Reservoir Characteristics and Influencing Factors of the Jurassic Yan'an Formation in the Hao Tan Area of the Ordos Basin

To study the reservoir characteristics and main controlling factors of Jurassic Yan'an formation in Hao Tan area of Ordos Basin. The reservoir characteristics and its main controlling factors were revealed by the experimental observations such as rock sheet analysis, high pressure mercury pressure experiment and cathodoluminescence. The Jurassic reservoirs in Hao Tan area are mainly located in Yan 10~Yan 8 section.The results show that the main types are feldspathic sandstone and feldspathic quartz sand with medium to low maturity, and the main types of pores include intergranular pores, intergranular dissolution pores and feldspathic dissolution pores. The physical properties of the reservoir are dominated by mesopore mesoturbidity, with medium throat radius and low drainage pressure. The reservoir has experienced moderate to strong mechanical compaction with various types of cementation dominated by carbonate, siliceous and clay minerals, among which the pore structure of the reservoir has been significantly improved by dissolution. The reservoirs of the Yan'an Formation have certain storage capacity and development potential, especially the Yan 10 and Yan 8 reservoirs have better physical properties, and the sedimentation and diagenesis have affected the inhomogeneity of the reservoirs. It is concluded that the Yan 8 reservoir (72% class II) and the local sweet spot of Yan 10 (class I porosity >16%) have development potential, but different development strategies should be formulated for the high permeability zone of Yan 9. The results of the study can provide a theoretical basis for the exploration and development of the same type of Jurassic tight sandstone reservoirs in the Ordos Basin.