准噶尔盆地乌夏地区二叠系层序地层特征研究

Sequence stratigraphy characteristics of Permian in Wuxia Area, Junggar Basin

准噶尔盆地乌夏地区的构造、沉积、成藏等地质研究较早,并取得了很大进展,但对于该区层序地层学方面的研究却不成熟,且多集中于区块研究,层位也主要是侏罗系地层,因此,巨厚的二叠系地层进行深入细致的层序划分对于寻找隐蔽圈闭是十分有意义的。文中应用经典层序地层学原理和方法,通过在地震、钻(测)井等资料上寻找识别层序界面标志,综合运用井-震联合、联井格架层序分析等方法,建立了准噶尔盆地西北缘乌夏地区二叠系地层的层序划分方案。研究表明,该区二叠系共划分为3个二级层序,11个三级层序。研究区二叠系各层序的地层展布在平面上呈现一种早期退积、晚期进积的旋回,构造运动是地层发育特征的主要控制因素。

The structure, sedimentation and hydrocarbon migration and accumulation were early studied in Wuxia Area, Junggar Basin, and the great success was achieved. But the research on the sequence stratigraphy are immature, and it is limited only in some blocks and Jurassic strata. So the embedded sequence division of thick Permian strata is very significant for searching for the concealed traps in Junggar Basin＇s Wuxia Area. This paper utilizes the principle and method of classic sequence stratigraphy. Through the identification of sequence boundaries relating to the seismic and logging data, Permian sequence division＇s scheme are framed by the methods of log and seismic combined calibration, sequence analysis of well-tied framework in Wuxia Area of Junggar Basin. The Permian strata in Wuxia Area of Junggar Basin are divided into three second-order sequences and eleven three-order sequences. The Permian sequences present a cycle of early retrogradtional type and terminal progradational type. The tectonic movement is the most important controlling factor of development feature of the strata.