Salt rhythmite formation and organic matter enrichment in the Qianjiang formation, Jianghan Basin, China: Constraints from alternating dry and wet climates

Ge, Taoyuan; Jiang, Zaixing; Kong, Xiangxin; Bao, Hanyong; Chen, Fengling; Wu, Shiqiang; Guo, Lixin; Yang, Yongbo; Liu, Tong; Zhang, Jiazhi

doi:10.1016/j.marpetgeo.2022.106067

Cited by 4 publications

(2 citation statements)

References 58 publications

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“…Therefore, ∑C 21 − /∑C 22 + can indicate the type of vegetation. A lower ∑C 21 − /∑C 22 + indicates a greater contribution from woody plants, and a higher ∑C 21 − /∑C 22 + indicates a slightly larger contribution from aquatic organisms (Yang, 2018; Ge et al, 2023). ∑C 21 − /∑C 22 + in the K9–K7 section ranged from 0.13 to 0.42 and that in the K5–K4 section ranged from 0.04 to 0.09 (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Mechanism of organic matter enrichment in a basin with shallow biogenic gas: a case study of Pleistocene shale in the Qaidam Basin

Liu,

Jiang,

Tang

et al. 2024

J Quaternary Science

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Organic matter is the material basis of shale gas. The Qaidam Basin is a key exploration and development area for shallow biogenic shale gas in China. In this study, we have focused on Quaternary Pleistocene shale in the Qaidam Basin, and the mechanism of organic matter enrichment was investigated in terms of water column stratification and paleoclimate. The results show that the K9–K7 section has greater biological productivity than the K5–K4 section. During the early–middle Pleistocene (K9–K7 deposition period), due to a warm and humid climate, the water column was strongly stratified and herbaceous plants developed, resulting in increased biological productivity. Stronger stratification also led to a reducing environment in the lower layer, which was conducive to the preservation of organic matter from the upper layer. During the late Pleistocene (K5–K4 deposition period), with a dry and hot climate, stratification became weaker and the vegetation evolved into woody plants, reducing biological productivity. Weaker stratification led to destruction of the reducing environment, which was not conducive to enrichment of the sedimentary organic matter. Moreover, the increased temperatures increased the activity of methanogenic bacteria, which consumed a lot of the organic matter.

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Section: Resultsmentioning

confidence: 99%

“…( indicates a slightly larger contribution from aquatic organisms (Yang, 2018;Ge et al, 2023). ∑C 21 − /∑C 22 + in the K9-K7 section ranged from 0.13 to 0.42 and that in the K5-K4 section ranged from 0.04 to 0.09 (Fig.…”

Section: Indicators Of Vegetation Typesmentioning

confidence: 99%

Mechanism of organic matter enrichment in a basin with shallow biogenic gas: a case study of Pleistocene shale in the Qaidam Basin

Liu,

Jiang,

Tang

et al. 2024

J Quaternary Science

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Shale oil content evaluation and sweet spot prediction based on convolutional neural network

Wu,

Jiang,

et al. 2024

Marine and Petroleum Geology

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Carbon Isotopic Behavior During Hydrocarbon Expulsion in Semiclosed Hydrous Pyrolysis of Type I and Type II Saline Lacustrine Source Rocks in the Jianghan Basin, Central China

Li,

Zheng,

Guo

et al. 2024

Lithosphere

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Organic carbon isotopic analysis is a significant approach for oil-source correlation, yet organic carbon isotopic behavior during oil expulsion from saline lacustrine source rocks is not well constrained, and this hinders its wide application for fingerprinting oils generated by saline lacustrine source rock. To resolve this puzzle, semiclosed hydrous pyrolysis was conducted on typical saline lacustrine source rocks from the Qianjiang Formation (type I kerogen) and Xingouzui Formation (type II kerogen) sampled in the Jianghan Basin, China, under high-temperature high-pressure conditions (T = 275℃–400℃; P = 65–125 MPa). Experimental results show that there is minor carbon isotopic fractionation (<3‰) between pyrolyzed and nonpyrolyzed retained oil fractions during the main oil generation/expulsion stage of both type I and II source rocks. Carbon isotopic fractionations between expelled and retained oil fractions are also minor (<2‰) during this stage. The δ13C values of retained and expelled oil fractions generated by the type I saline lacustrine source rock correlate positively with the degree of oil expulsion, whereas the influence of oil expulsion on the δ13C values of oil fractions generated by the type II source rock was not consistent. In addition, carbon isotopic analysis also unravels the mixing of oil-associated gases with different maturity levels and/or generated via different processes. Outcomes of this study demonstrate that oil expulsion from type I and II saline lacustrine source rocks cannot be able to result in large-degree carbon isotopic fractionation, indicating that carbon isotopic analysis is a feasible approach for conducting oil-source correlation works in saline lacustrine petroleum systems.

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Salt rhythmite formation and organic matter enrichment in the Qianjiang formation, Jianghan Basin, China: Constraints from alternating dry and wet climates

Cited by 4 publications

References 58 publications

Mechanism of organic matter enrichment in a basin with shallow biogenic gas: a case study of Pleistocene shale in the Qaidam Basin

Mechanism of organic matter enrichment in a basin with shallow biogenic gas: a case study of Pleistocene shale in the Qaidam Basin

Shale oil content evaluation and sweet spot prediction based on convolutional neural network

Carbon Isotopic Behavior During Hydrocarbon Expulsion in Semiclosed Hydrous Pyrolysis of Type I and Type II Saline Lacustrine Source Rocks in the Jianghan Basin, Central China

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