Geochemistry and possible origins of biodegraded oils in the Cretaceous reservoir of the Muglad Basin and their application in hydrocarbon exploration

Yang, Zhe; Li, Meijun; Deng, Cheng; Xiao, H.; Lai, Hongfei; Chen, Qingyao

doi:10.1016/j.petrol.2018.10.077

Cited by 10 publications

(2 citation statements)

References 22 publications

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“…More recently, Sun et al reported the genetic relationship between hopanes and 25-norhopanes in severely to extremely biodegraded oils from the southern Junggar Basin by compound-specific isotope analysis. Any case investigations have shown a common understanding that there was a good correlation between the decrease of biodegradative precursors (e.g., TTs and hopanes) and the corresponding increase of biodegradative products (e.g., demethylated tricyclic terpenoids and norhopanes). − Similarly, a similar understanding was found in the heavily to extremely biodegraded oils from the Chepaizi Uplift in the Junggar Basin in this study. If we can recover the original appearance of source-related molecular biomarkers in biodegraded oils, this will achieve an effective oil–source correlation.…”

Section: Introductionsupporting

confidence: 80%

Origin of Mesozoic Biodegraded Crude Oils from the Eastern Chepaizi Uplift (Junggar Basin) Constrained by the Biomarker Recovery Method

Wang

Chang

et al. 2023

Energy Fuels

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The Mesozoic (Jurassic and Cretaceous) sandstone reservoirs in the eastern Chepaizi Uplift of the Junggar Basin (NW China) have become hot targets in recent years for their substantial amounts of oils discovered. However, the oil origin has been a controversial issue due to biodegradation. In this study, hierarchical cluster analysis and principal component analysis show that the Mesozoic crude oils can be divided into three oil families (A1, A2, and A3). Meanwhile, the biodegradation level of the three oil families (PM 6 to 9+) was evaluated based on the PM scale and the parameter-stripping method of strongly resistant parameters. Allowing for this extremely high biodegradation case, this study adopted a biomarker recovery method to recover the original appearances of the three oil families. Here, eight parameters related to hopane (H), tricyclic terpane (TT), and C24-tetracyclic terpane (C24 Tet) were recovered, the dispersion of eight parameter sets is significantly reduced, and the geochemical characteristics are more obvious, especially for TT. Thus, this reliability and robustness, as well as the similarity between the source rock and the biodegraded crude oils, encourage us to perform oil–source correlation. The oil–source correlation revealed that family A1 was derived from the Permian source rocks in the Shawan Sag, family A2 was mainly derived from the Permian source rocks in the Shawan Sag and mixed with a small amount of oils generated by the Jurassic source rocks in the Sikeshu Sag and the Carboniferous source rocks in the Chepaizi Uplift, and family A3 mainly originated from the Permian source rocks in the Shawan Sag mixed with a small amount of oil produced by the Carboniferous source rocks in the Chepaizi Uplift. This conclusion is also further supported by effective biomarker parameters and a stable carbon isotope (δ13C), discriminant analysis, hydrocarbon migration, and restored paleogeomorphology. The parameter recovery is evidenced as one of the most useful methods and showed higher resolution than the conventional oil–source correlation to identify the origins of biodegraded oils.

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Section: Introductionsupporting

confidence: 80%

Origin of Mesozoic Biodegraded Crude Oils from the Eastern Chepaizi Uplift (Junggar Basin) Constrained by the Biomarker Recovery Method

Wang

Chang

et al. 2023

Energy Fuels

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“…The HDM can use hydrocarbons as a source of energy and carbon [58,59], preferably alkanes, cyclic and aromatic, and they metabolize organic and carbon compounds, drastically reducing oil quality [45,60]. With increasing levels of biodegradation, the content of asphaltenes and resins, acidity, and oil viscosity increase, while the content of saturated and aromatic hydrocarbons decreases [60,61]. These alterations have a negative effect on oil production by reducing the flow rates from reservoirs, as well as refining operations, and increasing process costs [61,62].…”

Section: Rna Amplification and Sequencing Methodsmentioning

confidence: 99%

Metabolically Active Microbial Communities in Oilfields: A Systematic Review and Synthesis of RNA Preservation, Extraction, and Sequencing Methods

Gomes,

García,

Dutra

et al. 2023

Applied Microbiology

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Characterizing metabolically active microorganisms using RNA-based methods is a crucial tool for monitoring and mitigating operational issues, such as oil biodegradation and biocorrosion of pipelines in the oil and gas industry. Our review, a pioneering study, addresses the main methods used to preserve, isolate, and sequence RNA from oilfield samples and describes the most abundant metabolically active genera studied. Using the MEDLINE/PubMed, PubMed Central, Scopus, and Web of Science databases, 2.561 potentially eligible records were identified. After screening, 20 studies were included in our review, underscoring the scarcity of studies related to the subject. Data were extracted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). These studies evaluated different samples, including produced water (PW), injection water (IW), solid deposits (SD), oil (OIL), and oily sludge (OS) collected from oilfields located in Australia, China, India, Mexico, and the United Arab Emirates. Environmental samples accounted for 55% of the studies, while enriched cultures and microbial consortia represented 35% and 15% of studies, respectively. PW was the most frequently studied sample, comprising 72% of all samples. Filtration and centrifugation were the only processes employed to concentrate the biomass present in samples. For RNA preservation, the most used method was a solution composed of 95:5 v/v ethanol/TRIzol, while for RNA isolation, the TRIzol reagent was the most cited. The Sanger sequencing method was used in all studies evaluating functional genes (alkB, dsrA, aprA, assA, and mcrA), and the Next-Generation Sequencing (NGS) method was employed in studies for sequencing transcripts of the 16S rRNA gene and metatranscriptomes. Pseudomonas (16S rRNA = PW: 2%; IW: 8%; metatranscriptome = PW: 20%) and Acinetobacter (16S rRNA = PW: 1%; IW: 4%; metatranscriptome = PW: 17%) were the most abundant genera. This study outlined the primary methods employed in researching metabolically active microorganisms. These data provide a foundation for future research. However, it is essential to note that we cannot yet determine the most effective method. We hope that this study will inspire further research related to the standardization of RNA preservation, extraction, and sequencing methods and significantly contribute to our understanding of active microbial communities in oilfields.

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Short chain tricyclic terpanes as organic proxies for paleo-depositional conditions

Xiao,

Li,

Nettersheim

2024

Chemical Geology

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Geochemistry and possible origins of biodegraded oils in the Cretaceous reservoir of the Muglad Basin and their application in hydrocarbon exploration

Cited by 10 publications

References 22 publications

Origin of Mesozoic Biodegraded Crude Oils from the Eastern Chepaizi Uplift (Junggar Basin) Constrained by the Biomarker Recovery Method

Origin of Mesozoic Biodegraded Crude Oils from the Eastern Chepaizi Uplift (Junggar Basin) Constrained by the Biomarker Recovery Method

Metabolically Active Microbial Communities in Oilfields: A Systematic Review and Synthesis of RNA Preservation, Extraction, and Sequencing Methods

Short chain tricyclic terpanes as organic proxies for paleo-depositional conditions

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