准噶尔盆地呼图壁河侏罗系齐古组点坝砂体叠迁样式及演化特征

The lateral accretion styles and its evolution of point bar for the Qigu Formation of Jurassic in Junggar basin Toutunhe river

点坝砂体是我国重要的油气储集层之一。随着河道的迁移,点坝砂体内部构型具有复杂性和多变性,使得现代沉积和古代露头都难以完全完整定量表征。因此,常常需要结合现代沉积和古代露头,运用先进的辅助工具(如航拍、遥感影像等)和数学方法,对点坝砂体的分布和迁移过程进行表征。本文通过分析良好的野外露头并结合卫片,识别了准噶尔盆地南缘发育的侏罗系齐古组古代露头剖面上的点坝砂体,精细解剖了点坝的平面与剖面叠迁样式,并分别对扩张型、迁移型、扩张旋转型及迁移旋转型四种点坝砂体类型的平面结构表征参数(弯度、曲率及扩张系数)、剖面叠迁样式进行了分析,建立了点坝砂体叠迁模式。该研究对于油气开发具有现实的指导意义,为古河道重建和储层构型建模提供依据。

Point bar is one of the important reservoirs.With the migration of channel,the internal architecture of point bar are complexity and variability,which makes it difficult to completely and quantify describe by the modern sediment and ancient outcrops.Therefore,it makes combine modern sediment with ancient outcrops,and use to advance tools(aerial photo and remote sensing image)and mathematical method,and the distribution and migration process of point bar was characterized.In this paper,combine the ancient outcrop with aerial photo,the point bar for Qigu Formation of Jurassic in Junggar Basin was discriminated,the plan view and cross-section of lateral accretion styles were anatomized carefully.The parameters(S,C and E)of plan view,and the lateral accretion styles of cross section for the four kinds of point bar(expansion,migration,expansion with rotation and migration with rotation)were analyzed.The model of lateral accretion styles was established.The study has practical guiding significance for the hydrocarbon development,and suggest for reconstruction of ancient fluvial systems and reservoir models.