Abstract:

This paper utilizes the basic theory and study methods of High resolution sequence stratigraphy, and divides Yanchang Formation into 5 long-term base level cycle and 23 middle-term level cycles, based on outcrop, drilling core data and spectral analysis of logging. The sequence stratigraphic framework of Yanchang Formation on basis of cross-well profile is constructed, which demonstrates that the development and distribution of reservoir has been apparently controlled by the A/S and boundary of sequence stratigraphy of Yanchang Formation according to the relationship between sequence constitution and reservoir. Sandstone reservoirs with relatively good properties occurred mainly in the early stage of the ascending long baselevel cycle and the late stage of the descending middle base-level cycle, and that interface of longterm base level cycle and middleterm level cycles, such as MSC5, MSC10, MSC15 and MSC21, sour fluids migrating along interface, forming induced porosity.  The study will play an important role in petroleum exploration and exploitation.

Key words: sequence framework, baselevel cycle, reservoir, Yanchang formation

摘要：

采用高分辨率层序地层学的基本理论和研究方法，结合露头剖面、岩心资料及测井曲线频谱分析，共识别出5个长期层序、23个中期层序旋回；通过层序地层与储层的关系研究,认为A/S比值及层序界面对储层的空间展布和物性变化具有明显的控制作用，最有利的储层发育位置出现在长期基准面上升早期和下降晚期，特别是中期和长期两个级次基准面相互重叠的界面两侧，酸性孔隙流体沿着界面运移，有利于形成次生孔隙。该项研究成果为进一步的油气勘探和开发提供了依据。

关键词: 层序格架, 基准面旋回, 储层, 延长组