煤层气与常规天然气地球化学控制因素比较

Differences for geochemical controlling factors between coal-bed and conventional natural gases

山西沁水盆地南部晋城地区和西部霍州地区的煤层热演化史和煤层气地球化学特征的对比研究表明,演化程度最高的地质时期决定了煤层气的组分和组分碳同位素组成特征,煤层气的组分和组分碳同位素组成特征也反映了煤层所经历的热演化过程。由于煤层气储集于其源岩煤层中,因此热演化过程对其地化特征的控制作用既不同于常规气藏的阶段聚气过程,也不同于常规气藏的连续聚气过程。由于储气方式的差异,次生作用对煤层气和常规天然气地球化学特征的影响方式和效果也不同。

Contrasting the coal-bed thermal evolution and the coal- bed gas geochemical characteristics in the Jincheng area of south Qinshui Basin and in the Huozhou area, western Qinshui Basin, central China, suggests that the geochemical characteristics of coalbed gas, such as components and carbon isotopic compositions, are controlled by the key geological period, when the coal-bed reached the highest mature rank. Whereas the components and carbon isotopes of the coal-bed gas could reflect the coal-bed thermal evolution. Because the coal-bed gas is very different from conventional natural gas in storage mechanism, the effect on the geochemical characteristics of coal-bed gas by thermal evolution is different from stage and consecution accumulation processes for the conventional natural gas. The storage mechanism difference has obvious effects on the geochemical characteristics of coal-bed gas, which is different from that of the conventional natural gas.