Abstract
Existing studies highlight the uncertainty in the process of CO2 sequestration in deep coal seams, mainly due to the associated CO2 adsorption-induced coal matrix rearrangements. This complexity is further increased by the highly heterogeneous nature of the coal mass which causes issues in reproducing field conditions under laboratory conditions. The main objective of this study is therefore to determine the permeability behaviour in coal for CO2 flow using macro-scale reconstituted coal specimens (203 mm in diameter and 1000 mm in length), particularly under various effective stress conditions. A series of core flooding experiments was conducted on Australian brown coal, using an advanced core flooding apparatus, for a range of CO2 injection pressures and axial stresses. According to the findings, CO2 permeability decreases with increasing CO2 injection pressure, and the reduction is greater for super-critical CO2 at greater depths. The critical zone of influence for CO2 injection into a selected coal seam is greater at lower injection pressures and at shallow depths, and it reduces with increasing CO2 pressure and seam depth. CO2 storage capacity in a selected coal seam is greater at lower depths and higher CO2 injection pressures. However, the reduction of CO2 storage capacity with depth was not very significant, which is important for field CO2 sequestration projects, which normally use deep seams to store CO2 .
Original language | English |
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Pages (from-to) | 13-28 |
Number of pages | 16 |
Journal | Geomechanics and Geophysics for Geo-Energy and Geo-Resources |
Volume | 3 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2017 |
Keywords
- CO2 storage
- Coal permeability
- Core flooding test
- Effective stress
- Low rank coal