云南大河煤矿区中深部煤层气特征及含气量影响因素分析

Analysis on Coalbed Methane Characteristics and Influencing Factors of Gas Content in Middle and Deep Part of Dahe Coal Mine Area,Yunnan Province

通过对煤层气参数测试井实测含气量、镜下鉴定及收集等温吸附性实验数据等方法,对大河煤矿区煤储层煤岩煤质、渗透率、含气性等进行研究。研究表明,大河煤矿区浅部以低煤级的肥煤为主,深部以中、高煤级的焦煤、瘦煤为主。大部分可采煤层渗透率<1mD,煤层气含气饱和度14.17%~68.91%,储层压力梯度0.62~1.07 MPa/100m,临界解吸压力0.26~3.03MPa,煤层气含气量主要受聚煤环境、煤层厚度、埋深、构造等地质因素的影响。

Through testing gas content of the coalbed methane parameter wells,microscopic identification and collecting isothermal adsorption experiment data,this paper studies the coal rock,coal quality,permeability and gas content of coal reservoirs in Dahe coal mine area.The research shows that the coal seams in Dahe coal mine area are mainly fat coal in the shallow area,and mainly coking and lean coal in deep area.The permeability of most recoverable coal seams is less than 1mD,the gas saturation of coalbed methane is 14.17%~68.91%,the reservoir pressure gradient is 0.62~1.07 MPa/100m,and the critical desorption pressure is 0.26~3.03MPa.The gas content of coalbed methane is mainly affected by coal accumulating environment,thickness,depth and geological structure factors.