准噶尔盆地克—百断裂带石炭系内幕储层测井岩性识别

摘要

s:Lithology of Carboniferous volcanic inner buried-hill reservoirs in the Ke-Bai fractured zone is com-plicated and various,so it is hard to recognize the lithology comprehensively by conventional logging data and interpretation process.On the basis of classification and naming of the rocks,hierarchical decomposition strategy was used to solve the problem of lithology identification. The main connotation of the strategy is"component identification in first,structural division later".By establishing logging parameters of M[(Δtf-Δt)/(ρb-ρf)], N[(φNf-φN)/(ρ b-ρ f)]and Rt/Rxo,the crossplots of N-GR,N-M and GR-Rt/Rxowere compiled.New parameters M and N are more useful to identify lithology,Rt/Rxois sensitive to rock texture and structure by eliminating the effect of oil and water in pores,while,GR responses the levels of radioactive substances.By using the crossplots created and the method of FMI,which is visually effective in texture and structure recognition,lithology of the Carboni-ferous volcanic inner buried-hill reservoirs was identified.Crossplot of N-GR is useful to distinguish sedimentary rocks and volcanic rocks;N-M crossplot is effective to recognize basic volcanic rocks and intermediate volcanic rocks;Crossplot of Rt/Rxo-GR is helpful to identify lava rocks,pyroclastic rocks and subvolcanic rocks in terms of their specific textures.The identification results were tested by petrographical identification of eighteen wells and the accuracy rate was eighty-nine percent.This study establishes a new means and technique process for lithology identification in Carboniferous volcanic inner buried-hill reservoirs of the Ke-Bai fractured zone.It is also useful for comprehensive lithology identification,volcanic rocks exploration and seismic calibration of the research area.%准噶尔盆地西北缘克—百断裂带上盘石炭系内幕储层火山岩岩性复杂,常规测井解释难以满足岩性精细识别的要求.在岩石分类及命名的基础上,采用"先成分识别、后结构区分"层次分解思路,通过常规测井系列构建参数M[(Δ tf-Δ t)/(ρ b-ρ f)]与N[(φNf-φN)/(ρ b-ρ f)]及其和GR,Rt/Rxo相互之间的交会图版,并辅以成像测井(FMI),对该区石炭系内幕储层进行了测井岩性综合识别.结果发现,N-GR交会图可有效区分火山岩与沉积岩;N-M交会图可识别基性与中性火山岩;GR-Rt/Rxo交会图结合成像测井图版可进一步区分火山熔岩、火山碎屑岩与次火山岩.通过18口井的岩心薄片鉴定检验,符合率为89%.从而建立了克—百断裂带石炭系内幕储层火山岩岩性识别技术流程,这对加大火山岩油藏勘探具有重要的价值.