The exploration level of tight sandstone gas reservoirs in the Denglouku Formation (DF) in the Xujiaweizi Fault Depression is low, and hydrocarbon source and accumulation process remain unclear. Through the analysis of natural gas geochemistry, X-ray diffraction, thin section observation, scanning electron microscope, physical property testing, cathodoluminescence, fluid inclusions, and basin simulation, we examine source of hydrocarbon, the period of hydrocarbon accumulation, and the evolution of physical properties of the tight sandstone gas in the DF. Additionally, the formation process of tight sandstone gas reservoirs in the DF is discussed. The results reveal the following: (1) the tight sandstone gas in the DF is categorized as III kerogen cracking gas, primarily sourced from dark mudstone of the second member of the DF, with some contribution from dark mudstone of the Shahezi Formation. (2) The tight sandstone in the DF is in stage B of middle diagenesis. Based on apparent compaction rate, apparent cementation rate, and apparent dissolution rate, it can be divided into four diagenetic facies: (1) strong compaction–medium cementation–weak dissolution facies; (2) medium compaction–strong cementation–medium dissolution facies; (3) medium compaction–strong cementation–weak dissolution facies; and (4) medium compaction–medium cementation–medium dissolution facies. The predominant diagenetic facies are the medium compaction–strong cementation–medium dissolution facies and medium compaction–medium cementation–medium dissolution facies. (3) The hydrocarbon charging period of the DF in study area ranged from 98 to 67.5 Ma. This period is earlier than the tight period of the strong compaction–medium cementation–weak dissolution facies sandstone and later than the tight period of the medium compaction–strong cementation–medium dissolution facies, medium compaction–strong cementation–weak dissolution facies, and medium compaction–medium cementation–medium dissolution facies sandstone. Consequently, two types of tight sandstone gas reservoirs exist in study area: (1) tight sandstone gas reservoir with tight first and then accumulation type and (2) composite tight sandstone gas reservoirs. Our research offers theoretical instruction for exploration of deep tight sandstone gas in northern Songliao Basin.

徐家围子断陷登娄库组致密砂岩气藏勘探程度较低，烃源及成藏过程尚不明确。通过天然气地球化学、X射线衍射、薄片观察、扫描电镜、物性测试、阴极发光、流体包裹体、盆地模拟等分析，探讨油气来源、油气成藏期、演化演化等。 DF 中致密砂岩气的物理性质。此外，还探讨了东风区致密砂岩气藏的形成过程。结果表明：（1）东风区致密砂岩气属于Ⅲ类干酪根裂解气，主要来源于东风二段暗色泥岩，沙河子组暗色泥岩也有一定贡献。 (2)东风区致密砂岩处于中成岩作用B期。根据视压实率、视胶结率、视溶蚀率可分为4个成岩相：（1）强压实—中胶结—弱溶蚀相； (2) 中压实—强胶结—中溶蚀相； (3) 中压实—强胶结—弱溶蚀相； (4)中压实-中胶结-中溶蚀相。主要成岩相为中压实-强胶结-中溶蚀相和中压实-中胶结-中溶蚀相。 (3) 研究区DF的油气充注周期为98~67.5 Ma。 该期早于强压实—中胶结—弱溶蚀相砂岩致密期，晚于中压实—强胶结—中溶蚀相、中压实—强胶结—弱溶蚀相、中压实—强胶结—弱溶蚀相致密期。压实—中胶结—中溶蚀相砂岩。因此，研究区存在两种类型的致密砂岩气藏：（1）先致密后成藏型致密砂岩气藏和（2）复合致密砂岩气藏。该研究为松辽盆地北部深层致密砂岩气勘探提供了理论指导。