石油与天然气地质 ›› 2018, Vol. 39 ›› Issue (3): 429-437.doi: 10.11743/ogg20180302

• 油气勘探 • 上一篇    下一篇

贵州地区下寒武统牛蹄塘组烃源岩热水沉积成因鉴别与强度评价

贾智彬1,2,3, 侯读杰1,2,3, 孙德强4, 姜玉涵1,2,3, 张自鸣1,2,3, 洪梅1,2,3   

  1. 1. 中国地质大学(北京)能源学院, 北京 100083;
    2. 海相储层演化与油气富集机理教育部重点实验室, 北京 100083;
    3. 国土资源部页岩气资源战略评价重点实验室, 北京 100083;
    4. 中国科学院 科技战略咨询研究院, 北京 100190
  • 收稿日期:2017-09-26 修回日期:2018-05-10 出版日期:2018-06-28 发布日期:2018-06-21
  • 通讯作者: 侯读杰(1964-),男,教授、博士生导师,油气运移与成藏及地球化学。E-mail:hdj@cugb.edu.cn。 E-mail:hdj@cugb.edu.cn
  • 作者简介:贾智彬(1985-),男,博士,油气成藏与地球化学。E-mail:didajiazhibin@163.com。
  • 基金资助:
    国家自然科学基金项目(41472108)。

Genesis and intensity of hydrothermal sedimentation in hydrocarbon source rocks in the Lower Cambrian Niutitang Formation,Guizhou area

Jia Zhibin1,2,3, Hou Dujie1,2,3, Sun Deqiang4, Jiang Yuhan1,2,3, Zhang Ziming1,2,3, Hong Mei1,2,3   

  1. 1. School of Energy Resources, China University of Geosciences(Beijing), Beijing 100083, China;
    2. Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism(Ministry of Education), China University of Geosciences(Beijing), Beijing 100083, China;
    3. Key Laboratory of Shale Gas Exploration and Evaluation, Ministry of Land and Resources, Beijing 100083, China;
    4. Institutes of Science and Development, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2017-09-26 Revised:2018-05-10 Online:2018-06-28 Published:2018-06-21

摘要: 为了准确地判别烃源岩是否受热水沉积作用影响并对其影响强度进行评价,以贵州地区下寒武统牛蹄塘组烃源岩为主要研究对象,通过对其微量元素进行分析后发现,V/Sc-V/Cr图能够用于判别研究区烃源岩是否为热水沉积成因并反映其氧化还原环境的变化,还可利用斜率Sc/Cr比值来评价热水沉积作用的影响强度。当Sc/Cr ≥ 0.144时,以正常沉积作用为主,很少受到热水沉积作用的影响,V/Cr比值和V/Sc比值之间呈线性相关关系,能够反映氧化还原环境的变化;当Sc/Cr ≤ 0.120时,以热水沉积作用为主。受热水沉积物中元素含量异常影响,V/Cr比值受到干扰,无法反映真实的氧化还原环境变化,但V/Sc比值仍可用于指示氧化还原环境。当0.120 ≤ Sc/Cr ≤ 0.144时,受两种沉积作用共同影响,此时V/Cr比值对氧化还原变化的指示作用受到影响,但仍能反映氧化还原环境的变化趋势,V/Sc比值则仍能用于反映氧化还原环境的变化。V/Sc-V/Cr图能够准确地判别烃源岩受热水沉积作用影响并对其影响强度进行评价。

关键词: 微量元素, 热水沉积, 烃源岩, 牛蹄塘组, 寒武系, 贵州地区

Abstract: The study case is the source rocks of the Lower Cambrian Niutitang Formation in Guizhou area.Their trace element content is analyzed to accurately identify the hydrothermal sedimentation effect on source rocks and evaluate the intensity of the effect.The results show that(1)the diagram V/Sc-V/Cr can be used to judge whether hydrothermal sedimentation effect is a contributing factor for the composition of source rocks in the study area,which in turn,can reflect the redox environment change;(2)the slope Sc/Cr ratio is applicable for evaluating the intensity of hydrothermal sedimentation:when the Sc/Cr ratio is more than or equal to 0.144,normal sedimentation dominates and hydrothermal sedimentation effect is weak,and there is a linear correlation between V/Sc and V/Cr ratios,reflecting the redox environment change;when the Sc/Cr ratio is less than or equal to 0.120,hydrothermal sedimentation dominates,and the V/Cr ratio,which is distorted by the element content anomaly in the hydrothermal sediments,can not indicate the actual change of the redox environment,but remain useful to indicate the environment change;however,when the Sc/Cr ratio varies from 0.120 to 0.144(with both ends included),both sedimentary processes function,and the value of V/Cr ratio is influenced by the hydrothermal sediments,but can still indicate the trend of redox environment change,and thus can be applied normally.The conclusion can be drawn that the diagram V/Sc-V/Cr can accurately identify the influence and indicate the intensity of the hydrothermal sedimentation on source rocks.

Key words: trace element, hydrothermal sedimentation, source rock, Niutitang Formation, Cambrian Guizhou area

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