Development of buried hills of the eastern Zhanhua subbasin, Jiyang depression, northern Shandong, China and controlling factors of the formation of petroleum accumulations

Based on the characteristics of the development and evolution of main faults and balanced cross sections and extensional rates of the main seismic profiles, the development of berried hills and its relationship with basin evolution in the east of the Zhanhua subbasin were studied and the controlling factors of the formation of buried hill oil-gas accumulations were analyzed. The development of the berried hills in the study area experienced the early stage of Early-Mid Triassic, Late Triassic and Early-Mid Jurassic development of buried hills, the stage of Late Jurassic to Cretaceous development of buried hills, the stage of Paleocene reworking and finalization of buried hills and the stage of Neogene to Quaternary reservoir formation of buried oilgas accumulations. The activity of faults was the main controlling factor for the formation and evolution of buried hills. The formation of buried hill oil-gas accumulations in the east of the Zhanhua subbasin was mainly controlled by the superposition of Meso-Cenozoic basins in the area. The site of superposition of the Mesozoic uplift and Paleogene subbasin is most favorable for the formation of buried hill accumulations, while the site of superposition of the Mesozoic uplift and Paleogene subbasin is unfavorable for the formation of buried hill accumulations, where buried hill drape anticlinal traps usually formed.