Skip to main content
Log in

Pore Fractal Dimensions of Bituminous Coal Reservoirs in North China and Their Impact on Gas Adsorption Capacity

  • Original Paper
  • Published:
Natural Resources Research Aims and scope Submit manuscript

Abstract

Coal pores not only serve as the storage space for coalbed methane but also provide channels for gas migration. The accurate characterization of coal pore structures is of significance to study the methane adsorption behaviors. In this work, the quantitative relationship between gas adsorption and pore characteristics was investigated in depth for bituminous coals. Results of scanning electron microscopy showed that the surface morphological characteristics of these samples differ greatly. Some typical pore types including cylindrical pores and conical pores were found in these samples. The remarkable hysteresis loop was observed, which is attributed to the bottle-shaped pores with poor connectivity. Fractal theory was introduced to quantitatively evaluate the surface roughness of coal. Pore fractal dimensions, D1 and D2, were calculated using low-pressure N2 gas adsorption data, and their values were in the range of 2.125–2.721 and 2.084–2.461, respectively. D1 was larger than the corresponding D2 for the same sample, suggesting that micropore structures in coal were more complex when compared with mesopores and transition pores. Both D1 and D2 were enhanced with increase in micropore specific surface area, but they were reduced with increase in mesopore specific surface area. Gas adsorption in coal was estimated from the perspective of fractal dimension. Judging from the fitting degree, the influence of D1 on adsorption capacity of coal was remarkably greater than that of D2. D1 is expected to be used as one of the major adsorption indicators in the future study.

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

Access this article

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

Instant access to the full article PDF.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9

Similar content being viewed by others

References

  • Cavelan, A., Boussafir, M., Mathieu, N., & Laggoun-Défarge, F. (2020). Impact of thermal maturity on the concomitant evolution of the ultrafine structure and porosity of marine mudstones organic matter; contributions of electronic imaging and new spectroscopic investigations. International Journal of Coal Geology, 231, 103622.

    Article  Google Scholar 

  • Ceglarska-Stefańska, G., & Brzóska, K. (1998). The effect of coal metamorphism on methane desorption. Fuel, 77, 645–648.

    Article  Google Scholar 

  • Chalmers, G. R. L., & Bustin, R. M. (2007). On the effects of petrographic composition on coalbed methane sorption. International Journal of Coal Geology, 69(4), 288–304.

    Article  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. International Journal of Coal Geology, 228, 103556.

    Article  Google Scholar 

  • Chattaraj, S., Mohanty, D., Kumar, T., Halder, G., & Mishra, K. (2019). Comparative study on sorption characteristics of coal seams from Barakar and Raniganj formations of Damodar Valley Basin, India. International Journal of Coal Geology, 212, 103202.

    Article  Google Scholar 

  • Chen, K., Liu, X. F., Wang, L. K., Song, D. Z., Nie, B. S., & Yang, T. (2021). Influence of sequestered supercritical CO2 treatment on the pore size distribution of coal across the rank range. Fuel, 306, 121708.

    Article  Google Scholar 

  • Chen, L. W., Wang, L., Yang, T. H., & Yang, H. M. (2021). Deformation and swelling of coal induced from competitive adsorption of CH4/CO2/N2. Fuel, 286, 119356.

    Article  Google Scholar 

  • Chen, M., Yang, Y., Gao, C., Cheng, Y. P., Wang, J. C., & Wang, N. (2020). Investigation of the fractal characteristics of adsorption-pores and their impact on the methane adsorption capacity of various rank coals via N2 and H2O adsorption methods. Energy Science & Engineering, 8(9), 3228–3243.

    Article  Google Scholar 

  • Clarkson, C. R., & Bustin, R. M. (1999). The effect of pore structure and gas pressure upon the transport properties of coal: A laboratory and modeling study. 2. Adsorption rate modeling. Fuel, 78(11), 1345–1362.

