The Reservoir Characteristics And 3D Geological Modeling Of The Lower Karamay Group In The 7^th Central Region Of Karamay Oilfield

The complex reservoir geologic features of Karamay oilfield are very difficult to accurately predict the oil and gas reserves and formulate the overall development plan.Therefore,the static 3D geological model of reservoir is established.It is of great significance for the optimization design of the overall development scheme of Karamay oilfield to provide the adjustment basis and technical support for the later crypto adjustment of the lower Karamay group.In this paper,regional faults are verified by combining 3D seismic data of overpass well and secondary development.The study shows that the Ke-Wu fault has a great change in the middle of 7^th central area.Through the use of new wells,coring well data and a large number of overpass wells,and comparing secondary development of 3D seismic research results to subdivide and finely compare,the lower Karamay group in the 7^th central region is divided into 12 single layers.Taking the reservoir 3D geological modeling as an important goal and comprehensively applying various logging data to study the four-reservoir relationship of reservoirs,it was found that the relationship between porosity and permeability of the lower Karamay group in the 7^th central region was poor,and some sandstone conglomerates showed extremely low porosity,extremely low permeability.The establishment of the lithology,porosity,permeability model,and the multiple regression model for the restoration of the original oil saturation of the lower Karamay group in the 7^th central region were carried out.According to the lithology discrimination criterion of logging curves,the lithology is divided into 5 types:conglomerate,glutenite,gravelly sandstone,medium-fine sandstone and mudstone.The accuracy of porosity and permeability model is verified by cross plot.On this basis,the original oil saturation was restored.Based on the study of reservoir characteristics,reservoir distribution characteristics,reservoir characteristics,the characteristics of reservoir heterogeneity were studied in detail.The layer is distributed in sand and mud interbedding,mudstone interlayer develops,and the S₇^2-3 interlayer is stable and gradually thinning down.The difference of permeability and transverse permeability between layers is larger in plane.There is a positive correlation between the heterogeneity of the layers and the variation of permeability gradation.The difference of reservoir parameters and heterogeneity between single layers is large.According to geological coring well data and logging data,combined with sedimentary facies,diagenetic facies,macroscopic heterogeneity of reservoirs and microscopic pore structure,a comprehensive evaluation of reservoir classification was conducted.The conglomerate reservoirs are classified as type I,II,III and IV.The middle and low permeability heterogeneous stratified type II reservoirs are distributed in this layer and the effective reservoir standard was determined.The 3D geological model of reservoir is established by using stochastic modeling and deterministic modeling method,the results show that the stochastic modeling method is more effective,which provides geological basis for reservoir characterization and later adjustment.