Study On Liquid Production Capacity And Influencing Factor Of Oil Field In Ultra-high Water Cut Later Stage

At present,the vast majority of our country's eastern old oilfield developed by waterflooding has entered the ultra-high water cut later stage,when water cut is more than95%.The overall water flooding reservoir is at"double-high"stage of development with extra high water cut and high recovery.Oilfield development must be based on the current situation of reservoir in ultra-high water cut period,thus the study on liquid production capacity and its influence factors of ultra-high water cut reservoir is of great significance for improving both the reservoir liquid production capacity and the development efficiency of oil field.In this paper,reservoir in later stage of ultra-high water cut is taken as the research object,the liquid producing capacity characteristic is analysed from two aspects of theory and field,and its influence factors are s?mmarized as the water phase,oil-water viscosity ratio and oil-water relative permeability.The production characteristics of typical oil field is analysed,and the differences between theoretical and practical dimensionless liquid production index are compared.Using the n?merical simulation method,research is conducted on main geological and development factors of reservoir liquid producing capacity,including their influence regulation and influence degree.Among 4 main geological factors,crude oil viscosity has the dominant influence of on dimensionless liquid production index,followed by reservoir thickness,positive rhythm permeability,inverse rhythm permeability and permeability.On the basis of theoretical formula and mathematical methods,the comprehensive influencing multi-factor model of dimensionless liquid production index is established.Finally,the actual reservoir 7~4-8~1 unit is taken as an example to analyse the development process and fluid production of typical reservoir in late ultra-high water cut.The feasibility of the multi-factor model method is verified by matching dimensionless liquid production index is calculated by the improved theory method and multi-factor model method..