Kerogen characterisation by 13C NMR spectroscopy and pyrolysis-mass spectrometry

Autor: Geoffrey Eglinton, C.S. Gutteridge, A.M.K. Wardroper, A.L. Mann, A.P. Gowar, A.J.G. Barwise
Rok vydání: 1984
Předmět:
Zdroj: Organic Geochemistry. 6:343-349
ISSN: 0146-6380
Popis: Solid state 13C nuclear magnetic resonance (NMR) spectroscopy has been applied to the examination of source rocks, demineralised kerogens and oils. In addition, a range of source rocks and kerogens have been examined by pyrolysis-mass spectrometry. Using solid state NMR techniques a measure of the aromaticity of a sample can be obtained. This can be used to “type” immature kerogens or, in the case of a given source rock (a Cretaceous limestone from the Middle East), it can be used to monitor changes in the maturity of the formation across the basin in which it occurs. A steady increase in aromaticity is observed up to the oil generation threshold, followed by a faster increase in aromaticity at greater depths. This faster increase in aromaticity is due to the onset of generation and migration of hydrocarbons. Oils sourced by this formation have been examined in solution by 13C NMR and a variation in aromaticity complementing that seen in the sediments is observed. Preliminary work using pyrolysis-mass spectrometry has shown that it may be of value in the rapid typing of kerogens. It has the advantage over NMR of rapid processing of samples and possible use without prior demineralisation of samples.
Databáze: OpenAIRE