南襄盆地泌阳凹陷赵凹油田安棚主体区古近系核桃园组三段四砂组2小层(H3 IV2)为厚层近岸水下扇扇中砂体沉积,不同期次沟道砂体相互切割叠置,形成复杂的空间结构样式,极大影响了油田开发.亟需开展厚层砂体内部结构解剖,揭示不同期次沟道砂体分布,明确其结构样式对油水运动影响及剩余油分布控制.本文以储层构型要素分析法为指导,综合利用岩芯、测井、生产动态资料,对近岸水下扇扇中厚砂体构型进行了精细刻画.通过研究明确了研究层段构型界面6级级次划分方案,建立了复合辫状沟道内部单砂体边界的垂向和侧向识别标志,其中垂向边界识别标志有泥质类岩性界面和底冲刷界面2种,侧向边界的识别标志包括不同单砂体的顶面高程差异、厚度差异、测井曲线形态差异等5种;在单砂体识别的基础上开展了目的层厚砂体井间构型分布规律研究,将复合辫状沟道砂体解剖为单一期次辫状沟道砂体,明确了各单期辫状沟道砂体的展布特征,并统计分析了辫状沟道单砂体构型单元的特征参数;通过上述研究总结了研究区单砂体构型单元接触样式,主要包括孤立式、叠加式、叠切式3种垂向接触样式和分离式、对接式、侧切式3种平面接触样式;分析了单砂体对剩余油的控制作用,研究发现4级构型单元内部韵律性以及构型单元之间接触样式对油水运动有重要影响,是造成剩余油富集的两个重要因素.%Objective:The thick sandbody of the IV2 layer of He-3 Formation in the Anpeng main zone,Zhaowa Oilfield is formed by braided channel of middle nearshore subaqueous fan.The complex erosion and superimposition of the braided channel in different time results a complex movement of oil and water and the difficulty of enhancement of oil recovery in development stage.So a detail anatomization of thick sandbody is urgent to reveal the distribution of braided channels and its influence on the remaining oil.Methods:Using the architectural element analysis method,the fine characterization is conducted for the thick sandbody configuration by integrating various data including cores;well logging and production performance data.Six fold hierarchy of the reservoir architectural surface is identified and the vertical and lateral recognition marks of the single sandbody boundary are established within the composite braided channels.The vertical marks include muddy lithologic interface and bottom erosion interface,the lateral marks include top surface elevation difference,difference of thickness,shape difference of well logging curve between different single sandbodies.Based on the single sandbody indentification,the distribution and configuration of thick sandbody between the wells are carried out to reveal the distribution characteristics of single braided channel sandbodies from composite braided channel.Then the statistical characteristic parameters of the single sand body configuration unit have analyzed.Result:Three main vertical contact styles between single sandbody architectural units are summarized as isolated type,overlap-type,overlay cutting type;and three main lateral contact styles as separated type,butt-joint type,side shear type.Moreover,the control effect of single sandbody on remaining oil is analyzed,showing that the internal rhythm of the fourth grade architectural unit and contact styles between architectural units have an important influence on the oil—water movement,which are the two important factors for enrichment of remaining oil.
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