| Citation: |
LIU Jiajia，LI Yuanlong，GAO Jianliang，et al. Microscopical and macroscopic structural damage evolution of low-rank coal by supercritical CO2 pulsation treatment[J]. Coal Science and Technology，2025，53（2）：190−199. DOI: 10.12438/cst.2024-0758
|
In order to clarify the effect and mechanism of supercritical CO2 pulsation on low-rank coal, deep low-rank coal from the Aiwiergou Mine in Xinjiang was collected as the experimental object. Experimental research was carried out through an independently built supercritical CO2 pulsation fracturing experimental system. Before and after the pulsation, the coal samples were respectively measured by XRD, FTIR, low-temperature liquid nitrogen adsorption test, low-field nuclear magnetic resonance, and uniaxial compression test. The changes in the microscopic structure, pore structure, and mechanical properties of the coal before and after the supercritical CO2 pulsation were quantitatively analyzed. The results show that after the supercritical CO2 pulsation, the mass fractions of calcite and clay minerals in the coal increase. The change in the mass fraction of clay minerals is mainly affected by the increase of ammoniated illite. The peak values of various organic functional groups in the coal show different degrees of decrease, indicating that the extraction effect of supercritical CO2 on organic matter is obvious. After the pulsation, the microcrystalline structure of the coal is damaged, the crystal lamellar spacing increases by 0.002 9 nm, and the coal structure tends to be loose. Compared with before the supercritical CO2 pulsation, the effective porosities of coal samples XJ-A and XJ-B increase by 66.7% and 128.6% respectively after the pulsation. The connectivity of pores inside the coal is enhanced, and the pulsation has a more obvious effect on the modification of micropores and mesopores. After the supercritical CO2 pulsation, the mechanical properties of the coal deteriorate significantly. The uniaxial compressive strength and elastic modulus decrease by 54.73% and 59.82% respectively. The acoustic emission ring-down count and cumulative energy are both greatly reduced. The peak value of the ring-down count drops to 51% of that before the pulsation, the cohesion of internal particles in the coal sample decreases, and the cumulative energy decreases by 62%. In conclusion, the supercritical CO2 pulsation can significantly damage the micro-macro structure of low-rank coal, which is of great significance for the fracturing and permeability enhancement of deep low-rank coal reservoirs and the extraction of coalbed methane.
| [1] |
SHI Q L,QIN B T,BI Q,et al. An experimental study on the effect of igneous intrusions on chemical structure and combustion characteristics of coal in Daxing Mine,China[J]. Fuel,2018,226:307−315. doi: 10.1016/j.fuel.2018.04.027
|
| [2] |
袁亮. 煤炭工业碳中和发展战略构想[J]. 中国工程科学,2023,25(5):103−110. doi: 10.15302/J-SSCAE-2023.05.009
YUAN Liang. Strategic conception of carbon neutralization in coal industry[J]. Strategic Study of CAE,2023,25(5):103−110. doi: 10.15302/J-SSCAE-2023.05.009
|
| [3] |
陈浮,王思遥,于昊辰,等. 碳中和目标下煤炭变革的技术路径[J]. 煤炭学报,2022,47(4):1452−1461.
CHEN Fu,WANG Siyao,YU Haochen,et al. Technological innovation paths of coal industry for achieving carbon neutralization[J]. Journal of China Coal Society,2022,47(4):1452−1461.
|
| [4] |
包一翔,李井峰,郭强,等. 二氧化碳用于地质资源开发及同步封存技术综述[J]. 煤炭科学技术,2022,50(6):84−95.
BAO Yixiang,LI Jingfeng,GUO Qiang,et al. Review on technologies of geological resources exploitation by using carbon dioxide and its synchronous storage[J]. Coal Science and Technology,2022,50(6):84−95.
|
| [5] |
陈峰,宋普洪. 西北煤层气资源特征及开发潜力评价[J]. 能源与节能,2023(6):51−54. doi: 10.3969/j.issn.2095-0802.2023.06.010
CHEN Feng,SONG Puhong. Resource characteristics and development potential evaluation of coalbed methane in northwest China[J]. Energy and Energy Conservation,2023(6):51−54. doi: 10.3969/j.issn.2095-0802.2023.06.010
|
| [6] |
曾梦茹. 不同温度超临界CO2条件下煤微观结构特征及改造机理研究[D]. 重庆:重庆大学,2020.
ZENG Mengru. Study on the coal microstructural characteristics and transformation mechanism treated by supercritical CO2 at different temperatures[D]. Chongqing:Chongqing University,2020.
|
| [7] |
卢义玉,廖引,汤积仁,等. 页岩超临界CO2压裂起裂压力与裂缝形态试验研究[J]. 煤炭学报,2018,43(1):175−180.
LU Yiyu,LIAO Yin,TANG Jiren,et al. Experimental study on fracture initiation pressure and morphology in shale using supercritical CO2 fracturing[J]. Journal of China Coal Society,2018,43(1):175−180.
|
| [8] |
JIA J L,CAO L W,SANG S X,et al. An experimental study on the damage characteristics of mechanical properties of anthracite induced by supercritical CO2 injection[J]. Environmental Earth Sciences,2019,79(1):12.
|
| [9] |
赵林,蒋尔梁,王树森,等. 二氧化碳注入对低渗透储层矿物及孔隙结构的影响[J]. 油田化学,2021,38(4):659−664,670.
