SEQUENCE STRATIGRAPHY AND SEDIMENTARY SYSTEM OF THE UPPER Es4 IN THE HUIMIN DEPRESSION,SHANDONG

The Upper Submember of the 4th Member of the Shahejie Formation in Huimin Depression represents one third-order sequence according to sequence stratigraphic analysis based on well log and seismic reflective data.Lowstand,lacustrine transgressive and highstand systems tracts can be recognized based on the stacking patterns and changes of lithology and lithofacies.The sequence stratigraphic correlation of well-tie sections made it possible to construct the regional stratigraphic framework.Fan delta,near-shore underwater fans,turbidite fan delta,beach bar and lake sedimentary system facies can be identified using core,drilling,logging,and paleontological data.The sedimentary mode of these structural zones is established.The architecture,evolution,distribution of sedimentary facies of the upper Es_4 in Huimin Depression are analyzed,The favorable sedimentary facies is predicted,These results have great significance in the identification of subtle traps in this depression.