中文摘要：

运用层序地层学理论分析了梨树断陷七棵树地区层序地层学特征。将七棵树地区沙河子组一营城组划分为3个三级层序和6个体系域，建立了层序地层格架。七棵树地区隐蔽油气藏成藏要素与层序地层格架有着密切的关系，湖侵体系域至高位体系域的转换时期是优质烃源岩发育的时期，湖侵体系域的早期和高位体系域的晚期是砂体发育的时期，三级层序界面与层序界面附近的砂体是油气运移的良好通道。与长期活动的断层一起构成了七棵树地区复杂的油气运移输导体系。七棵树地区发育砂岩透镜体油气藏和砂岩上倾尖灭油气藏2种隐蔽油气藏类型，不同类型的隐蔽油气藏在层序格架中出现的位置是可以预测的。其中砂岩透镜体油气藏主要发育在各层序旋回的中部，砂岩上倾尖灭油气藏多分布在基准面上升半旋回和基准面下降半旋回的中部。以SWll井区油藏为例，简要分析了层序地层学在隐蔽油气藏勘探中的应用。

英文摘要：

Sequence stratigraphic analysis was applied to divide the Shahezi Formation-Yingcheng Forma- tion of the Qikeshu area into three third-order sequences and six system tracts, and build up a sequence stratigraphic framework for the Qikeshu area. There is a close relationship between the sequence strati- graphic framework and the petroleum deposits of the subtle oil-gas reservoirs in the Qikeshu area. The transition point from the transgressive system tract to the high sea level is the location for development of hydrocarbon source rocks. The lower part of the transgressive system tract and the upper part of the high sea level tract are the development locations of sandstone. The third-order sequence boundary and the sand body near the boundaries are good pathways for hydrocarbon migration, which constitutes the complex hy- drocarbon migration system in combination with the long-term active fault systems. There are two kinds of subtle oil-gas reservoirs in the Qikeshu area. The location and appearance of these reservoirs in the se- quence framework may be predicted. Sandstone lens oil and gas reservoirs are mainly developed in the mid- dle of each sequence cycle, sandstone up-dip pinch out oil and gas reservoir are located more-often in rising half-cycles and the center of dropping half-cycles of the base level cycle. The oil reservoir of well SWll is discussed as an example to briefly illuminate the sequence stratigraphic analysis applied to the exploration for subtle oil-gas reservoirs.