Simulation of fluid flow in tight rocks, such as shale gas reservoirs, has been a challenging task because of the coexistence of various flow regimes, including the continuum flow, slippage, transition flow, and Knudsen diffusion within the porous structure. Currently, both numerical and analytical methods have been applied to address this issue. In this paper, we have extended the application of most widely used analytical solution for single uniform capillary proposed by Beskok and Karniadakis (Microscale Thermophys Eng 3(1):43-77,1999) to the porous media. The porous structure is represented by a bundle of tortuous capillary tubes with different diameters. Fractal theory is applied to mathematically express the capillary diameter distribution and their tortuosity. For shale gas and coal seam gas formations where adsorption gas is present, the effect of surface diffusion is also included in the analytical solution. Thus, the presented analytical model has allowed us to study the effect of pore size distribution, fractal dimensions for pore size and tortuosity, porosity, surface diffusivity and Langmuir parameters on flow processes. Experimental data from 100 tight gas sand samples and one shale sample, with equivalent liquid permeability ranging from nanodarcy to millidarcy, are used to effectively evaluate the application of the analytical model in the study of flow behavior of gas in tight rocks. The results of this study also show that in tight formation, there has been an increase in apparent gas permeability through the life of production by a factor of 2.2.