Optimum Selection Of Productive Zones For Chang 8 Reservoir In Baima Shanzhuang Area

Chang 8 reservoir in Baima Shanzhuang area has the characteristics of low permeability,low porosity and low saturation.It belongs to typical low permeability and ultra-low permeability reservoir,and the main reservoir type is lithologic reservoir.Combining with oil testing data,logging data,core analysis data and other data in this area,the characteristics of sedimentary microfacies and sand body distribution,pore filling,reservoir petrology,pore structure and reservoir control factors are studied.Combining with the fine logging interpretation technology under geological conditions and the results of oil testing,the favorable areas for production construction are predicted finally.The following understandings have been obtained:1.Making full use of the core and logging data of Chang 8 reservoir in the study area,combining with the distribution characteristics of rock composition,heavy minerals and debris content,through provenance analysis and sedimentary microfacies study,it is clear that the source of the study area is North East and In the southwest direction,the delta front sediments are developed,and the underwater distributary channel sand bodies are dominant reservoirs,which are distributed in the northeast-southwest direction.2.Through the analysis of reservoir characteristics,it is clear that Chang 8 reservoir is dominated by lithic feldspar sandstone,with chlorite,iron calcite and hydromica as the main filling materials,with well-developed residual intergranular pore and dissolution pore.The reservoir physical properties are generally dominated by ultra-low permeability reservoirs,and relatively high porosity and permeability areas are locally developed.3.According to the research results of sedimentary microfacies,sand body distribution and reservoir characteristics of Chang 8 reservoir in the study area,combined with the classification criteria of Chang 8 reservoir,comprehensive reservoir evaluation is carried out for each sublayer in the study area.The main reservoirs of Chang 811 and Chang 812 are well developed,and the oil testing effect of corresponding blocks is better.4.Based on the analysis of the main controlling factors of reservoirs,it is concluded that the reservoir-forming model of Chang 8 reservoir in the study area is mainly controlled by lateral compactness of sand body and lateral mudstone facies change.The reservoir type is mainly lithologic reservoir,and the structural-lithologic reservoir is partly controlled by micro-structure.5.On the basis of fine description of sand body shape,reservoir characteristics and analysis of main controlling factors of reservoir,combined with secondary interpretation of well logging and oil testing results,the target areas for production construction are optimized by sublayer.A total of 12 favorable areas for production construction are predicted,of which 3 are in type? favorable areas,4 are in type ? favorable areas and 5 are in type ? avorable areas.