摘要
煤的孔隙率影响煤的吸附、渗透能力,且它也是衡量煤体内部结构及孔、裂隙发育状况的重要指标.而水力增透技术在瓦斯抽采中的作用效果常常受到水的影响,且瓦斯抽采量也会受到含水煤层的影响,为更客观地了解含水煤层状态下的孔隙率的变化情况,采用超声波透射法对赵固二矿二1煤层不同层理方向煤样在干燥及自然饱和吸水状态下进行三轴加载超声波测试试验,研究干燥及自然饱和水三轴加载状态下煤样超声波波速与孔隙率关系.研究结果表明:相同条件下,加载煤样饱和煤样波速大于干燥煤样,且加载煤样饱和状态下不同层理方向波速变化易区别.而加载煤样饱和煤样与干燥煤样孔隙率变化与波速变化相反,加载煤样饱和状态下不同层理方向孔隙率变化不易区别;通过分析加载条件下饱和煤样与干燥煤样波速与孔隙率关系,发现无论是干燥煤样还是饱和煤样在加载条件下都符合对数关系φ=-aIn(VP)+b且a值与围压有关,b值与孔隙率变化量有关.通过研究含水煤样在不同加载条件下对煤体波速和孔隙率的影响以及波速和孔隙率之间的关系,为煤炭物性勘探技术提供有效试验数据与理论基础,也为煤炭物性预防安全开采提供理论基础.
Coal porosity is not only an important index to measure the development of coal pores and fractures, but also an important factor to influence the adsorption and permeability of coal. The role of hydraulic anti-reflection technology in gas extraction effect is often affected by the water, the gas extraction quantity is also affected by the water-bearing coal seam, to a more objective understanding of the water condition of the change of porosity of coal seam, the ultrasonic transmission method for Zhao Gu 2 coal mine NO.2-1 coal seam in different direction of bedding in dry coal samples and the natural state of saturated water absorption under triaxial loading ultrasonic testing experiment, the study of dry and natural saturated coal sample under triaxial loading state water ultrasonic wave velocity and porosity. The results show that under the same condition, the wave velocity of the saturated coal sample loaded with coal sample is higher than that of the dry coal sample, and it is easy to change the wave velocity in different bedding directions under the saturated coal sample loaded with coal sample. However, the porosity change of the loaded coal sample is opposite to that of the dry coal sample. The porosity change of different bedding directions is not easy to distinguish when the loaded coal sample is saturated. By analyzing the relationship between wave velocity and porosity of saturated coal samples and dry coal samples under loading conditions, it is found that both dry coal samples and saturated coal samples conform to logarithmic relationship φ=-aIn(V;)+b under loading conditions and the a is related to the confining pressure, and the b is related to the change in porosity. By studying the influence of water-bearing coal samples on the wave velocity and porosity of coal under different loading conditions and the relationship between wave velocity and porosity, it provides the experimental reference and theoretical basis for the later development of coalbed methane, ultrasonic geophysical exploration a
作者
陈世强
李东会
张明杰
梁雁侠
王云刚
CHEN ShiQiang;LI DongHui;ZHANG MingJie;LIANG YanXia;WANG YunGang(State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Henan Polytechnic University,Jiaozuo 454000,China;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Jiaozuo 454000,China)
出处
《地球物理学进展》
CSCD
北大核心
2021年第5期2151-2158,共8页
Progress in Geophysics
基金
河南联合国家自然科学基金项目(U1704129)
河南省自然科学基金项目(182300410138)
河南省博士后经费项目(19030070)联合资助。
关键词
含水煤样
三轴加载
孔隙率
波速
线性拟合
Water bearing coal sample
Triaxial loading
Porosity
Wave velocity
Linear fitting
