Organic geochemistry of Carboniferous source rocks and their generated oils from the Eastern Junggar Basin, NW China

Yu, Shuang; Wang, Xulong; Xiang, Baoli; Liao, Jiande; Wang, Jun; Li, Ertin; Yan, Yonghe; Cai, Yong; Zou, Yan–Rong; Pan, Changchun

doi:10.1016/j.orggeochem.2014.09.011

Cited by 25 publications

(14 citation statements)

References 41 publications

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“…With increasing experimental temperature, the Pr/Ph ratio gradually decrease, and these ratios in expelled oil are larger than their counterparts in bitumen, showing that the thermal maturity of retained oil is a little higher than expelled oil under the same experimental systems (Jiang, Philp, & Lewis, 1988). As a general rule, light components of produced oil and gas can be expelled from source rocks more easily and heavy components are mostly retained in source rocks according to Yu et al (2014). Generally, the thermal maturity of expelled oil is commonly higher than that in bitumen, which is opposite to the experimental results.…”

Section: Discussionmentioning

confidence: 99%

Comparison of biomarkers in retained oil and expelled oil of lacustrine marlstone determined by hydrous pyrolysis: Application to hydrocarbon migration determination in the tight oil reservoir

et al. 2021

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Oil in an unconventional tight reservoir is considered to migrate from a very adjacent reservoir or be impregnated in situ within source rocks, but their large hydrocarbon molecular fractions during short‐distance migration in the tight system are poorly understood. In order to explore the evolution characteristics and differences of the geochemical properties, especially the biomarkers, between expelled oil (just detached from source rock and not undergoing long‐distance migration) and retained oil under different thermal evolution stages of lacustrine marlstone. Semi‐open hydrous pyrolysis was conducted on an immature lacustrine marlstone collected from the third member of the Eocene Shahejie Formation in Shulu Sag, Bohai Bay Basin and the hydrocarbon product expelled from and remained in the rock during pyrolysis were collected and analysed with gas chromatography–mass spectrum instrument. The results indicate that the saturates compositions show expelled oil having commonly lower thermal maturity than retained oil because expelled oil is a mixture of multiple‐term hydrocarbon expulsions, while retained oil is the remained final hydrocarbon product of pyrolysis in semi‐open experimental system. The hydrocarbon migration has a significant effect on the maturity‐related parameters distribution such as 20S/(20S + 20R) and αββ/(αββ + ααα) for C29 steranes. Hydrocarbon expulsion enables Ts/(Ts + Tm) ratio in expelled oil is much greater than that of retained oil at lower matural stage. The saturated hydrocarbon maturity biomarkers in retained oil and expelled oil vary in a subtly different pathways with increasing maturity, comparatively the aromatic hydrocarbon biomarkers, such as triaromatic steroids and methyl‐phenanthrene (MPI1 and MPI2), regularly changed during maturation, which is not obviously affected by migration effects and can be used not only for thermal maturity predications but also for oil–oil or oil–source correlation. C29 20S/(20S + 20R) and C29 αββ/(αββ + ααα) commonly are preferable maturity parameters for shale or mudstone, reflecting that mineral matrix and oil in source rock are not affected by migration and supposed to have an oil thermal maturity corresponding to depth. Combined with some tight reservoir cases in North America and China, the biomarker ratios variation along depth and its abnormal value can be used to predict sweet spots in tight reservoirs.

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Section: Discussionmentioning

confidence: 99%

Comparison of biomarkers in retained oil and expelled oil of lacustrine marlstone determined by hydrous pyrolysis: Application to hydrocarbon migration determination in the tight oil reservoir

et al. 2021

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“…The organic elements of kerogen and Rock–Eval parameters can reflect the organic matter type very well (Peters et al, ; Yu et al, ). The plots of the mudstone samples H/C versus O/C (Figure ) and HI versus T max values (Figure ) both indicate that most of the Eh 2 and Eh 3 organic matter is oil prone, with a minority gas prone.…”

Section: Discussionmentioning

confidence: 99%

Geochemistry of source rocks and oil–source rock correlation in the Hetaoyuan Formation of the Nanyang Sag, Nanxiang Basin, eastern China

