Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at consta...Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at constant temperature but different equilibrium pressure conditions. Based on these experimental results, the temporal evolution of component fractionation in the field was investigated. The results show that the CO2 concentration in the adsorbed phase is always greater than that in the original gas mixture during the desorption process, while CH4 shows the opposite characteristics. This has confirmed that CO2 , with a greater adsorption ability has a predominant position in the competition with CH4 under different pressures. Where gas drainage is employed, the ratio of CO2 to CH4 varies with time and space in floor roadways used for gas drainage, and in the ventilation air in Nos.1 and 2 coal seams, which is consistent with laboratory results.展开更多
为了探究Klinkenberg效应及不同状态的Klinkenberg因子在注CO_(2)提高煤层气采收率(CO_(2)-Enhanced Coal Bed Methane,CO_(2)-ECBM)过程中的作用,借助COMSOL有限元软件模拟分析了Klinkenberg因子为0、固定Klinkenberg因子与动态Klinken...为了探究Klinkenberg效应及不同状态的Klinkenberg因子在注CO_(2)提高煤层气采收率(CO_(2)-Enhanced Coal Bed Methane,CO_(2)-ECBM)过程中的作用,借助COMSOL有限元软件模拟分析了Klinkenberg因子为0、固定Klinkenberg因子与动态Klinkenberg因子3种状态对CO_(2)-ECBM及有效渗透率的影响,以及CH_(4)与CO_(2)压力随该因子的动态变化情况,并将CH_(4)产气量与工程实际作了对比验证。结果表明,CH_(4)与CO_(2)有效渗透率呈先缓慢增长再急速下降后逐渐趋于平缓的态势,相较于固定Klinkenberg因子或Klinkenberg因子为0,动态Klinkenberg因子影响下的CH_(4)与CO_(2)有效渗透率更大,当Klinkenberg因子为动态变量时,受不同气体的摩尔质量与动力黏度影响,CO_(2)有效渗透率小于CH_(4)有效渗透率。在动态Klinkenberg因子作用下,煤层中CH_(4)压力下降和CO_(2)压力上升均更快,当Klinkenberg因子为固定值或0时,会高估煤层内CH_(4)压力,低估CH_(4)抽采与CO_(2)压注的影响范围,并且估值均随时间增长而增大。工程验证表明,考虑动态Klinkenberg因子作用下的CH_(4)累积产气量更接近真实情况。研究成果有助于分析CH_(4)与CO_(2)有效渗透率变化趋势,预估CH_(4)抽采与CO_(2)压注的影响范围及CH_(4)产气量,在探究煤层增渗,优化井网布置,定量评价煤田产气量等方面具有理论指导意义。展开更多
La Yesca银多金属矿区位于环太平洋成矿带的科迪勒拉褶皱带上,处于西马德雷火山岩带南部与墨西哥中部火山岩带西段北部的交汇部位。该矿位于墨西哥块状硫化物型Cu-Pb-Zn-Au-Ag成矿带北部,成矿地质条件优越。为查明该地区银多金属矿床资...La Yesca银多金属矿区位于环太平洋成矿带的科迪勒拉褶皱带上,处于西马德雷火山岩带南部与墨西哥中部火山岩带西段北部的交汇部位。该矿位于墨西哥块状硫化物型Cu-Pb-Zn-Au-Ag成矿带北部,成矿地质条件优越。为查明该地区银多金属矿床资源潜力及其成矿规律,相继开展了1∶25000水系沉积物测量、1∶10000地质简测、1∶2000地质简测、槽探、钻探施工等。研究表明:①新近系Tm组地层为主要的含矿层,矿床在空间上都与破火山口构造边缘同心状切向断裂、断裂带关系密切;②矿床工业类型为银锰铅锌型,矿床成矿元素分带展布,深部为铅锌银矿床,含少量锰,中上部及周边为银锰伴生铅锌矿床,顶部为锰银铅锌矿床;③矿区内共圈出了27条矿化蚀变带(矿带),33条矿体,矿床Ag平均品位为243.18×10-6,Ag金属量4416 t;④La Yesca银多金属矿为一大型蚀变岩型低温热液银锰多金属矿床。在上述分析的基础上,总结了银多金属矿区的成矿规律,探讨了今后的找矿方向。展开更多
The objective of this work is to study the gas desorption characteristics of the high-rank intact coal and fractured coal.The gas adsorption,mercury porosimetry and gas desorption experiments were carried out in this ...The objective of this work is to study the gas desorption characteristics of the high-rank intact coal and fractured coal.The gas adsorption,mercury porosimetry and gas desorption experiments were carried out in this study.Then,the theories of thermodynamics,diffusion mechanism and desorption kinetics were used to estimate the gas desorption characteristics.The results of gas adsorption experiments show that the initial isosteric adsorption heat of the intact coal is greater than that of the fractured coal,indicating that the gas molecules desorb more easily from fractured coal than intact coal.Using the mercury porosimetry,we find that the diffusion channels of fractured coal are more developed than those of intact coal.The difficult diffusion form dominates in the intact coal during the gas diffusing,while the easy diffusion form dominates in the fractured coal.The results of gas desorption experiments show that the initial gas desorption volume and velocity of the fractured coal are both greater than those of the intact coal.Using the Fick diffusion law,the study calculates the gas diffusion coefficients of the intact coal and fractured coal.The diffusion coefficients of the fractured coal are 2 times and 10 times greater than those of the intact coal at the time of 0-120 and 0-10 min,respectively.展开更多
