The Sedimentary Facies And Sand Body Distribution Research Of Upper Member Of Tenggeer Formation In Daerqi Area Of Baiyinchagan Sag

Daerqi locates in the southern slope of the Baiyinchagan sag,the northwest of Chuanjin depression in the western of Erlian basin.The sag which is slim and podiform,is a half graben structure characterized as faults in the north accompanied with stratigraphic overlap in the south.Its long axis is from northeast to southwest.The main part is described as large,developed faults,various types of traps,and thick bed thickness in western cave.Zhongyuan Petroleum Exploration Bureau obtained the qualification of risk exploration in Baiyinchagan sag,erlian basin in 1993,and then started to explore this area entirety.So far,they have detected three hydrocarbon reservoirs,namely Aershan,Dou hongmu and Tenggeer Formatiom.These reservoirs are divided into two types: thin and heavy oil.In this study,on the basis of stratigraphic division,combining well logging with drilling to study single sand body and then calculate the accumulative thickness of sandstone in every sands group to set the foundation of studying the regularities of sands distribution.Furthermore,drilling,logging,core descriptions and assays has been used to confirm rock composition,texture and structure comprehensively.Additionally,rock types have been confirmed based on petrology characteristics in Tenggeer upper member.From all of these,it is because of nearing source and rapid deposition,resulting in insufficiently differentiation,lithologic chaos between sand and mud.Besides,lower extent of mineralization brings about the indistinct characteristics of rock electrical response of SP.Moreover,it is lithologic chaos in some areas that result in inconspicuous characteristics of rock electrical response of GR near the margin of this basin.Due to the invalid rock identificating of these two curves,which make facies studying and sand recognising difficult.Consequently,I obtained the effective information from CALI,AC,GR and corresponded lithologic information to curves to establish the log facies plates which agree with the complex features in this area.I solved the problem of difficulty establishing plates in the areas of complex lithology eventually.In this paper,based on petrologic date derived from coring,with the application of logging facies analysis,integrated with previous research,understandings and achievements are as follows:The southwest area of Daerqi is composed of relatively fine-grained braided river delta facies sediment.The main microfacies include under water distributary channel,estuary sandbar,and sand sheet;the east area of Daerqi is dominated by alluvial fan and fan delta facies sediments.