东营凹陷第三纪层序地层格架及沉积体系类型

根据钻井岩心、录井资料、测井曲线及三维地震反射特征，以层序地层学和沉积体系分析为指导，建立了东营凹陷第三纪充填序列和层序地层格架。凹陷充填可分为下第三系的张扭断陷充填和上第三系的压扭拗陷充填。前者可进一步分为初始沉降、加速沉降和湖盆萎缩３个阶段。东营凹陷层序地层格架由２个构造层序、５个超层序组成，其中下第三系可进一步划分为６个层序。第三系主要发育６种沉积体系；识别出３种不同于被动大陆边缘盆地的体系域，包括冲积体系域、扩展体系域和萎缩体系域。沉积体系、体系域的时空展布与凹陷的构造演化阶段和凹陷的边界条件密切相关。

TERTIARY SEQUENCE STRATIGRAPHIC FRAMEWORK AND SEDIMENTARY SYSTEM TYPES IN DONGYING DEPRESSION

Based upon the data of drilling core, logs and the characteristics of 3D seismic reflection, the Tertiary sequence stratigraphic framework and filling order have been set up in Dongying depression according to sequence stratigraphy and sedimentary system analyses. The evolution of the depression can be divided into two periods: Lower Tertiary tenso shear stress faulted stage and Upper Tertiary compression shear subsidence stage. The first period can be further subdivided into three stages of initial subsidence, accelerating subsidence and lacustrine contract. The sequence stratigraphic framework consists of two tectonic sequences and four supersequences. Six types of sedimentary system developed in Tertiary. Three types of system tract are identified which are much different from the ones developed on the passive continental margin basin. There are alluvial system tract(AST), extension system tract(EST)and contraction system tract(CST). The spatial distribution of the sedimentary systems and system tracts are closely related to the tectonic evolution and the boundary statutes of the sag.