Study On Fractures Identification And Water Flooding Law Of Chang 6 Reservoir In Bai 257 Area Of Huaqing Oilfield

The research area,Bai257 well area,is located in the Huqing area in the south-west of the Yishan slope.It is the development area of ultra-low permeability reservoir in Yanchang formation of Triassic in Ordos Basin,and it is one of the hot spots of oil and gas exploration and development at present.However,with the progress of oilfield development,the stable production situation is grim.In order to improve the development benefit of Chang-6 reservoir in Bai 257 area,it is of great significance to make clear the development law of this reservoir,the law of fracture development and distribution,and the law of water flooding and sweep.Based on the well logging,oil testing,core observation and analysis of laboratory data,the geological characteristics of the Triassic Yanchang formation and the status of reservoir development in this area are studied and analyzed.Through the analysis of single well productivity,decline law,pressure displacement system and so on,it is concluded that the reservoir is facing the contradiction of low single well productivity,high initial decline,high local water cut,hard displacement system and low oil well response.Based on the study of reservoir connectivity,heterogeneity and oil well performance characteristics,the corresponding relationship between injection and production is studied by using logging and production performance data,and the uniform effect is put forward.Three patterns of directional and weakly effective well groups were observed.Make full use of dynamic monitoring data,water absorption profile and production dynamic data,the method of "preliminary identification-comprehensive identification-fracture correction" is established,and a total of 33 fractures in the study area are finally implemented.Based on the evaluation of reservoir water drive characteristics,the uneven degree of reservoir water absorption is quantitatively characterized by Lorentz curve method in longitudinal direction,and the dominant direction coefficient of water drive is calculated by cross-well resistance and correlation degree method on the plane.Furthermore,it provides an effective basis for stable production in Bai 257 well area.