松辽盆地北部西斜坡青山口组四级层序划分及变化特征分析

Fourth-order sequence division and its variation in Qingshankou Formation of the west slope, the northern Songliao basin

从地层沉积时期地形变化、湖平面变化、物源供应及气候变化等地质条件分析入手,辅以高分辨率地震解释成果,通过单井四级层序界面的岩性、电性特征分析和化石带确定,将松辽盆地北部西斜坡青山口组划分为5个四级层序,分别与高台子油层和葡萄花油层的砂组相对应。对研究区青山口组四级层序的分布特征以及四级层序内沉积体系平面变化与油气分布的关系进行了分析,以期为在研究区青山口组四级层序格架中确定沉积体系分布和寻找地层-岩性圈闭提供依据。

Several geological factors during Qingshankou Formation deposition are first analyzed, such as landform, lacustrine level, provenance and climate, and the lithologic and electric features of fourth-order sequence boundary in the Formation and the associated fossil zones are determined in single wells by the assistance from seismic interpretation results with high resolution. Finally, five fourth-order sequences are divided in Qingshankou Formation of the west slope, the northern Songliao basin, and can be correlated with different sand units in G and P oil pays respectively. Furthermore, the fourth-order sequences distribution and the relationship between their areal changes and hydrocarbon distribution are analyzed in the study area, in order to provide bases for researching depositional systems and looking for stratigraphic-lithologic traps in the Formation.