大民屯凹陷是在前古近系基底上发育的一个新生代富油气凹陷，截止2007年底已探明石油地质储量3.2亿t，其古近系是重要勘探目的层和产层。根据凹陷的构造演化史与地层、沉积发育特征，利用钻井取心、岩屑录井、测井和高分辨率的三维地震资料，将凹陷古近系划分为2个二级层序、7个三级层序。通过精确的速度分析及井震结合，建立了全凹陷古近系等时层序地层格架，并对层序发育的主控因素进行了探讨，认为构造沉降、沉积物供应、湖平面变化与气候等因素共同控制了大民屯凹陷层序的形成，其中构造沉降对层序形成起主要控制作用。高精度层序地层划分与等时格架建立对大民屯凹陷岩性油气藏研究与勘探具有十分重要的指导意义。
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Damintun Sag is a hydrocarbon rich Cenozoic sag developed on a pre Paleogene base, 0.32 billion tons petroleum were found till 2007. Paleogene is the main oil producing and target layers. According to the tectonic evolution and characteristics of strata and deposition in Damintun Sag, by using drilling cores, cutting logs, well logs and high resolution 3\|D seismic data, 2 second\|order sequences including 7 third order sequences were classified in the Paleogene System. By accurate velocity analysis and combination of well and seismic data, a synchronic stratigraphic sequence framework was established, and the main sequence controlling factors were discussed. Tectonic subsidence, supply of deposits, lake level fluctuation and climate were considered controlling the formation of sequences, and tectonic subsidence was the main factor. The high precision sequence classification and the foundation of the synchronic stratigraphic sequence framework are of great significance to the exploration and research of lithological reservoirs in Damintun Sag.
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