Determining source-reservoir spatial assemblages and their tight reservoir disparities is essential for revealing the differential accumulation mechanism of continental tight sandstone oil, but systematic classification and case studies are rarely reported. In this article, based on lithological combination characteristics, the source-reservoir spatial assemblages of the Triassic Chang 7 Member in the Qingcheng area of the Ordos Basin are systematically divided into three categories, namely, reservoir-sandwiching source (RSS), source-reservoir interbed (SRI) and source-sandwiching reservoir (SSR). Moreover, the tight sandstone reservoirs in different assemblages were characterized by a combination of macro observations from cores and geophysical logs and microscopic analysis from cast thin sections, FE-SEM, HPMI and XRD data. The results demonstrate that the tight sandstone reservoirs within different source-reservoir assemblages have similar lithological properties, but vary greatly in reservoir quality and natural fracture networks. In general, the RSS sandstones have the broadest pore-throat size distribution and the best physical properties due to the prevalence of residual intergranular pores, and the reservoir quality is slightly better than that of the SRI sandstones and significantly better than that of the SSR sandstones. Additionally, natural fracture types and fracture intensities vary greatly in different source-reservoir assemblages. The RSS assemblage contains mainly high-dip angle fractures with relatively low fracture intensities, the SSR assemblage is dominated by low-dip angle bedding-parallel fractures with relatively high intensities, and the SRI assemblage is characterized by a combination of these two assemblages. Under the control of overpressure derived from hydrocarbon generation, tight reservoirs with different source-reservoir assemblages present different lower limits of petrophysical properties for tight oil charging, and the effective reservoir proportion leads to a decreasing enrichment degree in the RSS, SRI and SSR assemblages successively. Furthermore, the natural fractures in different source-reservoir assemblages enhance the storage capacity while contributing to disparities in the vertical migration of tight oil. The natural fracture network of the vertically stacked RSS assemblage allows tight oil to migrate upward for a relatively long distance, while the SSR assemblage can effectively prevent the upward migration of the tight oil, thus forming differential tight oil accumulation and distribution characteristics in the different source-reservoir assemblages.

确定源储空间组合及其致密储集层差异对于揭示陆相致密砂岩油差异成藏机制至关重要，但系统分类和案例研究鲜有报道。本文根据岩性组合特征，将鄂尔多斯盆地青城地区三叠系长7段源储空间组合系统划分为储层-夹心源（RSS）、源-储三类。夹层（SRI）和源夹层（SSR）。此外，通过岩心和地球物理测井的宏观观察与铸造薄片的微观分析、FE-SEM、HPMI和XRD数据相结合，对不同组合的致密砂岩储层进行了表征。结果表明，不同源储组合内的致密砂岩储层具有相似的岩性特征，但储层质量和天然裂缝网络差异很大。总体而言，RSS砂岩因发育残余粒间孔而具有最宽的孔喉尺寸分布和最佳物性，储集层质量略优于SRI砂岩，明显优于SSR砂岩. 此外，不同源储组合的天然裂缝类型和裂缝强度差异很大。RSS 组合以断裂强度相对较低的高倾角裂缝为主，SSR 组合以强度相对较高的低倾角顺层缝为主，SRI 组合的特点是这两个组合的组合。在生烃超压控制下，不同源储组合致密油藏致密油充注物性下限不同，有效储集层比例导致RSS、SRI、SSR组合富集程度依次降低. 此外，不同源储组合中的天然裂缝增强了储集能力，同时导致致密油垂直运移的差异。RSS 垂直叠置组合的天然裂缝网络使致密油向上运移较长距离，而 SSR 组合可有效阻止致密油向上运移，