Paleogeomorphic Analysis And Sedimentary Facies Characteristics Of Jurassic Fuxian-Yan 10 Reservoir Group In Huanxian Area,Ordos Basin

Huanxian area is located on the southwestern Ordos Basin,the Fuxian Series-Yan10 group is an important oil gas-generating strata in the Early-Middle jurassic strata.It is characterized by thickness of sand bodies changed a lot?severe reservoir heterogeneity?complex contact between oil and water.In this paper,through drilling profile,core observation combined with physical data,well logging data and test data analysis,on the basis of Fuxian series-Yan 10 oil-bearing formation paleogeomorphology restoration,stratigraphic division,sedimentary facies and systematic study on characteristics of sand body distribution,built up sedimentary models?discusses the control action of paleogeomorphology on sedimentary facies on this basis.Through the research above,some progresses and new apperception are made during the research in several aspects:?1?Based on tectonic background and previous research,through interpretation of drilling data and logging data in Fuxian area.Combining the marker bed of coal seam?the stratum equal thickness principle and the principle of cycle correlation,the Fuxian Series-Yan 10 section of the study area was divided,divide Yan-10 sections into four subsections:Yan-10₁,Yan-10₂,Yan-10₃,and Yan-10₄,on the basis of stratigraphic divi-sion,the strata in different regions were compared and a complete formation class-ification basic database was established.?2?The restore paleogeomorphology of Jurassic Fuxian series-Yan 10oil-bearing formation applying the Pre-Jurassic paleogeologic map,combination of well data with seismic data,formation thickness impression method.The study area is located in the junction of the Gan-Shan paleochannel?the ancient Qingxi River and the northern branch of the town,the north is the Jiyuan uplands,the southern part is the Yanwu uplands,and the south and north sides develop low monadnock and slope zone,the middle of the river develop mound.The fine characterization of paleogeomorphological feature laid the foundation for the study of the sedimentary facies of Fuxian Series-Yan 10 oil-bearing formation.?3?On the basis of provenance analysis,through facies marker analysis,the type and characteristics of sedimentary facies in the study area were studied.It is believed that the Fuxian Series and the Jurassic Yan-10 oil-bearing formation in the study area are mainly controlled by the western and southwest provenance,the braided river sediments mainly developed,braided river beach sand body is the main reservoir sand body type in the study area,the braided river channel bar sand bodies are the main types of reservoir sand bodies in the study area.Based on the study of sedimentary facies developmental characteristics,built up sedimentary models in the study area.?4?Based on the correlation between paleogeomorphology and superface structures,discusses the control action of paleogeomorphology on sedimentary facies.Under the effect of late tectonic uplift and differential compaction,the superface structures of the Fuxian series and Yan10 oil-bearing formation in the Huanxian area entirety show a west-tilted monocline with a high east and a low west,Nasal uplift zone is basically consistent with the trend of paleogeomorphological highlands,and is extending in the east-west.The embankment is developed at the valley side of the paleogeomorphology,and the channel bar is developed at low laying areas,and paleogeomorphism has obvious control over the types of sedimentary facies during this period.