ZHAO Lin,JIANG Erliang,WANG Shusen,et al. Effect of carbon dioxide injection on mineral and pore structure of low permeability reservoirs[J]. Oilfield Chemistry,2021,38(4):659−664,670.
|
| [10] |
苏二磊. 超临界CO2作用下烟煤结构响应及对力学和渗透特性的影响机理[D]. 重庆:重庆大学,2021.
SU Erlei. Structural response of bituminous coal under supercritical CO2 and its influence mechanism on mechanical and permeability properties[D]. Chongqing:Chongqing University,2021.
|
| [11] |
刘佳佳,聂子硕,于宝种,等. 超临界二氧化碳对煤体增透的作用机理及影响因素分析[J]. 煤炭科学技术,2023,51(2):204−216.
LIU Jiajia,NIE Zishuo,YU Baozhong,et al. Analysis of the mechanism and influencing factors of supercritical carbon dioxide on coal permeability enhancement[J]. Coal Science and Technology,2023,51(2):204−216.
|
| [12] |
李贤忠. 高压脉动水力压裂增透机理与技术[D]. 徐州:中国矿业大学,2013.
LI Xianzhong. The mechanism and technology of permeability enhancements in coal seam based on high pressure pulsating hydraulic fracturing[D]. Xuzhou:China University of Mining and Technology,2013.
|
| [13] |
刘厅,林柏泉,赵洋,等. 瓦斯非均衡赋存煤层精准冲孔增透技术及应用[J]. 煤炭科学技术,2023,51(2):217−231.
LIU Ting,LIN Baiquan,ZHAO Yang,et al. Precise permeability enhancement technique with hydraulic flushing for coal seams with non-uniformly distributed gas[J]. Coal Science and Technology,2023,51(2):217−231.
|
| [14] |
李军军,余梦飞,李国富,等. 航天固体推进剂对煤储层致裂增透试验研究[J]. 煤炭科学技术,2023,51(9):121−128.
LI Junjun,YU Mengfei,LI Guofu,et al. Experimental study of aerospace solid propellant fracturing in simulated coal sample[J]. Coal Science and Technology,2023,51(9):121−128.
|
| [15] |
王亮,廖晓雪,褚鹏,等. 瓦斯抽采穿层钻孔钻扩造穴卸压增透机理研究[J]. 煤炭科学技术,2021,49(5):75−82.
WANG Liang,LIAO Xiaoxue,CHU Peng,et al. Study on mechanism of permeability improvement for gas drainage by cross-seam cavitation borehole[J]. Coal Science and Technology,2021,49(5):75−82.
|
| [16] |
陈娟,闫涛. 煤中各族组分FTIR解析[J]. 化学与生物工程,2019,36(9):57−59,63. doi: 10.3969/j.issn.1672-5425.2019.09.013
CHEN Juan,YAN Tao. FTIR analysis of coal group component[J]. Chemistry & Bioengineering,2019,36(9):57−59,63. doi: 10.3969/j.issn.1672-5425.2019.09.013
|
| [17] |
LIU J J,NIE Z S,LI Y L,et al. Evolution characteristics of coal microstructure before and after supercritical CO2 treatment based on the L-weighing-LNMR method[J]. Energy & Fuels,2023,37(13):9347−9358.
|
| [18] |
刘佳佳,胡建敏,杨明,等. 不同层理高阶煤孔隙特征的核磁共振试验[J]. 中国安全科学学报,2021,31(9):83−89.
LIU Jiajia,HU Jianmin,YANG Ming,et al. Nuclear magnetic resonance experimental study on pore characteristics of high rank coal with different bedding[J]. China Safety Science Journal,2021,31(9):83−89.
|
| [19] |
LU Y Y,WANG L,GE Z L,et al. Fracture and pore structure dynamic evolution of coals during hydraulic fracturing[J]. Fuel,2020,259:116272. doi: 10.1016/j.fuel.2019.116272
|
| [20] |
何立国,杨栋. 超临界CO2对煤体力学特性劣化影响研究[J]. 矿业研究与开发,2021,41(2):94−99.
HE Liguo,YANG Dong. Study on the degradation effect of supercritical CO2 on the coal mechanical properties[J]. Mining Research and Development,2021,41(2):94−99.
|
| [21] |
陈爱坤,翟成,丛钰洲,等. 液氮循环冷冲击作用下煤体受拉破坏特征[J]. 中国矿业大学学报,2023,52(2):342−353.
CHEN Aikun,ZHAI Cheng,CONG Yuzhou,et al. Tensile failure characteristics of coal after the cyclic cold shock of liquid nitrogen[J]. Journal of China University of Mining & Technology,2023,52(2):342−353.
|
Supported by: Beijing Renhe Information Technology Co., Ltd. 
DownLoad: