Research On Meandering River Reservoir Architecture Of Minghuazhen Formation In Gangxi Oilfield

Gangxi oilfield is one of the main oilfields in Dagang Oilfield.After nearly 50 years of development and production adjustment,it has entered the late stage of ultra-high water cut stage.However,according to previous research results,there are still a large number of remaining oil enrichment in this area and stored in the sand body.This part of remaining oil is mainly controlled by the complex internal configuration of the reservoir,so it is necessary to carry out more detailed reservoir configuration characterization research.Therefore,it is of great guiding significance to carry out multi-level fine configuration characterization in the study area and clarify the spatial distribution law of sub configuration units at all levels,so as to improve the final recovery and development effect.Aiming at the meandering river reservoir in the lower member of Minghuazhen Formation in block 4 of Gangxi oilfield,using core logging data,on the basis of establishing the fine isochronous framework of the whole region and under the guidance of sedimentary model,this thesis carried out the fine characterization research of multilevel reservoir configuration,and defined the spatial distribution law and characteristics of different levels of configuration units.The research shows that:(1)the fine isochronous stratigraphic framework based on single layer in the fourth area of Gangxi oilfield is established to complete the threedimensional closure of stratigraphic correlation in the whole area,and it is concluded that the stratigraphic development style is generally equal thickness aggradation.(2)The development types and recognition characteristics of different levels of configuration units in the study area are summarized;The main configuration units of Minghuazhen Formation in block 4 of Gangxi oilfield include: river channel(mainly point dam),overflow Bank(NATURAL dike,crevasse fan,floodplain sand),abandoned river channel and flood plain,of which river channel and flood plain are the most developed.(3)The plane distribution pattern of hierarchical configuration units of composite sand bodies in channel belt is summarized,and the identification method and quantitative scale prediction of single channel boundary are defined.The plane distribution pattern of composite river channel in the study area is mainly divided into continuous and strip.Four identification characteristics of single river channel are determined: abandoned river channel,inter river sedimentation,elevation difference and scale difference.(4)The identification marks of point dams in the study area and the distribution characteristics of secondary configuration units of internal lateral accumulation layer are defined.The span of single point dam developed in nmiii-2-1 single layer in the study area is about 340 m ～460m,the thickness of single lateral accumulation body is about 2m ～ 6m,and the vertical thickness of lateral accumulation layer is about 0.2m ～ 1m,which is in imbricate lateral superposition distribution.The lateral accumulation layer tends to point to the direction of abandoned river channel,the dip angle range of lateral accumulation layer is about 5 °～ 8 °,the horizontal width range of lateral accumulation body is 53 m ～ 80 m,and the horizontal spacing of adjacent lateral accumulation layers is about 15 m ～ 24 m.(5)This modeling adopts the face-based deterministic modeling method,technically combined with human-computer interaction,establishes the three-dimensional configuration model of composite channel level and point dam level of target reservoir in the study area,characterizes the distribution characteristics of configuration characterization results in three-dimensional space,and provides the basis for fine anatomy of reservoir configuration.