Extended 3{beta}-alkyl steranes and 3-alkyl triaromatic steroids in crude oils and rock extracts

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Geochimica et Cosmochimica Acta

DOI:https://doi.org/10.1016/0016-7037(95)00271-Z· OSTI ID:150512

Dahl, J ^[1]; Moldowan, J M ^[2]; Summons, R E ^[3]

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1. Chevron Overseas Petroleum, Inc., San Ramon, CA (United States)
2. Stanford Univ., CA (United States)
3. Australian Geological Survey Organization, Canberra City (Australia); and others

In oils and Precambian- to Miocene-age source rocks from varying depositional environments, we have conclusively identified several novel 3-alkyl sterane and triaromatic steroid series, including (1) 3{beta}-n-pentyl steranes, (2) 3{beta}-isopentyl steranes, (3) 3{beta}-n-hexyl steranes, (4) 3{beta}-n-hepatyl steranes, (5) 3,4-dimethyl steranes, (6) 3{beta}-butyl,4-methyl steranes, (7) triaromatic 3-n-pentyl steroids, and (8) triaromatic 3-isopentyl steroids. We have also tentatively identified additional homologs with 3-alkyl substituents as large as C{sub 11}. The relative abundances of these compounds vary substantially between samples, as indicated by (1) the ratio of 3{beta}-n-pentyl steranes to 3{beta}-isopentyl steranes and (2) the ratio of 3-n-pentyl triaromatic steroids to 3-isopentyl triaromatic steroids. These data suggest possible utility for these parameters as tools for oil-source rock correlations and reconstruction of depositional environments. Although no 3-alkyl steroid natural products are currently known, several lines of evidence suggest that 3{beta}-alkyl steroids result from bacterial side-chain additions to diagenetic {delta}{sup 2}-sterenes.

• OSTI ID: 150512
• Journal Information: Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 18 Vol. 59; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
GEOCHEMISTRY
GEOLOGIC MODELS
ORIGIN
PETROLEUM
QUANTITATIVE CHEMICAL ANALYSIS
RESERVOIR ROCK
STEROIDS