Analysis And Characterization Of Reservoir Architecture Of The Carboniferous Donghe Sandstone In Hudson Oilfield

Since the Donghe sandstone reservoir of Hudson oilfield was put into development in 1998,with the deepening of exploitation,the comprehensive water cut of the reservoir has been rising.Up to now,the comprehensive water cut of most wells has exceeded eighty percent,and it has entered the stage of high water cut or even ultra-high water cut.The relationship between the remaining oil and the injected water has become more and more complicated.Therefore,it is necessary to carry out effective reservoir architecture analysis in this area.Supported by core,logging,analytical testing and dynamic data,and guided by the idea of "analytic hierarchy process,method combination,multi-dimensional interaction and dynamic verification",this study analyzes the reservoir architecture of the Donghe sandstone in Hudson oilfield.Firstly,The principle of high-resolution sequence stratigraphy is combined with the method of fine division and correlation of oil layers,according to the stratigraphic development characteristics of the study area,the fine stratigraphic framework of the study area is established in two steps,and the Donghe sandstone section is divided into one third-order sequence,two parasequence sets and eight parasequences.The Donghe sandstone body in the study area is characterized by "overlying and uplifting",that is,the lower stratum and the underlying Silurian strata are in unconformity contact,and the upper stratum is eroded;Secondly,the petrological characteristics and lithofacies types of the Donghe sandstone body are summarized,which are divided into 4 subfacies and 12 microfacies;Thirdly,the Donghe sandstone body in the study area is divided into six levels by using the analytic hierarchy process of reservoir architecture interface.This study focuses on the level 3 and level 4 architecture elements,and considers that there are three types of architecture interface in the study area: scouring surface,argillaceous interface and calcareous interface;In the vertical direction,the four level architecture elements are mainly composed of composite bar sand,composite beach bar and bar sand groove deposits,and the plane distribution characteristics of each layer are slightly different.The level 3architecture elements are divided into three architecture elements: dam sand,beach sand and groove.The dam sand has the best physical property and is widely distributed.It is distributed on the beach sand in a long strip shape.The groove has poor physical property and is mostly interlayer.It is usually distributed on the landward side of the beach sand edge.Based on the classification of architecture elements,32 single bar sand bodies in the study area are sampled and analyzed quantitatively,and the reservoir architecture model of Donghe sand bodies in the study area is established.On this basis,the control effects of reservoir architecture on remaining oil is further analyzed.