    Article  Google Scholar 

  • Crosdale, P. J., Beamish, B. B., & Valix, M. (1998). Coalbed methane sorption related to coal composition. International Journal of Coal Geology, 35(1–4), 147–158.

    Article  Google Scholar 

  • De Boer, J. H. (1958). The shape of capillaries (pp. 68–92). Butterworth.

    Google Scholar 

  • Farmer, I. W., & Pooley, F. D. (1967). A hypothesis to explain the occurrence of outbursts in coal, based on a study of West Wales outburst coal. International Journal of Rock Mechanics and Mining Sciences, 4(2), 189–193.

    Article  Google Scholar 

  • Fernandez-Diaz, J. J., Gonzalez-Nicieza, C., Alvarez-Fernandez, M. I., & Lopez-Gayarre, F. (2013). Analysis of gas-dynamic phenomenon in underground coal mines in the central basin of Asturias (Spain). Engineering Failure Analysis, 34, 464–477.

    Article  Google Scholar 

  • Gao, W., Yi, T. S., & Jin, J. (2017). Pore integrated fractal characteristics of coal sample in western Guizhou and its impact to porosity and permeability. Journal of China Coal Society, 42(5), 1258–1265.

    Google Scholar 

  • Garbacz, J. K. (1998). Fractal description of partially mobile single gas adsorption on energetically homogeneous solid adsorbent. Colloid Surfaces A, 143(1), 95–101.

    Article  Google Scholar 

  • Gentzis, T. (2000). Subsurface sequestration of carbon dioxide-an overview from an Alberta (Canada) perspective. International Journal of Coal Geology, 43, 287–305.

    Article  Google Scholar 

  • Gerami, A., Armstrong, R. T., Jing, Y., Wahid, F. A., Arandiyan, H., & Mostaghimi, P. (2019). Microscale insights into gas recovery from bright and dull bands in coal. Journal of Petroleum Science and Engineering, 172, 373–382.

    Article  Google Scholar 

  • Groshong, R. H., Jr., Pashin, J. C., & McIntyre, M. R. (2009). Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin. Journal of Structural Geology, 31(9), 874–886.

    Article  Google Scholar 

  • Hamawand, I., Yusaf, T., & Hamawand, S. G. (2013). Coal seam gas and associated water: A review paper. Renewable and Sustainable Energy Reviews, 22, 550–560.

    Article  Google Scholar 

  • He, X., Liu, X., Nie, B., & Song, D. (2017). FTIR and Raman spectroscopy characterization of functional groups in various rank coals. Fuel, 206, 555–563.

    Article  Google Scholar 

  • He, X., Liu, X., Song, D., & Nie, B. (2019). Effect of microstructure on electrical property of coal surface. Applied Surface Science, 483, 713–720.

    Article  Google Scholar 

  • Jing, Y., Armstrong, R. T., Ramandi, H. L., & Mostaghimi, P. (2017). Topological characterization of fractured coal. Journal of Geophysical Research: Solid Earth, 122(12), 9849–9861.

    Article  Google Scholar 

  • Karacan, C. O., & Okandan, E. (2001). Adsorption and gas transport in coal microstructure: Investigation and evaluation by quantitative X-ray CT imaging. Fuel, 80, 509–520.

    Article  Google Scholar 

  • Karacan, C. Ö., Ruiz, F. A., Cotè, M., & Phipps, S. (2011). Coal mine methane: A review of capture and utilization practices with benefits to mining safety and to greenhouse gas reduction. International Journal of Coal Geology, 86(2–3), 121–156.

    Article  Google Scholar 

  • Keshavarz, A., Sakurovs, R., Grigore, M., & Sayyafzadeh, M. (2017). Effect of maceral composition and coal rank on gas diffusion in Australian coals. International Journal of Coal Geology, 173, 65–75.

    Article  Google Scholar 

  • Kiani, A., Sakurovs, R., Grigore, M., & Sokolova, A. (2018). Gas sorption capacity, gas sorption rates and nanoporosity in coals. International Journal of Coal Geology, 200, 77–86.

