塔北地区三叠纪拗陷湖盆异重流沉积特征及主控因素  

Sedimentary Characteristics and Controlling Factors of Hyperpycnal Flow in Triassic Depressed Lake Basin,Northern Tarim Basin

作　　者：仲米虹[1] 唐武 ZHONG Mihong;TANG Wu(Technology Research&Development Center,CNOOC Gas&Power Group Co.,Ltd.,Beijing 100028,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)

机构地区：[1]中海石油气电集团有限责任公司技术研发中心,北京100028 [2]中海油研究总院有限责任公司,北京100028

出　　处：《新疆石油地质》2023年第1期1-8,共8页Xinjiang Petroleum Geology

基　　金：国家自然科学基金(41372115);国家科技重大专项(2016ZX05026)。

摘　　要：针对异重流的研究主要集中在现代海洋环境,对古代陆相拗陷湖盆异重流发育特征和主控因素研究甚少。为此,以塔北地区为例,利用岩心、钻井、测井及三维地震资料,分析了三叠系TⅡ油组的异重流沉积。结果表明,湖侵—高位体系域沉积时期,研究区TⅡ油组发育2种典型的异重流沉积序列,均由1个向上变粗和1个向上变细的沉积单元构成,发育大量爬升波纹层理和沙纹层理,其中一种序列的2个单元间为突变,发育冲刷面,而另一种序列的2个单元间为渐变,反映了洪泛能量的差异。研究区异重流主要来自西南部与东北部2个方向,其中,西南部异重流居主导地位,分布范围广,延伸距离长,垂向上多期异重流沉积相互叠置。该区异重流具备洪水重力流的特征,其形成与洪泛密切相关,受气候、构造活动、湖平面、物源等多因素控制。Previous studies on hyperpycnal flow mainly focused on modern marine environment and paid little attention to sedimentary characteristics and controlling factors of hyperpycnal flow in ancient continental depressed lake basins. In this paper,taking Tabei area as an example,the hyperpycnal flow deposits of the Triassic TⅡ oil member are analyzed by using core,drilling,logging and 3D seismic data.The results show that during the deposition of lacustrine transgressive system tract(TST)-highstand systems tract(HST),the TⅡ oil member in the study area developed two typical hyperpycnal flow sedimentary sequences,and each sequence is a compound of a basal coarsening-upward unit and a top fining-upward unit,with climbing ripples and ripple cross lamination. In one sequence,an erosive surface is developed between the two units,while in the other sequence,the two sedimentary units present a trend of gradual change,reflecting different flooding energy. The hyperpycnal flow in the study area mainly comes from two directions such as southwest and northeast,among which the hyperpycnal flow from southwest is the dominant with wide distribution,long extending distance and vertical superimposition of hyperpycnal flow deposits of multiple periods. The hyperpycnal flow in the study area has the characteristics of flood gravity flow,and its formation is closely related to flooding and controlled by multiple factors such as climate,tectonic activities,lake level,and provenance.

关 键 词：塔里木盆地 塔北地区 三叠纪 异重流 异重岩 洪泛 主控因素 沉积模式 

分 类 号：TE122.1[石油与天然气工程—油气勘探]