At the mature development phase of an oilfield,the analysis of monogenetic sand reservoir architecture is efficient to instruct the research on the oil-water movement pattern and the operation of tapping remaining oil.Based on the reservoir configuration theory,this paper divided the composite sand reservoir into multiple monogenetic sandbodies in Oil-groupⅠ and Ⅱ of the E3dL2 in Oilfield Z of the Bohai Bay Basin using three vertical stage identification markers and four lateral delimitation identification markers.The vertical stage identification markers include shale interlayers,pebbly sandstones,calcareous interlayers and the lateral delimitation identification markers include logging curve shape difference,lithology difference,thickness difference and water flooding feature difference.Each monogenetic sandbody represents a single sedimentary microfacies (e.g.underwater distributary channel or mouth bars,etc).In addition,the definite logarithm correlation between interwell sandbody thickness variation and top boundary dip was used to quantitatively identify the pinch out point of the single sandbody.Therefrom,the subsurface complex sedimentary characteristics were reconstructed to display the contiguous distribution of mouth bars and the cross superimposition of underwater distributary channels within this oilfield.Combing with the other static and dynamic data,the comprehensive analysis revealed that the quality difference of monogenetic sandbody is the major factor influencing the oil-water movement and remaining oil distribution in the study area.The independent flow unit develops within the individual lobe,within which the different types of monogenetic sandbodies with different reservoir quality correspond to different seepage capacities and flooding features.The premium monogenetic sandbodies are prone to form dominant pathways and result in enrichment of remaining oil.The study of oil-water movement based on monogenetic sandbody analysis will provide a solid geological foundation for tapping the potential of remaining oil through infill drilling and enhancing the oil recovery in the oilfield.%在油田开发后期,通过解剖单成因砂体构型,可用于指导油水运动规律分析以及后续的剩余油挖潜工作.以储层构型理论为指导,根据3种垂向分期识别标志(泥质夹层、含砾砂岩层和钙质夹层)和4种侧向划界识别标志(曲线形态差异、岩性差异、厚度差异和水淹特征差异),将渤海湾盆地Z油田东营组二段下亚段Ⅰ和Ⅱ油组三角洲前缘沉积复合砂体划分为多个代表单一沉积微相(水下分流河道、河口坝等)的单成因砂体,并依据井间砂体厚度变化与砂体顶面角度二者之间较好的对数相关性,定量确定了单一砂坝砂体尖灭点.由此,重构了油田范围内复杂沉积中河口坝连片分布和水下分流河道交叉叠置的特征.以此为基础,综合分析油藏其他动静态资料,认为单成因砂体质量差异是影响油水运动和剩余油分布规律的主要因素.单个朵叶体形成相对独立的流体单元,不同类型单成因砂体由于其质量差异,表现出不同的渗流能力和水淹特征,优质单成因砂体易形成优势通道并造成剩余油的富集.开展基于单成因砂体的油水运动规律研究,可为油田后期加密挖潜和有效提高油田采收率奠定必要的地质基础.
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