scholarly journals Crude oils from Austral and Golfo San Jorge Basins. Similarity and differences based on Biomarker Ratios

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 62-68
Author(s):  
Germán Javier Tomas ◽  
Walter Vargas ◽  
Adrián Javier Acuña
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Matter ◽  
Crude Oil ◽  
Oxygen Concentration ◽  
Crude Oils ◽  
Geochemical Analysis ◽  
Type Ii ◽  
Thermal Maturity ◽  
Organic Matter Type

The biomarker profiles are characteristic of oils. The goal of this study was to evaluate the biomarkers in oil samples using geochemical analysis. Oil samples were obtained from Austral Basin and from Golfo San Jorge Basin. Specifically, the aliphatic and aromatic fractions were analyzed by Gas Chromatography coupled to Mass Spectrometry. Biomarker ratios were calculated for isoprenoids, terpanes, steranes to correlate the organic matter precursor, deposition environment, and others to differentiate distinct crude oil sources. Based on the specific parameters, the crude of the Austral Basin appears to have been generated from organic matter type II-III (mixed), in deposition environments with moderate oxygen concentration, associated with a siliciclastic lithology and a moderate to high thermal maturity. On the contrary, the crude oils from the Golfo San Jorge Basin displayed biomarkers profiles characteristics to a type II (marine) kerogen, corresponding to an anoxic deposition environment, carbonated lithology and low thermal maturity.

Organic Geochemical Characteristics of Core Samples from Central Primorsk-Emba Province, Precaspian Basin, Kazakhstan

2021 ◽  
Author(s):  
Tolganay Jarassova ◽  
Mehmet Altunsoy
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Matter ◽  
Aromatic Hydrocarbons ◽  
Oil And Gas ◽  
Gas Chromatography Mass Spectrometry ◽  
Type Ii ◽  
Core Samples ◽  
Chromatography Mass Spectrometry ◽  
Potential Type

Abstract The Primorsk-Emba province is one of the main oil and gas region of the Precaspian basin. The resources of the Primorsk-Emba oil and gas region range from 5 to 12 billion tons of oil and from 2 to 6 trillion m³ of natural gas. This study primarily concentrates on investigating the organic geochemistry and petroleum geology characteristics of sedimentary units that generated oil in the central Primorsk-Emba province. 20 core samples taken from the Jurassic units in the western part of the study area are characterized by organic matter amount, hydrocarbon production potential, type of organic matter, maturity of organic matter. According to the Rock-Eval results Jurassic aged rocks generally have a petroleum potential ranging from weak to excellent, the organic matter is between Type II (oil prone), Type II-III (gas-oil prone) and Type III (gas prone), and the degree of maturation is immature-mature stage. Oil extracts were characterized by geochemical methods including Gas Chromatography (GC) and Gas Chromatography–Mass Spectrometry (GC–MS). n-alkanes and isoprenoids were evaluated by High-Resolution Gas Chromatography (GC-HR), aromatic hydrocarbons were evaluated by Low Thermal Mass Gas Chromatography (GC-LTM), terpanes (hopanes), steranes / diasteranes and aromatic hydrocarbons were evaluated by Gas Chromatography-Mass Spectrometry (GC-MS). The GC and GC-MS data obtained, it has been determined whether the paleoenvironment characteristics of the study area, hydrocarbon potential, type of kerogen, maturity level of organic matter and whether it is affected by biodegradation. Distribution of n-alkanes in the GC showed that no biodegradation was observed in analyzed samples, source rock deposited in a marine environment under reducing conditions and an organic matter that occurred were generated by marine carbonates. Based on maturity parameters, studied oils are mature and located on the oil generation window. According to biomarker age parameters C28 / C29 and norcholestane (NCR)/nordiacholestane (NDR) samples are generally Mesozoic (Triassic-Jurassic- Cretaceous) origin, nevertheless there are also levels corresponding to the Paleozoic (Permian) late stages.

scholarly journals Saturated biomarkers in the estimation of organic geochemical homogeneity of crude oils from four oil fields in Libya

2020 ◽  
Vol 85 (11) ◽  
pp. 1489-1499
Author(s):  
Ramadan Saheed ◽  
Tatjana Solevic-Knudsen ◽  
Musbah Faraj ◽  
Zlatko Nikolovski ◽  
Hans Nytoft ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Matter ◽  
Relative Concentration ◽  
Oil Fields ◽  
Source Rocks ◽  
Gas Chromatography Mass Spectrometry ◽  
Crude Oils ◽  
Terrestrial Organic Matter ◽  
Migration Pathways

Seven crude oils from four oil fields in the Sirte and Murzuq Basins in Libya were investigated in order to estimate their organic geochemical homogeneity. Saturated biomarkers (n-alkanes and isoprenoids) were analyzed using gas chromatography?mass spectrometry (GC?MS). The parameters calculated from the distributions of n-alkanes and isoprenoid aliphatic alkanes, pristane and phytane were used to interpret the organic geochemical characteristics of the oils. Based on the high relative concentration of lower n-alkane homologues in the C11?C16 range and high API values, the oils were classified as light oils. These results also implied that the oils were not biodegraded. The parameters calculated from the distributions of saturated biomarkers indicated that all investigated oils were generated from source rocks containing organic matter of a similar marine origin but with a contribution of terrestrial organic matter. The results also demonstrated that these source rocks were deposited in an oxic environment. The same source rock or the same type of source rocks for all seven samples were postulated. It was concluded that, if the crude oils from these distant basins originated from the same source rocks, they must have had different lengths of their migration pathways.

