Abstract: According to many core observation, thin section identification and X-ray diffraction, lithofacies of fine-grained sedimentary rocks in upper Es4 to lower Es3 in Dongying Depression can be divided into 8 main lithofacies based on rock constituents, sedimentary structure, TOC and carbonate crystal structure: organic-rich laminated cryptocrystalline argillaceous limestone facies, organic-rich laminated microcrystalline argillaceous limestone facies, organic-rich laminated calcareous mudstone facies, organic-rich layered argillaceous limestone facies, organic-rich layered calcareous mudstone facies, organic-rich massive calcareous mudstone facies, organic layered calcareous mudstone facies, organic layered gypsum mudstone facies. We first reconstructed of the ancient environment of climant, salinity, water depth and oxidation and reduction of water bodies on the basis of geochemical elements, then fine-grained sedimentary rock lithofacies assemblage characteristics and origin of different depositional environment was determined. On this basis, fine-grained sedimentary rock sedimentary model of upper Es4 to lower Es3 in Dongying Depression was built. The study is of guideance value for shale oil exploration.

Key words: fine-grained sedimentary rock, depositional environment, lithofacies assemblage characteristics, sedimentary model, Dongying Depression