南图尔盖盆地萨雷布拉克地区侏罗系沉积层序及地层不整合圈闭

南图尔盖盆地是重要的油气探区，受区域构造的影响，侏罗系沉积层序的发育演化与构造活动密切相关，研究区尚未勘探的有利构造圈闭逐渐减少，岩性-地层油气藏已经成为重要的勘探目标。 为此，在对地震、测井及岩心等资料综合分析的基础上，通过构造演化分析、层序地层格架建立以及沉积相分析，对南图尔盖盆地 A 探区萨雷布拉克地区侏罗系沉积层序特征及有利地层不整合圈闭进行了研究。 结果表明：①萨雷布拉克地区在侏罗纪和白垩纪时期经历了 3 次较为明显的构造运动，可将其构造演化划分为 3 个阶段，即断陷期、断-坳转换期及坳陷期，形成了 3 个二级层序，并在其层序格架内将侏罗系划分为 7 个三级层序，每个三级层序中可划分出 2～3 个体系域；②早侏罗世断陷期（SQ1，SQ2）主要发育湖泊及辫状河三角洲沉积体系，中侏罗世断-坳转换期（SQ3，SQ4）主要发育湖泊及三角洲沉积体系，晚侏罗世坳陷期（SQ5，SQ6，SQ7）主要发育湖泊、三角洲及河流沉积体系；③侏罗系有利的地层不整合圈闭主要为 SQ1 和 SQ2 与上覆地层形成的地层削蚀不整合圈闭，以及 SQ5 与下伏地层形成的地层超覆不整合圈闭。

Sedimentary sequence and stratigraphic unconformity trap of Jurassic in Sarybulak area,South Turgai Basin

The South Turgai Basin in kazakhstan is an important hydrocarbon prospect area, and influenced by the regional structure, the development evolution of Jurassic sedimentary sequence is closely related with tectonic evolution. Because the unexplored favorable structural traps gradually reduced in the study area, the lithostratigraphic reservoirs become an important exploration target. Based on comprehensively analysis of seismic, well logging and core data, through tectonic evolution analysis, establishing sequence stratigraphic framework and sedimentary facies analysis, this paper studied the characteristics of sedimentary sequence and stratigraphic unconformity trap of Jurassic in Sarybulak of A prospect area, South Turgai Basin. The results show that: ①The Jurassic and Cretaceous in the A prospect area experienced three times of large tectonic movements, and formed three second-order sequences. In those second-order sequence stratigraphic frameworks, the target formations of Jurassic can be divided into seven third-order sequences, and each third-order sequence can be subdivided into two to three systems tracts. ②Lacustrine and braided delta sedimentary systems mainly developed in early Jurassic fault depression stage（SQ1 and SQ2）, lacustrine and delta sedimentary systems mainly developed in Middle Jurassic fault-depression transform stage（SQ3 and SQ4）, and lacustrine, delta and fluvial sedimentary systems mainly developed in Late Jurassic depression stage（SQ5，SQ6 and SQ7）. ③The favorable stratigraphic unconformity traps mainly include two types: stratigraphic erosion unconformity traps formed by SQ1, SQ2 and the overlying strata, and stratigraphic onlap unconformity trap formed by SQ5 and the underlying strata.