗透率的影响。先前的研究表明：（i）贵州牛头塘组的页岩孔隙主要分布在1–100 nm范围内，单位质量总孔隙体积小，平均孔径大，BET比表面积大和孔隙度大；（ii）分形维数与平均孔径和TOC含量呈负相关，与BET比表面积呈二次关系；（iii）渗透率与Kn正相关，孔隙率和分形维数。在过渡扩散区，分形维数和孔隙度对渗透率有重要影响。在克努森扩散区，孔隙度对渗透率没有明显影响。提出的方法和结果将能够更准确地表征多孔介质的孔隙结构的复杂性，并使人们进一步了解页岩气的渗流规律。