南堡凹陷曲流河点坝储层内部构型解剖与剩余油挖潜

Reservoir Architecture Anatomy in Meandering River Point Bar and Tapping the Potential of Remaining Oil in Nanpu Sag

以南堡凹陷柳赞南区明化镇组(Nm)曲流河沉积为例,应用"垂向分期、侧向划界"的方法,通过标志识别确定单河道、点坝及其内部构型分布,重点对点坝内部各构型要素进行定量描述,建立点坝内部构型模型,分析剩余油分布模式。研究结果表明,柳赞南区L25-26井区NmⅢ11-2单层发育的点坝长度为587.7m,由13个侧积体叠加而成,侧积层水平间距约29m,侧积层倾角为8°,倾向指向废弃河道外法线的北东方向。由于泥岩侧积层的影响,剩余油主要分布在点坝侧积体的上部,可通过水井卡封无效注水循环层、在油水井之间点坝上部钻水平井的方式挖潜剩余油。研究结果有效地指导了柳赞南区特高含水开发阶段开展的层内剩余油精细挖潜。

By taking the meandering river sedimentation of Minghuazhen Formation in South Liunan Area of Nanpu Sag for example,according to the method of vertical stage and lateral delimitation and different marks,the single river sand body,point bar and architecture,and the quantitative characterization were identified for establishing an architecture model of internal point-bar structure,analyzing the remaining oil distribution pattern.The results show that NmⅢ1-21 single bed in L25-26 well block,the length of point bar is 587.7m,which is stacked by 13 lateral accretion body.Its horizontal interval is about 29m,and the angle is 8°,direction is external abandoned channel.Because of the effect of lateral accretion bedding of mudstone,the remaining oil distribution in point bar is mainly in the upper accretion body,which can be potentially tapped by plugging ineffective water injection formation and horizontal wells are drilled in the upper part of point bar between water injection wells and oil wells.It provides guidance for tapping the potential of remaining oil in South Liuzan Block at extra-water-cut stage.