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Effects of CO2 on the Micron-Scale Pore-Fracture Structure and Connectivity in Coals from the Qinshui Basin

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Proceedings of the International Field Exploration and Development Conference 2020 (IFEDC 2020)

Part of the book series: Springer Series in Geomechanics and Geoengineering ((SSGG))

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Abstract

The changes in the micron-scale pore and fracture structure in coal caused by CO2 are critical to CO2 injection and CH4 output in coal seams. To investigate the effects of CO2 on the characteristics and connectivity of micron-scale pores and fractures in coal, four coal samples from the Qinshui basin were selected. These samples were exposed to CO2 and water for 240 h at 80 °C and 20 MPa using a CO2 geochemical reactor. X-ray micro-CT (computed tomography), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS) were used to identify the characteristics and connectivity of micron-scale pores and fractures in the coal samples before and after CO2 treatment. Then, the influence of mineral dissolution on the micron-scale pores and fractures was discussed. After CO2 treatment, the massive dissolution of carbonate minerals significantly increased the pore contents and volumes of the coal samples. For this reason, the grain size and volume of carbonate minerals determined the increase in pore number and volume after CO2 treatment. The dissolution of calcite, dolomite, and other carbonate minerals in the coal matrix formed a large number of dissolution-created pores <10 μm in diameter, which affected the pore number in the coal after CO2 treatment but contributed little to the coal connectivity at the micron-scale. Carbonate minerals filling micro-fractures were heavily dissolved by CO2, which increased the aperture and connectivity of the micro-fractures. The dissolution of carbonate minerals in micro-fractures was the major contributor to the increase in the volume of pores >50 μm in diameter and the main reason for the increase in coal connectivity at the micron-scale.

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References

  1. Day, S., Duffy, G., Sakurovs, R., et al.: Effect of coal properties on CO2 sorption capacity under supercritical conditions. Int. J. Greenhouse Gas Control 2(3), 342–352 (2008)

    Article  Google Scholar 

  2. White, C.M., Smith, D.H., Jones, K.L., et al.: Sequestration of carbon dioxide in coal with enhanced coalbed methane recovery - a review. Energy Fuels 19(3), 659–724 (2005)

    Article  Google Scholar 

  3. Hol, S., Gensterblum, Y., Massarotto, P.: Sorption and changes in bulk modulus of coal -experimental evidence and governing mechanisms for CBM and ECBM applications. Int. J. Coal Geol. 128–129, 119–133 (2014)

    Article  Google Scholar 

  4. Fujioka, M., Yamaguchi, S., Nako, M.: CO2-ECBM field tests in the Ishikari Coal Basin of Japan. Int. J. Coal Geol. 82(3), 287–298 (2010)

    Article  Google Scholar 

  5. Faiz, M.M., Saghafi, A., Barclay, S.A., et al.: Evaluating geological sequestration of CO2 in bituminous coals: the southern Sydney Basin, Australia as a natural analogue. Int. J. Greenhouse Gas Control 1(2), 223–235 (2007)

    Article  Google Scholar 

  6. Pan, Z., Ye, J., Zhou, F., et al.: CO2 storage in coal to enhance coalbed methane recovery: a review of field experiments in China. 60(5–6), 754-776 (2018)

    Google Scholar 

  7. Wong, S., Law, D., Deng, X.H., et al.: Enhanced coalbed methane and CO2 storage in anthracitic coals - Micro-pilot test at South Qinshui, Shanxi, China. Int. J. Coal Geol. 1(2), 215–222 (2007)

    Google Scholar 

  8. Bertier, P., Swennen, R., Laenen, B., et al.: Experimental identification of CO2-water-rock interactions caused by sequestration of CO2 in Westphalian and Buntsandstein sandstones of the Campine Basin (NE-Belgium). J. Geochem. Exploration 89(1), 10–14 (2006)

    Article  Google Scholar 

  9. Dawson, G.K.W., Golding, S.D., Biddle, D., et al.: Mobilisation of elements from coal due to batch reactor experiments with CO2 and water at 40 °C and 9.5 MPa. Int. J. Coal Geol. 140, 63–70 (2015)

    Google Scholar 

  10. Du, Y., Sang, S., Wang, W., et al.: Experimental study of the reactions of supercritical CO2 and minerals in high-rank coal under formation conditions. Energy Fuels 32(2), 1115–1125 (2018)

    Article  Google Scholar 

  11. Hayashi, J., Takeuchi, K., Kusakabe, K., et al.: Removal of calcium from low rank coals by treatment with CO2 dissolved in water. Fuel 70(10), 1181–1186 (1991)

    Article  Google Scholar 

  12. Kolak, J.J., Burruss, R.C.: The use of solvent extractions and solubility theory to discern hydrocarbon associations in coal, with application to the coal–supercritical CO2 system. Org. Geochem. 73, 56–69 (2014)

    Article  Google Scholar 

  13. Liu, S.Q., Ma, J.S., Sang, S.X., et al.: The effects of supercritical CO2 on mesopore and macropore structure in bituminous and anthracite coal. Fuel 223, 32–43 (2018)

    Article  Google Scholar 

  14. Anggara, F., Sasaki, K., Sugai, Y.: Mineral dissolution/precipitation during CO2 injection into coal reservoir: a laboratory study. Energy Procedia 37, 6722–6729 (2013)

    Article  Google Scholar 

  15. Kutchko, B.G., Goodman, A.L., Rosenbaum, E., et al.: Characterization of coal before and after supercritical CO2 exposure via feature relocation using field-emission scanning electron microscopy. Fuel 107, 777–786 (2013)

