Identification And Characterization Of Guantaobarriers And Interlayers In Du 84 Blockof Liaohe Oilfield

Du-84 block inLiaohe Oilfield is located in the middle part of the western slope belt of theLiaohe Depression,which shows a long-strip shape with a monoclinic structure.Interlayerwith kinds of types and patternsin reservoir has a significant effect on the oil exploration and production,but there is little research on the reservoir structure and interlayer in Guantaoformation in Du-84 block.So the present research on the interlayers in Guantaoformation in Du-84 block has a great importance for design of the future work program in the study area.Based on the core and logging data,we summarized the types and distribution features of sedimentary microfacies,and recognized the types of interlayerand its identifying signals in logging curves of cored wells when associated with the logging curve cross-plot and spider diagram.We proposed aclassification method for interlayers based on the production data and the identification principles of interlayers.The main sedimentary facies in Guantaoformation in Du-84 block is alluvial fan including seven microfacies:mudslides,main river channel,diffusing flood in root fan,and mudslides,braided river,braided streams and overflow dam in middle fan.There are two types of interlayers in the study area,namely argillaceous interlayerand physical interlayer,lack of calcareous interlayer.The two types of interlayers can be divided into argillaceous interlayer-?,argillaceous interlayer-?,physical interlayer-?A,physical interlayer-?B,physical interlayer-? and physical interlayer-III on the basis of their effects on production.The interlayers which have a great effect on the production are mainly found in Guan 1,Guan 2 and Guan 5 member,so the Guan 3 and Guan 4 memberhave the favorable reservoirs for oil production.The development of interlayers in reservoiris controlled by sedimentary facies.Thereare two mechanismsfor the argillaceous interlayers development:one is the argillaceous sediments between two channel sand bodies,the other one is the argillaceous sedimentswithin one channel sand body.There are three formation mechanisms for the physical interlayers:the first one is the fine-grained sediments developed on the top of a channel sedimentation,the second one is the fine-grained sediments developed during the time interval between adjacenttwo channel sand bodies sedimentation,the third one is that the new channel sand body cutdown to the old one,and those fine-grained sediments on the top of the older channel sand body were denudated,resulting in the formation of interlayers on the bottom of the new channel sand body.Because of the strong heterogeneity and lots of interlayers developed in the reservoirin Guantao formation,we musthave a good understanding of these different kinds of interlayers and their influences on the heavy oil development and production in Du-84 block.