石油与天然气地质 ›› 2018, Vol. 39 ›› Issue (5): 889-898.doi: 10.11743/ogg20180504

• 油气勘探 • 上一篇    下一篇

四川盆地绵阳-长宁凹槽构造演化的沉积约束

李双建1,2, 高平1,2, 黄博宇3, 王海军4, 沃玉进1,2   

  1. 1. 页岩油气富集机理与有效开发国家重点实验室, 北京 100083;
    2. 中国石化 构造与沉积储层实验室, 北京 100083;
    3. 中国石油大学(北京) 地球科学学院, 北京 102249;
    4. 中国石化 西南油气分公司, 贵州 贵阳 550001
  • 收稿日期:2018-05-15 修回日期:2018-07-08 出版日期:2018-10-28 发布日期:2018-09-06
  • 作者简介:李双建(1978-),男,博士、高级工程师,油气盆地分析。E-mail:lishuangjian.syky@sinopec.com。
  • 基金资助:
    国家自然科学基金重点支持项目(91755211);国家科技重大专项(2017ZX05005-001);中石化重点科技攻关项目(P16079,P17049)。

Sedimentary constraints on the tectonic evolution of Mianyang-Changning trough in the Sichuan Basin

Li Shuangjian1,2, Gao Ping1,2, Huang Boyu3, Wang Haijun4, Wo Yujin1,2   

  1. 1. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China;
    2. Laboratory of Structural and Sedimentological Reservoir Geology, Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;
    3. College of Geosciences, China University of Petroleum(Beijing), Beijing 102249, China;
    4. Southwest Oil and Gas Branch of SINOPEC, Guiyang, Guizhou 550001, China
  • Received:2018-05-15 Revised:2018-07-08 Online:2018-10-28 Published:2018-09-06

摘要: 系统收集了四川盆地绵阳-长宁凹槽内外的露头和钻井资料,根据地层不整合、岩性变化、测井曲线对比和岩石地球化学等沉积记录,对绵阳-长宁凹槽在震旦纪—早寒武世的构造演化进行了研究。研究发现,凹槽内下寒武统存在明显的上超,保留了下寒武统与震旦系灯影组之间的侵蚀暴露界面,并且残留的灯影组具有早期岩溶现象,表明凹槽在寒武纪沉积前存在暴露侵蚀过程。地层沉积旋回对比表明,凹槽内黑色岩系较正常的麦地坪组多一套沉积旋回,而且凹槽内资阳1井元素测井显示黑色岩系下部发育20 m厚的含硅泥质白云岩,结合邻区钻井分层认识,认为凹槽内黑色岩系不止是寒武系麦地坪组,还包括震旦系灯影组三段和四段。另外,灯影组四段硅质岩具有明显的热水成因特征,也证明当时具有强烈的区域拉张背景。结合中新元古代—寒武纪岩浆岩活动记录和南华纪地层发育特征,认为绵阳-长宁凹槽是在南华纪裂谷基础上,持续负地貌继承性发育起来的,是间歇性拉张沉降和暴露剥蚀联合作用的结果,因此该凹槽的构造属性为拉张-侵蚀槽。

关键词: 沉积记录, 灯影组, 寒武系, 震旦系, 绵阳-长宁凹槽, 四川盆地

Abstract: Mianyang-Changning trough is developed during the transitional period from the Sinian to Early Cambrian in Sichuan Basin.We systematically collected the outcrop samples and drilling data both inside and outside the trough and analyzed its tectonic evolution according to stratigraphic unconformity,lithological variation,log correlation and geochemical data.The results show that there are pronounced onlaps on the Lower Cambiran sequences in the trough,keeping the erosional unconformity between the Lower Cambrian and Sinian Dengying Formation intact.In addition,evidences of early stage karstification occur in the residual Dengying Formation,indicating that the trough has experienced exposure and erosion before the Cambrian sedimentation.Meanwhile,the sedimentary cycle correlation demonstrates that there is an additional sedimentary cycle in the Maidiping Formation with normal proportion of black rocks in the trough.Moreover,elemental logging in Well Ziyang-1 inside the trough shows that there are 20 m-thick siliceous argillaceous dolomites deve-loped in the lower part of the black rocks.Thus,in combination with the stratigraphic division based on drilling data in the adjacent areas,we believed that the black rocks within the trough include not only the Cambrian Maidiping Formation,but also the 3rd and 4th members of the Sinian Dengying Formation.Besides,the hydrothermal origin of siliceous rocks in the 4th member of the Dengying Formation proves that strong regional extension exists during that time.According to the Middle Neoproterozoic-Cambrian magmatic activity records and the characters of the Nanhua sedimentary strata,we considered that the Mianyang-Changning trough inherited from the persistent negative landforms on the basis of Nanhua rift,and it was formed under the combined effect of intermittent extensional subsidence and denudation from exposure.Therefore,the trough is an extensional-erosional trough in tectonics.

Key words: sedimentary record, Dengying Formation, Cambrian, Sinian, Mianyang-Changning trough, Sichuan Basin

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