Research On The Reservoir Architecture In The Lower Part Of Minghuazhen Formation In Yangerzhuang Oilfield

The sand body of fluvial reservoir changes rapidly in transverse phase with great heterogeneity,and the internal structure and interlayer of reservoir is complex.The fluvial reservoirs in the old oilfields of eastern China are currently entering the high(extra high)waterbearing stage.The sedimentary heterogeneity within the sedimentary microfacies has become a key geological factor that constrains the economic and efficient development of oilfields,which needs to be recognized.In view of the above problems,the reservoir of meandering river in the lower part of Minghuazhen Formation in Yangerzhuang oilfield is taken as the research object,and we started to research the features of the reservoir architecture and quantitative characterization on the basis of the sedimentary research.On the basis of previous studies,this study based on “marker bed constraining,sedimentary cycle controlling and gradual division and correlation”,target bed stratigraphic detailed division and correlation is finished.With the constraint of isochronal stratigraphic framework,the paper summarized a reasonable and complete layer division and contrast scheme,and nine main stratigraphic profiles had been built.The eastern part of the strata is as thick as the western part,and the southern part is thicker than the northern part.The lithology,granularity,color and sedimentary structure of the rocks were analyzed according to the cores and the slices data in the study area,and the lithofacies combination of the rocks was determined.Ten types of lithofacies were identified,and different combinations of different types of lithofacies formed different sedimentary microfacies.Based on the analysis of rock type and grain size,composition maturity and structure maturity,channel curvature and other factors,the study area is characterized by the deposition of far-source fine grains and high-curvature meandering river developed on the alluvial plains of the Yanshan Mountains.Reference to the meandering river sedimentary model,adopt core,seismic,logging and other multi-scale data,and carry out the meandering river reservoir architecture research to establish the meandering river reservoir architecture division scheme guided by hierarchical analyzing and model fitting.Based on the study of the sedimentary facies,the architectural elements is identified based on the sedimentary structure,sand body morphology,paleocurrent flow direction and transverse(longitudinal)orientation of the lithofacies.The method of “seismic data shaping,single well data phasing,and dense well network data quantification” is used to analyze a single channel,a single point bar,and some parameters are quantitatively analyzed to analyze the reservoir architecture.The architectural element is quantitatively characterized by single meander belt width,meander channel full bank width,meander channel full bank depth and other parameters,which has a good correlation.The effects of various factors on the formation and distribution of remaining oil in different architectural element are summarized,and the influence of reservoir architecture on the formation and distribution of remaining oil was preliminarily analyzed.This paper provides a complete set of ideas for the study of meandering river reservoir architectural.Combining qualitative and quantitative analysis,it not only provides suggestions for the later development and adjustment of Yangerzhuang oilfield,but also provides reference for other high water-bearing stage reservoirs.