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Coal Geology & Exploration

Authors

LIU Gaofeng, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China; Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454003, ChinaFollow
LI Baolin, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China
ZHANG Zhen, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China
LIU Huan, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China
GUAN Wenbo, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China
SI Nian, Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China ; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Henan Polytechnic University, Jiaozuo 454003, China

Abstract

To achieve an elevated accuracy in the prediction of coal and gas outbursts, this study conducted mercury injection capillary pressure (MICP) tests and isotherm adsorption experiments on selected six coal samples with different metamorphic degrees. Furthermore, it calculated the gas expansion energy of coals and analyzed the evolutionary characteristics of the gas expansion energy of coals with different metamorphic degrees, as well as their relationships with the prediction indices of coal and gas outbursts. The results of this study are as follows: (1) The differences in the pore structures and adsorptivity of coals with different metamorphic degrees led to different gas expansion energy. (2) The total gas expansion energy and the adsorbed-gas expansion energy increased with gas pressure, with the increasing trend gradually slowing down. Under the same gas pressure, a higher metamorphic degree of coals was associated with higher total gas expansion energy and adsorbed-gas expansion energy. (3) The free-gas expansion energy increased exponentially with gas pressure. Under the same gas pressure, the free-gas expansion energy increased with the pore volume per unit mass of coals. (4) When Rmax > 1.6%, the free-gas expansion energy corresponding to the gas pressure of 0.74 MPa was roughly equivalent to the critical values (42.98 mJ/g) of initially released expansion energy that induced outbursts. This further verifies that free gas plays a major role in the triggering stage of outbursts and also provides a scientific basis for the rationality of using 0.74 MPa as the critical gas pressure value for outburst prediction. When Rmax ranged between 0.6%‒1.6%, the free-gas expansion energy corresponding to the gas pressure of 0.74 MPa was below 42.98 mJ/g, leading to exaggerated outburst potential of coals and increased efforts paid to outburst prevention. When Rmax < 0.6%, the free-gas expansion energy corresponding to 0.74 MPa exceeded 42.98 mJ/g, leading to the occurrence of outbursts under a low index. Therefore, it is necessary to fully consider the influence of coals’ metamorphic degrees on coal and gas outbursts. This study will provide a novel scientific basis and a method reference for the prediction of coal and gas outbursts.

Keywords

coal and gas outburst, gas expansion energy, coal metamorphic degree, pore structure, gas pressure, gas content

Reference

[1] CHENG Yuanping,PAN Zhejun. Reservoir properties of Chinese tectonic coal:A review[J]. Fuel,2020,260:116350.

[2] 李希建,林柏泉. 煤与瓦斯突出机理研究现状及分析[J]. 煤田地质与勘探,2010,38(1):7−13.

LI Xijian,LIN Baiquan. Status of research and analysis on coal and gas outburst mechanism[J]. Coal Geology & Exploration,2010,38(1):7−13.

[3] HE Xueqiu,CHEN Wenxue,NIE Baisheng,et al. Classification technique for danger classes of coal and gas outburst in deep coal mines[J]. Safety Science,2010,48(2):173−178.

[4] 郭德勇,胡杰,王彦凯. 煤与瓦斯突出层次–可拓预警技术及应用[J]. 中国安全科学学报,2017,27(1):88−92.

GUO Deyong,HU Jie,WANG Yankai. Coal and gas outburst early–warning technology and application based on AHP and extension theory[J]. China Safety Science Journal,2017,27(1):88−92.

[5] 张子戌,刘高峰,吕闰生,等. 基于模糊模式识别的煤与瓦斯突出区域预测[J]. 煤炭学报,2007,32(6):592−595.

ZHANG Zixu,LIU Gaofeng,LYU Runsheng,et al. Regional forecast of coal and gas burst based on fuzzy pattern recognition[J]. Journal of China Coal Society,2007,32(6):592−595.

