论文部分内容阅读
鄂尔多斯盆地东缘煤层气甲烷碳同位素分布及其成因对认识该区煤层气藏的形成和分布规律,煤层气资源评价具有重要意义.在系统总结该区煤层气组分和煤层气碳同位素的地域、时域和煤阶分布特征的基础上,结合煤储层演化过程,分析了甲烷碳同位素的变化规律.该区甲烷碳同位素分布范围宽,同位素组成总体偏轻,地域上由北往南呈现“变轻-加重-变轻”的趋势,针对性分析认为北部低煤阶次生生物气的生成,中部水动力活跃地区引起的水溶解分馏,南部构造演化过程中地层抬升造成的解吸分馏,以及局部岩浆运动引起的快速增温生烃分馏是造成该区甲烷碳同位素普遍偏轻的主要因素.
Methane isotope distribution and genesis of coalbed methane in the eastern margin of Ordos Basin Understanding of the formation and distribution of coalbed methane reservoirs and the evaluation of coalbed methane resources are of great significance.After systematically summarizing the CBM components and the carbon isotope of coalbed methane , The time domain and the rank of coal rank, combined with the evolution process of coal reservoir, the variation law of methane carbon isotope was analyzed.The methane carbon isotope in this area has a wide range of distribution, the isotope composition is generally light, and the region appears from north to south The trend of “light - aggravating - light” is pointed out. Targeted analyzes suggest that the formation of low - rank coal biogenic gas in the north, water - dissolving fractionation caused by active hydrodynamics in the central part and desorption caused by stratigraphic uplift in the southern tectonic evolution Fractionation, as well as the rapid warming of hydrocarbon generation caused by local magmatic movement, are the main factors contributing to the generally lighter carbon isotopes in the area.