Generation and migration of oil from perhydrous Longyear coal
Hydrous pyrolysis of immature Longyear coal samples was done to assess the source of bitumen found in the coal, the petroleum generation potential and the possibility of liquid hydrocarbon migration within the coal. Hydrous pyrolysis results obtained showed an impressive average bitumen yield of 320...
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| Format: | Thesis |
| Language: | English |
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2011
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| Online Access: | http://eprints.nottingham.ac.uk/12382/ https://eprints.nottingham.ac.uk/12382/3/Generation_and_Migration_of_Oil_from_Perhydrous_Longyear_Coal.pdf |
| Summary: | Hydrous pyrolysis of immature Longyear coal samples was done to assess the source of bitumen found in the coal, the petroleum generation potential and the possibility of liquid hydrocarbon migration within the coal. Hydrous pyrolysis results obtained showed an impressive average bitumen yield of 320 mg/g TOC which increases towards the upper portion of the seam. This increase coincides with an increase in original hydrogen content and hydrogen index of the samples indicating an improvement in oil generation potential of the kerogen up-seam. The hopane ratios indicated thermal maturity which was consistent in both the initial coal and generated bitumen. High proportion of C29 steranes was observed in initial extracts and generated bitumen indicating high plant input in the original organic matter. The uniformity of the source and maturity parameters in the bitumen extract and pyrolysis bitumen yield indicates that the bitumen located in-situ was generated by the coal. The Longyear seam showed an unusual high loss of lower molecular weight hydrocarbons towards the upper portion of the seam as shown by the decrease of the aliphatic fractions of the initial coal bitumen. This loss was marked by an exceptional increase in Pr/nC17 and Ph/nC18 ratios towards the upper portion of the seam. Having established uniform thermal maturity and source input at all portions of the seam, the most probable explanation for this loss is that liquid hydrocarbon migration has occurred within the Longyear seam. The generative capacity of the Longyear coal and the observed migration profile makes the Longyear seam significant as a source rock in the Arctic basin and as a source of oil via retorting. |
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