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

基本信息

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

项目摘要

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.

Chaos（Hydro-Coar Hydrate积累了Okhotsk海洋中积累）由Kitami Technology Institute在2003年，调查结果揭示了与Seec的特征性的特征性的特征性的表演，该项目由Chaos（Hydro-Cary Hydrate积累在Okhotsk Sea）中。在10 x 20公里的调查区域中发现了40多个渗流结构。观察到的渗漏结构的最大尺寸为直径约为600 m。从渗水结构中释放到上述水中的甲烷气体通过水力声学分析被检测到耀斑图像。从这些渗流结构中获得气体水合物和沉积物核心样品，并通过气相色谱，液相色谱，氧气/氢/碳同位素，13C-NMR，热分析，物理分析，物理分析和其他分析技术运送到基塔米技术研究所进行实验室研究。在海底2-3米的深度内观察到大量形式，层和/或小块的甲烷水合物。核心恢复后立即将气体水合物样品存储在液氮温度容器中，以防止水合样品解离。所获得的主要结果总结如下。被困在水合物中的客人气体主要是甲烷，只有少量的乙烷，丙烷等。水合物的晶体结构是覆盖水合物结构I，水合数接近六个，显示出非常高的气体水合物。碳同位素和气体成分测量结果表明，气体水合物中的甲烷气体是微生物起源的。发现测量的气体水合物的潜热与人造纯甲烷水合物相当接近。