Steranes and terpanes in kerogen pyrolysis for correlation of oils and source rocks
Comparison of biological marker alkanes in the kerogen pyrolyzate and bitumen from a sediment is a useful test for the indigenous nature of sediment extracts. For the pyrolysis conditions used, the bulk of the hydrocarbons is released from the kerogen matrix between 375 and 550/sup 0/C; and its stereochemistry is almost the same as that observed in the extractable bitumen in a genuine source rock. Examples are given to demonstrate that, during pyrolysis, the sterane/terpane ratio decreases and secondary terpanes are generated at the expense of primary ones. The mechanism of artificial petroleum generation by pyrolysis differs from 'natural' diagenesis during geological time and is reflected in the composition of certain C/sub 27/--C/sub 29/ steranes, as demonstrated by simulation experiments and C/sub 29/--C/sub 30/ moretanes and hopanes. The 5..cap alpha../5..beta..-sterane ratios, jointly with 17..cap alpha..(H)-hopane/17..beta..(H)-moretane ratios, tricyclic terpane concentrations, and 17..cap alpha..(H)/17..beta..(H)-trisnorhopane ratios, allow the differentiation of kerogens from adjacent stratigraphies.
- Research Organization:
- Chevron Oil Field Research Co., Richmond, CA
- OSTI ID:
- 6837069
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 42:5; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
040500* -- Oil Shales & Tar Sands-- Properties & Composition
ALKANES
CHEMICAL REACTIONS
CORRELATIONS
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
KEROGEN
ORGANIC COMPOUNDS
ORIGIN
PETROLEUM
PHYSICAL PROPERTIES
PYROLYSIS
QUANTITY RATIO
RESERVOIR ROCK
ROCKS
STEREOCHEMISTRY
THERMODYNAMIC PROPERTIES