基金financially supported by the Natural Science Foundation for the Youth of China (No. 41202118)the Fundamental Research Funds for the Central Universities (No.2012QNB03)
文摘Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at constant temperature but different equilibrium pressure conditions. Based on these experimental results, the temporal evolution of component fractionation in the field was investigated. The results show that the CO2 concentration in the adsorbed phase is always greater than that in the original gas mixture during the desorption process, while CH4 shows the opposite characteristics. This has confirmed that CO2 , with a greater adsorption ability has a predominant position in the competition with CH4 under different pressures. Where gas drainage is employed, the ratio of CO2 to CH4 varies with time and space in floor roadways used for gas drainage, and in the ventilation air in Nos.1 and 2 coal seams, which is consistent with laboratory results.
文摘为了探究Klinkenberg效应及不同状态的Klinkenberg因子在注CO_(2)提高煤层气采收率(CO_(2)-Enhanced Coal Bed Methane,CO_(2)-ECBM)过程中的作用,借助COMSOL有限元软件模拟分析了Klinkenberg因子为0、固定Klinkenberg因子与动态Klinkenberg因子3种状态对CO_(2)-ECBM及有效渗透率的影响,以及CH_(4)与CO_(2)压力随该因子的动态变化情况,并将CH_(4)产气量与工程实际作了对比验证。结果表明,CH_(4)与CO_(2)有效渗透率呈先缓慢增长再急速下降后逐渐趋于平缓的态势,相较于固定Klinkenberg因子或Klinkenberg因子为0,动态Klinkenberg因子影响下的CH_(4)与CO_(2)有效渗透率更大,当Klinkenberg因子为动态变量时,受不同气体的摩尔质量与动力黏度影响,CO_(2)有效渗透率小于CH_(4)有效渗透率。在动态Klinkenberg因子作用下,煤层中CH_(4)压力下降和CO_(2)压力上升均更快,当Klinkenberg因子为固定值或0时,会高估煤层内CH_(4)压力,低估CH_(4)抽采与CO_(2)压注的影响范围,并且估值均随时间增长而增大。工程验证表明,考虑动态Klinkenberg因子作用下的CH_(4)累积产气量更接近真实情况。研究成果有助于分析CH_(4)与CO_(2)有效渗透率变化趋势,预估CH_(4)抽采与CO_(2)压注的影响范围及CH_(4)产气量,在探究煤层增渗,优化井网布置,定量评价煤田产气量等方面具有理论指导意义。
基金provided by the National Basic Research Program of China(No.2011CB201204)the Natural Science Foundation for the Youth of China(Nos.41202118 and 51204173)
文摘The objective of this work is to study the gas desorption characteristics of the high-rank intact coal and fractured coal.The gas adsorption,mercury porosimetry and gas desorption experiments were carried out in this study.Then,the theories of thermodynamics,diffusion mechanism and desorption kinetics were used to estimate the gas desorption characteristics.The results of gas adsorption experiments show that the initial isosteric adsorption heat of the intact coal is greater than that of the fractured coal,indicating that the gas molecules desorb more easily from fractured coal than intact coal.Using the mercury porosimetry,we find that the diffusion channels of fractured coal are more developed than those of intact coal.The difficult diffusion form dominates in the intact coal during the gas diffusing,while the easy diffusion form dominates in the fractured coal.The results of gas desorption experiments show that the initial gas desorption volume and velocity of the fractured coal are both greater than those of the intact coal.Using the Fick diffusion law,the study calculates the gas diffusion coefficients of the intact coal and fractured coal.The diffusion coefficients of the fractured coal are 2 times and 10 times greater than those of the intact coal at the time of 0-120 and 0-10 min,respectively.
