Reservoir-forming characteristics of inner buried hills in Jizhong Depression, Bohai Bay Basin

The reservoir-forming characteristics of inner buried hills in the Jizhong Depression of the Bohai Bay Basin were studied based on seismic, well drilling and logging data as well as exploration practice. The results show that source rocks, reservoir-cap rock association and hydrocarbon migration pathways together controlled the formation of inner buried hill reservoirs. Two reservoir-forming patterns (related to unconformity and fault, respectively) and six reservoir types (layers along slope, blocks along slope, layers against slope, blocks in residual hill, blocks along fault wall and layers along fault wall) generated in the study area. Explorations should be focused on the deep inner traps in the central uplift belt, and the inner traps of the eastern slope belt and the western fault-step belt.