鄂尔多斯盆地东缘煤层气藏演化及其差异分析

Evolution History of Coalbed Methane Reservoir and Its Difference in Eastern Ordos Basin

文章结合区域构造热事件及构造史、煤系沉积-埋藏史恢复、气体成因分析等重建了研究区煤层气藏演化过程,并对北、中、南段演化差异进行了对比,同时指出了煤层气成藏演化主要事件及其发生的地质时间。研究结果表明,鄂尔多斯盆地东缘煤层气成藏演化过程可以分为4个阶段:北段达到的最大埋藏深度浅、经历的最大古地温低、煤的热成熟度低,气体生成量少,中部上述各项指标居中,南部最大。从现今含气量的分布可以发现同样的规律。

By analyzing the tectonic history,the thermal events,the simulation of burial history,gas-generated history and gas origin,the gas evolution process is rebuilt,the difference among the north,central and the south parts is contrasted and the main reservoir-forming events is studied.The result shows that the evolution of CBM reservoir is divided into four stages.In the north part,the maximum depth is shallow in the geological history,the maximum paleotemperature and the coal rank is low and the quantity of generated gas is little;the above index is medium in the central part;however,the index is biggest in the south part.The same distribution of the gas content is found and shows the increasing trend from the north to the south.