青石峁气田是鄂尔多斯盆地致密气勘探开发的新领域，也是宁夏回族自治区内发现的第1个天然气储量超过1 000×10⁸ m³大气田。该气田在试采阶段表现为产气量低、水气比高等生产特征，气藏效益开发难度大。为了探究气藏气水渗流特征和开发机理，以该气田试采区二叠系下石盒子组8段为研究对象，采用岩石孔渗、铸体薄片与恒速压汞等分析方法，研究了砂岩储层物性与微观孔喉结构；基于密闭取心干馏称重、常规取心驱替与核磁共振相结合的方法，厘定了气藏原始含水饱和度；进而借助气水两相渗流实验方法，明晰了储层气水渗流规律和开发机理。研究结果表明：①该气田盒8段总体为低孔隙度、低渗透率、致密、中高含水饱和度气藏，发育基质孔隙型、裂缝发育型、基质孔隙—裂缝欠发育型3种储层类型；②在基质致密、局部裂缝发育、原始含水饱和度较高的储层条件下，局部水体易沿裂缝产生非均匀突进，因而在气藏开发过程中，控制气藏水锁/水封伤害是该气田实现高效开发的关键；③在未取心的情况下，可以依据储层物性与含气性初步建立产出流体判识标准，为射孔层段优选、控水开发提供地质预判。结论认为，该研究成果可以为该气田后续有利目标区及开发层段优选提供借鉴和参考。

As a new exploration and development domain of tight gas in Ordos Basin, Qingshimao gasfield is the first large one with the natural-gas reserves exceeding 100 billion cubic meters in Ningxia Hui Autonomous Region. Low gas production and high water-gas ratio emerged at the process of production test in this field, creating more challenges in beneficial development of tight-gas sandstone reservoirs. Thus, the eighth member of the Permian Lower Shihezi Formation (He 8 Member) was taken as an example to probe into physical properties and pore-throat microstructure in such reservoirs by means of porosity and permeability analysis, cast thin-section identification, and constant-rate mercury injection in order to figure out gas-water seepage laws and development mechanisms. Then, the initial water saturation was ascertained for these reservoirs on the basis of the sealed coring for pyrolysis weighing, routine coring or displacement and nuclear magnetic resonance. Additionally, both seepage laws and development mechanisms were made clear with the help of gas-water two-phase seepage experiments. Results show that (i) with low porosity and permeability, and medium to high water saturation, this member is generally tight gas reservoirs in which three types are developed, i.e., matrix porous type, fractured type, and matrix porous or underdeveloped fractured type; (ii) partial waterbody in some reservoirs whose characteristics are tight matrix, locally developed fractures and higher initial water saturation, is prone to non-uniform fingering along fractures. Hence, controlling water lock effect and avoiding water block damage are crucial to the beneficial development; and (iii) without cores, the criteria can be roughly established to identify produced fluids in the light of physical properties and gas content, providing geological evidence for selecting the best perforation interval and water control. In conclusion, all above results offer references for the selection of targeted zones and intervals for subsequent development in Qingshimao gasfield.