Study On The Characterization Method Of The Petrophysical Phase Of The Ke 2 Member In Lukeqin Oilfield

The second member of the Ke Formation in the Lukeqin Oilfield is a braided river delta front subfacies with various types of reservoir rocks and strong reservoir heterogeneity.After more than ten years of water injection development,the distribution of remaining oil is very complicated.In order to improve the oil recovery efficiency and accurately characterize the reservoir differences,based on the study of reservoir sedimentary microfacies,this paper systematically carried out the study of petrophysical phase characteristics and characterization methods,and revealed the distribution of petrophysical phases.Based on the analysis of core facies and logging facies,the sedimentary model of the braided river delta front in the study area is clarified,and three types of sedimentary microfacies are divided into underwater distributary channels,mat-shaped sand and interdistributary channel.In the vertical direction,the sediments of the 3rd sand group in the Ke 2 Member have the coarsest grain size,mainly in conglomerate deposits;the sediments in the 1st sand group have the finest grain size,mainly in fine sandstone deposits.On the plane,it is mainly composed of continuous sheet-like underwater distributary channels.The technical idea of petrographic phase characterization based on the fusion of lithofacies type and physical property parameters is proposed.The six types of logging lithofacies are clarified,and a BP neural network-based lithofacies division method is established.The model prediction accuracy rate reaches more than 90%.Using the core calibration logging method,a log interpretation model of porosity and permeability is established.Based on the drilling coring data,seven types of petrophysical phases were determined,and the differences in reservoir quality under the control of different petrophysical phase types were revealed.Type I petrophysical facies develops between the underwater distributary channels of the braided river delta front,which is a nonreservoir;Type II petrophysical facies develops at the end of the braided river delta front underwater distributary channel,mainly distributed in the second member of Ke The upper part of the Ersha Formation is in the form of a thin layer,which is a poor reservoir;the type III rock physical phase is developed in the braided river delta underwater distributary channel,and muddy cementation occurs mostly,so the physical properties of the reservoir are poor,which is poor Reservoir;Class IV petrophysical facies is developed in the braided river delta underwater distributary channel.It is a widely developed and widely distributed type of petrophysical facies type with good physical properties.It is a favorable reservoir in the study area;Class V and VI Types VII and VII are developed in the braided river delta's underwater distributary channels,and are coarse-grained sediments at the bottom of the river bed.They are mainly distributed at the bottom of the2 nd and 3rd sand formations in the Ke 2 Member,and are medium-quality reservoirs in the study area.Finally,according to the distribution law of rock physical phase and physical properties,the distribution of water flow dominant channels in the study area is predicted.