The physical characteristics of a CO2 seeping fault: the implications of fracture permeability for carbon capture and storage integrity

Clare E. Bond, Yannick Kremer, Gareth Johnson, Nigel Hicks, Robert Lister, Dave G. Jones, R. Stuart Haszeldine, Ian Saunders, Stuart M.V. Gilfillan, Zoe K. Shipton, Jonathan Pearce

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

To ensure the effective long-term storage of CO2 in candidate geological storage sites, evaluation of potential leakage pathways to the surface should be undertaken. Here we use a series of natural CO2 seeps along a fault in South Africa to assess the controls on CO2 leakage to the surface. Geological mapping and detailed photogrammetry reveals extensive fracturing along the mapped fault trace. Measurements of gas flux and CO2 concentration across the fracture corridor give maximum soil gas measurements of 27% CO2 concentration and a flux of 191 g m−2 d−1. These measurements along with observations of gas bubbles in streams and travertine cones attest to CO2 migration to the surface. Permeability measurements on the host rock units show that the tillite should act as an impermeable seal to upward CO2 migration. The combined permeability and fracture mapping data indicate that fracture permeability creates the likely pathway for CO2 migration through the low permeability tillite to the surface. Heterogeneity in fracture connectivity and intensity at a range of scales will create local higher permeability pathways along the fracture corridor, although these may seal with time due to fluid-rock interaction. The results have implications for the assessment and choice of geological CO2 storage sites, particularly in the assessment of sub-seismic fracture networks.
LanguageEnglish
Pages49-60
Number of pages12
JournalInternational Journal of Greenhouse Gas Control
Volume61
Early online date12 Apr 2017
DOIs
Publication statusPublished - 30 Jun 2017

Fingerprint

Carbon capture
permeability
tillite
carbon
leakage
Seals
Rocks
travertine
soil gas
Fluxes
geological mapping
fracture network
Gas fuel measurement
photogrammetry
gas
Photogrammetry
host rock
bubble
connectivity
Gases

Keywords

  • fracture permeability
  • CO2
  • leakage
  • natural analogue
  • Bongwana fault fracture corridor
  • cap rock permeability
  • flow barrier
  • fracture corridor
  • permeability heterogeneity

Cite this

Bond, Clare E. ; Kremer, Yannick ; Johnson, Gareth ; Hicks, Nigel ; Lister, Robert ; Jones, Dave G. ; Haszeldine, R. Stuart ; Saunders, Ian ; Gilfillan, Stuart M.V. ; Shipton, Zoe K. ; Pearce, Jonathan . / The physical characteristics of a CO2 seeping fault : the implications of fracture permeability for carbon capture and storage integrity. In: International Journal of Greenhouse Gas Control . 2017 ; Vol. 61. pp. 49-60.
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The physical characteristics of a CO2 seeping fault : the implications of fracture permeability for carbon capture and storage integrity. / Bond, Clare E.; Kremer, Yannick; Johnson, Gareth; Hicks, Nigel ; Lister, Robert ; Jones, Dave G.; Haszeldine, R. Stuart; Saunders, Ian ; Gilfillan, Stuart M.V.; Shipton, Zoe K.; Pearce, Jonathan .

In: International Journal of Greenhouse Gas Control , Vol. 61, 30.06.2017, p. 49-60.

Research output: Contribution to journalArticle

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T2 - International Journal of Greenhouse Gas Control

AU - Bond, Clare E.

AU - Kremer, Yannick

AU - Johnson, Gareth

AU - Hicks, Nigel

AU - Lister, Robert

AU - Jones, Dave G.

AU - Haszeldine, R. Stuart

AU - Saunders, Ian

AU - Gilfillan, Stuart M.V.

AU - Shipton, Zoe K.

AU - Pearce, Jonathan

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