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DOI	10.1016/j.petrol.2021.108516
	Evolution of carbon isotopic compositions for gas generated in semi-closed pyrolysis system: Reflections on the formation of isotopic abnormal gases
	Song, Dongjun; Wu, Chenjun; Tuo, Jincai; Wang, Xiaoqi; Zhang, Mingfeng; He, Wei; Ma, Zunqing; Su, Long; Jin, Xu
通讯作者	Tuo, JC (通讯作者)，Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, Key Lab Petr Resources, Lanzhou 730000, Gansu, Peoples R China. ; Wang, XQ (通讯作者)，Res Inst Petr Explorat & Dev, Beijing 10083, Peoples R China.
发表日期	2021
ISSN	0920-4105
EISSN	1873-4715
卷号	201
英文摘要	Carbon isotope anomalies are signals for highly productive shale gas, but are poorly duplicated in completely closed or open pyrolysis systems. In this study, five low-maturity shale samples and one high-maturity shale sample were subjected to semi-closed pyrolysis experiments to investigate whether isotopically anomalous gases could be generated in laboratory simulations of the full maturity range. The results reveal that the first rollover of methane, ethane, and propane delta C-13 values occurs at the late oil-window stage, and the second rollover of delta C-13 (C2H6) and delta C-13(C3H8) values occurs at the overmature stage. Partial carbon isotopically reversed gases are produced, with isotope compositions evolving from delta C-13(C2H6) > delta C-13(C3H8) > delta C-13(CH4) through delta C-13(CH4) > delta C-13(C3H8) > delta C-13(C2H6) to delta C-13(C3H8) > delta C-13(CH4) > delta C-13(C2H6 as thermal maturity increases, whereas complete carbon isotopically reversed gases are not reproduced. These findings are slightly different from the carbon isotope and chemical characteristics of shale gas under natural conditions, which is universally characterized by full carbon isotope reversal. Compared to closed or open systems, the carbon isotopically anomalous gases are superimposed results of gaseous compounds from each episodic expulsion during semi-closed pyrolysis, illustrating that multiple periods of preservation and loss of gases are more important for carbon isotope reversal than thermal maturity. Carbon isotope fractionation via gas diffusion can be amplified by some large-scale processes of preservation and loss; for example, the uplift of a shale would lead to preferential diffusion of methane rich in C-12, resulting in full isotopic reversal in the residual gas in shales. These processes generally occur under natural conditions, but such factors have yet to be considered in conventional open or closed pyrolysis simulations. This study provides a reasonable reference for the issue of why (full) isotopically reversed gases can barely be produced in conventional pyrolysis experiments.
英文关键词	Shale gas; Carbon isotope rollover; Carbon isotope reversal; Semi-closed pyrolysis; Multiperiod preservation-loss processes
语种	英语
WOS研究方向	Energy & Fuels ; Engineering
WOS类目	Energy & Fuels ; Engineering, Petroleum
WOS记录号	WOS:000628869500078
来源期刊	JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/254280
作者单位	[Song, Dongjun; Tuo, Jincai; Zhang, Mingfeng; He, Wei; Su, Long] Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, Key Lab Petr Resources, Lanzhou 730000, Gansu, Peoples R China; [Song, Dongjun; He, Wei] Univ Chinese Acad Sci, Beijing 100049, Peoples R China; [Wu, Chenjun] Yangtze Univ, Coll Resources & Environm, Wuhan 430100, Peoples R China; [Wang, Xiaoqi; Jin, Xu] Res Inst Petr Explorat & Dev, Beijing 10083, Peoples R China; [Ma, Zunqing] Nanjing Univ, Sch Earth Sci & Engn, Nanjing 210000, Peoples R China
推荐引用方式 GB/T 7714	Song, Dongjun,Wu, Chenjun,Tuo, Jincai,et al. Evolution of carbon isotopic compositions for gas generated in semi-closed pyrolysis system: Reflections on the formation of isotopic abnormal gases[J]. 中国科学院西北生态环境资源研究院,2021,201.
APA	Song, Dongjun.,Wu, Chenjun.,Tuo, Jincai.,Wang, Xiaoqi.,Zhang, Mingfeng.,...&Jin, Xu.(2021).Evolution of carbon isotopic compositions for gas generated in semi-closed pyrolysis system: Reflections on the formation of isotopic abnormal gases.JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING,201.
MLA	Song, Dongjun,et al."Evolution of carbon isotopic compositions for gas generated in semi-closed pyrolysis system: Reflections on the formation of isotopic abnormal gases".JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING 201(2021).