Research On Logging Interpretation Of Water Flooded Layer In Xingshugang Oilfield

With the development of oil and gas reserves less and less in the early stage,the research center of oilfield exploration is gradually transitioning to remaining oil.In the eastern part of the study area,the water cut is higher after the third infill of water flooding,and the remaining oil is more difficult to tap potential.As the premise of remaining oil research,the evaluation of water-flooded zone is of great significance to the exploration and development in the later stage of the study area.Due to the change of reservoir properties after waterflooding,some original interpretation methods of water-flooded zone are not accurate enough to be applied to the present stage,so it is necessary to re-summarize the logging response characteristics suitable for the target zone in the study area.And the technology and evaluation method of water flooded zone identification and judgment are readjusted and supplemented.Based on the above questions On the basis of qualitative identification,the quantitative interpretation parameters are optimized on the basis of qualitative identification,and a quantitative interpretation model of water flooded layer is set up.In this paper,the basic characteristics of reservoir in the study area are analyzed,and the core analysis data of 5 coring wells in the study area are used for statistical analysis.The lithology,physical property,electrical property and oil content of the reservoir in this area are studied.The pore structure of different sedimentary facies is classified according to the characteristics of pore structure and capillary pressure curve.By using the logging data at the early stage of development and the log data of the closed coring wells in the later period of adjacent development,the changes of oil content and distribution of oil and water,the salinity of formation water and the changes of pore structure and permeability after water flooding are analyzed.The changes of natural potential,acoustic time difference,resistivity and natural gamma curve before and after flooding are analyzed.Based on the constraints of different sedimentary microplates,the intersection plate of natural potential and acoustic wave curve,density and acoustic wave curve,deep lateral resistivity and acoustic time difference curve are established respectively.The recognition effect of deep lateral resistivity and sonic time difference intersection is the best.A total of 5 wells are identified and the coincidence rate is above 90%.According to the characteristics of pore structure,a class of sheet sand and estuarine dam are classified as a class of qualitative identification plates.The logging interpretation model for each reservoir is established,and the standard forquantificationally dividing the watered-out level of watered-out zone is established by using the flooding efficiency.The interpretation accuracy is relatively high: a total of 184 small layers in 3 coring wells are interpreted,and the coincidence rate is more than 85%.