3-Alkyl and 3-carboxyalkyl steranes in marine evaporitic oils of the Potiguar Basin, Brazil

Lopes, José Arimateia Dantas; Neto, Eugênio V. Santos; Mello, M.R.; Koike, Luzia; Marsaioli, Anita J.; Reis, Francisco de A.M.

doi:10.1016/s0009-2541(99)00013-3

Cited by 32 publications

(29 citation statements)

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“…This is analogous to the mass fragments of dealkylated diginane steranes published by Wingert and Pomerantz (1986) and Requejo et al (1997). The 3β-methyl position at ring A is suggested based on previous studies of Brazilian crude oils (Lopes et al, 1999;Rodrigues et al, 2000). Taking into account that the distribution shows seven isomer peaks (M +• 302), these compounds may be represented by C 22 3-and 4-methyl steranes (Fig.…”

Section: Ring-a Methylated Short-chain Steranessupporting

confidence: 75%

“…In addition, alkyl steranes with methyl to heptyl side chains at C-3 have been reported Capon, 1988, 1991;Dahl et al, 1992Dahl et al, , 1995Schaeffer et al, 1993;Lopes et al, 1999). Nevertheless, the absence of known biological precursors in living organisms and uncertain formation mechanisms for 3β-alkyl steranes are key challenges for understanding their occurrence and distribution in crude oil (Summons and Capon, 1988).…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the absence of known biological precursors in living organisms and uncertain formation mechanisms for 3β-alkyl steranes are key challenges for understanding their occurrence and distribution in crude oil (Summons and Capon, 1988). The first report of 3β-alkyl steranes (13) in the Brazilian marginal basins was in marine evaporitic crude oils from Potiguar Basin in the Fazenda Belem field (Lopes et al, 1997(Lopes et al, , 1999.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Uncommon steranes in Brazilian marginal crude oils: Dinoflagellate molecular fossils in the Sergipe-Alagoas Basin, Brazil

Araújo

Azevedo

2016

Organic Geochemistry

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Section: Ring-a Methylated Short-chain Steranessupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Uncommon steranes in Brazilian marginal crude oils: Dinoflagellate molecular fossils in the Sergipe-Alagoas Basin, Brazil

Araújo

Azevedo

2016

Organic Geochemistry

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“…3-alkyl steroids might substitute for hopanols in bacterial membranes. What is more, 3-alkyl and 3-carboxyalkyl steranes have been identified in marineevaporitic oils from Potiguar Basin in Brazil, providing further evidence for the postulation [21] . Some researches have showed that 3β-methyl steranes are rich in Paleozoic and pre-Cambrian, and poor in Mesozoic and Cenozoic [4,16,22] (Fig.…”

mentioning

confidence: 83%

Identification and significance of 3β-alkyl steranes in the Eogene lacustrine sediments and petroleum of China

Wang

Zhang²,

Wang

2006

CHINESE SCI BULL

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Several homologous series of steranes with alkyl side chains (C 1 to C 4 ) at the 3β position have been identified in the Jiyang Eogene lacustrine deposition. It is postulated that its precursors represent a new class of steroids, alkylated at the C-3 position with a polyhydroxy n-alkane. These precursors may have been formed by the bacterial addition of a ribose sugar to Δ 2 -sterenes, diagenetic alteration products of steroids synthesized by eukaryotes. 3-alkyl steroids might substitute for hopanols in bacterial membranes. When they are present in a sample, the patterns of the isomer distributions of 3-alkyl steranes are similar to desmethyl steranes except for lower rearranged ones. It is shown that the configurational isomerization of 3-alkyl steranes is trending in line with that of desmethyl steranes with increasing of maturity. The abundance of 3-alkyl steranes may be controlled by the depositional environments; they are primary in saline or near shore lacustrine, moderate in shallow lacustrine, poor in sub-deep to deep lacustrine relative to the 4-methyl steranes.

