Seismic geomorphology and depositional evolution of the Paleogene Shahejie Formation, Central-North Dongying Depression, Bohai Bay Basin, China

Abstract

The main objective of this article is to demonstrate the utility of stratal slice images for exploring the sequence stratigraphy and sedimentology of complex depositional systems. The Dongying Depression is underlain by a productive, petroleum-prone, non-marine Cenozoic stratigraphic section. Here, we have integrated the recent 3D seismic profiles and borehole data to map sediment dispersal characteristics of the second member of the Shahejie Formation in the central-north Dongying Depression, located in the Bohai Bay Basin, China. We have documented the following key points: (i) the main strata under study were divided into two long-term sequence cycles (LSC1–2) with 14 middle-term sequence cycles (MSC1–14); (ii) five microfacies, distributary channel, inter-channel, mouth bar, underwater distributary channel, and tributary bay, were identified from well-based analysis of sedimentary facies; (iii) the mouth bar was generated at the center of the study area during the deposit stage of MSC6–7; (iv) the channel was distributed along the EW direction. The seismic sedimentological study on the second member of the Shahejie Formation in this study area highlights the distribution of the most important potential reservoirs.