吐哈盆地大南湖褐煤生物气和热成因气模拟研究

发布时间：2018-02-21 18:29

本文关键词： 褐煤生物气热成因气生烃模拟实验煤层气成因类型判识模型　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：为了阐明微生物与煤中有机质相互作用及煤岩热演化过程中产气的特征和机理,本文选择新疆吐哈盆地大南湖凹陷最低煤化程度褐煤(Ro,max0.3%左右)为研究对象,设计了生物生烃模拟实验和热解生烃模拟实验,探讨了生物产气和热解产气机理,提出了适合研究区的煤层气成因类型判识标准。在成功富集了产甲烷菌的基础上,跟踪生物生烃模拟实验生气过程中气体的组分变化、碳氢同位素组成特征,揭示了不同产气周期微生物降解的显微组分类型以及产气机理。研究表征第一个产气周期产甲烷菌主要降解煤中腐植组而产气,第二个产气周期主要是降解稳定组和惰质组产气。δ13C(CH4)值与原煤中腐植组含量呈负相关趋势,与惰质组含量有正相关趋势。基于热解生烃模拟实验,揭示了煤岩热演化产气的过程和机理,总结出气态烃碳氢同位素组成与样品热演化阶段对应关系及演化特征。认为随着煤岩演化程度升高,δ13C(CH4)值和δ13C(C2H6)值随着温度的升高呈现先变小后变大的趋势,δD(CH4)值呈现逐渐变大的趋势。采用数理统计方法系统分析模拟实验的数据结果,从地质构造、成煤盆地环境、烃源岩的演化程度及气态烃的碳氢同位素组成特征等方面,提出原生生物气和次生生物气、生物成因气和热成因气的判识指标,并建立适合该区的热成因气烃源岩有机质演化阶段划分的判识模型和煤层气成因类型的判识模型。
[Abstract]:In order to elucidate the interaction between microorganisms and organic matter in coal, and the characteristics and mechanism of gas production during the thermal evolution of coal and rock, this paper chooses the lowest degree of lignite Romax0.3% in the Donanhu sag of Turpan-Hami Basin, Xinjiang) as the object of study. The biological hydrocarbon generation simulation experiment and pyrolytic hydrocarbon generation simulation experiment were designed. The mechanism of biogas production and pyrolysis gas production was discussed, and the criteria for identifying the genetic types of coal bed methane suitable for the study area were put forward. On the basis of successful enrichment of methanogenic bacteria, the biohydrocarbon-generating simulation experiment and pyrolytic hydrocarbon-generation simulation experiment were designed. Tracking the gas composition changes and hydrocarbon isotopic composition characteristics during the gas generation simulation experiment of biogenic hydrocarbon generation, The maceral types and gas production mechanism of microbial degradation in different gas production periods were revealed, and the gas production was characterized by the main degradation of saprophytic groups in coal by methanogenic bacteria in the first gas production period. The second gas production cycle is mainly gas production from stable and inertinite groups. 未 13CU Ch 4) values show a negative trend with the content of saprophytic groups in raw coal, and a positive correlation trend with the content of inertinite groups. Based on the pyrolytic hydrocarbon generation simulation experiments, the second cycle of gas production mainly shows a negative correlation with the content of saprophytic groups in raw coal. The process and mechanism of gas generation in thermal evolution of coal and rock are revealed. The relationship between hydrocarbon isotopic composition of gaseous hydrocarbon and the thermal evolution stage of the sample and its evolution characteristics are summarized. It is concluded that with the increase of coal and rock evolution degree, 未 13 C (Ch 4) and 未 13 C (C 2H 6) values tend to decrease first and then to increase with the increase of temperature, and 未 DU Ch 4) values show a tendency of first decreasing and then increasing with the increase of coal and rock evolution degree. Using mathematical statistics to systematically analyze the results of the simulation experiment, From the aspects of geological structure, coal-forming basin environment, evolution degree of hydrocarbon source rock and hydrocarbon isotopic composition of gaseous hydrocarbon, the identification indexes of proto-biogenic gas, secondary biogenic gas, biogenic gas and thermogenic gas are put forward. The classification model of organic matter in thermogenic gas source rock and the model of genetic type of coalbed methane are established.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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