Skip to main content
SpringerLink
Log in

Comparative experimental study on porosity, mechanical and CO2 adsorption characteristics of coal and shale

  • Research Article
  • Published:
Frontiers of Earth Science Aims and scope Submit manuscript

Abstract

To compare the pore structure, mechanical and CO2 adsorption properties of coal and shale, a series of experiments were carried out using nuclear magnetic resonance (NMR), uniaxial compression, Brazilian splitting, and high-pressure CO2 adsorption. The results show that the total porosity of coal is 7.51 times that of shale, and shale is dominated by adsorption pores, while adsorption pores and seepage pores in coal are equally important. Moreover, it is found that the micropores in shale are more advantageous, while meso-macropore in coal are more significant. The adsorption pore surface of coal is rougher than that of shale, and the seepage pore structure of shale is more complex. The uniaxial compressive strength, elastic modulus and absorption energy of shale are 2.01 times, 2.85 times, and 1.27 times that of coal, respectively, indicating that shale has higher compressive capacity and resistance to elastic deformation than coal. The average tensile strength, Brazilian splitting modulus, absorbed energy and brittleness index of shale are 7.92 times, 6.68 times, 10.78 times, and 4.37 times that of coal, respectively, indicating that shale has higher tensile strength and brittleness, but lower ductility, compared with coal. The performed analyses show that under the same conditions, the CO2 adsorption capacity of coal is greater than that of shale. The present article can provide a theoretical basis to implement CO2-enhanced coalbed methane (CBM)/shale gas extraction.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Aybar U, Eshkalak M O, Sepehrnoori K, Patzek T W (2014). The effect of natural fracture’s closure on long-term gas production from unconventional resources. J Nat Gas Sci Eng, 21: 1205–1213

    Article  Google Scholar 

  • Cao T T, Song Z G, Luo H Y, Liu G X (2015). The differences of microscopic pore structure characteristics of coal, oil shale and shales and their storage mechanisms. Nat Gas Geosci, 26(11): 2208–2218

    Google Scholar 

  • Chandra D, Vishal V, Bahadur J, Sen D (2020). A novel approach to identify accessible and inaccessible pores in gas shales using combined low-pressure sorption and SAXS/SANS analysis. Int J Coal Geol, 228: 103556

    Article  Google Scholar 

  • Chen S, Zhu Y, Wang H, Liu H, Wei W, Luo Y, Li W, Fang J (2010). Research status and trends of shale gas in China. Acta Petrol Sin, 31(4): 689–694

    Google Scholar 

  • Chen S, Tang D, Tao S, Ji X, Xu H. (2019). Fractal analysis of the dynamic variation in pore-fracture systems under the action of stress using a low-field NMR relaxation method: an experimental study of coals from western Guizhou in China. J Petrol Sci Eng, 173: 617–629

    Article  Google Scholar 

  • Feng G, Kang Y, Sun Z, Wang X, Hu Y (2019). Effects of supercritical CO2 adsorption on the mechanical characteristics and failure mechanisms of shale. Energy, 173: 870–882

    Article  Google Scholar 

  • Gao S, Jia L, Zhou Q, Cheng H, Wang Y (2022). Microscopic pore structure changes in coal induced by a CO2–H2O reaction system. J Petrol Sci Eng, 208: 109361

    Article  Google Scholar 

  • Geng W, Huang G, Guo S, Jiang C, Dong Z, Wang W (2022). Influence of long-term CH4 and CO2 treatment on the pore structure and mechanical strength characteristics of Baijiao Coal. Energy, 242: 122986

    Article  Google Scholar 

  • Gholami R, Rasouli V, Sarmadivaleh M, Minaeian V, Fakhari N (2016). Brittleness of gas shale reservoirs: a case study from the north Perth Basin, Australia. J Nat Gas Sci Eng, 33: 1244–1259

    Article  Google Scholar 

  • Hou P, Xue Y, Gao F, Dou F, Su S, Cai C, Zhu C (2022). Effect of liquid nitrogen cooling on mechanical characteristics and fracture morphology of layer coal under Brazilian splitting test. Int J Rock Mech Min Sci, 151: 105026

    Article  Google Scholar 

  • Jin K, Cheng Y, Liu Q, Zhao W, Wang L, Wang F, Wu D (2016). Experimental investigation of pore structure damage in pulverized coal: implications for methane adsorption and diffusion characteristics. Energy Fuels, 30(12): 10383–10395

