松南西斜坡前缘带青山口组层序界面识别及特征研究

在前人研究的基础上,应用高分辨层序地层学理论与研究方法,对松辽盆地南部西斜坡地区的青山口组地层进行了层序地层划分与对比工作,从中识别出6个具等时意义的层序界面,将其划分为5个中期基准面旋回(4级层序)。建立了层序界面的岩心识别标志,即旋回叠加样式的变化面、岩性突变面—冲刷面、相类型的变化面和暴露剥蚀面,在测井曲线上,层序界面位于测井曲线幅度发生明显变化或曲线组合型式的转换处,在研究区地震剖面上的层序界面识别标志(超削反射终止特征)不明显。根据层序划分和层序界面的识别标志,把4级层序界面划分为不整合面、沉积作用转换面和顶超面,并对层序界面特征进行了详细研究。确定了研究层段湖泛面包括三角洲体系—湖泛面、深水湖—浊积体系—湖泛面和河流体系—洪泛面3种类型。层序界面和湖泛面的识别和确定,对于研究区高分辨率层序地层格架的建立和对储层分布规律的研究与预测具有重要意义。

Recognition of sequence boundary and its characteristics study in Qingshankou Formation of front zone of the west slope in southern Songliao Basin

Guided with the theory of high resolution sequence stratigraphy and based on previous research results,we constructed sequence stratigraphic scheme of Qingshankou Formation which was in front zone of the west slope in southern Songliao Basin,where six sequence boundary surfaces were identified and 5 medium-term base-level cycles(fourth order sequence)were divided. Core identification marks of the surfaces were established,that is,channel scouring surfaces,formation stacking transformation,changes of facies type,exposure erosion surface. The sequence boundary existed in which abrupt changes of amplitude happened or in conversion point of composite forms on logging curve,and the identification marks of seismic profile were not apparent in this area. According to the identification marks,the sequence boundary surfaces were divided into unconformity surface,depositional turnaround surface and toplap surface,and a detailed analysis was given to their characteristics. Flooding surfaces in Qingshankou Formation included fluvial deposits,delta and deep lake facies. Identification of the sequence boundaries and the flooding surfaces was very significant for building framework of the sequence stratigraphy and researching the distribution and prediction of reservoir.