论文部分内容阅读
从目前的研究来看,低熟气的源岩母质类型主要以有机质丰度较高的Ⅲ型煤系为主。低熟气热演化程度(RO)值在0.4%~0.8%之间,根据煤型气CH4碳同位素组成与热演化程度RO之间的“二阶模式”关系,煤型气CH4碳同位素组成应该分布在-54‰~-39‰之间,目前发现的低熟气CH4碳同位素组成主要集中在-49‰~-39‰之间。一般认为煤型气的C2H6碳同位素组成重于-28‰,但是,当考虑低熟气时,将这一指标定为-29‰更为合适。根据煤型气CH4碳、氢同位素关系,低熟煤型气的CH4氢同位素组成分布在-300‰~-216‰之间。天然气轻烃参数中,低熟煤型气的庚烷值分布在16%~22%之间,异庚烷值分布在2.2~5.0之间。生物气不仅在CH4、C2H6碳同位素组成上与低熟气存在明显的差别,同时在轻烃含量的参数上也存在明显的差别。
According to the current research, the source rock types of low-grade gas are dominated by Type III coal measures with high organic matter abundance. According to the “second-order mode” relationship between the CH4 carbon isotopic composition and the degree of thermal evolution RO of coal-type gas, the carbon monoxide CH4 carbon isotope The composition should be distributed between -54 ‰ ~ -39 ‰, and the carbon isotope compositions of CH4 currently found are mainly concentrated between -49 ‰ and -39 ‰. It is generally accepted that the C2H6 carbon isotope composition of coal-based gas is more than -28 ‰, but it is more appropriate to set this indicator at -29 ‰ when considering low-grade gas. According to the CH4 carbon and hydrogen isotope relationship of coal gas, the CH4 hydrogen isotopic composition of low-mature coal gas distributes between -300 ‰ ~ -216 ‰. Gas light hydrocarbon parameters, low-cooked coal gas heptane distribution between 16% to 22%, isoheptane distribution between 2.2 ~ 5.0. Biogas not only has obvious difference from low-grade gas in CH4, C2H6 carbon isotope composition, but also has obvious difference in parameters of light hydrocarbon content.