Based on data of thin section and SEM as well as the observations of rate-controlled mercury injection,the influence of diagenesis on the micro-and nano-scale reservoir spatial evolution,as well as the occurrence and distribution of tight oil and gas were analyzed in Quantou4 member of southern Songliao Basin. The results show that the diagenetic environment experi-enced a transition from alkalinity through acidity to alkalinity. During the formation of authigenic minerals in different diagenet-ic environments,a large number of nano-scale intercrystalline pores were also formed when the minerals cemented and/or filled the micro-scale reservoir spaces. Because of the transformation of reservoir spaces from micro-scale to nano-scale, the storage capacity and percolation ability of tight sandstones are reduced,and the driving force is enhanced in the process of tight oil and gas charging,which led to the mercury saturation of throat and the breakthrough pressure increase gradually with the decrease of porosity and permeability in rate-controlled mercury injection experiments. The migration and accumulation of tight oil and gas is the result of dynamic mechanical equilibrium. Therefore,the exploration and development of tight oil and gas in areas far a-way from source rocks should be pivoted around the sandstones dominated by the micro-scale spaces,whereas the exploration of near-source tight oil and gas should be expanded to the sandstones dominated by the nano-scale spaces.%基于薄片/扫描电镜观察以及恒速压汞实验结果,分析松辽盆地南部泉四段成岩作用对储层中微—纳米储集空间演化以及油气赋存和分布的影响.结果表明:研究区泉四段经历了碱性—酸性—碱性的成岩环境,不同成岩环境下形成的自生矿物在胶结/充填微米级储集空间时,也形成了大量的纳米级晶间孔;储集空间的纳米化使得致密砂岩的储集性能和渗流能力降低,油气充注所需的驱动力增强,在恒速压汞表现为随着孔渗的降低,喉道的进汞量逐渐增多以及突破压力逐渐增大;致密油气的运聚是力学动态平衡的结果,当油气运移距离相对较长时,致密油勘探应注重以微米级储集空间占主导的致密砂岩,当储层紧邻源岩或油气运移通道时,以纳米级储集空间为主的致密砂岩也应成为油气勘探的重要目标.
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