The reservoirs in the Chang 8 oil layer to the west of Tianhuan depressionPengyang in the Ordos basin are rich in oil and gas resources with strong heterogeneity, complex pore structures, and are affected by abnormal low pressure, additional conductivity of clay minerals, and high bound water saturation. The oilwater layer is difficult to distinguish, the difference in logging response characteristics are not obvious, and the identification of fluid properties is difficult. In this paper, the well cores, thin sections, well log results were analyzed to study the four properties of Chang 8 oil layer reservoir from the Triassic Yanchang Formation in the Ordos basin. The results show that the lithology of Chang 8 oil layer is mainly medium and fine sandstone, with physical porosity of 14.68% and permeability of 7. 13×10-3 μm2. On this basis, the apparent water resistivity is introduced as an effective parameter to establish the RwaAC intersection board. This method takes into account the influence of the differences in physical properties of different reservoirs on the electrical properties of the reservoir, and overcomes the influence of the complex factors of the pore structure of the reservoir. The oil and gas information is highlighted, which can effectively identify different fluid types. By this method, the fluid properties of 70 layers in 12 wells are discriminated by logging, which is well verified with the test data. The research results provide guidance for the logging evaluation and oil and gas exploration and development of the Chang 8 oil layer.