    Article  Google Scholar 

  16. Liu, C.J., Wang, G.X., Sang, S.X., et al.: Fractal analysis in pore structure of coal under conditions of CO2 sequestration process. Fuel 139, 125–132 (2015)

    Article  Google Scholar 

  17. Liu, C.J., Wang, G.X., Sang, S.X., et al.: Changes in pore structure of anthracite coal associated with CO2 sequestration process. Fuel 89(10), 2665–2672 (2010)

    Article  Google Scholar 

  18. Massarotto, P., Golding, S.D., Bae, J.S., et al.: Changes in reservoir properties from injection of supercritical CO2 into coal seams - a laboratory study. Int. J. Coal Geol. 82(3–4), 269–279 (2010)

    Article  Google Scholar 

  19. Liu, S.Q., Sang, S.X., Ma, J.S., et al.: Effects of supercritical CO2 on micropores in bituminous and anthracite coal. Fuel 242, 96–108 (2019)

    Article  Google Scholar 

  20. Perera, M.S.A., Ranjith, P.G., Choi, S.K., et al.: The effects of sub-critical and super-critical carbon dioxide adsorption-induced coal matrix swelling on the permeability of naturally fractured black coal. Energy 36(11), 6442–6450 (2011)

    Article  Google Scholar 

  21. Ranjith, P.G., Perera, M.S.A.: Effects of cleat performance on strength reduction of coal in CO2 sequestration. Energy 45(1), 1069–1075 (2012)

    Article  Google Scholar 

  22. Xu, Y.S., Liu, X.W., Zhang, P.H., et al.: Role of chlorine in ultrafine particulate matter formation during the combustion of a blend of high-Cl coal and low-Cl coal. Fuel 184, 185–191 (2016)

    Article  Google Scholar 

  23. Zerai, B., Saylor, B.Z., Matisoff, G.: Computer simulation of CO2 trapped through mineral precipitation in the Rose Run Sandstone, Ohio. Appl. Geochem. 21(2), 223–240 (2006)

    Article  Google Scholar 

  24. Wang, A., Wei, Y., Yuan, Y., et al.: Coalbed methane reservoirs’ pore-structure characterization of different macrolithotypes in the southern Junggar Basin of Northwest China. Mar. Pet. Geol. 86, 675–688 (2017)

    Article  Google Scholar 

  25. Zhou, H.W., Zhong, J.C., Ren, W.G., et al.: Characterization of pore-fracture networks and their evolution at various measurement scales in coal samples using X-ray μCT and a fractal method. Int. J. Coal Geol. 189, 35–49 (2018)

    Article  Google Scholar 

  26. Liu, S.Q., Sang, S.X., Liu, H.H., et al.: Growth characteristics and genetic types of pores and fractures in a high-rank coal reservoir of the southern Qinshui basin. Ore Geol. Rev. 64, 140–151 (2015)

    Article  Google Scholar 

  27. Liu, S.Q., Sang, S.X., Pan, Z.J., et al.: Study of characteristics and formation stages of macroscopic natural fractures in coal seam #3 for CBM development in the east Qinnan block, Southern Quishui Basin, China. J. Nat. Gas Sci. Eng. 34, 1321–1332 (2016)

    Article  Google Scholar 

  28. Liu, S.Q., Sang, S.X., Wang, G.X., et al.: FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism. J. Pet. Sci. Eng. 148, 21–31 (2017)

    Article  Google Scholar 

  29. Zhong, L.W., Chen, P.Y., Ren, D.Y.: China National Standards: Sampling of Coal Petrology (GB/T 19222-2003). Standards Press of China, Beijing (2003)

    Google Scholar 

  30. Song, W., Yao, J., Ma, J., et al.: Pore-scale numerical investigation into the impacts of the spatial and pore-size distributions of organic matter on shale gas flow and their implications on multiscale characterization. Fuel 216, 707–721 (2018)

    Article  Google Scholar 

Download references

Acknowledgments

This study was supported by the National Key Research and Development Plan (No. 2018YFB0605601), the National Natural Science Foundation of China (No. 41972168), and the Foundation of Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization (No. 2019A001). We would like to thank engineers from the Shanxi CBM Branch of Huabei Oilfield Company and Lu’an Group and a number of research students from China University of Mining and Technology for their assistance in the coal sampling and some experiments.

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Authors and Affiliations

  1. Jiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Low Carbon Energy Institute, China University of Mining and Technology, Xuzhou, China

    Shi-qi Liu

  2. Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process, Ministry of Education, School of Mineral Resource and Geoscience, China University of Mining and Technology, Xuzhou, China

    Shu-xun Sang, Tian Wang, Yi Du & Hui-huang Fang

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  1. Shi-qi Liu
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  3. Tian Wang
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  5. Hui-huang Fang
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Correspondence to Shi-qi Liu .

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  1. College of Petroleum Engineering, Xi'an Shiyou University, Xi’an, Shaanxi, China

    Jia'en Lin

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Liu, Sq., Sang, Sx., Wang, T., Du, Y., Fang, Hh. (2021). Effects of CO2 on the Micron-Scale Pore-Fracture Structure and Connectivity in Coals from the Qinshui Basin. In: Lin, J. (eds) Proceedings of the International Field Exploration and Development Conference 2020. IFEDC 2020. Springer Series in Geomechanics and Geoengineering. Springer, Singapore. https://doi.org/10.1007/978-981-16-0761-5_50

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  • DOI: https://doi.org/10.1007/978-981-16-0761-5_50

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