Study on pre-Jurassic palaeogeomorphology reconstruction of Huanjiang region,Ordos basin

As sedimentary development and hydrocarbon enrichment regularity of middle-lower Jurassic series was controlled by Pre-Jurassic palaeogeomorphology,it is of great importance to accurately reconstruct and depict the ancient topography.By taking Huanjiang region of Ordos Basin for example,through a large number of studies on ancient geology,sedimentary facies and palaeogeography,and ancient flow direction,a clear background of Jurassic sedimentary deposition before the tectonic framework and provenance direction has been made.Combined with a large number of logs and core data,the study on Yan-10+Fuxian study sedimentary thickness has been carried out.By using sediment thickness impression method,pre-Jurassic palaeogeomorphology was restored.Pre-Jurassic palaeogeomorphology reconstruction of Huanjiang region,Ordos Basin pres-ents westhigh and east-low,into the highlands erosion area,slope and residual hill,valley and river between the ancient mound.Pre-Jurassic palaeogeomorphology was the major factor controlling sedimentary facies distribution and reservoir distribution of Fuxian and Yan'an early periods.Palaeogeomorphology slope zone is the most favorable for the formation of the reservoir.