关键词: 层序格架, 基准面旋回, 储层, 延长组

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