Study On The Characteristics Of Chang 6 Reservoir And Its Oil And Gas Enrichment Law In Zhengning Area, Ordos Basin

In recent years,with the exploration of Yanchang Formation of ordos basin,the basin of the peripheral prospecting strength is also rapidly growing.Abundant oil reserves that has been found recently in Chang 6 Formation of Zhengning area indicates that southeast edge of ordos basin also has a good exploration prospects.But the reservoir characteristics and oil and gas enrichment laws of Chang 6 Formation in Zhengning are uncertain,which certainly limit the exploration and development of southeast edge of ordos basin.Therefore,studying reservoir characteristics and oil and gas enrichment laws of Chang 6 Formation in Zhengning area is of great significance for exploration and development disposition.Based on sorting and summarizing predecessors' research data,with the geology theory guidance including the sedimentary petrology?petroleum geology?logging geology and petroleum geochemistry,using drilling,well logging,petrophysical,oil test data,this article is studying reservoir characteristics?oil and gas sources?hydrocarbon reservoir dynamics?transporting system,and the pattern of reservoir and oil and gas enrichment.Studies have shown that the lithology of Chang 6 Formation is mainly sandstone and feldspar lithic sandstone.Filling types are mainly hydromica?chlorite and iron calcite.The particles is mainly fine-grained sandstone,which have well separaton?sub-angular.The main pore types are intergranular pores and feldspar dissolved pores,including some sedimentation rock fragment?intercrystallinepore and Micro-fracture.The reservoir physical properties of Chang 6 Formation are poor,the average porosity and permeability were 7.41%and 0.075×10-3?m2.the pore and throat is tiny,belonging to typical tight reservoir.Physical properties of the reservoir are mainly affected by sedimentation and diagenesis.Tiny particle size,compaction effect and strong cementation,and construction effect such as dissolution weak was the main reason for the reservoir density.The type of kerogen of Chang 7 hydrocarbon source rocks in this area is well,and the kerogen are abundance of organic material?large thickness?generating oil in mature stage,which are the mainly oil and gas sources,controlling by the source rocks distribution.Reservoir forming dynamics of this area is mainly from undercompaction of source rocks and abnormal high pressure from hydrocarbon generating pressurization.The cracks are the mainly transporting system which connects between source rocks and reservior.Scale of sand body and reservoir physical properties are crucial factors to control hydrocarbon enrichment.In the plane,sand body development control the oil and gas distribution;Vertically,well reservoir property is related to oil and gas enrichment in sand body.In general,the oil and gas enrichment of Chang 6 Formation in Zhengning area controlled by many factors,such as source rocks distribution?scale of sand body?reservoir physical property and the degree of fracture development.Based on the research of oil and gas enrichment regularity,two favorable areas of Chang 6 Formation in Zhengning area can be predicted,and it can supports geological basis for further exploration and development.