三叠盆地三叠系Tagi组沉积相分析

Sedimentary Facies Features of Tagi Formation in Triassic,Triassic Basin

三叠盆地位于非洲中北部,主要储层为三叠系Tagi组,主要由一套细砂-粉砂岩与泥岩互层组成。根据对研究区取心井的观察和描述,并依据岩石颜色、岩石结构和沉积构造等一系列沉积相标志,对三叠盆地三叠系Tagi组沉积相进行了研究。研究结果表明,Tagi组沉积环境为曲流河沉积,可进一步划分出2个亚相和5个沉积微相,其中河道亚相包括河床滞留微相和边滩微相,漫滩亚相包括天然堤微相、决口扇微相和泛滥平原微相;研究区Tagi组曲流河在平面上呈NE-SW向延伸,并形成数千米宽的边滩砂体,连续性较好,有利于储层的发育和形成岩性油气藏。

Trassic Basin is located in the Northen Africa,the main reservoir is Triassic Tagi Formation,According to the observation and description of the cored well,Tagi Formation is mainly consisted of the fine-silty sands and silty mudstone interbeds.Based on a series of the facies indicators such as colors,rock textures and sedimentary structures,it determines that the depositional environment of Tagi Formation is meandering river deposition.And it can be further divided into 2 types of depositional sub-facies and 5 types of depositional micro-facies,river channel sub-facies include channel lag and point bar micro-facies,and floodplain sub-facies can be divided into natural levee,crevasse splay and bed lands micro-facies.On the plane,the meandering river extends from NW to SE and forms the point bar of thousands of meters wide,it is beneficial to develop the lithologic reservoirs.