Research On The Sedimentary Facies And Diagenetic Facies Of Fuyu Reservoir In Fuxin Uplift Belt In The South Of Songliao Basin

The fuyu oil layer of Zhongxin-Qianguo south area is a set of shallow water delta sedimentary strata.The reservoir condition of the study area is complex,the density and the conventional reservoirs are all developed,previous studies of the sedimentary facies is controversial,the research of diagenesis is weak,which cause the influencing factors of reservoir formation are not clear,and the favorable reservoir is difficult to predict.In view of the problems above,this paper combined core,casted thin section,logging data,analysis and laboratory data and previous research results to carry out the reservoir sedimentary facies and diagenetic characteristics of the study area.On the base of the studies above,the influence factors of the density and conventional reservoir are analyzed,and the reservoirs have been classified and evaluated.Combined the characteristics of the composition,structure and formation,we classified gray,gray green,purple red massive bedding mudstone facies;small scale cross bedding silty mudstone(argillaceous siltstone)facies;small groove,wedge shaped staggered bedding siltstone facies;gray white calcium massive bedding pebbled sandstone facies and parallel stratification siltstone facies five kinds of lithofacies.We make a comprehensive use of lithological characteristics and logging features to defined the study area as shallow water delta deposit,and futher divided into delta plain and delta front two kinds of sub facies and seven kinds of sedimentary microfacies.Distributary channel,natural levee,crevasse splay,interdistributary bay four kinds of microfacies are developed in delta plain;under water diversion channel,sheet sand and underwater diversion three kinds of microfacies are developed in delta-front.We also established the sedimentary facies model,analyzed thedistribution rules of microfacies sand bodies,the distribution law of wide-narrow channel sand bodies and the characteristics of single sand bodies.On the basis of the research of sedimentary facies,the diagenesis,diagenetic stage and diagenetic facies of the reservoir are studied.According to rock types,rock grain size and composition,cement type,structures and logging response characteristics and other comprehensive characteristics,divided into five diagenetic facies types: strong compacted silty sand facies;calcium,clay strong cementation silty mudstone facies and feldspar medium erosion,dawsonite strongly cementation fine sandstone facies three kinds of lithofacies of densification and feldspar medium erosion siltstone facies,shallow deepth feldspar strong dissolution siltstone facies two kinds of lithofacies of expansion.Through the typical anatomical areas analysis,starting from the factors of sedimentation and diagenesis,analyzes the affecting factors of reservoir,determined the distribution of favorable reservoir.