Coal Geology & Exploration


The stress sensitivity of coal reservoir reduces the permeability, which in turn affects the productivity of coalbed methane (CBM)wells. So how to reduce this effect from stress sensitivity deserves further study in the CBM wells drainage process. To clarify the stress sensitivity characteristic and differences of different rank coal reservoirs, coal samples collected respectively from Fanzhuang block (high rank coal), Baode block (medium rank coal) and Erlian Basin (low rank lignite) were employed in this study. The stress sensitivity experiments of different rank coal samples were systematically carried out during loading and unloading process. Meanwhile, stress sensitivity mechanism was analyzed. The results demonstrate that with the increase of coal rank, the stress sensitivity of coal samples gradually strengthens, and those samples containing obvious fractures showing stronger stress sensitivity. When loading effective stress is 10MPa, compared with the initial value, the permeability of Erlian low rank lignite coal decreases by 79.26% and the average irreversible permeability damage rate after unloading is 33.4%. For Baode medium rank coal, the permeability decreases by 79.4% and the average irreversible permeability damage rate is 51.4%. As for Fanzhuang high rank coal, the permeability drops by 92.33% after loading, and the permeability can only recover about 30% after unloading. For different rank coals, the stress sensitivity mechanism is mainly due to the different material composition, pore and fracture structure, and percolation form. The low rank lignite coals with a low degree metamorphism, large and medium pores are mainly developed, but cleats and fractures are not. The seepage is mainly through matrix pores and throats, and permeability is controlled by connected throats. When the stress is loaded, the large and medium pores are mainly compressed and deformed seriously, while the small-scale throats are less compressed and deformed, so the stress sensitivity of low rank lignite coals is relatively weak. However, high rank coal reservoir is dominated by micro and small pores. Thanks to high vitrinite content, cleats and fractures are developed, which control coal’s permeability. When the stress is loading, the micro and small pores are difficult to be compressed. But to the fractures, owing to their weak resistance to deformation, they are easy to fail due to ductile deformation or closure, and difficult to recover even unloading. Therefore, the high rank coal reservoir shows strong stress sensitivity. Considering the deeper burial depth and higher stress, stress sensitivity of high rank coal reservoir will cause greater damage to CBM well’s deliverability, so it is advisable to carry out with lower strength at the initial drainage stage to reduce irreversible permeability damage and expand formation pressure drop range. However, for the low rank lignite reservoir characterized by low stress and higher original permeability, stress sensitivity causes relatively small impact on productivity, therefore, early drainage speed can be appropriately accelerated to improve efficiency.


permeability, different coal rank, stress sensitivity characteristic, control mechanism, coalbed methane, drainage




[1] PALMER I,MANSOORI J. How permeability depends on stress and pore pressure in coalbeds:A new model[J]. SPE Reservoir Evaluation & Engineering,1998,1(6):539−544.

[2] SHI Jiquan,DURUCAN S,SHIMADA S. How gas adsorption and swelling affects permeability of coal:A new modelling approach for analysing laboratory test data[J]. International Journal of Coal Geology,2014,128–129:134–142.

[3] HUY P Q,SASAKI K,SUGAI Y,et al. Carbon dioxide gas permeability of coal core samples and estimation of fracture aperture width[J]. International Journal of Coal Geology,2010,83:1−10.

[4] 陈世达,汤达祯,高丽军,等. 有效应力对高煤级煤储层渗透率的控制作用[J]. 煤田地质与勘探,2017,45(4):76−80

CHEN Shida,TANG Dazhen,GAO Lijun,et al. Control of effective stress on permeability in high–rank coal reservoirs[J]. Coal Geology & Exploration,2017,45(4):76−80

[5] ZHU Qingzhong,XIAO Qianhua,MENG Yanjun,et al. Experimental investigations into stress sensitivity in three Chinese coal samples by NMR[J/OL]. Energy Sources,Part A:Recovery,Utilization,and Environmental Effects,2019:1–10[2022-04-26]. DOI:10. 1080/15567036. 2019. 1644398.

[6] 陈振宏,王一兵,郭凯,等. 高煤阶煤层气藏储层应力敏感性研究[J]. 地质学报,2008,82(10):1390−1395

CHEN Zhenhong,WANG Yibing,GUO Kai,et al. Stress sensitivity of high–rank coalbed methane reservoir[J]. Acta Geologica Sinica,2008,82(10):1390−1395

[7] 孟召平,侯泉林. 煤储层应力敏感性及影响因素的试验分析[J]. 煤炭学报,2012,37(3):430−437

MENG Zhaoping,HOU Quanlin. Experimental research on stress sensitivity of coal reservoir and its influencing factors[J]. Journal of China Coal Society,2012,37(3):430−437

[8] 杨延辉,陈彦君,郭希波,等. 沁水盆地南部高煤阶煤岩渗透率压敏效应分析[J]. 煤炭科学技术,2015,43(12):152−156

YANG Yanhui,CHEN Yanjun,GUO Xibo,et al. Analysis on effect of stress sensitivity on permeability of high–rank coal in southern Qinshui Basin[J]. Coal Science and Technology,2015,43(12):152−156