    Article  Google Scholar 

  • Kong, X. G., Li, S. G., Wang, E. Y., Ji, P. F., Wang, X., Shuang, H. Q., & Zhou, Y. X. (2021). Dynamics behaviour of gas-bearing coal subjected to SHPB tests. Composite Structures, 256, 113088.

    Article  Google Scholar 

  • Kong, X. G., Li, S. G., Wang, E. Y., Wang, X., Zhou, Y. X., Ji, P. F., Shuang, H. Q., Li, S. R., & Wei, Z. Y. (2021). Experimental and numerical investigations on dynamic mechanical responses and failure process of gas-bearing coal under impact load. Soil Dynamics and Earthquake Engineering, 142, 106–579.

    Article  Google Scholar 

  • Li, Q., Liu, D. M., Cai, Y. D., Zhao, B., Lu, Y. J., & Zhou, Y. F. (2021). Effects of natural micro-fracture morphology, temperature and pressure on fluid flow in coals through fractal theory combined with lattice Boltzmann method. Fuel, 286, 119–468.

    Article  Google Scholar 

  • Li, W., Liu, H., & Song, X. (2015). Multifractal analysis of Hg pore size distributions of tectonically deformed coals. International Journal of Coal Geology, 144, 138–152.

    Article  Google Scholar 

  • Liao, Z. W., Liu, X. F., Song, D. Z., He, X. Q., Nie, B. S., Yang, T., & Wang, L. K. (2021). Micro-structural damage to coal induced by liquid CO2 phase change fracturing. Natural Resources Research, 30(2), 1613–1627.

    Article  Google Scholar 

  • Liu, S. M., Li, X. L., Wang, D. K., & Zhang, D. M. (2021b). Experimental study on temperature response of different ranks of coal to liquid nitrogen soaking. Natural Resources Research, 30(2), 1467–1480.

    Article  Google Scholar 

  • Liu, X., Nie, B., Wang, W., Wang, Z., & Zhang, L. (2019b). The use of AFM in quantitative analysis of pore characteristics in coal and coal-bearing shale. Marine and Petroleum Geology, 105, 331–337.

    Article  Google Scholar 

  • Liu, X., Song, D., He, X., Wang, Z., Zeng, M., & Deng, K. (2019d). Nanopore structure of deep-burial coals explored by AFM. Fuel, 246, 9–17.

    Article  Google Scholar 

  • Liu, X. F., & Nie, B. S. (2016). Fractal characteristics of coal samples utilizing image analysis and gas adsorption. Fuel, 182, 314–322.

    Article  Google Scholar 

  • Liu, X. F., Nie, B. S., Guo, K. Y., Zhang, C. P., Wang, Z., & Wang, L. K. (2021). Permeability enhancement and porosity change of coal by liquid carbon dioxide phase change fracturing. Engineering Geology, 287, 106106.

    Article  Google Scholar 

  • Liu, X. F., Song, D. Z., He, X. Q., Nie, B. S., & Wang, L. K. (2019a). Insight into the macromolecular structural differences between hard coal and deformed soft coal. Fuel, 245, 188–197.

    Article  Google Scholar 

  • Liu, X. F., Song, D. Z., He, X. Q., Wang, Z. P., Zeng, M. R., & Wang, L. K. (2019c). Quantitative analysis of coal nanopore characteristics using atomic force microscopy. Powder Technology, 346, 332–340.

    Article  Google Scholar 

  • Liu, X. F., Wang, Z. P., Song, D. Z., He, X. Q., & Yang, T. (2020). Variations in surface fractal characteristics of coal subjected to liquid CO2 phase change fracturing. International Journal of Energy Research, 44(11), 8740–8753.

    Article  Google Scholar 

  • Loucks, R. G., Reed, R. M., Ruppel, S. C., & Jarvie, D. M. (2009). Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the mississippian barnett shale. Journal of Sedimentary Research, 79(12), 848–861.

