Methane hydrate investigations on sediment core samples obtained in the Sea of Okhotsk

对鄂霍次克海沉积物岩心样本进行甲烷水合物研究

• 批准号: 14254003
• 负责人: SHOJI Hitoshi
• 金额: $ 21.63万
• 依托单位: Kitami Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14254003/
• 关键词: Methane Hydrate; Clathrate Hydrate; Sea Sediment Core; Offsore Sakhalin, Okhotsk Sea; Methane Seep; Seepage Structure; Gravity Corer; Sea Bottom Survey; ガスハイドレート; オホーツク海; サハリン沖; 海洋調査; 海底土壌; バイカル湖; チムニー; 結晶成長; クラスレート構造1型

Side-scan-sonar survey with high-resolution seismo-acoustic profiling was performed offshore Sakhalin, Okhotsk Sea by the members of CHAOS (hydro-Carbon Hydrate Accumulations in the Sea of Okhotsk) Project lead by Kitami Institute of Technology in 2003. The survey results revealed characteristic distributions of gas hydrate accumulations with unique images of gas seepage structures and vertical fluid channel at/near sea bottom. More than 40 seepage structures were found within a 10 x 20 km survey area. The maximum size of seepage structure observed is about 600 m in diameter. Methane gas released from the seepage structures into the above water was detected as flare images by hydro-acoustic profiling. Gas hydrate and sediment core samples were obtained from those seepage structures and transported to Kitami Institute of Technology for laboratory studies by gas chromatography, liquid chromatography, oxygen/hydrogen/carbon isotopes, 13C-NMR, thermal analysis, physical analysis and other analytical techniques. Methane hydrates of massive forms, layers and/or small pieces were observed in silty-clay, sea sediment cores within a depth of 2-3 meter below the sea floor. Gas hydrates samples were stored in a liquid-nitrogen-temperature container immediately after core recovery, preventing hydrate samples from the dissociation. Main results obtained are summarized as below. Guest gases trapped in hydrates are mainly of methane and only small amount of ethane, propane and others. Crystal structure of hydrates is of clathrate hydrate structure I, and the hydration number is close to six, showing very high quality of gas hydrates. The results of carbon isotope and gas composition measurements show the methane gas in gas hydrates is of microbial origin. Latent heat of gas hydrate measured is found to be quite close to that of artificial, pure methane hydrate.

2003年，由Kitami理工学院领导的CHOS(鄂霍次克海碳氢化合物水合物积累)项目的成员在鄂霍次克海库页岛近海进行了具有高分辨率地震声学剖面图的侧扫声纳调查。调查结果揭示了天然气水合物聚集的特征分布，具有独特的海底天然气渗流结构和垂直流体通道图像。在10×20公里的调查范围内发现了40多个渗漏结构。观测到的渗流结构最大直径约为600m。从渗流结构释放到上述水中的甲烷气体通过水声剖面法探测到为耀斑图像。从这些渗流结构中提取天然气水合物和沉积物岩心样品，并将其输送到北上理工学院进行实验室研究，采用气相色谱、液相色谱、氧/氢/碳同位素、13C-核磁共振、热分析、物理分析等分析技术。在海底以下2-3米深的粉质粘土海洋沉积物岩心中观察到块状、层状和/或小块的甲烷水合物。天然气水合物样品在岩心回收后立即储存在液氮温度容器中，防止水合物样品解离。取得的主要成果总结如下。滞留在水合物中的客体气体主要是甲烷，只有少量的乙烷、丙烷等。水合物的晶体结构为笼状水合物结构I，水化数接近6，表明天然气水合物的质量很高。碳同位素和气体成分测定结果表明，天然气水合物中的甲烷气为微生物成因。测得的天然气水合物的潜热与人工纯甲烷水合物的潜热非常接近。

项目成果

Formation and dissociation processes of gas hydrate composed of methane and carbon dioxide below freezing

冰点以下由甲烷和二氧化碳组成的天然气水合物的形成和分解过程

• 发表时间: 2005
• 期刊: Ocean and Polar Research 26・3
• 作者: A.Hachikubo et al.

庄子 仁, 高橋信夫: "オホーツク地域とメタンハイドレート"高温学会誌. 29・3. 92-98 (2003)

Hitoshi Shoko、Nobuo Takahashi：“鄂霍次克地区和甲烷水合物”《高温科学学会杂志》29・3（2003）。

Methane hydrate formation and dissociation experiments in submarine sediments from the Okhotsk Sea,

鄂霍次克海海底沉积物中甲烷水合物的形成和解离实验，

• 发表时间: 2005
• 期刊: Proceedings of the Fifth International Conference on Gas Hydrates
• 作者: O.Kitamura et al.

Crystallographic analysis of natural gas hydrate by 13C-NMR method (text in Japanese)

采用 13C-NMR 法对天然气水合物进行晶体分析（日语文本）

• 发表时间: 2005
• 期刊: Chikyu Monthly 27(12)
• 作者: M.YORITOMI;A.MIYAJI;M.MORI;the others;M.Kida et al.
• 通讯作者: M.Kida et al.

Gas hydrates of the Okhotsk Sea : a review of available data and current state of research

鄂霍次克海的天然气水合物：现有数据和研究现状的回顾

• 发表时间: 2002
• 期刊: Proceedings of 4th International Conference on Gas Hydrates, Yokohama, Japan
• 作者: 佐々恭二;T.Matveeva et al.
• 通讯作者: T.Matveeva et al.