鄂尔多斯盆地演武地区中侏罗统直罗组沉积相

摘要

为查明鄂尔多斯盆地西南部演武地区中侏罗统直罗组沉积相及砂体发育分布规律,在露头剖面实测、钻井岩心观察、测井资料解释和薄片鉴定的基础上,对直罗组进行了小层划分对比和沉积相分析,提出了小层划分方案,确立了沉积相类型及优势相划分标准,编制了岩相古地理图,建立了直罗组由辫状河-辫状河三角洲转变为曲流河三角洲沉积环境的沉积演化模式.基于精细小层划分的沉积相研究揭示了直罗组砂体发育的优势相带分布及变迁,是潜在的油气储层和砂岩铀矿发育的新层系.%Based on the analyses of outcrop section measurement,drilling core observation,logging data interpretation and thin section identification,stratigraphic correlation and sedimentary facies analysis,the distribution of sedimentary facies and sand bodies in the Middle Jurassic Zhiluo Formation in the southwestern Ordos Basin are studied.The subdivision of the 4th and 8th Member of the Middle Jurassic Zhiluo Formation in the Ordos Basin is proposed,and the classification of sedimentary facies and dominant phase of the Zhiluo Formation are established.The sedimentary evolution model of the 8th sub-sections of Zhiluo Formation in Yanwu area is characterized by the sedimentary environments of braided river-braided river delta to the meandering river delta.This study has unraveled the distribution and change of dominant facies belt of the Zhiluo Formation sand bodies,and proved that the Zhiluo Formation sand bodies are potential targets for oil and gas reservoir and sandstone uranium deposit.