孔店油田馆陶组辫状河储层构型及剩余油分布规律

Reservoir Architecture and Remaining Oil Distribution in Braided River of Guantao Formation,Kongdian Oilfield

孔店油田新近系馆陶组是该油田的重要储层,发育河流相沉积。其河流相砂体展布特征及连通关系复杂,导致注水开发过程中存在复杂的油水关系,进而控制剩余油的形成和分布。本文从储层构型的角度,综合应用测井、岩心等资料,确定了研究区馆三段沉积类型并建立了沉积模式;然后对储层构型进行精细刻画,对构型控制下的剩余油分布特征进行分析,总结了研究区剩余油的分布规律。研究认为:孔店油田馆三段为辫状河沉积体系,发育辫状河道、心滩、堤岸等主要构型要素。心滩是辫状河体系中最重要的油气富集单元,注水开发会影响并改变心滩内部剩余油分布形式;其内部发育泥质、钙质和物性3种类型的落淤层,平面上心滩可分为滩头、滩主体、滩尾和滩翼4个部分。其中:滩头落淤层保存较差;滩主体落淤层发育较好呈近水平产状;滩尾落淤层保存较好呈低角度倾斜状;滩翼落淤层受坡度影响,坡度较小则落淤层易被水流冲刷保存较差,坡度较大则底部落淤层保存较差但中上部落淤层可完整保存。解剖区心滩分析认为剩余油主要集中在落淤层发育较差滩左翼中部和落淤层遮挡作用明显的滩尾部。

The Guantao Formation（Neogene）is the most important reservoir in the Kongdian oilfield with fluvial facies developed.The complex distribution characteristics and connectivity of the fluvial sand bodies cause a complex relationship between oil and water in the process of water flooding,and which,in turn,control the formation and distribution of the remaining oil.Through the detailed study of the core and logging data,the sedimentary model of the GuantaoⅢ Member in the study areawas determined,and a detailed characterization of the reservoir architecture was completed.On the analysis of the reservoir architecture characteristics,the distribution types of remaining oil were summarized.The authors believe that the third member of Guantao Formation is a braided river with the elements of braided channel,central bar,and levee developed.The central bar is the most important oil and gas enrichment unit in the braided river sediments,and the distribution form of remaining oil can be influenced by water injection.Three types of the silting layers of muddy,calcium and silty exist in the strata.The central bar can be divided into four parts including bar head,bar main part,bar tail,and bar limbs.The silting layer in bar head is poorly preserved;The silting layer in bar main part is preserved relatively complete in a nearly horizontal shape;The silting layer with a low angle in bar tail is preserved relatively well;The silting layer in bar limb is influenced by slope,preserved well in a steepslope but poor in a gentle slope.The remaining oil in a central bar of anatomy area is mainly concentrated in the middle part of the left bar limb and the bar tail that is blocked by a silting layer.