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现代地质 ›› 2008, Vol. 22 ›› Issue (4): 586-591.

• 油气运移 • 上一篇    下一篇

塔东地区古城4井上寒武统-中、上奥陶统流体地球化学示踪

王东1,王国芝1,冉启贵2,刘树根3,胡九珍3,张长俊3   

  1. 1成都理工大学 地球科学学院,四川 成都 610059;
    2中国石油勘探开发研究院 廊坊分院,河北 廊坊 065007;
    3成都理工大学 油气藏地质及开发工程国家重点实验室,四川 成都 610059
  • 收稿日期:2008-03-28 修回日期:2008-06-17 出版日期:2008-04-20 发布日期:2008-04-20
  • 作者简介:王东,男,硕士研究生,1981年出生,构造地质学专业,主要从事含油气盆地分析研究
  • 基金资助:

    国家重点基础研究发展规划项目(2005CB422106)

Geochemical Tracing of Fluid from Upper Cambrian-Ordovician in Well Gucheng 4,Eastern Tarim Basin

WANG Dong1,WANG Guo-zhi1,RAN Qi-gui2,LIU Shu-gen3,HU Jiu-zhen3,ZHANG Chang-jun3   

  • Received:2008-03-28 Revised:2008-06-17 Online:2008-04-20 Published:2008-04-20

摘要:

通过对塔东地区古城4井上寒武统和中、上奥陶统碳酸盐岩围岩及充填物的碳、氧、锶同位素地球化学和流体包裹体成分的对比研究表明,充填于中、上奥陶统和上寒武统的流体分属于2个不同来源的流体体系。充填于中、上奥陶统灰岩裂缝中方解石脉的w(87Sr)/w(86Sr)介于0.708 4~0.708 8,它与早奥陶世海水的w(87Sr) /w(86Sr)相近;流体体系为CH4-H2O体系;充填物与围岩间具有明显的碳、氧同位素差异,表明上部流体体系中的流体来自于奥陶系地层本身。上寒武统白云岩裂缝中方解石脉的w(87Sr)/w(86Sr)为0.713 8,明显地高于同时代海水的锶同位素值;流体体系为CH2-H2O体系;下部流体体系中的流体为外来富锶流体。上、下流体体系间互不连通暗示着上寒武统地层具有相对较好的保存条件。

关键词: 寒武系, 奥陶系, 流体, 地球化学, 塔东地区, 古城4井, 碳、氧、锶同位素

Abstract:

Comparison studies for Upper Cambrian and Ordovician in well Gucheng 4 in eastern Tarim basin based on carbon,oxygen,strontium isotope geochemistry and fluid inclusions between country rocks of carbonate and fills in fissure,suggest that source of fluid in the MiddleUpper Ordovician is much different from that in Upper Cambrian.87Sr/86Sr of calcites filled in limestone fissure in Middle-Upper Ordovician is 0.708,4-0.708,8 and it is similar to that from Ordovician seawater;the fluid belongs to CH4-H2Osystem.Obvious isotopic differences of carbon and oxygen between fills in fissure and country rock indicate that the fluid is not directly  from the country rock and from Ordovician carbonate at other locations.The87Sr/86Sr of calcites filled in dolomite fissure in Upper Cambrian is 0.713,8 and it is higher than that of contemporary seawater,and the fluid belongs toCH2-H2O system.Fluid in the lower system is an introduced fluid with abundant Sr.Different fluid sources in Upper Cambrian and Ordovician imply that Upper Cambrian has a better preservation condition.

Key words: Cambrian, Ordovician, fluid, geochemistry, eastern Tarim basin, well Gucheng 4, carbon,oxygen,and strontium isotopes

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