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研究了第四纪生物气特征、成藏条件及勘探方向．结果表明，河漫滩和近岸浅海泥质沉积物既是气源岩，又是盖层，后者可作为区域盖层．气源岩有机碳一般大于０．４％，但由于其埋藏浅，有机质属于未成熟阶段，尚未大量裂解成烃．盖层的孔隙水压力可能对生物气藏保存起着最主要的封闭作用．分布在下切河谷内的河漫滩砂质透镜体为唯一具工业价值的储气层，气藏岩性圈闭，属自生自储型．下切河谷和古河口为生物气形成和富集提供了有利条件
The Quaternary biogas characteristics, reservoir forming conditions and exploration directions were studied. The results show that the floodplain and the coastal shallow sea muddy sediments are both gas source rocks and cap rocks, and the latter can serve as regional cap rocks. The source rock organic carbon is generally more than 0.4%, but because of its shallow burial, organic matter belongs to the immature stage, not yet a lot of cracking into hydrocarbons. The pore water pressure of the cap layer may play a major role in the preservation of biogas reservoirs. The floodplain sand lens distributed in the undercut valley is the only gas reservoir with industrial value. The lithologic traps of the gas reservoirs are of the generative type. Undercut valleys and ancient estuaries provide favorable conditions for the formation and enrichment of biogas