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“…Essa discrepância entre os parâmetros indicativos de evolução térmica provavelmente se deve aos efeitos de fonte da matéria orgânica ou da matriz mineral da rocha geradora. 12 Entretanto, estes resultados confirmam que todos os petróleos são oriundos de rochas geradoras que passaram por processos de maturidade térmica semelhantes e eficientes o bastante para gerarem petróleos de boa qualidade em termos de conteúdo de hidrocarbonetos leves, classificados como parafínicos e parafínicos-naftênicos, 34 exceção registrada apenas para o petróleo P1, com características de óleo biodegradado após sua acumulação no reservatório.…”

Section: Determinação Da Evolução Térmica Dos Petróleos Através Do Usunclassified

Geochemical Correlations Between Petroleum Samples From the Potiguar Basin and Definition of Their Possible Generating Rocks

et al. 2018

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publicado na web em 01/02/2018 GEOCHEMICAL CORRELATIONS BETWEEN PETROLEUM SAMPLES FROM THE POTIGUAR BASIN AND DEFINITION OF THEIR POSSIBLE GENERATING ROCKS. Eight petroleum samples from Potiguar Basin were submitted for determination of saturated biomarkers by gas chromatography (fingerprint), liquid chromatography (saturates, aromatics, resins and asphaltenes), gas chromatography-mass spectrometry (GC-MS), nickel and vanadium by high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). The geochemical parameters provided information on type of depositional paleoenvironment in which organic matter that gave rise to each oil sample and level of thermal maturation reached by generating rocks that make up the Potiguar Basin were deposited. The relationships between the stable isotopes of carbon (δ 13 C) and between Ni and V concentrations of each petroleum sample were also evaluated. The evaluations separated for oil samples into two distinct groups. Group 1 formed by samples P1, P2, P5 and P8, with characteristics of generating rock that was deposited in a marine hypersaline environment. Group 2 composed of samples P3, P4, P6 and P7 with freshwater lacustrine depositional paleoenvironment, which were elucidated through the geochemical parameters studied. The hierarchical cluster analysis was presented as promising chemometric tool for characterization of petroleum samples in the according to their origin of the generating rock by ratio parameters of hopane/sterane , tetracyclic polyiprenoids/diastereomers and diastereos R+S/cholestane R+S.Keywords: petroleum; biomarkers; nickel; vanadium; carbon isotopes. INTRODUÇÃOA Bacia Potiguar foi formada durante o rompimento do supercontinente Gondwana, que culminou com a separação das placas Sul-Americana e Africana. Ela apresenta diferentes tipos de rochas geradoras e, consequentemente, petróleos com diferentes características químicas decorrentes das condições físico-químicas dos paleoambientes deposicionais nos quais a matéria orgânica, que deu origem a esses petróleos, foi depositada, como por exemplo: ambientes lacustres, transicional e marinho. [1][2][3] O petróleo é uma mistura complexa de milhares de componentes. Dentre as espécies orgânicas que compõem os vários tipos de petróleos, encontram-se os compostos biomarcadores, isto é, aqueles provenientes dos seres vivos que deram origem ao petróleo. Estes compostos mantiveram seus esqueletos carbônicos praticamente inalterados durante as etapas de transformação da matéria orgânica (seres vivos) depositada na rocha geradora em petróleo, sua migração e acumulação em rochas reservatórios. 4 Os biomarcadores são usados para orientar a exploração para áreas mais favoráveis à existência de acumulações comerciais de óleo e gás. 5Desse modo, o estudo geoquímico molecular das frações do petróleo, baseado na determinação de biomarcadores e de outros hidrocarbonetos, auxilia na avaliação do tipo de sua rocha geradora e do seu paleoambiente deposicional, bem como na avaliação do nível de calo...

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3-Alkyl and 3-carboxyalkyl steranes in marine evaporitic oils of the Potiguar Basin, Brazil

Cited by 32 publications

References 17 publications

Uncommon steranes in Brazilian marginal crude oils: Dinoflagellate molecular fossils in the Sergipe-Alagoas Basin, Brazil

Uncommon steranes in Brazilian marginal crude oils: Dinoflagellate molecular fossils in the Sergipe-Alagoas Basin, Brazil

Identification and significance of 3β-alkyl steranes in the Eogene lacustrine sediments and petroleum of China

Geochemical Correlations Between Petroleum Samples From the Potiguar Basin and Definition of Their Possible Generating Rocks

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