Genetic mechanism of heavy oil in the Carboniferous volcanic reservoirs of the eastern Chepaizi Uplift, Junggar Basin

Li, Yang; Chang, Xiangchun; Zhang, Jinliang; Xu, Youde; Gao, Dengkuan

doi:10.1007/s12517-019-4849-3

Cited by 11 publications

(2 citation statements)

References 40 publications

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“…On the basis of the occurrence and relative abundance of different biomarkers, Peters et al (2005) divided the degree of biodegradation into 10 orders. The DOB of the oil samples was verified qualitatively by reference to the above standard (Wenger et al, 2002;Li et al, 2019). Some n-alkanes and isoprene, both of which were exhausted, were detected in the chromatograms of the four samples, indicating that the samples suffered from biodegradation on an order of at least PM 5 (Ni et al, 2005).…”

Section: Degree Of Biodegradation (Dob)mentioning

confidence: 99%

Origin of Shallow Jurassic Heavy Oils in the Northwestern Margin of the Junggar Basin, NW China: Constraints from Molecular, Isotopic and Elemental Geochemistry

Huang

Qin

et al. 2022

Acta Geologica Sinica (Eng)

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Oil group separation, gas chromatography–mass spectrometry analysis of saturated hydrocarbons, carbon isotope analysis of fractions and tests on trace elements were all carried out to determine the origin of shallow Jurassic heavy oils in the northwestern margin of the Junggar Basin, northwestern China. Results showed that all the crude oils had been subjected to different degrees of biodegradation, on an order ranging from PM 6 to 9, which yielded many unresolved complex mixtures (UCM) and formed a huge spike in the mass chromatogram (M/Z = 85). Two heavy oils from the Karamay area underwent slight biodegradation, characterized by the consistent ratios of biomarker parameters. C21/C23 and C23/H of the two samples were 0.81 and 0.85, while G/H, C27/C29 and C28/C29 were 0.38 and 0.40, 0.16 and 0.27, 0.87 and 0.86, respectively. The isomerization parameters of terpane and steranes were 0.50–0.53, and 0.48–0.49, respectively. The above geochemical indices indicated that the crude oils in the study area were in the marginally mature stage. The parent materials were a mixture, consisting of bacteria, algae and some higher plants, formed under reducing depositional conditions, which is in agreement with the source rocks of the Fengcheng Formation in the Mahu depression. The carbon isotopic compositions of saturated hydrocarbon, aromatic hydrocarbon, NSO and asphaltene were –31‰– to –30.3‰, –29.5‰ to –29.03‰, –29.4‰ to –28.78‰ and –28.62‰ to –28.61‰, respectively. These findings are in agreement with the light carbon isotope of kerogen from the lower Permian Fengcheng Formation. Furthermore, V/Ni and Cr/Mo of all the crude oils were 0.01 to 0.032, 0.837 to 10.649, which is in good agreement with the ratios of the corresponding elements of the extracts from the Fengcheng Fm. carbonate source rock. As a result, a two–stage formation model was established: (1) the oil generated from the carbonate source rocks of the Fengcheng Formation migrated to the Carboniferous, Permian and Triassic traps during the Late Triassic, forming the primary oil reservoirs; (2) during the Late Jurassic period, the intense tectonic activity of Yanshan Episode II resulted in the readjustment of early deep primary reservoirs, the escaped oils gradually migrating to the shallow Jurassic reservoir through cross‐cutting faults, unconformities and sand body layers. The oils then finally formed secondary heavy oil reservoirs, due to long–term biodegradation in the later stage. Therefore, joint methods of organic, isotopic and element geochemistry should be extensively applied in order to confirm the source of biodegradation oils.

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Section: Degree Of Biodegradation (Dob)mentioning

confidence: 99%

Origin of Shallow Jurassic Heavy Oils in the Northwestern Margin of the Junggar Basin, NW China: Constraints from Molecular, Isotopic and Elemental Geochemistry

Huang

Qin

et al. 2022

Acta Geologica Sinica (Eng)

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“…e fracture porosity is generally low, mainly microfractures, and belongs to mesoporous and ultralow permeability reservoirs. Carboniferous reservoirs are characterized by high displacement pressure, small median radius, poor sorting, and poor pore structure [5]. e Xiquan block is located in the Beisantai uplift, which is an inherited paleo-uplift formed in the Hercynian period, with a relatively high altitude.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Carboniferous Volcanic Reservoirs in Beisantai Oilfield, Junggar Basin

Cheng¹,

Ma²,

Dong³

et al. 2022

Mathematical Problems in Engineering

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In recent years, petroleum exploration in the Carboniferous volcanic rock reservoirs in the Junggar Basin has been the focus of important petroleum energy development in western China. The lithologic identification of volcanic rock reservoirs seriously restricts the accuracy of reservoir prediction and affects the success rate of oil exploration. Different types of volcanic rocks have different petrological characteristics and mineral assemblages, especially affected by the depositional environment. The volcanic rocks in different regions have their own uniqueness. This paper takes the Carboniferous volcanic reservoirs in Xiquan block, Beisantai Oilfield, Junggar Basin as the research target. Through a large number of core observations, casting slices, scanning electron microscopy, and X-ray diffraction methods, the Carboniferous volcanic rocks are analyzed. The petrology, pore characteristics, physical properties, and diagenetic evolution history of the reservoir are analyzed. The study shows that the volcanic facies in the Xiquan block can be divided into explosive facies, overflow facies, and volcanic sedimentary facies, among which the explosive facies is subdivided into empty subfacies (volcanic breccia-breccia tuff combination) and thermal base wave subfacies (tuff). The lithology of the reservoir is pyroclastic rock and volcanic lava, belonging to medium-porous and ultralow permeability reservoirs, and the storage space can be divided into three types: primary pores, secondary pores, and fractures. The lithology of key exploration is breccia tuff, followed by breccia tuff and volcanic breccia.

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Geochemical characteristics, genetic types, and controlling factors of natural gas in Jiyang Depression, Bohai Bay Basin (eastern China)

Chang

Zhuang

et al. 2022

Front. Earth Sci.

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Genetic mechanism of heavy oil in the Carboniferous volcanic reservoirs of the eastern Chepaizi Uplift, Junggar Basin

Cited by 11 publications

References 40 publications

Origin of Shallow Jurassic Heavy Oils in the Northwestern Margin of the Junggar Basin, NW China: Constraints from Molecular, Isotopic and Elemental Geochemistry

Origin of Shallow Jurassic Heavy Oils in the Northwestern Margin of the Junggar Basin, NW China: Constraints from Molecular, Isotopic and Elemental Geochemistry

Characteristics of Carboniferous Volcanic Reservoirs in Beisantai Oilfield, Junggar Basin

Geochemical characteristics, genetic types, and controlling factors of natural gas in Jiyang Depression, Bohai Bay Basin (eastern China)

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