Abstract: Chang 6₁ reservoirs distributed in Dingbian-Wuqi area are obvious zoning with clear major controlling factors. Core observation,a number of fluorescence images,cast sections,scanning electronic microscope observation,mercury injection data and physical property data were used to analyze the differences of physical property,sand body thickness and mudstone content of Chang 6₁ reservoir among different blocks,to determine the influencing factors of gas-bearing ability differences. The results show that it is characterized by low porosity and low permeability with intergranular pores and feldspar solution openings developed. Reservoir characters are obviously divided according to districts. The contents of quartz,debris and matrix increase while feldspar content decreases from eastern part to western part where the physical properties are poor. Eastern part has the best physical properties with low displacement pressure and good pore structure while intersection area in the middle has the worst physical properties. It is demonstrated that oil-bearing ability differences are closely associated with reservoir zoning characters. Sand bodies in eastern part are characterized by great thickness,low shale content,good physical properties and best oil-bearing ability. Because of the counteract of water power and fast accumulation of shale, the intersection area where the physical properties are poor with thin sand bodies and lamina is mainly consist of water wells. Reservoir oil-bearing ability is mainly affected by sands body thickness,shale content and reservoir properties. This research has some references for the next exploration.

Key words: high-precision reverse-time migration, high-order finite-difference method, reverse-time imaging condition, PML absorbing boundary condition