    Article  Google Scholar 

  • Lu, G., Wang, J., & Wei, C. (2018). Pore fractal model applicability and fractal characteristics of seepage and adsorption pores in middle rank tectonic deformed coals from the Huaibei coal field. Journal of Petroleum Science and Engineering, 171, 808–817.

    Article  Google Scholar 

  • Lu, G., Wei, C., Wang, J., Meng, R., & Tamehe, L. S. (2021). Influence of pore structure and surface free energy on the contents of adsorbed and free methane in tectonically deformed coal. Fuel, 285, 119087.

    Article  Google Scholar 

  • Mahamud, M., López, Ó., Pis, J. J., & Pajares, J. A. (2003). Textural characterization of coals using fractal analysis. Fuel Processing Technology, 81(2), 127–142.

    Article  Google Scholar 

  • Mendhe, V. A., Bannerjee, M., Varma, A. K., Kamble, A. D., Mishra, S., & Singh, B. D. (2017). Fractal and pore dispositions of coal seams with significance to coalbed methane plays of East Bokaro, Jharkhand, India. Journal of Natural Gas Science and Engineering, 38, 412–433.

    Article  Google Scholar 

  • Moore, T. A. (2012). Coalbed methane: A review. International Journal of Coal Geology, 101(1), 36–81.

    Article  Google Scholar 

  • Mostaghimi, P., Armstrong, R. T., Gerami, A., Hu, Y., Jing, Y., Kamali, F., Liu, M., Liu, Z. S., Lu, X., Ramandi, H. L., Zamani, A., & Zhang, Y. L. (2017). Cleat-scale characterisation of coal: An overview. Journal of Natural Gas Science and Engineering, 39, 143–160.

    Article  Google Scholar 

  • Murata, S., Hosokawa, M., Kidena, K., & Nomura, M. (2000). Analysis of oxygen-functional groups in brown coals. Fuel Processing Technology, 67(3), 231–243.

    Article  Google Scholar 

  • Nie, B. S., Liu, X. F., Yang, L. L., Meng, J. Q., & Li, X. C. (2015). Pore structure characterization of different rank coals using gas adsorption and scanning electron microscopy. Fuel, 158, 908–917.

    Article  Google Scholar 

  • Nie, B. S., Liu, X. F., Yuan, S. F., Ge, B. Q., Jia, W. J., & Chen, X. H. (2016). Sorption charateristics of methane among various rank coals: Impact of moisture. Adsorption, 22(3), 315–325.

    Article  Google Scholar 

  • Nie, B. S., Ma, Y. K., Hu, S. T., & Meng, J. Q. (2019). Laboratory study phenomenon of coal and gas outburst based on a mid-scale simulation system. Scientific Reports, 9, 15005.

    Article  Google Scholar 

  • Niu, Q., Cao, L., Sang, S., Wang, W., Zhou, X., Yuan, W., Ji, Z., Chang, J., & Li, M. (2021). Experimental study on the softening effect and mechanism of anthracite with CO2 injection. International Journal of Rock Mechanics and Mining Sciences, 138, 104614.

    Article  Google Scholar 

  • Niu, Q., Cao, L., Sang, S., Zhou, X., Wang, W., Yuan, W., Ji, Z., Wang, H., & Nie, Y. (2020). Study on the anisotropic permeability in different rank coals under influences of supercritical CO2 adsorption and effective stress and its enlightenment for CO2 enhance coalbed methane recovery. Fuel, 262, 116515.

    Article  Google Scholar 

  • Pan, J., Niu, Q., & Wang, K. (2016). The closed pores of tectonically deformed coal studied by small-angle X-ray scattering and liquid nitrogen adsorption. Microporous and Mesoporous Materials, 224, 245–252.

    Article  Google Scholar 

  • Pfeifer, P., & Avnir, D. (1983). Chemistry in noninteger dimensions between two and three. I. Fractal theory of heterogeneous surfaces. The Journal of Chemical Physics, 79(7), 3558–65.

