Sedimentary Study On Upper Youshashan Formation Of Neogene In Nanyishan,Qaidam Basin

This paper selects my country's Qaidam Basin and combines the current hotspots of oil and gas exploration to study the sedimentary characteristics of the Upper Youshashan Formation in the Nanyishan Oilfield.The oil layer group is divided and compared based on drilling and logging data;under the control of the oil layer group Based on electrical data,sub-layers are divided;on the basis of regional sedimentary system analysis and provenance analysis,key wells are selected for single-well facies analysis;the planar distribution characteristics of sedimentary subfacies and sedimentary facies sequence research are discussed Evolution law of sedimentary system.Three points of understanding are mainly obtained:(1)The upper Youshashan component of Nanyishan Oilfield is composed of five oil layer groups I,II,III,IV,and V.As the depth increases,the calcium content gradually increases,and the formation resistivity gradually increases.(2): Two types of sedimentary facies,shallow lakes and semi-deep lakes in the study area are clarified,mainly shallow lake subfacies,divided into mud flat microfacies,sand flat microfacies,gray cloud flat microfacies,and algae hill microfacies.Microphase.(3)The target layer is mainly shallow lake and semi-deep lake deposits.From bottom to top,it is a reverse cycle of sedimentation.The algal mound subfacies decreases,the sand flats increase,and the grain size becomes coarser.The algal mound subfacies mainly develop in the? and ? oil layer groups,and the pure mud flats are in the ?,?,?,and ? oil layer groups.More developed.