Abstract: Inadequate comprehension of the pore structure and physical properties of shale reservoirs impedes precise calculation of shale oil reserves and efficient development seriously. This study focuses on the core holes of Xinyishen-9, Liye-1, and wells Fanye-1 in the Paleogene Shahejie Formation within the Jiyang Depression. The pore structure of shale reservoirs is comprehensively characterized using N₂ adsorption, high-pressure mercury injection,physical properties measurement, and other experimental methods. Additionally, we determined the physical property cutoffs through a comprehensive approach involving irreducible water saturation method, pressed mercury displacement method, minimum flow pore-throat radius method, and oil testing method. The findings indicate that the nitrogen adsorption experiment primarily characterizes the small pores of shale samples. The pore morphology in the study area predominantly comprises ink bottle, transition, and flat types, mainly featuring nano-scale pores with a radius ranging from 1.50 to 40.00 nm and an average pore radius of 16.00 nm. Moreover, the high-pressure mercury injection experiment focuses on characterizing mesopores and macropores of shale, revealing a pore throat radius range of 0.03 ~ 66.13 μm. The lower limit of shale reservoir porosity falls within the range of 1.30% to 3.82%, while permeability's cutoff is between 0.03 ~ 0.12 mD, the minimum flow pore-throat radius is 14.60~23.50 nm and average value is 17.76 nm. The research outcomes offer valuable parameter indexes and technical support for reserve calculation and reservoir evaluation in Jiyang Depression's shale oil exploration.

Key words: shale oil, pore structure, lower limit of physical property, Jiyang Depression