Fine Study Of S? Reservoir In Lamadian Oilfield North East Area And Its Application In Polymer Flooding

Lamadian Oilfield has entered into the ultra-high water cut stage since 1996.And the integral water content is close to 94.68%at present.The water-flooding exploration becomes more difficult,and the development benefit becomes variation gradually,all because of the complicated interlayer,in-layer and plane heterogeneity of reservoir.In order to effectively develop highly scattered remaining oil at super-high water-cut stage,we launched the fine geological study on reservoir depositional characteristics,structures of sand bodies,heterogeneity and remaining distribution.This article chose oil layers S?4-10 in Lamadian Oil Field as supersedure potentiality of the polymer flooding oilfield.According to the basic principle of high resolution sequence stratigraphy,genetic sequence cycle division and tracking-correlation method,to divide the target layer into 6 stable distribution of sedimentary unit.According to the modern sedimentological principle and the single sand body phase zone boundary prediction method of sedimentary mod of each river style,dividing sand body sedimentary characteristics into three kinds:large-scale meandering river sedimentary,large-scale wide-belt and low-sinuosity fluvial deposit,middle-small distributary channel deposit.With the combination of methods of core analysis,water flooded layer interpretation results after polymer-flooding encryption and water absorption profile of water-injection well,we confirmed the inner interfacial distribution models of channel sand body with different types.The sand-body internal four-level structural interface of thick reservoir in Lamadian Oilfield has three distribution modes with layered,wavy and oblique.Between structure units,there are six combination patterns with stratification,superposition,cutting and overlay,inlaying,bottle base and suspension.According to fine geologic study of the study area,we established the model of sedimentary microfacies in North East Block.Under the control of microfacies model,using sequential Gauss modeling method to build the reservoir parameter model,including permeability model and porosity model.Using core,water-flooded layer interpretation and the results of numerical simulation,we study the reservoir production characteristics.Based on the fine reservoir description,We improved the precise description of remaining oil,synthetically predicted the characteristics of remaining oil distribution:The remaining oil in thick reservoir are mainly distributed in the upper structural unit,and inefficient and ineffective circulation are mainly concentrated in the lower structural unit.According to the existence of interlayer,in-layer and plane heterogeneity in target layer,we used interlayer to separate layer and optimized injection-production adjustment technology based on horizontal sand body connectivity plane.At the same time,we carried out fine tracking adjustment with combination of injection characteristics and response characteristics of different types of sand body.We took 1146 wells plan adjustments,cumulatively increased 642000 tons of oil,enhanced oil recovery by 6.7 percentage points and significantly improved the polymer flooding effect in the study area.Through the systematic research,a set of mature fine reservoir description technology and methods in high water cut stage was formed,which is a geological theory of innovation for Lamadian Oilfield.It reveals the internal structure characteristics of thick oil reservoir and distribution characteristics of remaining oil.It effectively guides the polymer-flooding comprehensive adjustment.Injection structure and liquid production structure of polymer flooding in oil layers S? for North East area I in Lamadian Oilfield gets optimizied.We achieves efficient polymer flooding development in progressive production in Class II Reservoirs.It has very important popularization and application value.