Authors / CoAuthors
Feitz, A.J. | Boreham, C.J. | Hortle, A.L. | Kuske, T.J. | Ransley, T.R.
Abstract
A major concern for regulators and the public with geologically storage of gas is the potential for the migration of gas (e.g. CO2) via a leaky fault or well into potable groundwater supplies. Given sufficient CO2, an immediate effect on groundwater would be a decrease in pH which could lead to accelerated weathering, an increase in alkalinity and the release of major and minor ions. Laboratory and core studies have demonstrated that on contact with CO2 heavy metals can be released under low pH and high CO2 conditions (particularly Pd, Ni and Cr). There is also a concern that trace organic contaminants could be mobilised due to the high solubility of many organics in supercritical CO2. These scenarios could potentially occur under a high CO2 leakage event but a small leak might be barely perceptible yet could provide an important early warning for a subsequent and more substantial impact. Different approaches are required for the detection and quantification of these low level leaks and are the subject of this paper. A 3 year groundwater survey was recently completed in the Surat Basin, which forms part of the Triassic-Cretaceous, Great Artesian Basin (GAB) aquifer sequence. In addition to a comprehensive water and isotopic analysis of samples from groundwater wells, gases were collected from groundwater samples and analysed for composition, '13CCO2, '13CCH4 and '2HCH4. Methane is prevalent in the major aquifers in the Surat Basin (e.g. Mooga, Gubbermunda and Hutton sandstones) and is invariably associated with a bacterial (methanogenic) carbonate reduction source, evident from its isotopic signature ('13CCH4 ~ -70', '2HCH4 ~ 220'). In addition to methane and low levels of CO2, trace levels of ethane are often detected.
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nonGeographicDataset
eCat Id
73544
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationAbstract
- ( Theme )
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- groundwater
- ( Theme )
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- geological storage of CO2
- ( Theme )
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- gas
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2012-01-01T00:00:00
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geoscientificInformation
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[-30.0, -22.0, 138.0, 147.0]
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