晋城煤层气藏成藏机制

Reservoir-Forming Mechanism of Coalbed Methane in Jincheng Anthracite

通过晋城煤层气的规模开发、压裂煤层气井的解剖、井下煤层瓦斯抽放、构造地应力场研究、煤储层大裂隙系统"CT"式解剖与煤层气封闭保存条件研究,发现3#煤储层内部存在大量煤层气包,构造微破裂作用促使煤层气包之间广泛合并联通,煤层气包内部储层的非均质性弱化,渗透率增加,煤层气包内部的游离气体比例增加,流体压力系统边界逐渐清晰并形成煤层气藏.揭示煤层气藏的成藏机制,认识煤层气藏的内部细节特征,促进了该区的煤层气开发技术进步,提高了井下煤层瓦斯的抽放效率.

With the aim of studying reservoir-forming mechanism of coalbed methane （CBM） in the area of Jincheng, through the continuous development of coalbed methane in Jincheng, the dissection of fracturing coalhed methane wells, the extraction of underground coal seam gas, the study of tectonic stress field, the ＂CT＂-dissection of the fracture system of coal reservoir and the sutdy of dosed preservation conditions on coalbed methane, we found that there are a lot of CBM packages in 3^# coal reservoir and these CBM packages merge together because of micro-structural breakdown As a result, the heterogeneity of reservoir in CBM packages becomes weak; the permeability increases; the proportion of free gas increases in CBM package and the fluid pressure system gradually clears. Eventually, the above factors jointly contribute to the formation of the border of coalbed methane reservoir. The study on the accumulation mechanism of coalbed methane and the characteristics of the internal details of coalbed methane reservoir promotes the development of coalbed methane exploiting technology and improves the efficiency of extracting the underground coal seam gas.