Abstract: The opposite opinions about the problem that coal-bed gas was derived from coal and its measure strata are presented. The carbon isotope composition of coal-bed gas（CH₄ and CO₂), the isotope compositions and products obtained from the thermal simulation experiment of coal and its measure strata as well as the abnormal high-mercury contents in the coal-bed gas were observed. The geotectonic environment of coal-bed gas reservoir formation and the gas eruption in the coal mine and forest fire were analyzed. The abnormity of satellite thermal ultra-red was found before gas eruption and forest fire. According to the practice and experiences of coal-bed gas exploration in the United States, the coal-bed gas might be derived from the deep crust or upper mantle, the form of the methane is depended on gas divorced from upper mantle and the Fischer-Tropsch synthetic, rather than coal and coal measures strata. On the basis of the above origins, a new plan for preventing coal-bed methane explosion may be discovered. The exploration targets of coal-bed gas will be reconsidered.

Key words: coal- bed gas origin, carbon isotope, coal measure strata, geotectonic environment

摘要： 对于煤层气来自于煤及煤系地层的问题提出了不同的观点。通过观察煤层气的碳同位素组成(CH₄和CO₂)、煤岩及烃源岩的热模拟产物及碳同位素组成、煤层气中异常高的汞含量,分析了煤层气储集地层的大地构造环境及煤矿气体突出和森林火灾,发现气体突出和森林火灾前有卫星热红外异常。根据美国煤层气的勘探实践经验,推断煤层气可能来自深部地壳或上地幔,甲烷气体是通过上地幔脱气作用或中地壳的费托合成而生成的,而不是来自煤及其煤系地层。根据这一成因模式,可以探索预防煤矿瓦斯爆炸的新方案,重新考虑煤层气勘探目标。

关键词: 煤层气成因, 碳同位素, 煤系地层, 大地构造环境