石油学报 ›› 2014, Vol. 35 ›› Issue (2): 219-232.DOI: 10.7623/syxb201402002

• 地质勘探 • 上一篇    下一篇

四川盆地及邻区早侏罗世构造-沉积环境与原型盆地演化

李英强, 何登发   

  1. 中国地质大学海相储层演化与油气富集机理教育部重点实验室 北京 100083
  • 收稿日期:2013-09-07 修回日期:2013-11-29 出版日期:2014-03-25 发布日期:2014-04-11
  • 通讯作者: 何登发,男,1967年12月生,1989年毕业于西北大学地质学系,1995年获中国石油勘探开发研究院博士学位,现为中国地质大学(北京)教授、博士生导师,主要从事含油气盆地构造研究。Email:hedengfa282@263.net
  • 作者简介:李英强,男,1987年2月生,2012年毕业于中国地质大学资源勘查工程专业,现为中国地质大学(北京)硕士研究生,主要从事沉积盆地构造特征研究。Email:yingqiangcugb@126.com
  • 基金资助:

    国家自然科学基金重点项目(No.40739906)和国家重大科技专项(2011ZX05008-001)资助。

Evolution of tectonic-depositional environment and prototype basins of the Early Jurassic in Sichuan Basin and adjacent areas

Li Yingqiang, He Dengfa   

  1. Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism of the Ministry of Education, China University of Geosciences, Beijing 100083, China
  • Received:2013-09-07 Revised:2013-11-29 Online:2014-03-25 Published:2014-04-11

摘要:

下侏罗统是四川盆地原油勘探的主力层系,研究其构造-沉积环境与原型盆地演化可为油气勘探奠定重要基础。从周缘构造环境、盆地构造沉降、盆-山耦合作用等出发,结合沉积相研究,将盆地沉积充填演化与周缘造山带演化有机结合,重建了四川盆地及邻区早侏罗世各沉积期构造-沉积环境,并探讨了盆地性质及演化规律。早侏罗世四川盆地构造动力学环境经历了强、弱伸展的交替变化,构造沉降经历了快速→缓慢→稳定的变化特征。自流井组珍珠冲段沉积期为强伸展期,于晚三叠世的断陷—坳陷盆地之上开始稳定的坳陷盆地沉积;自流井组东岳庙段沉积期为弱伸展期,盆缘隆升和基底沉降减慢,促进了岩相和岩性都比较稳定的大规模湖相沉积;自流井组马鞍山段沉积期为强伸展期,盆-岭、盆-山构造耦合作用加强,促进了盆地西缘、北缘以粗碎屑为主的辫状河和大型扇体的发育;自流井组大安寨段沉积期为伸展作用最弱、造山带活动最稳定的时期,盆地整体的拗陷速率远大于陆源碎屑的堆积速率,导致了四川盆地早侏罗世最大湖盆的形成。早侏罗世四川盆地及邻区主体为陆内弱拉张环境下的大型克拉通内坳陷盆地,周缘造山、造陆的间歇性活动,湖盆或快或慢的沉降以及局部的古隆起、古坳陷控制着沉积中心整体向盆地北部及NE方向迁移,其演化过程对油气聚集产生了深远的影响。

关键词: 构造-沉积环境, 原型盆地, 盆-山耦合, 早侏罗世, 自流井组, 四川盆地

Abstract:

Lower Jurassic is the main stratum for oil exploration in Sichuan Basin. Research on its tectonic-depositional environment and evolution of prototype basins lays an important foundation for oil and gas exploration. Based on the analysis of peripheral tectonic environment, tectonic subsidence and basin-mountain coupling process, and research of sedimentary facies, the tectonic-depositional environment of Early Jurassic in Sichuan Basin and adjacent areas is dynamically reconstructed by integrating the evolution of peripheral orogenic belts with sedimentary filling evolution, and then basin properties and evolution law are also explored. Tectonic dynamic conditions have experienced intense and weak extensional activities alternatively in the Early Jurassic Sichuan Basin. The tectonic subsidence has undergone fast, slow and stable development period. The deposition stage of Zhenzhuchong Member, Ziliujing Formation is an intense extension period, during which a stable down-warped deposition began in the Late Triassic fault-depression basin. During the weak extension period of Dongyuemiao Member, Ziliujing Formation the uplift of basin edge and basement subsidence slowed down, thus promoting the large-scale deposition of lacustrine facies with relatively stable lithofacies and lithological characteristics. The deposition stage of Ma'anshan Member, Ziliujing Formation is another intense extension period. The enhanced basin-ridge and basin-mountain coupling accelerated the development of braided river and large fan body with coarse clastics in western and northern edges of Sichuan Basin. Moreover, the deposition stage of Da'anzhai Member, Ziliujing Formation is the weakest extension period, in which orogenic belts were not active; as a whole, basin depression rate was far greater than the accumulation rate of terrigenous clastics, and thus led to formation of the largest lake basin in the Early Jurassic Sichuan basin. It is considered that the Early Jurassic Sichuan Basin and adjacent areas is a large intracratonic depression basin under weak intracontinental extension. The depocenter moves northward and northeastward during the four deposition stages, which is controlled by the intermittent activities of peripheral orogenic and epeirogenic belts, slow and fast depression of lake basin, and local paleo-highs and paleo-depressions. This evolution process has a significant influence on oil and gas accumulation in Sichuan Basin.

Key words: tectonic-depositional environment, prototype basin, basin-mountain coupling, Early Jurassic, Ziliujing Formation, Sichuan Basin

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