关键词: 鄂尔多斯, 侏罗系, 古地貌, 控制因素, 勘探潜力

Abstract: Over the past fifty years, breakthroughs have been continuously made in the exploration of the Jurassic system in the Ordos Basin. In order to clarify its controlling factors and exploration potential, based on the previously discovered oil reservoirs and completed drilling and evaluation wells, using drilling geological data, core analysis, and seismic data, a detailed characterization of the pre Jurassic paleogeomorphology, sand bodies, and structures in the basin has been systematically carried out. The characteristics of fault development in the three-dimensional area have been analyzed, and the types and controlling factors of Jurassic oil reservoirs in the study area have been identified. The exploration direction and potential of the Jurassic system in the basin have been pointed out. The results show that: （1）The pre Jurassic paleogeomorphology presents a “U+V” - shaped multi-stage ancient river structure, with nine types of subdivided units such as inter river hills and terraces, and significant reservoir control characteristics; （2）The Jurassic oil source mainly comes from the Triassic Chang 7 source rocks, and the Late Jurassic Early Cretaceous episodic charging laid the foundation for the widespread distribution of oil reservoirs; （3）The coupling of ancient rivers and low amplitude nose uplift structures controls the distribution of reservoir clusters, and the three-stage fault relay transmission forms a three-dimensional reservoir formation model; （4）The complex fault zone on the western edge of the basin, the northeastern part of the Jingbian slope, and mature areas still have the potential for billions of tons of resources through fine exploration. The research results have deepened the theoretical understanding of Jurassic reservoir formation and supported new breakthroughs in exploration.

Key words: Ordos Basin, Jurassic system, Ancient landforms, Control factors, Exploration potential