吉尔嘎朗图凹陷宝饶洼槽下白垩统层序地层与沉积体系

运用高分辨率层序地层学原理和方法,通过对钻井和地震资料的综合分析,在二连盆地吉尔嘎朗图凹陷下白垩统中识别出1个超长期基准面旋回(二级层序)SSC1和5个长期基准面旋回(三级层序):LSC1,LSC2,LSC3,LSC4,LSC5,分析了各旋回的发育特征。识别出五种类型的沉积体系:滨浅湖近岸水下扇、较深水湖浊积扇、滨浅湖扇三角洲、滨浅湖辫状河三角洲和河流沉积体系,并在等时地层格架内分析了各基准面旋回的沉积体系构成和储层砂体的发育情况。综合分析生、诸、盖条件后认为,在垂向上,LSC3旋回为本区最有利的储集层段,在平面上,本区的油气勘探应主要寻找宝饶构造带辫状河三角洲前缘砂体,主要储层砂体类型为前缘分流水道砂和前缘席状砂。

Sequence Stratigraphy and Depositional System of Lower Cretaecous Series in Baorao Trough, Jiergalangtu Sag

One super-term stratigraphic base level circle(the 2nd sequence) and the corresponding 5 long-term stratigraphic base level circles(the 3rd sequence) could be distinguished in lower Cretaceous series in Jiergalangtu sag,Erlian basin by using the ways and principles of the high resolution sequence stratigraphy.The long term stratigraphic base level circles could be described as LSC1,LSC2,LSC3,LSC4,LSC5 and their developed characters are analyzes in this paper.Within the correlation framework of the sag,five type depositional systems are identified,namely shallow lakenear bank submarine fan,relatively deep waterturbidite fan,shallow lakefan delta,shallow lakebraided river delta and fluvial depositional systems and it analyzed the consist of the depositional system and reservoir rock development in the cycles.It pointes out after the integrate analysis that LSC3 cycle is the most favorable segment of the reservoir rock in the uprightness,and the rock of the front of the braided river delta in the Baorao tectonic zone is the target of the oil exploration,the major reservoir rock types are in the facies of the subrivers and sand sheet.