    Article  Google Scholar 

  • Ruppel, T. C., Grein, C. T., & Bienstock, D. (1974). Adsorption of methane on dry coal at elevated pressure. Fuel, 53(3), 152–162.

    Article  Google Scholar 

  • Sampath, K. H. S. M., Perera, M. S. A., Matthai, S. K., Ranjith, P. G., & Li, D. Y. (2020). Modelling of fully-coupled CO2 diffusion and adsorption-induced coal matrix swelling. Fuel, 262, 116486.

    Article  Google Scholar 

  • Siddiqui, M. A. Q., Ueda, K., Komatsu, H., Shimamoto, T., & Roshan, H. (2020). Caveats of using fractal analysis for clay rich pore systems. Journal of Petroleum Science and Engineering, 195, 107622.

    Article  Google Scholar 

  • Song, D. Z., Liu, X. F., He, X. Q., Nie, B. S., & Wang, W. X. (2021). Investigation on the surface electrical characteristics of coal and influencing factors. Fuel, 287, 119–551.

    Article  Google Scholar 

  • Wang, Z. Y., Cheng, Y. P., Wang, L., Zhou, H. X., He, X. X., Yi, M. H., & Xi, C. P. (2020). Characterization of pore structure and the gas diffusion properties of tectonic and intact coal: Implications for lost gas calculation. Process Safety and Environmental Protection, 135, 12–21.

    Article  Google Scholar 

  • Wojtacha-Rychter, K., Honanie, N., & Smoliński, A. (2020). Effect of porous structure of coal on propylene adsorption from gas mixtures. Scientific Reports, 10(1), 1–11.

    Article  Google Scholar 

  • Xia, B. W., Liu, X. F., Song, D. Z., He, X. Q., Yang, T., & Wang, L. K. (2021). Evaluation of liquid CO2 phase change fracturing effect on coal using fractal theory. Fuel, 287, 119569.

    Article  Google Scholar 

  • Xie, H. P. (1996). Fractals—An introduction to rock mechanics (pp. 15–23). Science Press.

    Google Scholar 

  • Zhang, D. F., Li, C., Zhang, J., Lun, Z. M., Jia, S. Q., Luo, C. J., & Jiang, W. P. (2019a). Influences of dynamic entrainer-blended supercritical CO2 fluid exposure on high-pressure methane adsorption on coals. Journal of Natural Gas Science and Engineering, 66, 180–191.

    Article  Google Scholar 

  • Zhang, D. F., Liu, S. L., Fu, X. X., Jia, S. Q., Min, C. G., & Pan, Z. J. (2019b). Adsorption and desorption behaviors of nitrous oxide on various rank coals: Implications for oxy-coal combustion flue gas sequestration in deep coal seams. Energy & Fuels, 33(11), 11494–11506.

    Article  Google Scholar 

  • Zhang, M., Chakraborty, N., Karpyn, Z. T., Emami-Meybodi, H., & Ayala, L. F. (2021). Experimental and numerical study of gas diffusion and sorption kinetics in ultratight rocks. Fuel, 286, 119300.

    Article  Google Scholar 

Download references

Acknowledgments

This study was financially supported by the National Natural Science Foundation of China (Grant Nos. 52004042, U19B2009), Open Fund of Shaanxi Key Laboratory of Geological Support for Coal Green Exploitation (No. DZBZ2020-10), the State Key Laboratory Cultivation Base for Gas Geology and Gas Control (Henan Polytechnic University) (Grant No. WS2019B08).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Xiangguo Kong.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Liu, X., Kong, X., Nie, B. et al. Pore Fractal Dimensions of Bituminous Coal Reservoirs in North China and Their Impact on Gas Adsorption Capacity. Nat Resour Res 30, 4585–4596 (2021). https://doi.org/10.1007/s11053-021-09958-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11053-021-09958-7

Keywords

Navigation