开发后期三类油层沉积微相研究——以大庆萨北油田北二东两三结合试验区GⅡ油层组为例

萨北油田在进入特高含水开发期后,产量进入总递减期,后备优质储量不足,因此三类油层中的优质储层将成为今后相当长一个时期增储上产的主要资源基础。油田开发后期为实现对这类难动用储层精细开发调整,也为了更客观地描述各沉积单元的沉积特征,本文对该试验区GⅡ油层组进行了至单砂体级精细对比,将水下分流河道、河口坝、席状砂等微相进一步细分15类沉积微相(3类水下分流河道、3类河口坝、3类主体席状砂、6类席状砂),建立了15类测井微相模式,并依照此模式对研究区储层进行了精细刻画。本次研究发现GⅡ油层组部分小层具有明显水下分流河道特征,且在席状砂中预测出物性较好的主体席状砂可进行优先开发。这种对三类油层沉积微相的精细研究方法为今后同类油层的开发提供重要的理论指导,对油田开发后期持续稳产具有重要的意义。

Study on Sedimentary Microfacies of the Third Class Oil Layer at the Late Development Stage: Case Study on Northeast No.2 Two-three Combination Pllot Area G Ⅱ Oil Layer in Daqing-Sabei Oilfleld

After Sabei oilfield entered extra-high water cut period,while production entered into total decline period,the backup of well reserves is insufficient.Therefore,the well reserves in the third class oil layer will become the main resource base for quite a long time to increase reserves and production in the future.To realize the fine development and adjustment of such tough reservoir at late stage of oilfield development,in addition,for describing the sedimentary characteristics of each sedimentary objectively,this article uses fine contrast to the single sand in the pilot area,the subaqueous distributary channel,debouch bar and sheet sand is further divided into 15 kinds of microfacies(3 types of subaqueous distributary channel,3types of debouch bar,3 types of the main sheet sand,and 6 types of sheet sand),about 15 kinds logging microfacies model is established,and the reservoir in this area is well studied based on this model.The study found that some layers have obvious characteristics of subaqueous distributary channel.And the main sheet sand with good physical properties can be priority developed.The fine study on third class oil layer microfacies can be important theoretical guidance to similar reservoir in the future development and is of great significance to the continued stable late on oilfield development.