Carbon dioxide flow behaviour in macro-scale bituminous coal: an experimental determination of the influence of effective stress

Xiaogang Zhang, Chao Jin, Decheng Zhang, Chengpeng Zhang, P. G. Ranjith, Yong Yuan

Research output: Contribution to journalArticleResearchpeer-review

12 Citations (Scopus)

Abstract

Experimental studies on CO2 flow behaviour in coal are generally performed on meso-scale specimens (less than 100 mm in length), the results are not applicable at a larger scale. In this study, CO2 flow behaviours were experimentally tested on macro-scale reconstituted high rank coal samples (203 mm in diameter and 1 m in length). The permeability values, pressure development profiles, volumetric strains of the sample and the CO2 storage characteristics were recorded and compared to interpret the results. It was observed that CO2 permeability reduces with injection pressure, especially for supercritical CO2 injections but lower reduction rates were observed at higher CO2 injection pressures. With the increase of depth, CO2 permeability reduces and this reduction is greater for higher injection pressures. Maintaining a relatively high CO2 injection pressure creates greater pressure development in coal, and the effective zone of influence (areas where the CO2 pressure may remain at least 90% of the injection pressure) decreases with depth but increases with injection pressure to some extent. CO2 storage capacity reduces with depth, and the CO2 injection rate is greater for lower injection pressures during early stages of CO2 injection. However, the ultimate CO2 storage capacity increases with CO2 injection pressure for each injection.

Original languageEnglish
Article number126754
Number of pages12
JournalEnergy
Volume268
DOIs
Publication statusPublished - 1 Apr 2023

Keywords

  • CO sequestration
  • Coal permeability
  • Core flooding test
  • Effective stress
  • Macro-scale sample

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