Aiming at the “three‐low” challenges (low permeability, low gas saturation, and low critical desorption‐to‐storage ratio CDSR) of Chinese coalbed methane (CBM) reservoir materials, this study adopted chlorine dioxide (ClO 2 ) chemical modification on long‐flame, coking, and anthracite coal materials. Integrated macroseepage experiments with microscale characterization were used to quantify the regulation of key CBM parameters. Results show that ClO 2 simultaneously enhances permeability, gas saturation, and CDSR. Under optimal conditions, coking coal permeability rose from 0.62 to 4.85 mD (+682%); permeability of long‐flame coal and anthracite increased by 15.0% and 8.9%, respectively. Average gas saturation of the three ranks increased by 18.7%–25.3%, and critical desorption pressure dropped by 15.6%–22.3%. Microscopically, ClO 2 oxidizes coal materials to generate –OH and –COOH groups (peak areas +38.5%–46.2%) and dissolves clay minerals (kaolinite content −10.8%–14.5%), thereby widening fractures and refining pores. Coal rank responses differ: Anthracite requires 3.0% ClO 2 for 36 h, whereas long‐flame coal reaches optimum at 2.0% ClO 2 for 24 h. The findings demonstrate that ClO 2 can overcome the limitations of conventional stimulation techniques and provide a practical pathway for efficient development of “three‐low” CBM reservoirs in China.
Hu et al. (Thu,) studied this question.