[9] 刘会虎,桑树勋,冯清凌,等. 沁水盆地南部煤层气井排采储层应力敏感研究[J]. 煤炭学报,2014,39(9):1873−1878

LIU Huihu,SANG Shuxun,FENG Qingling,et al. Study on stress sensitivity of coal reservoir during drainage of coal–bed methane well in southern Qinshui Basin[J]. Journal of China Coal Society,2014,39(9):1873−1878

[10] 王晴,杨飞,龚伟成,等. 煤层气储层动态渗透率影响因素及排采管控措施[J]. 煤田地质与勘探,2020,48(2):114−119

WANG Qing,YANG Fei,GONG Weicheng,et al. Influencing factors of the dynamic permeability of CBM reservoir and CBM well drainage control measures[J]. Coal Geology & Exploration,2020,48(2):114−119

[11] 杨延辉,孟召平,张纪星. 煤储层应力敏感性试验及其评价新方法[J]. 煤田地质与勘探,2016,44(1):38−42

YANG Yanhui,MENG Zhaoping,ZHANG Jixing. Research on stress sensitivity of coal reservoir and a new method for its evaluation[J]. Coal Geology & Exploration,2016,44(1):38−42

[12] 桑逢云. 国内外低阶煤煤层气开发现状和我国开发潜力研究[J]. 中国煤层气,2015,12(3):7−9

SANG Fengyun. Research on current situation of global development of coalbed methane at low rank coal mines and its potential in China[J]. China Coalbed Methane,2015,12(3):7−9

[13] 陈刚,秦勇,杨青,等. 不同煤阶煤储层应力敏感性差异及其对煤层气产出的影响[J]. 煤炭学报,2014,39(3):504−509

CHEN Gang,QIN Yong,YANG Qing,et al. Different stress sensitivity of different coal rank reservoir permeability and its effect on the coalbed methane output[J]. Journal of China Coal Society,2014,39(3):504−509

[14] 鲍清英,东振,张义,等. 低煤阶应力敏感性机理及其对产气的影响:以二连盆地为例[J]. 煤炭学报,2017,42(3):671−679

BAO Qingying,DONG Zhen,ZHANG Yi,et al. Stress sensitivity mechanism of low–rank coal and its influence on gas production:A case study from Erlian Basin[J]. Journal of China Coal Society,2017,42(3):671−679

[15] 刘齐,陈强,孙中光,等. 煤层不同类型裂缝应力敏感性实验:以阜新盆地煤样为例[J]. 天然气地球科学,2021,32(3):437−446

LIU Qi,CHEN Qiang,SUN Zhongguang,et al. Stress sensitivity of coal seam with different fractures:Case study of Fuxin Basin[J]. Natural Gas Geoscience,2021,32(3):437−446

[16] 陈浩,秦勇,李贵中,等. 基于脉冲衰减法的煤岩渗透率应力敏感性研究[J]. 煤炭科学技术,2018,46(6):167−172

CHEN Hao,QIN Yong,LI Guizhong,et al. Study on stress sensitivity of coal rock permeability based on pulse–decay method[J]. Coal Science and Technology,2018,46(6):167−172

[17] MCLATCHIE A S,HEMSTOCK R A,YOUNG J W,et al. The effective compressibility of reservoir rock and its effects on permeability[J]. SPE 894–G,1958:49−51.

[18] 孙钦平,王生维,田文广,等. 二连盆地吉尔嘎朗图凹陷低煤阶煤层气富集模式[J]. 天然气工业,2018,38(4):59−66

SUN Qinping,WANG Shengwei,TIAN Wenguang,et al. Accumulation patterns of low–rank coalbed methane gas in the Jiergalangtu Sag of the Erlian Basin[J]. Natural Gas Industry,2018,38(4):59−66

[19] 张双全,吴国光. 煤化学[M]. 徐州:中国矿业大学出版社,2004.

[20] 陈振宏,贾承造,宋岩,等. 高煤阶与低煤阶煤层气藏物性差异及其成因[J]. 石油学报,2008,29(2):179−184

CHEN Zhenhong,JIA Chengzao,SONG Yan,et al. Differences and origin of physical properties of low–rank and high–rank coalbed methanes[J]. Acta Petrolei Sinica,2008,29(2):179−184

[21] 甘华军,王华,严德天. 高、低煤阶煤层气富集主控因素的差异性分析[J]. 地质科技情报,2010,29(1):56−60

GAN Huajun,WANG Hua,YAN Detian. Differential impact on high and low rank coal by the main factors of coalbed gas enrichment[J]. Geological Science and Technology Information,2010,29(1):56−60

[22] 贾慧敏,胡秋嘉,刘忠,等. 裂缝应力敏感性对煤层气井单相流段产水影响及排采对策[J]. 中国煤层气,2017,14(5):31−34

JIA Huimin,HU Qiujia,LIU Zhong,et al. Influence of fractures stress sensitivity on water production law for the single–phase flow of CBM wells and drainage countermeasures[J]. China Coalbed Methane,2017,14(5):31−34

[23] 杨焦生,赵洋,王玫珠,等. 沁水盆地南部煤层气压裂、排采关键技术研究[J]. 中国矿业大学学报,2017,46(1):131−138

YANG Jiaosheng,ZHAO Yang,WANG Meizhu,et al. Study of key technologies on coalbed methane fracturing and drainage in the southern Qinshui Basin[J]. Journal of China University of Mining & Technology,2017,46(1):131−138



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