我国煤层甲烷碳同位素分布特征与瓦斯成因类型划分探讨

A Discussion on Coal Seam Methane Carbon Isotope Distribution Features and Gas Genetic Classification in China

以170余组煤层甲烷碳同位素测定结果为依据,分析了我国煤层瓦斯的δ13C1值分布特征,探讨了瓦斯成因类型划分,研究结果显示:δ13C1值分布范围为-73.3‰～-27.3‰,δ13C1值随煤的变质程度的增加总体增大,无烟煤阶段以后,δ13C1的变化趋于平稳,在-35‰上下波动;根据煤层甲烷碳同位素与煤级之间的变化关系,以煤的最大镜质体反射率作为指标,将我国煤层瓦斯成因分为次生生物成因气、混合成因气和热成因气三大类,并指出了我国部分煤矿区的瓦斯成因类型。

Based on 170 plus sets of coal seam methane carbon isotope measured results, analyzed δ13C value distribution features of Chinese coal seam gas, discussed its genetic classification. The studied results have demonstrated that： the distribution range of δ13C value is within -73.3‰-27.3‰, the value increasing along with the degree of coal metamorphism. After the anthracite stage, the value variations tend to be stable, fluctuating about -35‰ or so. According to varying relations between coal seam methane carbon isotope and coal ranks, taking maximum reflectance of vitrinite as indicator, classified Chinese coal seam gas genesis into 3 major types： secondary biogenetic, mixing origin and thermogenetic gases, and pointed out gas genetic types of part coal mining areas in China.