Acidic biomarkers from Albacora oils, Campos Basin, Brazil

• Published in: Organic geochemistry Vol. 30; no. 9; pp. 1175 - 1191
• Main Authors: Nascimento, L.R., Rebouças, L.M.C., Koike, L., de A.M Reis, F., Soldan, A.L., Cerqueira, J.R., Marsaioli, A.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.1999; Elsevier Science
• Subjects: Acidic biomarkers; Albacora oil field; Analytical geochemistry; Applied sciences; Biodegradation; Brazil; Campos Basin; Carboxylic acids; Crude oil, natural gas and petroleum products; Crude petroleum; Earth sciences; Earth, ocean, space; Energy; Exact sciences and technology; Fuels; Geology and geochemistry. Geological and geochemical prospecting. Petroliferous series; Hydrocarbons; Lacustrine-sourced oils; Prospecting and exploration; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Sedimentary rocks; Stratigraphy; Temperature; Brazil; South Atlantic; Campos Basin; Southwest Atlantic; Brazil; Lacustrine-sourced oils; Acidic biomarkers; Campos Basin; Carboxylic acids; Albacora oil field; South America; Mesozoic; Atlantic Ocean; biomarkers; reservoirs; biodegradation; source rocks; Cretaceous; organic acids; spatial distribution; samples; Neocomian; oil and gas fields; lacustrine environment; Lower Cretaceous; carboxylic acids; ion chromatography; migration; Phanerozoic; petroleum
• ISSN: 0146-6380; 1873-5290
• DOI: 10.1016/S0146-6380(99)00107-2

Acidic biomarkers of 8 different oil samples from Albacora oil field, Campos Basin, Brazil, were analyzed in order to obtain additional information about biodegradation and thermal evolution. For this purpose, we selected oils (lacustrine saline origin) showing different biodegradation levels and at different distances from the fault that acted as migration pathway in the area. Previous analyses using hydrocarbon biomarkers suggested a mix of oil charges, characterizing two distinct oil cycles interrupted by meteoric water circulation in these reservoirs. Analyses of the naphthenic acid biomarkers revealed a parallelism between the hydrocarbon and the acidic biomarkers. Notwithstanding, there is evidence that the carboxylic acid biomarkers, more resistent to biodegradation, can provide information on past reservoir history when most important neutral biomarkers have been biodegraded. The limitations to the use of these biomarkers are their “de novo” synthesis in the biodegradation process and the complexity of the sample manipulation prior to the analysis.