Study On The Heterogeneity Of ES₃²⁺³ Reservoir In The Southern District Of Gaoshangbao

The reservoirs of the second and third member of the third member of Shahejie Formation of Paleogene in southern Gaoshangpu area are complex fault block reservoirs with large remaining oil reserves.The target stratum belongs to fan delta front subfacies deposit,and the reservoir is highly heterogeneous.At present,the understanding of interlayer,plane,intra-layer and micro-heterogeneity of reservoir is not clear,which restricts the effect of water injection development.Therefore,it is urgent to strengthen the study of reservoir heterogeneity in this area.Based on the theories and methods of sedimentology,geostatistics,reservoir geology and diagenesis,the interlayer,plane,intra-layer and micro-heterogeneity of reservoirs are analyzed by using core,thin section,well logging,production dynamic data and mercury injection curve,and the main influencing factors of reservoir heterogeneity are summarized.It is clear that reservoir heterogeneity is introduced by reservoir heterogeneity in water injection development of oilfields.Questions.The second and third member of the third member of Shahejie Formation in the study area can be divided into six oil groups from top to bottom,which are 0 to V.This paper mainly focuses on the ?-? oil group.In terms of interlayer heterogeneity,each oil group becomes worse with the depth of pore permeability,And the difference of porosity and permeability is the most obvious in I oil group.The heterogeneous parameters of interlayer permeability are generally on the high side and belong to the serious heterogeneous type.From the analysis of each oil group,the degree of heterogeneity of oil group ? is relatively light,followed by oil group ?,and oil group ? is the most serious.Relatively stable distribution of barrier layers in the study area is mainly ?-6 and ?-12 layers.On the plane heterogeneity,it is found that the main extension direction of sand bodies in the study area is NE and NW,the size of sand bodies is not large,the continuity belongs to the third and lower levels,and the connection mode is mainly isolated.From the plane distribution of physical properties,the sand bodies of ? and ? oil groups are the best developed,the physical properties are also better,and oil ? is the best.The sand bodies in the study area are also well developed,but their physical properties are poor.On the heterogeneity,the grain size and permeability characteristics of the study area are mainly positive rhythm and compound positive rhythm.The average ratio of vertical permeability to horizontal permeability is 0.548,which indicates that the vertical permeability of the study area is weak.During the process of water flooding development,the effect of water washing in the study area may be poor,and the phenomenon of tongue entry is easy to occur in the thick layer.According to the permeability heterogeneity parameters of each layer,most of the single sand layers belong to the serious heterogeneity type.The interlayer mainly develops two kinds of mud and physical properties,and its thickness is small and its stability is poor.Microscopic heterogeneity study found that reservoir pore is mainly secondary intergranular pore,throat is mainly flaky or curved flaky throat,pore structure type is fine throat,fine throat and extra-small pore,throat sorting is poor.The factors affecting reservoir heterogeneity mainly come from four aspects:sedimentary environment,diagenesis,tectonism and production performance.Based on the above research results,the influence of interlayer heterogeneity on water injection development in the study area is analyzed.It is found that interlayer heterogeneity mainly manifests as interlayer interference to oil and water wells,which results in low oil and water wells utilization degree;plane heterogeneity mainly manifests as residual oil accumulation near the edge of sand body and fault;and permeability rhythm characteristics in the layer have influence on vertical water washing effect and oil displacement efficiency;Homogeneity is the negative effect of pore structure characteristics on oil displacement efficiency in target intervals.