川东石炭系原油裂解型气藏成藏史分析

An analysis on pooling history of the Carboniferous thermal methane gas pool,eastern Sichuan basin

应用碳酸盐岩储层次生方解石脉中的烃类流体包裹体研究方法，对四川盆地东部石炭系气藏的形成及充注史进行了恢复研究。流体包裹体鉴定表明，现今气藏储层中除气态烃＋液态烃＋盐水包裹体外，还存在大量多相态（气相、固相及三相）包体，流体包裹体捕获的温度从100—135℃至140～180℃至185～220℃逐渐增高，同时由低温包裹体低含量的甲烷逐渐演变成高温包裹体高含量的甲烷，现今气藏的形成演变是古油藏经历了油气的生成、聚集、破坏乃至受热裂解为气藏的过程。

The formation process and charging history of the Carboniferous gas pools in eastern Sichuan basin are reconstructed through the study of hydrocarbon fluid inclusions from the secondary calcite vein in carbonate reservoirs. Besides gaseous hydrocarbons, liquid hydrocarbons, and saline inclusions, large quantity of multiphase inclusions exist in the present gas reservoirs. These fluid inclusions experienced an increase in their homogenization temperatures from 100℃ - 135℃ to 140℃ ~ 180℃, and to 185℃ -220℃, and during the process, low temperature inclusions with low CH4 content evolved into high temperature inclusions with high CH4 content. The present gas reservoirs are the result of a process through which the ancient hydrocarbon reservoirs went through hydrocarbon generation, accumulation, destruction, and finally thermal cracking into gases.