青海聚乎更钻探区天然气水合物拉曼光谱特征

了解天然气水合物的微观结构特征对水合物资源勘探和评价具有重要意义。采用显微激光拉曼光谱技术，对青海聚乎更钻探区内DK8-19、DK11-14 和DK12-13等3个站位共9个天然气水合物岩心样品进行了分析测试，探讨了钻探区天然气水合物的拉曼光谱特征。结果表明，青海聚乎更钻探区天然气水合物广泛分布，垂直方向在126.1~322.2 m范围内不连续分布，不同钻孔、不同埋深水合物样品的拉曼光谱特征基本一致，初步判断为Ⅱ型结构水合物，且为多元气体水合物。水合物客体除甲烷、乙烷、丙烷及丁烷等 烷烃外，普遍含有氮气组分。此外，在DK8-19站位埋深为126.1 m样品中发现水合物相中硫化氢组分的拉曼信号，这说明特定区域内可能存在硫化氢气体且形成了水合物。聚乎更钻探区水合 物样品拉曼光谱特征为冻土区天然气水合物成藏与分布规律研究提供了新的启示。

Raman Spectroscopic Characteristics of Natural Gas Hydrates from Juhugeng Drilling Area,Qinghai

The structure characteristics of natural gas hydrates play a significant role in the exploration and evaluation of natural gas hydrate resource. In this paper, the hydrate samples, recovered from DK8 -19, DK11-14 and DK12-13 holes in the Juhugeng drilling area in Qinghai, were investigated by micro-Raman spectroscopy for the structure characteristics. The results show that gas hydrates are widely distributed in the Juhugeng drilling area. In the vertical direction, gas hydrate are distributed discontinuously between the depth of 126.1 and 322.2 m. The Raman characteristics of gas hydrates from the three sites with different depths are almost the same, and show structure Ⅱ hydrate with various gas molecules. Besides hydrocarbons such as CH₄, C₂H₆, C₃H₈ and C₄H₁₀, N₂ is generally observed in these gas hydrates samples. In addition, the Raman signals attributed to H₂S in hydrate phase is found in the gas hydrate sample at depth of 126.1 m from DK8-19 hole, and it is the first time that H₂S in hydrate phase is found in Qilian Mountain hydrates,suggesting that H₂S gas molecules exist in some particular areas and gas hydrates form. The Raman spectroscopic characteristics of natural gas hydrates recovered from the Juhugeng drilling area may provide some new revelations for the study on the accumulation and distribution of gas hydrates located in the permafrost area in Qinghai.