对长江三角洲晚第四纪地层沉积特征进行了精细研究,探讨了研究区层序地层格架,在此基础上分析了浅层生物气成藏条件、特征和分布规律。研究表明,长江三角洲晚第四纪发育3期下切河谷,形成了3套沉积层序;因后期河流的强烈下切破坏,早期沉积层序往往被剥蚀殆尽,仅残留下部的河床相粗粒沉积,造成不同期河床相的叠置;相对而言,末次冰期以来形成的下切河谷沉积层序以相对完整的沉积相组合被保存下来。长江三角洲浅层天然气是未经运移的原生生物气,其主要富集于末次冰期以来的沉积层序内,气藏为自生自储同生型的岩性圈闭。河口湾—河漫滩和浅海相泥质沉积物既是气源岩,又是盖层,后者可作为良好的区域盖层;河口湾—河漫滩和河床相砂质沉积物为主要储集层。因此,研究区晚第四纪多期下切河谷沉积层序有利于浅层生物气藏的形成,特别是晚期下切河谷内河口湾—河漫滩相砂质透镜体以及河床相砂体可作为优先勘探目标。 The sedimentary characteristics of Late Quaternary stratigraphy in the Yangtze River Delta are studied in detail, and the sequence stratigraphic framework of the study area is discussed. Based on the analysis, the forming conditions, characteristics and distribution of shallow biogenic gas are analyzed. The results show that three sedimentary sequences were developed in the late Quaternary of the Yangtze River Delta during the late Quaternary Period. Due to the intense undercutting of the later rivers, the early sedimentary sequences were often denuded and only the lower sedimentary facies of the riverbed remained. , Resulting in the superimposition of river bed facies at different stages. In contrast, the sedimentary sequence of the undercut valleys formed since the last glacial period was preserved with a relatively complete assemblage of sedimentary facies. The shallow natural gas in the Yangtze River Delta is an undigrated native biogas. Its main enrichment is in the sedimentary sequence since the last glacial period. The gas reservoir is a lithologic trap that is self-generative and isotopic. The estuarine-floodplain and shallow marine muddy sediments are both gas-source rocks and cap rocks, and the latter can be regarded as good regional cap rocks. Estuarine Bay-floodplains and riverbed sediments are the main reservoirs. Therefore, the sedimentary sequence of the lower Quaternary sedimentary lower valley in the study area is favorable for the formation of shallow bio-gas reservoirs. In particular, the late undercut river valley-floodplain facies sand lens and river bed facies sandbody may be the priority exploration target .