Study On The Oil Shale Reservoir Metallogenic Model Of Jurassic In The Northern Margin,Qaidam Basin

By means of sedimentary petrolog,lithofacies paleogeography,petroleum geology,mineral petrology and organic geochemistry,The paleoclimatic,palaeotectonic,sedimentary facies,oil shale formation and oil shale characteristics of Jurassic in the North margin of Qaidam Basin,Achieve the following results.The oil shale is mainly present in the Middle Jurassic Shimengou Formation and the Lower Jurassic Xiaomeigou Formation in the northern margin of the Qaidam Basin.Oil shale is basically grayish brown to grayish black,with lumps or page,was luster,mainly developed in Tuanyushan area,Yuqia area,Quanji area and Wanggaxiu area.Shale oil content between 3.5%-19.5%,the average oil content of 6.11%.oil shale as a whole in the quality,high ash,ultra-low sulfur oil shale-based,high calorie,WangGaxiu area with low quality,ash,low sulfur oil shale-based.Paleoclimate,tectonics and sedimentary environment are the main factors affecting the formation of oil shale.Paleoclimatic conditions affect the formation of organic matter on certain conditions and control the formation of oil shale.It is suitable for the formation of oil shale in the early and Middle Jurassic.The structure mainly controls the burial and preservation conditions of oil shale,on the one hand,it affects the change of the depth of oil shale,on the other hand,it affects the preservation condition of oil shale,and then affects the residual thickness and distribution range of oil shale.The sedimentary environment mainly affects the formation,thickness,oil content,development and enrichment of oil shale.At the same time,these three factors affect the formation of oil shaleThe Jurassic oil shale in the northern margin of Qaidam Basin is composed of two types of metallogenic models,which are semi deep lake deep lake and lake bay,and the difference between the two is mainly in the environmental stability and organic matter supply.The stability of the semi deep lake deep lake is higher,but the organic matter supply is more abundant.Deep lake semi deep lake model,oil shale mineralization occurs in large section alone,lacustrine shale,high stability of sedimentary environment,single layer is thick,the cumulative thickness is large,the rate of oil medium range is generally larger,metallogenic characteristics.Oil shale is enriched in the transition zone from shallow lake to semi deep lake to deep Tuanyu shan area,Yuka area,Quanji area,wanggaxiu area of Shimengou Formation oil shale ditch group are such metallogenic model.Under the model of the lake bay,the oil shale is associated with coal measures,and has the characteristics of single layer thin,medium thickness,fast and abundant organic matter supply,high oil content,and small range of mineralization.Oil shale is mainly concentrated in the center of the environment of the Bay,and the oil shale of the Xiaomeigou Formation metallogenic model in Quanji area.