| The study area is located in the tectonic belt of the middle section of the Fuyu-Huazijing terrace in the southern part of the central depression of the Songliao Basin.The target layer of this study is the Fuyu oil layer in the fourth section of the Lower Cretaceous Quantou Formation.The Munan fault block group has entered the later stage of reservoir development,that is,the high-yield liquid,high water content,and highly scattered remaining oil development stage,so that the development contradiction is becoming increasingly more serious,and the development situation is increasingly severe.Therefore,the accurate dissection of the reservoirs in the study area,the distribution characteristics of the sand bodies and the reservoir heterogeneity are of great significance for the next effective development.In this paper,using logging data,core data and historical data,the isochronous stratigraphic framework of the Fuyu oil layer is established by using the comparison method of “ approaching the base cycle contrast under control of the step-by-step standard isochronic planes”.Firstly,the author carried out a fine partition and contrast of the single sand body level to the Fuyu oil layer group,and established an isochronous stratigraphic framework of 15 deposition units in the study area.Under the control of isochronous stratigraphic framework,the sedimentary background was analyzed to identify the development of two subfacies and 13 microfacies.The logging microfacies model was established based on the characteristics of logging curves.On this basis,the sedimentary microfacies fine identification technology is applied to finely describe the sedimentary characteristics of each sedimentary unit and the distribution characteristics of single sand bodies.Through these characteristics,the sedimentary evolution law of the whole study area is analyzed.Based on the above research,systematic study on the heterogeneity of Fuyu oil reservoir is carried out.Interior-layer heterogeneity includes permeability parameters characteristics and distribution of interlayer in interior layers;inter-layer heterogeneity includes comparison of interlayer parameter differences and defining the distribution characteristics and impact of the interlayer;planar heterogeneity is controlled by the sedimentary facies.The authors combined the above results to clarify the plane variation of the sand body distribution,porosity,permeability and other parameters.The study shows that F1~F3 belong to the delta front subfacies,and the channel sand bodies are distributed in strips,and the sand bodies are poorly developed,mainlyin the form of sheet sand;F4~F12 belong to the delta plain subfacies,and the channel sand bodies develop in a large area,the channel sand bodies are most developed during the F4-2 period.The thickness of the delta front layer is larger,the permeability parameters change obviously,and the interlayer heterogeneity is strong;The thickness of the interlayer in the delta plain is relatively small,the permeability parameters vary greatly,and the interlayer heterogeneity is strong.The interlayer thickness of the F1~F3 layer is 0~1 m,The author concludes that the F1~F3 is homogeneous in combination with the permeability heterogeneity parameter analysis;The interlayer thickness of the F4-1~F9 layer is 1-2 meters,and the permeability parameters are all medium and high values,showing of medium heterogeneous;The thickness of F10~F12 interlayer is more than 2 meters,and the permeability parameters are high,showing strong heterogeneity.Combined with the change of the shape,scale,porosity and permeability of the sand bodies in the plane,the heterogeneity of the F1 and F3 planes is relatively weak;F2,F4-1,F4-2,and F6-2 are medium-weak heterogeneity on the plane;F5-1,F5-2,F6-1,F9,F10 belong to medium-strong heterogeneity;F8,F11 and F12 are strongly heterogeneous. |
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