辫状河砂体三维构型地质建模研究

STUDY ON THE 3D ARCHITECTURE GEOLOGICAL MODELING OF BRAIDED FLUVIAL SANDBODY

采用"模式预测"的砂体内部构型研究方法,对萨北油田高含水后期密井网条件下辫状河砂体构型模式、夹层类型和夹层延伸规模进行了精细描述。建立了适合萨北油田辫状河砂体的"叠覆泛砂体"构型沉积模式,根据构型沉积模式把砂体内部夹层分为3种类型,确定了垂直水流方向夹层空间延伸规模。采用基于目标的算法建立了砂体内部构型模型及参数模型,总结出高含水后期辫状河砂体内部呈现低未水淹部位少、剩余油潜力较小的基本特点。研究结果表明,辫状河砂体内部夹层空间延伸长度90～140m,总体呈水平分布,层内低未水淹部位少于10%。利用层内机械和化学堵水技术对19口油井进行了细分堵水,取得较好挖潜效果,为油田开发后期层内挖潜提供了地质依据。

Considering the production situations of braided fluvial sandbodies at late high water-cut stage under dense pattern condition in Daqing Sabei Oilfield,the hierarchy analysis method combined with matching model is applied in subsurface architecture anatomy.According to this method,three aspects of braided fluvial sandbody including sedimentation model,intercalated bed style,intercalated bed spread scale are identified and analyzed.The sedimentation model that channel sand dam forms large-scale sandy flat or overlap extensive sandbody on surface are described.Based the sedimentation model,intercalated bed is divided into three types and it's spread scale is identified.Based on these achievements,3D reservoir architecture model and petro physical property models are established with the target algorism.The remaining oil potential is little in braided fluvial sand bodies at late high water-cut stage.The results show that intercalated bed spread scale is between 90m and 140m.Inner layer subdivided water shut-off in nineteen oil wells for different types of remaining oil have achieved better effects.This paper will serve as a guide for tapping the potential of in-layer remaining oil during late oilfield development periods.