Authors / CoAuthors
Edwards, D.S. | Boreham, C.J. | Zumberge, J.E. | Hope, J.M. | Kennard, J.M.
Abstract
Petroleum accumulations have been discovered in the Bonaparte, Browse and Carnarvon basins over the last fifty years. However, a regional synthesis of the geochemistry of these North West Shelf hydrocarbons has not been published. To address this, this study documents the biomarker and isotopic analyses of ~300 North West Shelf oils/condensate samples that have been statistically characterised into genetically related families. Carbon and hydrogen isotopic signatures of ~50 gas samples, together with existing molecular data for ~1000 gas samples, show regional trends in wetness and abundance of non-combustible gases. These petroleum accumulations can be attributed to source rocks of Early Carboniferous, Permian, Triassic, Jurassic and Early Cretaceous age; however, most economic oil and gas accumulations are sourced from Mesozoic (Triassic Jurassic) sediments. The oils produced from the Bonaparte (Vulcan Sub-basin, northern Bonaparte) and Carnarvon (Dampier, Barrow and Exmouth sub-basins) basins are geochemically similar, being sourced from Late Jurassic marine rift-fill sediments (lower Vulcan Formation/Dingo Claystone) that contain variable amounts of terrigenous (particularly gymnosperm-derived) organic matter. Variations in their biomarker signatures can be explained by maturity differences, multiple charging and secondary alteration processes. Gas produced from the northern Rankin Platform is predominantly sourced from Triassic Jurassic fluvio-deltaic sediments. Proven and potential supergiant and giant gas accumulations occur in the deepwater areas of the North West Shelf. Case studies focussing on the geochemistry of the outer Browse (Scott Reef trend) and Carnarvon (deepwater Exmouth Plateau and Rankin Platform) gas accumulations will be presented with emphasis on d13C and d2H isotopic data.
Product Type
nonGeographicDataset
eCat Id
63982
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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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- petroleum exploration
- ( Theme )
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- geochemistry
- ( Theme )
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- geoscience databases
- ( Theme )
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- hydrocarbons
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- AU-WA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2006-01-01T00:00:00
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geoscientificInformation
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[-32.0, -7.0, 114.0, 132.0]
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