大型坳陷湖盆异重流成因的水道—湖底扇系统——以松辽盆地白垩系嫩江组一段为例

发布时间：2018-06-30 18:09

本文选题：松辽盆地 + 白垩系　；参考：《石油勘探与开发》2017年06期

【摘要】：以松辽盆地齐家—古龙地区白垩系嫩江组一段为研究对象,通过地震沉积学、沉积构造和沉积序列等分析,发现异重流成因的大型水道—湖底扇系统,对大型坳陷湖盆深水区分布的异重流及其形成的异重岩进行研究,构建了陆相湖盆异重流成因的水道—湖底扇沉积模式。研究表明,异重流发源于盆地边缘,经北部三角洲后在深水区形成完整的水道—湖底扇系统。自北向南依次发育顺直水道和弯曲水道,直线延伸距离超过80 km,宽度100~900 m;水道末端发育湖底扇,最大面积可达20 km~2。该系统主要以细粒沉积为主,发育块状砂岩和流水成因的沉积构造,内部发育侵蚀接触面,富含陆源有机质碎屑,具底床载荷和悬浮载荷兼有的形成机制。异重岩沉积序列表现为向上变粗和向上变细的旋回成对出现,反映洪水逐渐增强随后又减弱的动力学特点。
[Abstract]:Taking the first member of the Cretaceous Nenjiang formation in Qijia-Gulong area of Songliao Basin as the research object, through the analysis of seismic sedimentology, sedimentary structure and sedimentary sequence, it is found that the large-scale watercourse sublacustrine fan system of the origin of the heavy current is found. In this paper, the distribution of heavy currents in deep water area of large depression and their formation are studied, and the sedimentary model of watercourse and sublacustrine fan of the formation of density currents in continental lacustrine basins is constructed. The results show that the gravity current originated from the margin of the basin and formed a complete watercourse-lake fan system in the deep water area after the northern delta. The straight and curved waterways are developed from north to south in turn, with a straight line extension of more than 80 km and a width of 100 ~ 900 m, and a sublacustrine fan with a maximum area of 20 km2 at the end of the channel. The system is mainly composed of fine grain deposits, massive sandstones and sedimentary structures of fluvial origin, and internal erosion interface, rich in terrestrial organic matter clastic, with the formation mechanism of both bottom bed load and suspended load. The sedimentary sequence of different gravity rocks appears in pairs of upward coarsening and upward thinning reflecting the dynamic characteristics of flood gradually increasing and then weakening.
【作者单位】：中国石油勘探开发研究院西北分院;National
【基金】：“十三五”国家油气重大专项(2016ZX05001)
【分类号】：P534.53;P618.13

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