    Article  Google Scholar 

  • Joubert J I, Grein C T, Bienstock D (1973). Sorption of methane in moist coal. Fuel, 52(3): 181–185

    Article  Google Scholar 

  • Langmuir I (1918). The adsorption of gases on plane surfaces of glass, mica and platinum. J Am Chem Soc, 40(9): 1361–1403

    Article  Google Scholar 

  • Liu X, Zhang C, Nie B, Zhang C, Song D, Yang T, Ma Z (2022a). Mechanical response and mineral dissolution of anthracite induced by supercritical CO2 saturation: influence of saturation time. Fuel, 319: 123759

    Article  Google Scholar 

  • Liu Z, Lin X, Cheng Y, Chen R, Zhao L, Wang L, Li W, Wang Z (2022b). Experimental investigation on the diffusion property of different form coal: implication for the selection of CO2 storage reservoir. Fuel, 318: 123691

    Article  Google Scholar 

  • Liu Z, Lin X, Wang Z, Zhang Z, Chen R, Wang L, Li W (2022c). Modeling and experimental study on methane diffusivity in coal mass under in-situ high stress conditions: a better understanding of gas extraction. Fuel, 321: 124078

    Article  Google Scholar 

  • Satya, Harpalani, Basanta, K., Prusty, Pratik, et al. (2006). Methane/CO2 sorption modeling for coalbed methane production and CO2 sequestration. Energy Fuels, 20(4): 1591–1599

    Article  Google Scholar 

  • Shao X, Pang X, Li H, Zhang X (2017). Fractal analysis of pore network in tight gas sandstones using NMR Method: a case study from the Ordos Basin, China. Energy Fuels, 31(10): 10358–10368

    Article  Google Scholar 

  • Sing K (1982). Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Provisional). Pure Appl Chem, 54(11): 2201–2218

    Article  Google Scholar 

  • Song Y, Zou Q, Su E, Zhang Y, Sun Y (2020). Changes in the microstructure of low-rank coal after supercritical CO2 and water treatment. Fuel, 279: 118493

    Article  Google Scholar 

  • Su E, Liang Y, Chang X, Zou Q, Xu M, Sasmito AP (2020). Effects of cyclic saturation of supercritical CO2 on the pore structures and mechanical properties of bituminous coal: an experimental study. J CO2 Util, 40: 101208

    Article  Google Scholar 

  • Wang G, Qin X, Shen J, Zhang Z, Han D, Jiang C (2019). Quantitative analysis of microscopic structure and gas seepage characteristics of low-rank coal based on CT three-dimensional reconstruction of CT images and fractal theory. Fuel, 256: 115900

    Article  Google Scholar 

  • Wang H M, Zhu Y M, Li W, Zhang J S, Luo Y (2011). Two major geological control factors of occurrence characteristics of CBM. J China Coal Soc, 36(7): 1129–1134 (in Chinese)

    Google Scholar 

  • Wang X, Cheng Y, Zhang D, Liu Z, Wang Z, Jiang Z (2021a). Influence of tectonic evolution on pore structure and fractal characteristics of coal by low pressure gas adsorption. J Nat Gas Sci Eng, 87: 103788

    Article  Google Scholar 

  • Wang X, Cheng Y, Zhang D, Yang H, Zhou X, Jiang Z (2021b). Experimental study on methane adsorption and time-dependent dynamic diffusion coefficient of intact and tectonic coals: implications for CO2-enhanced coalbed methane projects. Process Saf Environ Prot, 156: 568–580

    Article  Google Scholar 

  • Wang X, Geng J, Zhang D, Xiao W, Chen Y, Zhang H (2022a). Influence of sub-supercritical CO2 on pore structure and fractal characteristics of anthracite: an experimental study. Energy, 261: 125115

    Article  Google Scholar 

  • Wang X, Liu H, Zhang D, Yuan X, Zeng P, Zhang H (2022b). Effects of CO2 adsorption on molecular structure characteristics of coal: implications for CO2 geological sequestration. Fuel, 321: 124155

    Article  Google Scholar 

  • Wang X, Zhang D, Liu H, Jin Z, Yue T, Zhang H (2022c). Investigation on the influences of CO2 adsorption on the mechanical properties of anthracite by Brazilian splitting test. Energy, 259: 125053

