Characteristics and significance of Dongying Formation incised valley in Gaoshangpu area, Nanpu Sag

Through overall analyzing seismic reflection characteristics, deposition, sequence stratigraphy and structural background, an incised valley deposit is recognized in Dongying Formation in Gaoshangpu area, Nanpu Sag. Formed on a fault slope break of the basin steep slope side, this incised valley is characterized by U-shape on seismic sections with obviously uncoordinated events. And the valley consists of mainly coarse clastics. The rapid lake level falling and faults were key factors to control the incised valley formation. Close to the source faults, Gaoshangpu incised valley was cut off by an antithetic fault in the updip direction, which provides favorable conditions for the hydrocarbon enrichment. Reservoirs associating with the valley include overlap unconformable reservoir, faulted-lithologic composite reservoir and sand lens reservoir. This incised valley has important significance in sequence boundary identification, formation correlation and reservoir prediction in Gaoshangpu area, Nanpu Sag.