扇三角洲前缘储层构型及其控油作用——以赵凹油田赵凹区块核桃园组三段Ⅳ3~1厚油层为例

Reservoir architecture of fan delta front and its oil-control models:a case of Eh_3Ⅳ3~1 reservoir in Zhaowa block of Zhaowa Oilfield,Biyang Depression

为了揭示扇三角洲前缘厚层砂体内部复杂结构特征,明确其对开发过程中油水运动的控制作用,以储层构型分析为指导,利用岩心、测井以及生产动态资料,在构型级次识别和划分的基础上,对赵凹油田赵凹区块核桃园组三段Ⅳ3砂层组扇三角洲前缘构型及其控油机理进行了研究。结果表明:研究区发育3类夹层,即泥质夹层、钙质夹层和泥质砂砾岩夹层;将核桃园组三段Ⅳ3~1厚油层划分为7个5级构型单元;在5级构型单元等时地层格架内,根据单一水下分流河道(或河口坝)的定性、定量识别标准,确定出4级构型单元的规模、空间形态及平面展布规律;建立了基于4级构型的3类储层构型控油模式,其中纵向相变和横向相变控油模式下的剩余油主要分布于水下分流河道中上部和非河道低渗相带内,构型单元内不稳定夹层控油模式下的剩余油主要富集在夹层下部。本次研究对改善油田开发效果具有重要意义。

In order to reveal the architecture characteristics of fan delta front reservoir and its control effects onthe migration of oil and water,the data of core,well logs and production,were used to analyze the reservoir architectureand its controls on the remaining oil of Eh3Ⅳ31in Zhaowa block based on the theory of fluvial facies reservoirarchitecture.The results show that the Eh3Ⅳ31reservoir was divided into seven fifth-level architectural unitswhich were separated by muddy interbed,calcitc-cement interbed and muddy sandy-conglomerate interbed.Accordingto the qualitative and quantitative identification criteria of single subaqueous distributary channel or bar,the size,spatial morphology and distribution of the fifth-level architectural unit were defined under the isochronousstratigraphic framework of the fifth-level architectural unit.There are three kinds of oil-control models.Theresidual oil under the longitudinal and lateral facies-change oil-control models is mainly distributed in the middleand upper part of the subaqueous distributary channel and low permeability zone of non-channels,while the residual oil under the unstable interbed oil-control model is mainly distributed in the lower part of the interbed.This studyis of great significance to improve the oilfield development effect.