祁连山冻土区天然气水合物游离气测量技术试验

在青海木里已知水合物发现区,利用west便携式土壤通量测量仪和Picarro公司的G2132-iAnalyzer甲烷碳同位素分析仪开展游离气甲烷现场测量技术试验.游离气甲烷含量特征值和地球化学异常空间分布特征显示,研究区已知水合物矿藏上方存在良好的游离气甲烷地球化学异常,异常展布受到控矿断裂和地下水合物矿藏的影响,具有对应关系.有机地化和甲烷碳同位素证实祁连山冻土区天然气水合物属于热解成因.研究区游离气甲烷地球化学异常成因主要为热解成因与微生物成因,冬季开展游离气甲烷试验能减少地表微生物作用的干扰.试验结果表明,游离气甲烷现场测量技术适用于木里地区天然气水合物地球化学勘查,能够指示水合物矿藏,其最佳采样时间为冬季,是天然气水合物勘查的有效补充技术.

Test of natural hydrate free-gas measuring technique in permafrost region of Qilian Mountain

The field measuring test of free-gas methane was carried out in Muli known hydrate region of Qinghai through west portable soil flux measuring instrument and G2132-iAnalyzer Methane-carbon isotope analyzer.The spatial distribution of free-gas methane characteristic values and geochemical anomaly reveals that there exist good free-gas methane geochemical anomalies above the hydrate deposit,while the spatial distribution of the anomalies is controlled by ore-controlling fractures and underground mineral resources,show ing corresponding relation.The research on organic geochemistry and carbon isotope indicates that the gas hydrates in Qilian permafrost region is of thermal origin.The free-gas methane field analysis shows that the free-gas methane geochemical anomaly is mainly of thermal and microorganism origin,and the free-gas methane experiment in winter can reduce the interference of the surface microbial action.The study results indicates that the free-gas methane field measuring technique is applicable to the natural gas hydrate exploration,which can not only indicate the hydrate deposits but also serve as the mutual supplement to other hydrates geochemical exploration techniques,with the best sampling time being winter.