The Water-flooded Mechanism Research In Block G Of A Oilfield

Nowadays,most oil-fields in China have entered the development stage of high water cut and extra high water cut,and waterflooding has become the main mining method.Since October 1969,in Block G of A oilfield has been injecting water for development.It has been mined for about 50 years and is now produced under high water cut conditions.It is difficult to comprehensively control,most of the oil layers are flooded,water absorption is large,and the oil layer is Interfere with each other.Therefore,it is necessary to establish a well-documented interpretation method for water-flooded layers in the area,and the study of water-flooding mechanism is particularly important as the basis for evaluation of water-flooded layers.Combined with the difficulties in the interpretation of the water-flooded layer in the G block,the paper is based on the experimental data,logging data,geological data and oil test data of the G block,through experimental data analysis and reservoir characteristics(lithological characteristics,physical properties,fluid characteristics,seepage characteristics,pore structure characteristics)analysis,based on water flooding rock and rock experimental data,pore structure parameters,reservoir heterogeneity in three aspects to study the flooding mechanism.waterflood electric petrophysical experiment data reveals that the relationship between the resistivity and water saturation of the reservoir during flooding.Based on the experimental data of water flooding rock and electricity,the influencing factors of resistivity change can be studied.The paper studies the mineral composition of reservoirs,the physical properties of reservoirs,and the mineralization concentration of mixed liquids after water injection.It is found that the influence of reservoir mineral composition and reservoir physical properties on resistivity is not the dominant factor in freshwater flooding.The dominant factor is the concentration of mineralization of the mixed liquid(formation water and injected water)after water injection.The resistivity value may appear five pattern which are anti-"L","V","U","S" and a monotonically decreasing,with the increase of the injected water volume..by using pore structure parameters to study of water-flooding mechanism is mainly to analyze the influence of pore structure parameters on reservoir flooding and oil displacement efficiency,and establishes the standard of pore structure parameters for flooding level of freshwater flooded layer.The influence of pore structure parameters on oil displacement efficiency is mainly based on the analysis of the variation of silt index,small pore size ratio,entry pressure,median pressure,maximum pore throat radius and pore throat radius.In the G block,the interlayer heterogeneity and microscopic heterogeneity are strong,and the heterogeneity within the layer is serious,which has an impact on the flooding law.Reservoir heterogeneity characteristics are reflected in micro and macro,horizontal and vertical.From a macroscopic point of view,it is mainly to study the law of flooding in small and small layers.The study of heterogeneity in layers is based on the flooding characteristics of three types of permeability rhythms,namely,positive rhythm,superposition anti-rhythm,and compound anti-rhythm.At the same time,the argillaceous and calcareous interlayers also have a certain influence on flooding;the plane heterogeneity mainly studies the water flooding law through the distribution characteristics of the plane sand bodies in each layer,and the connectivity is good.The paper achieved certain results,and made some innovations in the study of the water-flooded mechanism.