Sequence stratigraphy characteristics and sedimentary model of Lower Es_4 on the south slope of Dongying Depression

In recent years,the south slope of Dongying Depression has become the focus of the exploration target.Due to its special stratigraphic formation,the study of sequence stratigraphy and sand origin of the study area is relatively weak.Using V-C formation analysis,the authors have divided the study area into two sequences on the basis of sequence boundaries,well logging curve,seismic reflective characteristics and palaeontological features.The sequence can be subdivided into two mid-cycles according to the stacking patterns of stratigraphy as well as changes of lithology and lithofacies.The sequence stratigraphic correlation in well-tied sections makes it possible to construct the regional stratigraphic framework.Due to the tilting of Shicun fault,the eastern part of the study area has been denuded.Alluvial fan and saltwater lake are developed in the study area.The evolution and distribution of sedimentary faces of lower Es4 on the south slope of Dongying depression is analyzed for the first time in this paper,and the sedimentary model is established.These research results have great significance in search for subtle traps in this depression.