地球物理方法可以实现燃空区的间接探测,而钻孔探测可以更直接地获得燃空区样品,深入了解地下气化工况及燃空区形貌。依托煤炭地下气化现场试验工程,采用直接钻孔探测及取样,对获取的煤、岩、焦、渣样品进行了元素分析及灰分分析,采用XRD,SEM-EDS对其矿物质组成进行了表征。研究结果表明,高活性褐煤煤层空气气化,气化面的径向扩展宽度小于17 m。在沿主气化通道径向扩展4 m附近,煤层经历了高温气化反应并伴随高温特征矿物质的生成,气化后煤层残炭约为10%,煤层的气化引起了上覆盖岩层的松动与坍塌;距离气化通道径向扩展17 m位置,接近气化传热的边缘,只有上部煤层受到热的影响,煤层顶板未发生变形;在此基础上绘制了燃空区综合形貌图。

Geophysical methods have been applied for the indirect monitoring of combustion cavity,while exploration through drilling borehole could provide much more information about the combustion cavity,the cavity boundary,and the changes of the roof and bottom rock layer directly. In this study,based on the drilling exploration of a field test of underground coal gasification,the samples of coal,char,ash,slag and rock along the drilling boreholes were obtained, and then the proximate analysis,XRD and SEM-EDS analysis were performed to investigate the changes of their prop- erties. The results show that high activity lignite underground gasification through blowing air,the expanded width of gasification surface is less than 17 m. About 4 m away from the directional drilling channel,perpendicular to the direc- tion of the airflow,high temperature gasification reaction occurs in the coal seam and accompanied by the formation of typical minerals such as anorthite. In this area carbon residue in the ash is about 10% ,and coal seam gasification cau- ses the loose and collapse of overburden. The position 17 m away from the directional drilling channel is close to the boundary of heat transfer,where only the upper coal seam is affected by heat,and the deformation of roof rock is not observed. In addition,the comprehensive profile of the combustion cavity is plotted.

1 钻孔取样探测

   1.1 气化区煤田地质概述

   1.2 气化炉及气化试验描述

   1.3 钻探取样

   1.4 样品表征与分析

2 结果与讨论

   2.1 煤层气化状况分析

   2.2 特征矿物质组成变化

   2.3 燃空区形貌分析

3 结论