Abstract: The Member 2, 3 of Nenjiang Formation in Songliao Basin was studied based on core, log and seismic data. The lineups in seismic profile have the feature of low angle extension, continuous reflection and imbricates distribution, and have low angle progradation structure from east to west. Each sequence can distinguish 4?6 foreset beds, top laminated subject to certain erosion, and the continuity is relatively poor in muddy delta segment. Compared with sedimentary characteristics of the classic delta-mode, the muddy delta has low content of sandy-component than normal delta. The results show that the argillaceous sediment with a low-angle foreset structure has muddy deltaic deposition characteristics, which comes from highly suspension load deposit near the end of subaqueous channel system. The muddy deltaic depositional model of the Member 2, 3 of Nenjiang Formation was built.

Key words: Daqing Changyuan, muddy delta, depositional model, Nenjiang Formation, seismic facies

摘要： 通过对松辽盆地嫩江组岩芯资料、测井资料和地震资料处理和解释, 发现在松辽盆地大庆长垣地区嫩江组二、三段湖相泥岩层段中, 具有一定角度自东向西的前积结构, 地震剖面中底部同相轴表现为中强振幅、高连续反射、叠瓦状特征; 每个层序可分辨出4~6个主要由泥岩构成的前积层, 有的顶积层存在顶超现象, 延续性相对较差; 岩性组合中泥质组分含量高, 砂质组分含量低。经研究认为, 这种具有一定角度前积结构的富泥贫砂沉积是高悬浮载荷河流入湖而形成的泥质三角洲沉积。建立了嫩江组湖泊沉积环境中发育的泥质三角洲的沉积模式。

关键词: 大庆长垣, 泥质三角洲, 沉积模式, 嫩江组, 地震相