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  

Sublacustrine hyperpycnal channel-fan system in a large depression basin: A case study of Nen 1 Member, Cretaceous Nenjiang Formation in the Songliao Basin, NE China

作　　者：潘树新[1] 刘化清[1] ZAVALA Carlos 刘彩燕[1] 梁苏娟[1] 张庆石[3] 白忠峰[3] 

机构地区：[1]中国石油勘探开发研究院西北分院,兰州730020 [2]National University of the South,San Juan B8000CPB,Argentin [3]中国石油大庆油田公司,黑龙江大庆163000

出　　处：《石油勘探与开发》2017年第6期860-870,共11页Petroleum Exploration and Development

基　　金：“十三五”国家油气重大专项(2016ZX05001)

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。Based on the integrated analysis of the seismic sedimentology, drilling and core data from the Nen 1 Member of the Cretaceous Nenjiang Formation in the Qijia-Gulong area, a large channel fan system of hyperpycnal flow origin was found in the Songliao Basin, and the hyperpycnal flows and hyperpycnites distributed in the deep water area of large depression lake basin were examined to find out the depositional model of channel-fan of hyperpycnal flow origin in the continental lake basin. The study shows that the hyperpycnal flow in this area originated from the edge of the basin, passed the northern delta, and then gave rise to a complete channel-fan system in the deep water area. The channel-fan system consists of straight channel and meandering channel from north to south with a straight extension of over 80 km and width of 100-900 m, and distal fan lobes at the channel tip with the maximum area of 20 km-2. Dominated by fine-grained deposits, the system contains massive sandstone and sedimentary structures of flow water origin, internal erosion surfaces, and rich continental organic clasts, and shows bed-load and suspended-load transportation mechanisms. The hyperpycnite sequence has a coarsening-upward lower sequence and fining-upward upper sequence appearing in pairs, reflecting the dynamic feature of flood strengthening and then weakening cycle.

关 键 词：松辽盆地 白垩系 嫩江组一段 浊流 浊积岩 异重流 异重岩 沉积特征 水道—湖底扇系统 

分 类 号：TE121.3[石油与天然气工程—油气勘探]