�ber die Bevorzugung geradzahliger n-Alkane in Sedimentgesteinen

Welte, Dietrich H.; Waples, Douglas

doi:10.1007/bf00603253

Cited by 98 publications

(39 citation statements)

References 5 publications

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“…This signature was interpreted to indicate a contribution from a Palaeozoic source rock (Ohm et al, 2008). The predominance of even n-alkanes is characteristic of carbonate and evaporitic environments (Welte and Waples, 1973), and derives from the betacleavage of even-numbered fatty acids compared to the more common alpha-cleavage in siliciclastic sediments (Shimoyama and Johns, 1972). Other compounds indicating carbonate source rocks e.g.…”

Section: Variations In Maturation Parameters As Indications Of Mixingmentioning

confidence: 98%

Organic Geochemistry of Barents Sea Petroleum: Thermal Maturity and Alteration and Mixing Processes in Oils and Condensates

Lerch

Karlsen

Matapour

et al. 2016

Journal of Petroleum Geology

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The petroleum system in the Barents Sea is complex with numerous source rocks and multiple uplift events resulting in the remigration and mixing of petroleum. In order to investigate the degree of mixing, 50 oil and condensate samples from 30 wells in the SW Barents Sea were geochemically analysed by GC-FID and GC-MS to INTRODUCTIONRecent oil discoveries in the Barents Sea, such as Gotha, Alta, Wisting, Johan Castberg (Skrugard and Havis), Nucula and Goliat ( Fig. 1) (Norwegian Petroleum Directorate, 2014), are evidence for the presence of commercial volumes of liquid petroleum in an area which was long considered to be gas-prone (Stewart et al., 1995). These discoveries led to renewed geochemistry-based investigations of the petroleum systems in the Barents Sea (Bjorøy et al., 2009;Killops et al., 2014;Rodrigues-Duran et al., 2013). The presence of multiple potential source rocks may have resulted in the occurrence of mixed petroleum charges (Ohm et al., 2008;Vobes, 1998). Petroleum distribution and composition was influenced by several episodes of Cenozoic uplift and burial (Cavanagh et al., 2006;Ohm et al., 2008). Cenozoic uplift had a negative effect on the petroleum systems because it resulted in the cessation of hydrocarbon generation and expulsion (Henriksen et al., 2011). In addition, uplift resulted in alterations to the physical properties of trapped hydrocarbons, including changes to gas-to-oil ratios and associated expansion of gas columns, causing oil to be forced out of structures below the spill point (Nyland et al., 1992). Remigration/leakage of petroleum phases also occurred as a result of cap-rock failure or fault reactivation (Ohm et al., 2008;Ostanin et al., 2013). Thus geochemical interpretations in the Barents Sea suggest that uplift-related remigration/long-distance migration may be the key to understanding the complex petroleum systems present (Lerch et al., 2016;Ohm et al., 2008;Rodrigues-Duran et al., 2013).While Rodrigues Duran et al. (2013) focused mainly on the gaseous and light hydrocarbon maturation and alteration parameters in samples from the Hammerfest Basin, Ohm et al. (2008) among others investigated isotope signatures of oils from a larger area to identify potential source rocks. Bjorøy et al. (2009) correlated source rock extracts with oils to determine genetic relationships, and Killops et al. (2014) used novel age-related biomarkers to identify possible source rocks. However, until now few studies have attempted to correlate maturity signatures in order to understand regional variations in petroleum composition.The purpose of this study is to investigate the molecular evidence for the presence of mixed or transformed (biodegraded or water-washed) petroleum in the Barents Sea, and to assess regional similarities and/or differences in petroleum. Saturated and aromatic maturity parameters from the medium molecular (C 14 -C 18 ) and biomarker-range (C 20+ ) hydrocarbon fractions were analysed. Results were compared with results obtained by Lerch et al. (2016), who investigat...

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Section: Variations In Maturation Parameters As Indications Of Mixingmentioning

confidence: 98%

Organic Geochemistry of Barents Sea Petroleum: Thermal Maturity and Alteration and Mixing Processes in Oils and Condensates

Lerch

Karlsen

Matapour

et al. 2016

Journal of Petroleum Geology

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“…Although bacterial sources of some isoprenoids have been found (Volkman and Maxwell 1986), the quantitative contribution of chlorophyll-based phytol to coal probably outweighs any bacterial input. Depending on either transient oxidising or reducing depositional condition (Welte and Waples 1973), phytol is thought to be transformed into either pristane (C 19 ) by phytol oxidation and decarboxylation or into phytane (C 20 ) by dehydration and hydrogenation (Brooks et al 1969;Powell and McKirdy 1973;Murchison 1987). Both products constitute the most frequent isoprenoid hydrocarbons found in coal (White et al 1977).…”

Section: Isoprenoidsmentioning

confidence: 99%

Coal-Bearing Depositional Systems

Diessel¹

1992

398

416

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“…Pristane/phytane ratios range from 0.46 to 1.5 in the extractable hydrocarbons and average 0.94; the absence of measurable bound pristane precludes calculation of this ratio in the bound fractions. Although pristane/phytane ratios lower than 1 have been interpreted as indicators of anoxic depositional conditions (Welte and Waples, 1973;Didyk et al, 1978), the activity of methanogenic bacteria, which contain major amounts of phytane (Brassell et al, 1981;Risatti et al, 1984), evidently depresses pristane/phytane ratios regardless of the initial sedimentary setting. The combination of low pristane/phytane values and relatively low odd/ even w-alkane ratios (mean values 1.17 extractable and 1.06 bound) shows a dominance of reworked, detrital hydrocarbons in these Leg 92 sediments.…”

Section: Aliphatic Hydrocarbonsmentioning

confidence: 99%

Geolipids of Late Cenozoic Sediments from the Western Flank of the East Pacific Rise, Deep Sea Drilling Project Leg 92

Meyers¹,

Powaser²,

Dunham³

et al. 1986

Initial Reports of the Deep Sea Drilling Project

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Low concentrations of organic carbon in slowly accumulating sediments from Sites 597, 600, and 601 reflect a history of low marine productivity in the subtropical South Pacific since late Oligocene times. The distributions of n-alkanes, n-alkanoic acids, and n-alkanols provide evidence of the microbial alteration of sediment organic matter. Landderived hydrocarbons, possibly from eolian transport, dominate n-alkane distributions in these samples.

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�ber die Bevorzugung geradzahliger n-Alkane in Sedimentgesteinen

Cited by 98 publications

References 5 publications

Organic Geochemistry of Barents Sea Petroleum: Thermal Maturity and Alteration and Mixing Processes in Oils and Condensates

Organic Geochemistry of Barents Sea Petroleum: Thermal Maturity and Alteration and Mixing Processes in Oils and Condensates

Coal-Bearing Depositional Systems

Geolipids of Late Cenozoic Sediments from the Western Flank of the East Pacific Rise, Deep Sea Drilling Project Leg 92

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