| Porous media widely exist in nature and engineering applications. The study of the transport properties of fluids in porous medium plays a guiding role in understanding the physical reality of nature and improving the production efficiency of industry. Studies show that most of complex porous media materials have self-similar fractal characteristics.Therefore, the theory of fractal geometry can be used to describe and study the transport properties of the fluids in the porous media systems.In this paper, firstly we introduce the related theory of fractal porous media.In chapter 2, based on the theory of fractal geometry and the seepage mechanics, we analyze the permeability and the threshold pressure gradient of Bingham fluids in dual-porosity media, which takes into account the effect of the capillary pressure difference. The proposed model relates the transport properties of Bingham fluids to the microstructure parameters of dual-porosity media, and there are no empirical constant.The results reveal that the capillary pressure difference effect has a significant impact on the threshold pressure gradient at low porosity.In chapter 3, based on the hypothesis that the diameter distribution of mother channels in branched network follows the fractal scaling law, we develop a fractal model for two-phase flow in unsaturated branched network. The present model for the relative permeabilities are in fair agreement with experimental data and available expressions, and it can reveal much more physical principles of two-phase flow in unsaturated branched network.In chapter 4, the main conclusions of the present work are summarized, and some potential directions on future research of fluids transport characteristics in fractal porous media are presented. |
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