Characteristics of Natural Gas Hydrates Occurring in Pore-Spaces of Marine Sediments Collected from the Eastern Nankai Trough, off Japan

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• 作者：Masato Kida ; Kiyofumi Suzuki ; Taro Kawamura ; Hiroyuki Oyama ; Jiro Nagao ; Takao Ebinuma ; Hideo Narita ; Hiroyuki Suzuki ; Hirotoshi Sakagami ; Nobuo Takahashi
• 刊名：Energy & Fuels
• 出版年：2009
• 出版时间：November 19, 2009
• 年：2009
• 卷：23
• 期：11
• 页码：5580-5586
• 全文大小：808K
• 年卷期：v.23,no.11(November 19, 2009)
• ISSN：1520-5029

文摘

Pore-space gas hydrates sampled from the eastern Nankai Trough area off of Japan were minutely characterized using several instrumental techniques. Gas chromatographic results indicated that the natural gas in the sediment samples studied comprises mainly CH₄. The concentrations of minor components varied according to depth. The powder X-ray diffraction patterns showed that the pore-space hydrates were of structure I (sI); the lattice constants were 1.183−1.207 nm. Both ¹³C NMR and Raman spectra confirmed that CH₄ molecules were encaged in sI hydrate lattice. The average cage occupancies were calculated, respectively, from the Raman data as 0.83 for small cages and 0.97 for large cages. The hydration numbers were determined as 6.1−6.2.