Abstract: Taking the Chang 6 Member of the Yanchang Formation in Huangling Area of the Ordos Basin as the research object, the characteristics of the deep water sandstone of Chang 6 Member and the differences between different types of sand bodies are analyzed based on the abundant drilling and coring, logging and analysis of laboratory data. The results show that the reservoir rock types in the study area can be divided into three categories: sandy debris flow sand body, sandy slumping sand body and turbidite sand body according to their formation mechanism and structural characteristics. Among them, the content of quartz and feldspar and structural maturity in sandy debris flow sand body are relatively higher. The storage space is dominated by residual intergranular pores and feldspar dissolved pores. The physical properties of the reservoir are also significantly higher than those of the other two types of sand bodies. Further analysis found that due to the difference in structural maturity and mineral content, the compaction and dissolution of sandstone debris flow sand body is stronger in the early stage of diagenesis, and in the middle and late stages, soluble minerals increases pores and rupture increased fractures. It is determined that sandy debris flow sand bodies are the most favorable type of reservoir rock in the study area.

Key words: Chang 6 Member of Yanchang Formation, deep water deposition, sandy debris flow sand body, reservoir characteristics, analysis of reservoir difference