The Sedimentary System Of Es₁ Member In Shahejie Formation Of Paleogene In Dongxin Area, Eastern Central Uplift Belt Of Dongying Depression

Based on the tectonic setting of the study area, the analysis of seismic, core, well logging as well as analysis and test data, by using the theory of classic sequence stratigraphy, seismic stratigraphy, sedimentology and logging geology, this paper studies the sedimentary system of the Es1 formation of the Dongxin area in Dongying depression, and the regional sequence framework is established. Then the typies, sedimentatary features, vertical evolution, plane distribution and controlling factors of the sedimentary are analyzed, and establishing the depositional model. The main achievements are as follows:On the base of Vail classic sequence stratigraphy principles and related methods, the Es1 formation of the Dongxin area in the eastern central uplift belt of Dongying depression is devided into two systems tracts(transgressive systems tract and highstand systems tract), and further subdivided into five parasequence sets. And regional sequence stratigraphic framework is established.According to the lithology, sedimentary structures and logging response characteristics,the depositional environment of the Es1 is concluded as shoreland and shallow lake and the main subfacies are identified as braided river delta- beach bar. including the braided river delta front and the shoreland. And further divided into underwater braided river channel, mouth bar, sheet sand, underwater braided interchannel, beach bar, biodetritus beach, shoreland and shallow lake mud and other sedimentary microfacies.Comprehensive comparision and analysis of core, logging data and so on, and the main characteristics of the major sedimentary facies are summarized. The correlation of rock – electric logging of the main sedimentary microfacies of the Es1 formation is established.Using the point-line-plane idea, the characteristics of vertical evolution and plane distribution of the sedimentary system are concluded. The braided river delta-beach bar sedimentary system is developed in the Es1 formation of the Dongxin area, developing south and north two major provenances.In this paper, the controlling factors that the paleoclimate, provenance, palaeogeomorphology and so on have been analyzed in detail. The system of ‘paleoclimate-provenance-basin’ controlling beach-bar model of the Dongxin area in the central uplift belt of Dongying depression is established.There are three main reasons of the development of beach-bar in Dongxin area which is unconventional shoreland and shallow lake environment: the Xinzhen anticline and dome structure developed in the eastern central uplift belt provide favorable geographical conditions for beach-bar; During the period of deposition of Es1, study area influenced by level 4 of southeast wind and level 5 of north wind which is the favorable wind force in the formation of beach-bar; The enough sources supplied by the thick sandstone deposited in lowstand system tract and the braided river delta in the north.