Pore structure and percolation characteristics of the He 8 sandstone reservoir with low porosity and low to very low permeability, Middle Permian, Upper Paleozoic from the eastern Ordos Basin is studied. Impact of pore structure on sandstone reservoir percolationcharacteristics is discussed in this paper, based upon observation of vacuum impregnate with epoxy resin thin sections under microscope, pore and pore throat image and capillary pressure analysis, constant speed mercury injection and two facies of gas-water permeability experiments, nuclear-magnetic resonance measurement. Research result shows that the main factor affect percolation characteristics and sandstone reservoir quality with low porosity and low to very low permeability is the pore structure features. While pore characteristics were attributed to primary mineral assemblages and diagenetic evolution processes, types of products during which were produced and their distribution in the He $ sandstones. Among the pore structure parameters, pore throat size, valid pores, volume of pores and throats, and connectivity between pores and throats are the key parameters impacting reservoir quality and percolation capacity. Research also indicates that the larger pore throat is, the more contribution is to the reservoir percolation; Whereas, middle to small sized pore throat is relatively contributes more to reservoir quality. In addition to pore structure, the micro fractures and fissures in sandstones is one of the important factors effecting reservoir quality and percolation characteristics.