[6] 徐刚,李树刚,马瑞峰. 顺煤层剪切带煤与瓦斯突出机理分析[J]. 煤田地质与勘探,2014,42(4):16−20.

XU Gang,LI Shugang,MA Ruifeng. Analysis on coal and gas outburst mechanism of beding shear zone[J]. Coal Geology & Exploration,2014,42(4):16−20.

[7] HODOT BB. Outburst of coal and coalbed gas (Chinese Translation)[M]. Beijing:China Coal Industry Press,1966.

[8] 王刚,武猛猛,王海洋,等. 基于能量平衡模型的煤与瓦斯突出影响因素的灵敏度分析[J]. 岩石力学与工程学报,2015,34(2):238−248.

WANG Gang,WU Mengmeng,WANG Haiyang,et al. Sensitivity analysis of factors affecting coal and gas outburst based on a energy equilibrium model[J]. Chinese Journal of Rock Mechanics and Engineering,2015,34(2):238−248.

[9] 吕闰生,金毅,刘高峰. 中高煤阶煤储层水力压裂消突能量耗散特性[J]. 采矿与安全工程学报,2017,34(5):1015−1020.

LYU Runsheng,JIN Yi,LIU Gaofeng. Energy dissipation characteristics of eliminating outburst using hydraulic fracture for medium–high rank coal reservoirs[J]. Journal of Mining & Safety Engineering,2017,34(5):1015−1020.

[10] 王刚,程卫民,谢军,等. 瓦斯含量在突出过程中的作用分析[J]. 煤炭学报,2011,36(3):429−434.

WANG Gang,CHENG Weimin,XIE Jun,et al. Analysis of the gas content in the coal and gas outburst[J]. Journal of China Coal Society,2011,36(3):429−434.

[11] 何学秋,周广来,刘贞堂. 含瓦斯煤突出的能量耗散过程及非接触预测[J]. 煤炭科学技术,1993,21(12):18−21.

HE Xueqiu,ZHOU Guanglai,LIU Zhentang. Energy releasing process and non–contact prediction of coal and gas outburst[J]. Coal Science and Technology,1993,21(12):18−21.

[12] WANG Zhenyang,CHENG Yuanping,WANG Liang,et al. Analysis of pulverized tectonic coal gas expansion energy in underground mines and its influence on the environment[J]. Environmental Science and Pollution Research,2019,27(2):1508−1520.

[13] 王汉鹏,张冰,袁亮,等. 吸附瓦斯含量对煤与瓦斯突出的影响与能量分析[J]. 岩石力学与工程学报,2017,36(10):2449−2456.

WANG Hanpeng,ZHANG Bing,YUAN Liang,et al. Influence of adsorption gas content on coal and gas outburst and energy analysis[J]. Chinese Journal of Rock Mechanics and Engineering,2017,36(10):2449−2456.

[14] JIN Kan,CHENG Yuanping,REN Ting,et al. Experimental investigation on the formation and transport mechanism of outburst coal–gas flow:Implications for the role of gas desorption in the development stage of outburst[J]. International Journal of Coal Geology,2018,194:45−58.

[15] TAO Shu,CHEN Shida,PAN Zhejun. Current status,challenges,and policy suggestions for coalbed methane industry development in China:A review[J]. Energy Science & Engineering,2019,7(4):1059−1074.

[16] REN Jiangang,SONG Zhimin,LI Bing,et al. Structure feature and evolution mechanism of pores in different metamorphic degrees and deformation coals[J]. Fuel,2021,283:119292.

[17] 刘高峰,张子戌,张小东,等. 气肥煤与焦煤的孔隙分布规律及其吸附–解吸特征[J]. 岩石力学与工程学报,2009,28(8):1587−1592.

LIU Gaofeng,ZHANG Zixu,ZHANG Xiaodong,et al. Pore distribution regularity and absorption–desorption characteristics of gas coal and coking coal[J]. Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1587−1592.

