厚油层内部相结构模式及其剩余油分布特征

MICROFACIES ARCHITECTURE PATTERNS AND THE DISTRIBUTION OF THE REMAINING OIL WITHIN THICK PAYS

根据双河油田开发后期预测剩余油分布的需要 ,提出了厚油层内部相结构建模思路。由厚油层内部夹层分布特点 ,把其划分成多个流动单元 ,从而建立了厚油层内部结构框架。利用密井网和岩心资料 ,建立了厚油层内部相结构模式 :分流河道型、过渡型、席状砂型。它们反映出微相单元类型、规模、几何形态及组成比例上的差异。随着油田开发的深入 ,油层水淹程度的提高 ,剩余油分布趋于零散 ,但剩余油富集区明显地受相结构控制。小型透镜型和镶边搭桥型是油田开发后期剩余油富集的两种类型 ,是注采井网对规模小、物性差的微相动用和控制差所致。在相结构模式中 ,骨架性微相组成、规模及连接方式决定了油水运动方式、剩余油分布的特征。因此 ,可以利用厚油层内部的相结构来预测剩余油分布 ,为稳油控水方案的实施提供依据。

On the basis of predicting the remaining oil in Shuanghe Oilfield during the late period of development,this paper puts forward the procedure that builds the microfacies architecture pattern.According to the distribution of the interlayer,the thick pays are subdivided into many flow units to form the architecture framework.The built patterns include distributary channel,transition and front sheet sand types,which based on closely spaced wells and core data.Difference can be shown on the type,scale,geometry and buildup of microfacies.With the oil field developed deeply,waterflooding within thick pays is being more serious,and distribution of the remaining oil become more complex;however,the enrichment zones of remaining oil are restrained apparently with the microfacies architecture.Mini lens and edge bridge are two types of enrichment of remaining oil during the late period of development as the result of recovering and controlling badly the small scale and bad quality microfacies.In addition,the buildup,scale and joint manner of framework microfacies determine the movement of water and oil and the distribution of remaining oil.Thus,the remaining oil can be predicted by using the microfacies architecture within thick pays to provide basis for stabilizing production and controlling water cut.