1 The Physical Characteristics of a CO2 Seeping Fault: the implications of fracture 2 permeability for carbon capture and storage integrity 3 4 Clare E. Bond1* 5 Yannick Kremer2 6 Gareth Johnson3 7 Nigel Hicks4 8 Robert Lister5 9 Dave G. Jones5 10 Stuart Haszeldine3 11 Ian Saunders6 12 Stuart Gilfillan3 13 Zoe K. Shipton2 14 Jonathan Pearce5 15 16 1Department of Geology and Petroleum Geology, University of Aberdeen, Meston Building, 17 Kings College, Aberdeen, AB24 3UE, UK (
[email protected]) 18 2Department of Civil and Environmental Engineering, University of Strathclyde, James Weir 19 Building, Glasgow, G1 1XJ (
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[email protected]) 20 3School of Geosciences, University of Edinburgh, Grant Institute, Kings Buildings, James 21 Hutton Road, Edinburgh, EH9 3FE (
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[email protected]) 23 4 Council for Geoscience, 139 Jabu Ndlovu Street, Pietermaritzburg, KwaZulu-Natal, South 24 Africa 3200 (
[email protected]) 25 5 British Geological Survey, Environmental Science Centre, Nicker Hill, Keyworth, Nottingham 26 NG12 5GG (
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[email protected]) 27 6 Council for Geoscience, 280 Pretoria St, Silverton, Pretoria, 0184 (
[email protected]) 28 *Corresponding Author
[email protected] 29 30 31 32 Highlights 33 34 CO2 migration is spatially associated with the Bongwana fault fracture corridor. 35 Cap rock permeability suggests that without fractures it would act as a flow barrier. 36 Elevated CO2 concentration and flux are measured across the fracture corridor. 37 Fracture intensity and orientation variability creates permeability heterogeneity.