[18] 魏风清,史广山,张铁岗. 基于瓦斯膨胀能的煤与瓦斯突出预测指标研究[J]. 煤炭学报,2010,35(Sup.1):95−99.

WEI Fengqing,SHI Guangshan,ZHANG Tiegang. Study on coal and gas outburst prediction indexes base on gas expansion energy[J]. Journal of China Coal Society,2010,35(Sup.1):95−99.

[19] LIU Aihua,FU Xuehai,WANG Kexin,et al. Investigation of coalbed methane potential in low–rank coal reservoirs–Free and soluble gas contents[J]. Fuel,2013,112:14−22.

[20] MOORE T A. Coalbed methane:A review[J]. International Journal of Coal Geology,2012,101:36−81.

[21] YAO Yanbin,LIU Dameng,TANG Dazhen,et al. Fractal characterization of adsorption–pores of coals from North China:An investigation on CH4 adsorption capacity of coals[J]. International Journal of Coal Geology,2008,73(1):27−42.

[22] YAO Yanbin,LIU Dameng,TANG Dazhen,et al. Fractal characterization of seepage–pores of coals from China:An investigation on permeability of coals[J]. Computers & Geosciences,2009,35(6):1159−1166.

[23] 钟玲文,张慧,员争荣,等. 煤的比表面积、孔体积及其对煤吸附能力的影响[J]. 煤田地质与勘探,2002,30(3):26−29.

ZHONG Lingwen,ZHANG Hui,YUAN Zhengrong,et al. Influence of specific pore area and pore volume of coal on adsorption capacity[J]. Coal Geology & Exploration,2002,30(3):26−29.

[24] 钟玲文,张新民. 煤的吸附能力与其煤化程度和煤岩组成间的关系[J]. 煤田地质与勘探,1990(4):29−36.

ZHONG Lingwen,ZHANG Xinmin. The relationship between the adsorption capacity of coal and its degree of metamorphism and different macrolithotype[J]. Coal Geology & Exploration,1990(4):29−36.

[25] CAI Yidong,LI Qian,LIU Dameng,et al. Insights into matrix compressibility of coals by mercury intrusion porosimetry and N2 adsorption[J]. International Journal of Coal Geology,2018,200:199−212.

[26] 赵兴龙,汤达祯,许浩,等. 煤变质作用对煤储层孔隙系统发育的影响[J]. 煤炭学报,2010,35(9):1506−1511.

ZHAO Xinglong,TANG Dazhen,XU Hao,et al. Effect of coal metamorphic process on pore system of coal reservoirs[J]. Journal of China Coal Society,2010,35(9):1506−1511.

[27] 国家煤矿安全监察局. 防治煤与瓦斯突出细则[M]. 北京:煤炭工业出版社,2019.

[28] 齐黎明,陈学习,程五一. 瓦斯膨胀能与瓦斯压力和含量的关系[J]. 煤炭学报,2010,35(增刊1):105−108.

QI Liming,CHEN Xuexi,CHENG Wuyi. Relationship of expansion energy of gas with gas pressure and content[J]. Journal of China Coal Society,2010,35(Sup.1):105−108.

[29] JIANG Chenglin,XU Lehua,LI Xiaowei,et al. Identification model and indicator of outburst–prone coal seams[J]. Rock Mechanics and Rock Engineering,2015,48(1):409−415.

[30] 王汉鹏,张玉强,袁亮,等. 煤粒初始释放瓦斯膨胀能的影响规律与温度效应分析[J]. 采矿与安全工程学报,2019,36(5):1052−1060.

WANG Hanpeng,ZHANG Yuqiang,YUAN Liang,et al. Analysis of influence law and temperature effect of initial released gas expansion energy of the coal grain[J]. Journal of Mining & Safety Engineering,2019,36(5):1052−1060.

[31] YANG Dingding,CHEN Yujia,TANG Jun,et al. Experimental research into the relationship between initial gas release and coal–gas outbursts[J]. Journal of Natural Gas Science and Engineering,2018,50:157−165.

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