In recent years, low permeability reservoirs have accounted for 70% of China's new oil reserves, among which the Ordos basin accounts for more than half, with considerable development potential. Therefore, the efficient development of low permeability reservoir is urgent.. In order to fully understand the properties of reservoir before development, using core observation, rock thin section and other test data, this paper focused on the research of reservoir petrology characteristics, reservoir sedimentary microfacies and sand body distribution, reservoir physical characteristics and heterogeneity of Chang 4+522 formation in Wuqi oilfield in Ordos basin. Then, based on these research results, 3D geological model of reservoir was established. The results show that Chang 4+522 formation has the rock type of fine⁃grained feldspar sandstone; mainly develops subaqueous distributary channel sedimentary microfacies and large thickness, wide distributed and good continuity sand body; belongs to low porosity, low permeability heterogeneous reservoir. On the basis of comprehensive geological studies, the structural model, phase model, porosity and permeability model of Chang 4+522 reservoir in Wuqi oilfield established are accurate and reliable. Studies on reservoir physical characteristics plays a good constraint role in the modeling process. The established 3D static model of the reservoir will serve as the foundation for dynamic flow simulation in the next step. The research approach can also provide reference for the preliminary research of the similar project.

Oil reservoir has become an important way for CO₂ storage, while the injection of CO₂ to reservoir can also improve the oil recovery. According to Yanchang oilfield reservoir characteristics, an evaluation model for CO₂ storage was established using the formation storage, bound storage, dissolved storage and mineralization mechanism. The model was established under the consideration of CO₂ dissolution in the oil, CO₂ dissolution in formation water and free gas storage. The model was used to evaluate the CO₂ storage potential for Yanchang oilfield. The results show that the model can predict reservoir storage capacity, and the reservoir CO₂ storage stock is about 209.879×104 t. The reservoir shows very good storage potential, which can provide important basis for CO₂ displacement of Yanchang oilfield.