High-resolution sequence stratigraphic framework of the Upper Submember of the Fourth Member of the Shahejie Formation on the southern slope of the Dongying subbasin, northern Shandong, China

High-resolution sequence stratigraphic classification and correlation are made for the Upper Submember of the Fourth Member of the Shahejie Formation on the southern slope of the Dongying subbasin, northern Shandong, based on the theories of high-resolution sequence stratigraphy and sedimentology and an analysis of well log data and seismic information, and summarizes the mariners for recognition of various sequence stratigraphic units and their boundaries in well logs and seismic data. The base-level cycle in the study area is divided into the short-term, medium-term and long-term cyclic sequences. The Upper Submember of the whole Fourth Member of the Shahejie Formation is composed of a long-term base-level cycle, which is subdivided into five medium-term base-level cycles. The authors have for the first time estabhshed the high-resolution sequence stratigraphic framework of the submember. All these studies are conducive to intensive geological studies such as the sedimentary microfacies study and detailed description of reservoir structure in this submember on the southern slope of the Dongying subbasin.