为了查明致密砂岩储层油气充注物性下限。通过大量岩心化验数据分析，明确长8储层类型、孔喉结构及物性情况。利用含油产状（试油）法、排驱压力法、统计学法、每米采油指数法、最小孔喉半径法等厘定有效储层现今物性下限，结合油气成藏时序与孔隙演定量化，反演油气充注期物性临界值。结果表明：富县地区长8储层类型以长石砂岩和岩屑长石砂岩为主，孔喉关系复杂，为低—特低孔、特低—超低渗致密储层；优选出现今长8有效储层临界下限值分别为7.0%和0.15 mD；反演Ⅰ期油气充注（距今192.5 ~ 152.0 Ma），物性下限值分别为20.8%和7.37 mD，Ⅱ期油气充注（距今152.0 ~ 126.0 Ma），物性下限值分别为8.2%和0.22 mD，Ⅲ期油气充注（距今65.0 ~ 36.5 Ma），为调整逸散，与现今物性下限基本一致。研究结果可为该区储层含油性评价与有利区预测提供地质依据。

The physical properties lower limits of oil-gas charging in tight sandstone reservoirs are identified through a large number of core test and analysis data. The Chang8 reservoir types, pore-throat structure, and physical properties were clarified. Methods such as oil-gas occurrence, displacement pressure, physical property statistics, oil recovery index, and minimum pore-throat radius were employed to determine the current reservoir physical properties lower limit. By integrating the period of hydrocarbon accumulation and pore evolution, the critical physical properties during oil-gas charging were inverted. The results show that the reservoir types of Chang 8 are mainly feldspar sandstone and lithic feldspar sandstone in Fuxian area, with complex pore-throat relationship. These reservoirs are classified as tight reservoirs with low to extra-low porosity and extra-low to ultra-low permeability. It is preferred that the physical properties lower limits of the current reservoir are 7.0% and 0.15 mD, respectively. For inversion of oil-gas charging in Phase Ⅰ（192.5 ~ 152.0 Ma), the lower limits of physical properties are 20.8% and 7.37 mD, respectively, for oil-gas charging in Phase Ⅱ（152.0 ~ 126.0 Ma), the lower limits of physical properties are 8.2% and 0.22 mD. For oil-gas charging in Phase Ⅲ (65.0 ~ 36.5 Ma), the lower limits of physical properties are basically consistent with the current lower limits of physical properties. The research findings provide an significant geological basis for the evaluation of reservoir and the prediction of favorable in the study area.