黄河口凹陷古近系东营组沉积层序格架与油气聚集

Sedimentary sequence framework and hydrocarbon accumulation in Paleogene Dongying Formation,Huanghekou sag

综合利用钻井、测井、岩心资料,在黄河口凹陷古近系东营组中识别出了5个三级层序界面,将东营组划分为SQ1、SQ2、SQ3、SQ4等4个三级层序,分别对应于东一段、东二上亚段、东二下亚段和东三段。探讨了东营组层序格架内沉积体系展布特征及控制因素,认为SQ4层序主要受构造控制,湖盆边缘富砂,为东营组最有利勘探层位;SQ3层序受气候及湖侵影响,主要为泥质沉积,为区域盖层及烃源岩层之一;SQ1和SQ2层序主要受陆源物质供给影响,发育三角洲相砂体,在一定条件下可以富集油气。

By comprehensively using the drilling,logging and core data,five sequence boundaries are recognized in Paleogene Dongying Formation（E3d,）,Huanghekou sag,and therefore this Formation can be divided into four third-order sequences,i.e.SQ1,SQ2,SQ3 and SQ4,corresponding to the interval E3d1,E3d2L,E3d2U and E3d3 respectively.The distribution of sedimentary systems and its controls are discussed within the sequence framework of Dongying Formation,by which it has been considered that the sequences SQ1,controlled mainly by structure,may be the most favourable interval for exploration due to its high sand content along the lake margin.The sequence SQ3 is dominated by argillaceous sediments due to the climate and lake transgression,and may serve as one of the regional source rocks and seals.The main control on SQ1 and SQ2 may be the supply of terrigenous sediments,and they can contain hydrocarbon accumulations under some conditions,due to their development of deltaic sandbodies.