煤基质甲烷扩散系数测试及其影响因素分析  

Measurement of methane diffusion coefficient and analysis of its influencing factors in coal matrix

作　　者：赵俊龙[1,2] 汤达祯[1,2] 许浩[1,2] 李松[1,2] 陶树[1,2] 翟雨阳[3] 梁为[3] 林文姬[3] 霍祥盛[3] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]煤层气开发利用国家工程中心煤储层实验室,北京100083 [3]中联煤层气国家工程研究中心有限责任公司,北京100095

出　　处：《煤炭科学技术》2016年第10期77-82,145,共7页Coal Science and Technology

基　　金：国家科技重大专项资助项目(2016ZX05042-002);国家自然科学基金资助项目(41530314;41272175)

摘　　要：为准确测试煤岩甲烷扩散系数,通过采用片状煤基质作为检测样品,测试并分析了不同气体压力、煤阶与水分对甲烷扩散系数的影响。结果表明:片状样品保持了煤基质特有的空间结构,煤基质甲烷扩散系数(数量级10^(-11)~10^(-9)m^2/s)更符合实际;当温度一定时,无论是干燥样品、饱和水样品,还是低、中、高煤阶样品,煤基质甲烷扩散系数均随气体压力的增加而增大;而不同变质程度煤的吸附能力不同,随着煤的变质程度增加,煤岩吸附能力增强,但是煤基质的扩散系数随着变质程度增加呈现先降低后增加的趋势;水分的增加降低了基质对甲烷的吸附能力,难以形成较大浓度梯度,导致饱和水样品煤岩基质甲烷扩散系数比干燥样品低,干燥样品扩散速率快。In order to measure the methane diffusion coefficient accurately in the coal matrix,the coal matrix flakes were used as the samples to be measured,and the influencing factors（ such as gas pressure,coal rank and moisture content） of the methane diffusion coefficients were also analyzed. Results showed that due to the preservation of the intrinsic space structure of the coal matrix within the flake samples,the methane diffusion coefficients was on the order of 10^（-11）~ 10^（-9）m^2/ s,which were more truthful. Under the identical temperature,the methane diffusion coefficient increases with increasing gas pressure regardless of the water saturation and coal rank. The adsorption capacity increases when the metamorphic degree of coal increases,while the methane diffusion coefficient in coal matrixes exhibit has a trend of first dropping and then rising with an increase in coal rank. Moreover,the increasing moisture can reduce the matrix adsorption capacity for methane,which makes it difficult to form a larger concentration gradient because the diffusion coefficients of dry samples are higher than those of the saturated water samples and the diffusion rates of dry samples are also fast.

关 键 词：煤基质 扩散系数 气体压力 煤阶 水分 甲烷 

分 类 号：P618.11[天文地球—矿床学]