A macro-scale view of the influence of effective stress on carbon dioxide flow behaviour in coal: An experimental study

A.S. Ranathunga, M.S.A. Perera, P.G. Ranjith, G.P.D. De Silva

Research output: Contribution to journalArticleResearchpeer-review

29 Citations (Scopus)

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 languageEnglish
Pages (from-to)13-28
Number of pages16
JournalGeomechanics and Geophysics for Geo-Energy and Geo-Resources
Volume3
Issue number1
DOIs
Publication statusPublished - 2017

Keywords

  • CO2 storage
  • Coal permeability
  • Core flooding test
  • Effective stress
  • Low rank coal

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