@article{Deng2025, 
author = {Bozhi Deng and Bingyang Jiao and Baisheng Nie and Changbao Jiang and Minghui Li and Yumeng Zhao},
title = {Evolution of microstructural damage in coal under supercritical CO2-water exposure: A multi-scale study incorporating the indentation size effect},
year = {2025},
journal = {Advances in Geo-Energy Research},
volume = {17},
number = {3},
pages = {212-225},
keywords = {CO2-water-coal interaction, nanoindentation, erosion quantification, indentation size effect, micromechanical properties},
url = {https://www.sciopen.com/article/10.46690/ager.2025.09.04},
doi = {10.46690/ager.2025.09.04},
abstract = {CO2 sequestration in coal seams represents an effective strategy for mitigating CO2 emissions. However, the complicated interaction of CO2-water-coal at the micro-scale may compromise the structural integrity and mechanical strength of coal, thereby adversely impacting the efficacy and safety of CO2 sequestration in coal seams. This study introduces a novel indentation testing method that reveals the scale-dependent evolution mechanisms of coal microstructures, enabling the accurate and reliable quantification level of degradation in the micromechanical properties caused by supercritical CO2-water-coal interactions. Using this method, the extent of mechanical degradation in three types of coal microstructures could be accurately evaluated under supercritical CO2-water-coal interaction. The pure organic matrix exhibited remarkable stability under all fluid treatments, with minor changes in microstructure feature and a mechanical property reduction of less than 25%. In contrast, the mineral structures were significantly altered by treatment with fluid mixed with supercritical CO2 and brine, with erosion depths and mechanical property reductions reaching 1.6 µm and 80% in granular structures, and 6.4 µm and 90% in banded structures. However, in the absence of brine or supercritical CO2, the erosion depths and mechanical property reductions of fusinite were limited.}
}