Sequence Stratigraphy And Sedimentary Systems In Upper Shasi Member Of Eastern Dongying Depression

Under the guide of Vail sequence stratigraphic theory, and through the combination of seismic data, well logging data, drilling cores and other related analyzed data and experimental technique, in upper Shasi member of eastern Dongying depression, there is established the sequence stratigraphy framework which is divided into one third-order sequences. The boundary of the low-stand systems tract and transgressive systems tract is T7. Chunxia is the low-stand systems tract which can be divieded into three prograded parasequence sets. Chunshang is the transgressive systems tract which is divided into two retrograded parasequence sets and high-stand systems tract which is divided into a prograded parasequence set and an aggradated parasequence set.Based on analysis of core , drilling core well facies, single well facies multidisciplinary analysis, profile facies and plane facies, referring to modern sedimentology theory,this paper comprehensively studies sedimentary microfacies in upper Shasi member of eastern Dongying depression. Delta, lacustrine facies are developed in upper Shasi member. It is further divided into beach and bar, delta front, storm beach-bar, shallow lake, semi-deep lake to deep lake. Different facies models are established in the region of interest. The source in upper Shasi member of Eastern of Dongying depression is from south and north. Delta developed in south area. When the source is poorly shallow beach and bar developed. Storm beach-bar and turbidite developed in north area. The depositional system is controlled by many factors, such as structure, source, variation of lake level, palaeogeomorphology, hydrodynamic force, geologic climate, and so on.Beach-bar is divided into bar and beach through lithologic association, sedimentary structure, geometry of sandstone body. The beach-bar is controlled by hydrodynamic force, source-hydrodynamic force and storm wave. The formation and distribution of beach-bar is researched by many controlling factors, such as structure, palaeo-warter depth, the interface of sequence, paleoshoreline and the association with other depositional systems.