Abstract: To understand the distribution characteristics of less-explored granite buried hill reservoirs, based on the geological models and the effective grey energy to delineate weathering crust of granites, this paper describes the scope and thickness and analyzes the influences of tectonic activities, weathering leaching and paleogeothermal changes on the accumulation model and distribution of high quality granite reservoirs in the western segment of the Shaleitian bulge, the Bohai Sea. Finally, this paper proposes a reservoir prediction method combining geological genesis with geophysics. Application of this method in the study area shows that:1) high content of brittle minerals, such as feldspar, in the granite buried hill, provides the foundation for the development of high quality reservoir; 2) the displacement of fault walls induced the development of induced fractures, the tensile force of folded ridges promoted the development of high-dip fractures, and the temperature and pressure changes caused by structural uplifting controlled the development of nearly horizontal fractures; and 3) in the southwest margin of the study area, superposition of fractures of three types brought extremely developed fractures, and this zone evolved into good granite reservoir zone after weathering leaching for a long time. The prediction results are consistent with the actual geological conditions revealed by field drilling data, indicating that the geological genesis-geophysics method can effectively predict the distribution of high quality reservoirs in the study area. This provides a reference for prediction of high quality reservoirs in granite buried hills in less explored area.

Key words: granite buried hill, high quality reservoir, genetic analysis, gray energy, Shaleitian bulge