Study of the biodegradation levels of oils from the Orinoco Oil Belt (Junin area) using different biodegradation scales

摘要: Abstract This work presents a study of the molecular composition saturated and aromatic hydrocarbon fractions crude oils from Orinoco Oil Belt (Junin area) in Eastern Venezuelan Basin, with purpose classifying these samples following two distinct biodegradation assessment schemes: PM scale [Peters, K.E., Moldowan, J.M., 1993. The Biomarker Guide: Interpreting Molecular Fossils Petroleum Ancient Sediments. Prentice Hall, Englewood Cliffs, New Jersey, p. 363] Manco [Larter, S., Huang, H., Adams, J., Bennett, B., Snowdon, L.R., 2012. A practical for use reservoir geochemical studies biodegraded oils. Organic Geochemistry 45, 66–76]. Both scales agree on presence different levels analyzed oils, although they are based groups compounds. uses mainly compounds (e.g., n -alkanes, acyclic isoprenoids, terpanes steranes) as well steroids. On other hand, considers alkyltoluenes, naphthalene, methylnaphthalene, phenanthrene, alkylphenanthrenes methyldibenzothiophenes) not included scale. Thus, combined allows determination level both compound classes. Dibenzothiophene (DBT), which was score determination, also shows variations peak intensity when compared to C 4 -alkylnaphthalenes, presumably associated process biological alteration. differences observed present may be attributed parameters that control rates laterally across area or existence varying communities microorganisms, among possible factors.