Geochemical Characteristics of Crude Oils from the Tarim Basin by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

2011 ◽  
Vol 29 (6) ◽  
pp. 711-741 ◽  
Author(s):  
Sumei Li ◽  
Xiongqi Pang ◽  
Quan Shi ◽  
Baoshou Zhang ◽  
Haizu Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Cyclotron Resonance ◽  
Sulfur Compounds ◽  
Crude Oils ◽  
Ion Cyclotron Resonance ◽  
Thermal Maturity ◽  
Sulfur Species ◽  
Abnormal Distribution ◽  
Ion Cyclotron

Nine marine and two terrestrial oils from the Tarim Basin in Western China were analyzed by Fourier transform ion cyclotron resonance mass spectrometry. Sulfur compounds with 8–47 carbon atoms and double-bond equivalent (DBE) values of 0–21 are abundant in the crude oils. The most abundant sulfur species in Tazhong marine oils are S1 species (80.57–85.22%), followed by O1S1 (6.95–14.78%) and S2 (0.71–6.69%) species. The dominant species in Yingmaili terrestrial oils are S1 (51.41–52.76%), O1S1 (26.83–35.27%) and O2S1 (11.97–21.76%) species; no S2 species were detected. The results suggest that the sulfur compounds present in oil vary with the oil type. For the S1 and S2 species, as the thermal maturity increased, the degree of condensation increased, and the median and range of the number of carbon atoms decreased. Compounds with DBE values of 9, which are most likely dibenzothiophenes, became concentrated as the thermal maturity increased. Therefore, the unusually high abundance of dibenzothiophenes in the Lower Ordovician oils could be related to the thermal maturity. The TZ83 (O1) oil has an abnormal distribution of S1 species, and is characterized by sulfur species with relatively low DBE values (0–7). This abnormal distribution could be caused by thermochemical sulfate reduction, and a relatively high content of H2S in the associated gases and abundant sulfo-diamantane in the oil supported this theory. In conclusion, the thermal maturity, organic facies, paleoenvironment of the source rock, and possibly thermochemical sulfate reduction have a large impact on the sulfur compounds present in the oils. The O1S1/S1 and S2/S1 ratios could be used as indicators of the precursors/paleoenvironment, and C10–19/C20–50 DBE9 and DBE1,3,6 /DBE9 could be used as indicators of thermal maturity. Fourier transform ion cyclotron resonance mass spectrometry is very useful for detecting sulfur compounds, especially those with high molecular weights, in the crude oils. This technique has potential for determining the formation mechanisms of some unusual oils and the geochemical implications of the sulfur compounds they contain.

Liquid hydrocarbon characterization of the lacustrine Yanchang Formation, Ordos Basin, China: Organic-matter source variation and thermal maturity

2017 ◽  
Vol 5 (2) ◽  
pp. SF225-SF242 ◽  
Author(s):  
Xun Sun ◽  
Quansheng Liang ◽  
Chengfu Jiang ◽  
Daniel Enriquez ◽  
Tongwei Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Ordos Basin ◽  
Depositional Environments ◽  
Source Rocks ◽  
Type I ◽  
Hydrocarbon Generation ◽  
Type Ii ◽  
Thermal Maturity ◽  
Yanchang Formation

Source-rock samples from the Upper Triassic Yanchang Formation in the Ordos Basin of China were geochemically characterized to determine variations in depositional environments, organic-matter (OM) source, and thermal maturity. Total organic carbon (TOC) content varies from 4 wt% to 10 wt% in the Chang 7, Chang 8, and Chang 9 members — the three OM-rich shale intervals. The Chang 7 has the highest TOC and hydrogen index values, and it is considered the best source rock in the formation. Geochemical evidence indicates that the main sources of OM in the Yanchang Formation are freshwater lacustrine phytoplanktons, aquatic macrophytes, aquatic organisms, and land plants deposited under a weakly reducing to suboxic depositional environment. The elevated [Formula: see text] sterane concentration and depleted [Formula: see text] values of OM in the middle of the Chang 7 may indicate the presence of freshwater cyanobacteria blooms that corresponds to a period of maximum lake expansion. The OM deposited in deeper parts of the lake is dominated by oil-prone type I or type II kerogen or a mixture of both. The OM deposited in shallower settings is characterized by increased terrestrial input with a mixture of types II and III kerogen. These source rocks are in the oil window, with maturity increasing with burial depth. The measured solid-bitumen reflectance and calculated vitrinite reflectance from the temperature at maximum release of hydrocarbons occurs during Rock-Eval pyrolysis ([Formula: see text]) and the methylphenanthrene index (MPI-1) chemical maturity parameters range from 0.8 to [Formula: see text]. Because the thermal labilities of OM are associated with the kerogen type, the required thermal stress for oil generation from types I and II mixed kerogen has a higher and narrower range of temperature for hydrocarbon generation than that of OM dominated by type II kerogen or types II and III mixed kerogen deposited in the prodelta and delta front.

Petroleomics by ion mobility mass spectrometry: resolution and characterization of contaminants and additives in crude oils and petrofuels

2015 ◽  
Vol 7 (11) ◽  
pp. 4450-4463 ◽  
Author(s):  
Jandyson Machado Santos ◽  
Renan de S. Galaverna ◽  
Marcos A. Pudenzi ◽  
Eduardo M. Schmidt ◽  
Nathaniel L. Sanders ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Crude Oil ◽  
Ion Mobility ◽  
Drift Tube ◽  
Crude Oils ◽  
Ion Mobility Mass Spectrometry ◽  
Uniform Field ◽  
Field Drift

IM-MS, was performed in a new uniform-field drift tube, IM-QTOF instrument. It can resolve and characterize crude oil and its contaminants, as well as petrofuels and their additives.

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