煤系地层注入CO_2开采煤层气质交换的机理  

Mass exchange mechanism of coalbed methane exploitation by CO_2 injection in coal measure strata

作　　者：张美红[1] 吴世跃[1] 李川田[1,2] 

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原科技大学环境与安全学院,山西太原030024

出　　处：《煤炭学报》2013年第7期1196-1200,共5页Journal of China Coal Society

基　　金：国家科技支撑计划资助项目(2007BAK29B01);山西省科技攻关资助项目(2007031120-02)

摘　　要：论述了注CO2开采煤层气质交换机理和煤系地层封存CO2意义,建立了注CO2开采煤层气的物理数学模型。采用饱和食盐水集气方法测定了表征解吸阻力大小的综合参数——综合传质系数α随浓度、煤变质程度、放散时间的变化规律。试验结果表明:α随煤粒吸附基质浓度的增大而增大;变质程度相同时,CH4的α随时间的衰减较CO2的α随时间的衰减慢;基质浓度相同时,煤变质程度越高,α越小,且对不同变质程度的煤岩,CH4的α大于CO2的α,即不同变质程度的煤岩对CO2的吸附能力都大于CH4。说明注气增加储层压力促进气体解吸置换,各种煤岩对CH4的解吸量大于对CO2的解吸量这一现象与煤的变质程度无关。因此,在不同变质程度煤层,甚至煤系地层中,注气开采煤层气与储存CO2技术在理论上都是可行的。This study investigated the mass exchange mechanism of exploiting coal-bed methane by CO2 injection and the significance of carbon storage in coal strata. Also, a physical and mathematical model of exploiting methane by CO2 injection was developed. Gas collecting method by saturated salt solution was used for an experimental study on the re- lationship of mass transfer coefficients, which vary with the degree of coal metamorphism, the concentration and gas emission time. According to the analysis on experimental data, a positive correlation was found between c and concen-tration. With the same degree of coal metamorphism, the speed of a deduces over time, and the c speed reduction of CH4 is slower than that of CO2. With the same concentration level, a negative correlation was found between c and coal metamorphism. The a of CH4 is higher than that of CO2 with different metamorphisms, which means the adsorption ca- pacity of CO2 is higher than that of CH4 with different metamorphisms. The CO2 injection not only increases the reser- voir pressure, but also enhances the gas desorption displacement. The desorption amount of CH4 was more than that of CO2 has nothing to do with the coal metamorphic level. Therefore, the exploitation of coal-bed methane by gas injection and carbon dioxide storage is feasible in different metamorphic degrees of coal seam, even in the coal measure stratum.

关 键 词：煤系地层 注气 煤层气 质交换机理 综合传质系数 

分 类 号：P618.11[天文地球—矿床学]