Age correlation of petroleum of unknown source using biological markers
- Chevron Oil Field Research Co., Richmond, CA (USA)
- Chevron Overseas Petroleum, Inc., San Ramon, CA (USA)
Determination of age constraints on petroleums from unknown sources provides a means of choosing among possible source rock candidates, predicting migration scenarios for oil, and determining the timing of its emplacement in the reservoir. A number of parameters used to assign such age constraints to petroleum have been suggested by geochemists. However, any constraining marker, regardless of age, may not be found in a particular facies because the parent organisms are absent in those sediments. Thus, the presence of a specific age correlation marker may be significant whereas its absence may not. The authors have investigated two markers for their age-correlation significance. Oleanane, a marker related to pentacyclic triterpanes in flowering plants (angiosperms) occurs in many Late Cretaceous or younger rocks and oils, even though angiosperm fossils are known in older rocks. A survey of a sequence of middle to upper Cretaceous rocks from Wyoming provides an example of a Late Cretaceous age for the onset of oleanane. However, a level of uncertainty exists for older Cretaceous rocks where a trace component with many similarities to oleanane (which could in fact be oleanane) can occur. C{sub 30}-steranes (24-n-propylcholestanes) have been used as a widely occurring marker for marine organic input to petroleum. A recent report postulates the origin of C{sub 30}-steranes from marine Sarcinochrysidales order of Chrysophycase (golden brown algae). Although the fossil record of these algae has not been recorded, their sample base indicates that C{sub 30} steranes, and therefore their parent organisms, originate in the Middle Ordovician.
- OSTI ID:
- 6685541
- Report Number(s):
- CONF-900605--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 74:5; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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