烃类气体非生物成因及其判识标志

Abiogenesis of Hydrocarbon Gas and Its Identification Index

总结和评述了烃类气体非生物成因的代表性观点,以及最新的研究动态和进展。在蛇纹石化非生物成因烷烃理论的基础之上,分析了非生物成因烃类气体可能生成的地质背景。已经发现的非生物成因天然气的形成与运移,大部分都位于构造活动强烈、地质背景复杂的区域,如何将化学反应机理及其反应条件与具体的地质条件相匹配,是涉及非生物成因天然气成藏至关重要的科学问题。讨论了已有的多种非生物成因烃类气体的判别指标和划分模式,尽管甲烷δ^(13)C的典型分布区间对非生物成因烃类气体的识别非常重要,但需要结合具体的地质背景条件给予合理解释,非生物成因甲烷δ^(13)C可能具有更宽泛的分布区间。实例分析结果表明,综合利用烃类气体碳、氢同位素特征来判别烃类气体的成因具有明显的优越性。

The paper summarizes and reviews some typical viewpoints, latest researches and developments about abiogenic hydrocarbon gases. Based on the theory of serpentinized abiogenic hydrocarbon, the possible geological backgrounds for the formation of abiogenic hydrocarbon gases are analyzed. The discovered formation and migration of abiogenic hydrocarbon gases are mostly located in the areas with intense tectonic activities and complex geological environments. How to match the chemical reaction mechanisms and the reaction conditions with the specific geological conditions is essential to the accumulation of abiogenic hydrocarbon gases. Various identification indices and classification patterns are discussed for abiogenic gases. Although the typical distribution intervals of δ^13C values of methane are significant for abiogenic gas identification, a reasonable explanation should be given in combination with the specific geological background. Actually, δ^13Cvalues of abiogenic methane may have a wider distribution range. The case analysis results show that the comprehensive utilization of carbon and hydrogen isotopes has obvious advantages in identifying hydrocarbon gas genesis.