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为深入探讨煤层注水的防突机理,采用压汞法测试阳泉3号煤干燥煤样和高压注水后煤样的孔隙特性,通过试验发现:注水后煤样孔容、平均孔径、孔隙率及渗透率比注水前分别增加45.17%,48.88%,46.26%和122.95%;而且试验煤样孔隙发育,裂隙和大孔占总孔容的90%以上,过渡孔和微孔占总比表面积的99%以上。试验结果表明,注水前后试验煤样孔隙特性的发生明显变化,说明高压注水对阳泉3号煤的孔隙特性影响显著。通过分析认为,阳泉3号煤具备注水防突的条件,在孔容方面,裂隙和大孔发育,有利于煤层注水水分充分运移;在比表面积方面,以微孔为主,有利于水分在大孔通道中封堵吸附瓦斯,在毛细管力作用下形成抑制解吸效应。
In order to deeply discuss the mechanism of water outburst prevention in coal seams, the pore properties of coal sample after the injection of Yangquan No.3 coal were measured by mercury intrusion porosimetry. The pore volume, average pore diameter, porosity and permeation The rate of increase was 45.17%, 48.88%, 46.26% and 122.95% respectively than that before water injection. Moreover, the pores of coal samples developed, the fractures and macropores accounted for more than 90% of the total pore volume, the transition pores and micropores accounted for 99% of the total surface area, the above. The test results show that the pore characteristics of coal samples before and after water injection have obviously changed, which shows that the high pressure water injection has a significant effect on the pore properties of Yangquan No.3 coal. According to the analysis, Yangquan No. 3 coal has the conditions of water injection and prevention of outburst. In terms of pore volume, the development of fissures and macropores is conducive to the full migration of water injected into the coal seam. In terms of specific surface area, micropores are dominant, In the macroporous channel, the adsorbed gas is blocked and the desorption effect is formed under the capillary force.