Sedimentary Microfacies And Its Evolution Simulation Of Meandering River In NmⅢ Oil Group Of Yangerzhuang Oilfield

The study of fluvial reservoir has always been focused on in continental basin.The river sand body is characterized by extremely rapid phase change on the plane and commonly transformation of sand body in differnent periods,resulting in extremely strong heterogeneity.Insufficient understanding of the genesis and reservoir architecture heterogeneitylimited the exploitation of remaining oil distribution in oilfields,which is bottleneck for the development of fluvial reservoirs in mature oil fields in east of China.In this thesis,the meandering river reservoir in Minghuazhen Formation in Neogene(Nm)in Yangerzhuang Oilfield was studied.Study of sedimentary microfacies characteristics and sand body genesis was carried out to rebuilt the point bar formation process and evolution based on the technology of sedimentary numerical simulation.The aim is to reveal the sedimentation heterogeneity of reservoir and to provide geological support for efficient reservoir development.Stratigraphic correlation work of NmⅢ is carried out based on the principle of " marker bed constraining,sedimentary cycle controlling and gradual division and correlation ".Seven skeleton profiles(including three transverse one and four longitudinal one)and an isochronous stratigraphic framework have been established.it is found that the strata in the south is thicker than that in the north.According to the analysis of comprehensive data including local geological background,core,well logging,etc.,a total of ten lithofacies types were identified,including Ge,Sp,Sh,Sm,Fl,Fr,Fmb,Fsc,Fmg and Fmm.Different sedimentary microfacies were divided according to the combination of different lithofacies types.The NmⅢ layer is the deposition of far-source fine-grained and high-curvature meandering river in the alluvial plains.Based on the analysis of single-well facies and logging facies,the distribution of sedimentary microfacies in study area is analyzed with dense well network data.Based on hydrodynamic parameters and paleomorphological parameters obtained from the study of NmⅢ4 sedimentary microfacies,the evolution of a single meandering river was simulated with Delft3 D hydrodynamic numerical simulation software.The formation mechanism of serpentine process and the mechanism of river cutoff were discussed.The development and evolution characteristics of major sand bodies such as point bar were summerized,and was verified with geological research of study area.The development characteristics and formation process of the branch channel inside the point bar complex in the study area are recognized.Based on the research above,factors,such as slope,sediment grain size,and flow charge,which control meandering river evolution were simulated.The results provide guidance for the study of heterogeneity of meandering river reservoirs.Sedimentary numerical simulation method and the sedimentary characterization with dense well network area of mature oil field were combined.This provides ideas for the study of meandering river evolution.It is basis for the economic and effective development and adjustment of oilfield,and also helps to deepen the understanding of the sedimentary evolution of meandering rivers in Neogene in the Huanghua Depression and fine reservoir characterization.