    Article  Google Scholar 

  • Wang X, Zhang D, Su E, Jiang Z, Wang C, Chu Y, Ye C (2020). Pore structure and diffusion characteristics of intact and tectonic coals: implications for selection of CO2 geological sequestration site. J Nat Gas Sci Eng, 81: 103388

    Article  Google Scholar 

  • Wang Z, Fu X, Hao M, Li G, Pan J, Niu Q, Zhou H (2021c). Experimental insights into the adsorption-desorption of CH4/N2 and induced strain for medium-rank coals. J Petrol Sci Eng, 204: 108705

    Article  Google Scholar 

  • Wang Z, Pan J, Hou Q, Yu B, Li M, Niu Q (2018a). Anisotropic characteristics of low-rank coal fractures in the Fukang mining area, China. Fuel, 211: 182–193

    Article  Google Scholar 

  • Wang Z, Pan J, Hou Q, Niu Q, Tian J, Wang H, Fu X (2018b). Changes in the anisotropic permeability of low-rank coal under varying effective stress in Fukang mining area, China. Fuel, 234: 1481–1497

    Article  Google Scholar 

  • Wu T, Du X, Li Q (2020). Comparative analysis of pore structure and adsorption characteristics of coal and shale. Safe Coal Mines, 51(11): 6

    Google Scholar 

  • Yang K, Zhou J, Xian X, Jiang Y, Zhang C, Lu Z, Yin H (2022a). Gas adsorption characteristics changes in shale after supercritical CO2-water exposure at different pressures and temperatures. Fuel, 310: 122260

    Article  Google Scholar 

  • Yang K, Zhou J, Xian X, Zhou L, Zhang C, Tian S, Lu Z, Zhang F (2022b). Chemical-mechanical coupling effects on the permeability of shale subjected to supercritical CO2-water exposure. Energy, 248: 123591

    Article  Google Scholar 

  • Yang Q, Li W, Jin K (2020). Supercritical CO2 interaction induced pore morphology alterations of various ranked coals: a comparative analysis using corrected mercury intrusion porosimetry and low-pressure N2 gas adsorption. ACS Omega, 5(16): 9276–9290

    Article  Google Scholar 

  • Yu Y, Wang T (2004). Study on relationship between splitting behaviour and elastic modulus of Three Gorges granite. Chinese J Rock Mechan Eng, 23(19): 3258–3261

    Google Scholar 

  • Zhang K, Hou CH, Zhao DF, Guo YH, Hui XU (2017). Comparison of pore structure characteristics fractal characteristics between coal and shale through nitrogen adsorption experiment with the example of Shanxi Formation 15# Coal and shale in Yangquan Area. Sci Techn Eng, 29: 68–75

    Google Scholar 

  • Zhang X G, Ranjith P G, Ranathunga A S, Li D Y (2019). Variation of mechanical properties of bituminous coal under CO2 and H2O saturation. J Nat Gas Sci Eng, 61: 158–168

    Article  Google Scholar 

  • Zheng J, Huang G, Cheng Q, Zhen L, Cai Y, Wang W (2022). Degradation of mechanical and microporous properties of coal subjected to long-term sorption. Fuel, 315: 123245

    Article  Google Scholar 

  • Zhou J, Xie S, Jiang Y, Xian X, Liu Q, Lu Z, Lyu Q (2018). Influence of supercritical CO2 exposure on CH4 and CO2 adsorption behaviors of shale: implications for CO2 sequestration. Energy Fuels, 32(5): 6073–6089

    Article  Google Scholar 

Download references

Acknowledgments

This work was financially supported by the Jiangxi Provincial Thousand Talents Plan Project (No. jxsq2019102082).

Author information

Authors and Affiliations

  1. Exploration and Development Research Institute of PetroChina, Southwest Oil and Gas Field Company, Chengdu, 610051, China

    Haitao Li

  2. PetroChina Southwest Oil and Gas Field Company Planning Department, Chengdu, 610051, China

    Guo Yu

  3. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China

    Xiaolei Wang & Dongming Zhang

  4. School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China

    Dongming Zhang

Authors
  1. Haitao Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Guo Yu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Xiaolei Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Dongming Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Xiaolei Wang.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Li, H., Yu, G., Wang, X. et al. Comparative experimental study on porosity, mechanical and CO2 adsorption characteristics of coal and shale. Front. Earth Sci. 17, 788–796 (2023). https://doi.org/10.1007/s11707-022-1059-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11707-022-1059-1

Keywords

Search

Navigation