曲流河砂体三维构型地质建模及数值模拟研究

Study on 3D architecture geology modeling and digital simulation in meandering reservoir

应用岩心、测井和动态生产资料,采用"模式预测,分级控制"的砂体内部构型研究方法,对高含水后期密井网条件下曲流河砂体沉积单元、沉积微相、单一河道砂体、单一河道内部点坝砂体以及点坝内部构型进行了分级描述,精细研究了曲流河砂体内部构型,建立了点坝砂体侧积夹层的规模、产状定量分布模式,确定了描述侧积夹层产状的倾向、倾角、延伸和水平间距4个参数。在此基础上,采用序贯指示模拟与人机结合再处理的方法建立了小网格三维储层构型模型及参数模型,进行了实际区块的曲流河砂体内部构型三维地质模型油藏数值模拟。根据层内数值模拟的结果总结出高含水后期密井网条件下曲流河砂体内部4种剩余油分布模式,并提出相应的层内挖潜措施。研究结果表明,萨北油田主力油层曲流河砂体单一河道宽度为200～800m,点坝长度为120～500m,侧积夹层倾角为7°～10°,可延伸至河道砂体的2/3左右。采用完善单一河道内部注采关系及挖潜点坝之间剩余油的方式设计的北X-4-144井取得了较好挖潜效果,为油田开发后期层内剩余油精细挖潜提出了依据。

On the basis of the data from core analysis, well logging and production performance, the hierarchy analysis method combined with the model matching was applied to analyze the sedimentary units, sedimentary facies, single meandering belt, single point bar and lateral accretion bodies of meander sand bodies in the late stage of high water-cut under the condition of dense well-pattern in Daqing Oilfield. The scale and mode of the lateral accretion interlayer in the meander sand body were developed, and the four parameters for describing the modes of the lateral accretion interlayer including dip direction, dip angel, expanded range and horizontal range were determined. The 3D reservoir architecture model and physical property model were established by using the sequential indication simulation. The numerical reservoir simulation of real sand block based on the models was finished. According to the results of reservoir modeling and numerical simulation, the four patterns of remaining oil distribution in the meandering river reservoir at the late stage of high water-cut under the condition of the dense well pattern were summarized. The corresponding measures for increasing recovery of remaining oil controlled by the lateral accretion shale bedding were implemented. The results show that the width of the single meandering belt in North Saertu Oilfield is from 200m to 800 m, and the length of the point bar is from 120 m to 500 m. The dip angle of the lateral accretion interlayer is from 7° to 10°. The lateral accretion shale bedding extends downward to 2/3 of channel sand body in thickness. Good effect of injection-production relation in the single meandering belt of the designed Well 4-144 has been achieved. These measures can provide bases for tapping the potential of in-layer remaining oil during the late period of oil- field development.