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现代地质 ›› 2010, Vol. 24 ›› Issue (3): 576-580.

• 天然气水合物专辑:地球化学 • 上一篇    下一篇

南海北部天然气水合物钻探区烃类气体成因类型研究

黄霞,祝有海,卢振权,王平康   

  1. 中国地质科学院 矿产资源研究所,北京100037
  • 出版日期:2010-06-21 发布日期:2010-08-17
  • 作者简介:黄霞,女,助理研究员,博士,1982年出生,地质学专业,主要从事天然气水合物气体成因来源的研究工作。 Email:huangxia@live.com。
  • 基金资助:

    国家“973”项目(2009CB219501);中央级公益性科研院所基本科研业务费资助项目(K0909)

Study on Genetic Types of Hydrocarbon Gases from the Gas Hydrate Drilling Area, the Northern South China Sea

 HUANG  Xia, ZHU YOU-Hai, LEI  Zhen-Quan, WANG  Ping-Kang   

  1. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing100037, China
  • Online:2010-06-21 Published:2010-08-17

摘要:

南海北部天然气水合物钻探区水合物气、顶空气样品和沉积物样品烃类气体组分和甲烷同位素特征测试结果表明,气体样品中烃类气体以甲烷为主,含微量乙烷和丙烷,C1/(C2+C3)值均大于或接近1 000。甲烷的碳同位素值为-54.‰~-62.2‰,氢同位素值为-180‰~-255‰,属于微生物气或是以微生物气为主的混合气,甲烷由CO2还原生成,由原地提供或侧向运移而来。沉积物样品酸解烃分析显示多数样品甲烷丰度大于90%,含一定量的乙烷、丙烷及少量的丁烷,C1/(C2+C3)值均小于50。甲烷的碳同位素值为-29.8‰~-48.2‰,呈现典型的热解气特征,显示由深部运移而来。

关键词: 南海北部, 天然气水合物, 气体成因类型

Abstract:

Gas composition and isotopes of gas hydrate, headspace gas and sediment samples from the gas hydrate drilling area, the Northern South China Sea, are analysed. Results show that gas hydrate and headspace gas are nearly composed of methane with trace ethane and propane. Their ratios of C1/(C2+C3) are higher than or close to 1,000.δ13C1 values range from -54.1‰ to -62.2‰, and δDCH4 values vary from -180‰ to -255‰. Hence they are mainly bacterial or mixed with bacterial gases, derived from CO2 reduction and produced in situ or by side migration. Results of aciddegassed gases of sediment samples also indicate that methane is mostly higher than 90%, with some ethane, propane and minor butane. The ratios of C1/(C2+C3)are lower than 50 and δ13C1 values change from -29.8‰ to -48.2‰. These features are indicative of typical thermogenic gases migrated up from the depth.

Key words: the Northern South China Sea, gas hydrate, genetictypes of gases

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