吐哈盆地台北凹陷侏罗系储层砂体发育及其岩石学特征

根据薄片、扫描电镜和X-衍射等测试资料以及砂岩厚度统计,分析了吐哈盆地台北凹陷侏罗系储层砂体发育及其岩石学特征。研究区发育辫状河三角洲、扇三角洲和滨浅湖滩砂3种储集砂体,受控于南、北两大物源体系。储集岩主要是岩屑砂岩类,岩屑含量高,陆源杂基多,成分与结构成熟度均较低,但南、北物源砂体储集岩特征有明显差异。北物源主要是扇三角洲砂体,岩屑砂岩,储集性能差,属低-特低孔、低-特低渗型储集层;南物源主要是辫状河三角洲砂体,长石岩屑砂岩,储集性能较好,以低孔、低渗型储集层为主,部分中孔、中渗型储层。碎屑岩储层岩石学特征与储集性能关系密切,结合砂体发育对其研究,对寻找有利储集体具有重要意义。

Sandstone-bodies and their petrology characteristics of Jurassic reservoirs in Taibei depression of Turupan-Hami basin

According to the testing data of thin section, SEM and X-ray diffraction etc, as well as the statistic data of sandstone thickness, the sandstone bodies and their petrology characteristics of Jurassic reservoirs in Taibei depression of Turupan-Hami basin have been studied. There are three kinds of reservoir sandstone bodies in the study area, which are braid river delta, fan delta and shore-shallow lake. All the sandstone bodies are controlled by two primary provenance systems from south and north. The reservoir rocks are primarily litharenite and feldspathic litharenite, which possess much rock fragments and prevalent terrigenous matrix. The composition and structure maturity are both lower. But there are distinctive differences between the two reservoirs from the north and the south. The former are primarily litharenite of fan delta, which present poorly reservoir ability. The latter are primarily feldspathic litharenite of braid river delta, which present relatively well reservoir ability. There are close relation between the petrology characteristics and reservoir ability of reservoir rocks. It is very significance to find availing reservoir sandstone bodies for studying sandstone bodies and their petrology characteristics.