Study On Macroscopic Heterogeneity Of Fluvial Reservoir In Ng?² Oil Layer Of The 3^rd Fault Block In Dagang Liuguanzhuang Area

The 3^rd fault block of Liuguanzhuang Oilfield is located in the graben block clamped by Zhuang6 fault and Chengxi fault.The whole block is low-amplitude draped anticline structure.The two sub-layers of the third member of Neogene Guantao Formation have always been the main production interval of the oilfield.but at present,it is faced with such problems as unclear reservoir architecture and complex oil-water relationship caused by reservoir heterogeneity.Based on the core,well logging,seismic data and production performance data,this paper studies the sedimentary microfacies and reservoir architecture in the study area,and carries out the reservoir heterogeneity research based on the braided river sandbody architecture,so as to provide geological basis for the subsequent development of Liuguanzhuang Oilfield.The following achievements and understandings have been made:1.Based on the principle of multi-level subdivision and correlation of reservoirs,the stratigraphic division scheme of Ng?² in the study area was re-established.Ng?² is further divided into two small layers,which are Ng?²-2 and Ng?²-1 from bottom to top.Meanwhile,the top-to-bottom stratigraphic interface of Ng?²,namely the stable mudstone interface,is redefined.2.The sedimentary microfacies of each layer of Guan3 2 in the study area were studied in detail.Based on logging data and coring data,the logging facies identification template of sedimentary microfacies in the study area was established by analyzing the amplitude,shape,top-bottom contact relationship and combination characteristics of logging curves.It is considered that braided river deposits are the main sedimentary facies in the study area,and the main sedimentary microfacies are beach bar,braided channel,abandoned channel and flood plain.3.The reservoir architecture characteristics of each small layer in Ng?² of the three fault blocks were analyzed.Based on well logging data,combined with seismic data and production dynamic data,the classification standard of configuration interface is summarized,and the superposition relationship of configuration units in sand body is described.By comparing the sand bodies in the study area,five kinds of single sand body architecture and combination styles are summarized.The sand bodies are widely superimposed and laterally tangential superimposed,and six kinds of sand body boundary identification methods are summarized.4.The heterogeneity in each layer of Ng?² was studied.Based on the study of particle size rhythm,bedding structure and interlayer distribution,four patterns of positive rhythm,inverse rhythm,homogeneous rhythm and compound rhythm were developed in the study area,of which positive rhythm and homogeneous rhythm were the main ones.The intercalation is mainly divided into two types:argillaceous intercalation and physical intercalation.The intercalation is relatively developed in the Ng?²-2 layer,with a wide distribution range and strong heterogeneity within the intercalation.Combined with the permeability parameters,it is found that the heterogeneity of the two small layers is strong.5.To conduct research on interlayer and plane heterogeneity.By analyzing the stratification coefficient and sandstone density of the two small layers,it is found that the heterogeneity of the two small layers is strong,and the difference of some interval layers is significant.The main physical properties of channel sand are good,but the heterogeneity is weak.The physical property of river edge is poor and the heterogeneity is strong.