et al. 2018

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The Nanyang Sag in the Nanxiang Basin, eastern China, has a large petroleum resource, although the genetic potential of source rocks and oil–rock correlation in the Paleogene Hetaoyuan Formation is unclear. Organic geochemistry and molecular geochemistry analyses of mudstone and oil samples were performed to evaluate source rock potential, classify oil groups, and establish accurate oil–source rock correlation. The results suggest that the second member (Eh2) and the third member (Eh3) of the Hetaoyuan Formation are good source rocks, contain abundant organic matter and oil‐prone kerogen, and are thermally mature. Oil samples from Eh2 and Eh3 were separated into 3 groups derived from different source rocks. Group I oils are mainly distributed in the Eh2 and Eh3 members around the Dongzhuang (Dongz) structure belt and are characterized by a low saturated hydrocarbon content (SAT, 39.07–49.54%), high total resin (RE) and asphaltene (ASP) content (17.22–22.80%), low gammacerane index (gammacerane/C3017α(H)‐hopane < 0.60), and low Pr/Ph (<0.7). The organic matter is in an early mature stage and is mainly sourced from algae and land plants. The oils of this group are derived from the Eh2 and Eh3 source rocks around the Dongz secondary sag. Group II oils occur in the Eh2 around the Weigang–Beimazhuang (Weig–Beimz) structure belt and north of the Zhangdian–Heilongmiao (Zhangd–Heilm) structure belt and have intermediate SAT, RE, and ASP contents, a low gammacerane index (<0.47), and high Pr/Ph (0.72–1.25). The organic matter includes mainly algae and land plants. The source rocks should be the Eh2 and Eh3 in the Dongz and Niusanmen (Niusm) secondary sags. Group III oils are located in the Eh3 just north of the Weig–Beimz and Zhangd–Heilm structure belts, with a high SAT (55.62–78.42%), low RE and ASP proportion (3.60–6.16%), high gammacerane index (>0.88), and low Pr/Ph (<0.72). This organic matter is composed of mostly land plants. The oils in this group are mainly derived from the Eh3 near Baiqiu (Baiq).

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“…Hence, the Carboniferous source rocks are mainly in high-post mature stage. The oil correlation results of Carboniferous source rocks suggest that the oil from volcanic reservoir rocks within the C 2 b Formation generally correlates with the C 1 d source rocks based on molecular and carbon isotopic data (Yu et al 2014). However, a small amount of younger source rocks from the Middle Permian and Lower Jurassic also can feed to the Carboniferous reservoirs in some regions (Yu et al 2014).…”

Section: Carboniferous Source Rocksmentioning

confidence: 91%

“…The oil correlation results of Carboniferous source rocks suggest that the oil from volcanic reservoir rocks within the C 2 b Formation generally correlates with the C 1 d source rocks based on molecular and carbon isotopic data (Yu et al 2014). However, a small amount of younger source rocks from the Middle Permian and Lower Jurassic also can feed to the Carboniferous reservoirs in some regions (Yu et al 2014). Overall, these source rocks could provide effective supplies of oil and gas for the Carboniferous pyroclastic and the Permian clastic reservoirs (He et al 2010;Li et al 2009;Wang et al 2010).…”

Section: Carboniferous Source Rocksmentioning

confidence: 91%

Thermal and maturation history for Carboniferous source rocks in the Junggar Basin, Northwest China: implications for hydrocarbon exploration

Rao

Wang

et al. 2020

Pet. Sci.

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The reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration. Based on vitrinite reflectance data, we integrate the paleo-temperature gradient and paleo-heat flow methods to reconstruct the thermal history of Junggar Basin. Compared with present thermal state, the Junggar Basin experienced much a higher heat flow of ca. 80-120 mW/m 2 during the Carboniferous. This feature can be attributed to large-scale volcanic events and related thermal effects. The hydrocarbon maturation history of Carboniferous source rocks indicates that the temperature rapidly reached the threshold of hydrocarbon generation during the Late Carboniferous and has never achieved such a high level since then. This characteristic resulted in the early maturation of hydrocarbons in Carboniferous source rocks. Meanwhile, the results reveal that hydrocarbon maturities are different among various tectonic units in Junggar Basin. The kerogen either rapidly broke through the dry gas period so that cracking of gas occurred or remained in the oil maturation window forming oil reservoirs, which depended on the tectonic background and depositional environment. In this study, we present the thermal and hydrocarbon maturation history since the Carboniferous, which has important implications for further hydrocarbon exploration in Junggar Basin.

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Organic geochemistry of Carboniferous source rocks and their generated oils from the Eastern Junggar Basin, NW China

Cited by 25 publications

References 41 publications

Comparison of biomarkers in retained oil and expelled oil of lacustrine marlstone determined by hydrous pyrolysis: Application to hydrocarbon migration determination in the tight oil reservoir

Comparison of biomarkers in retained oil and expelled oil of lacustrine marlstone determined by hydrous pyrolysis: Application to hydrocarbon migration determination in the tight oil reservoir

Geochemistry of source rocks and oil–source rock correlation in the Hetaoyuan Formation of the Nanyang Sag, Nanxiang Basin, eastern China

Thermal and maturation history for Carboniferous source rocks in the Junggar Basin, Northwest China: implications for hydrocarbon exploration

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