Experimental simulation of thermal evolution of nitrogen content and isotopes in source rocks: Implications for nitrogen cycling characterization and oil-source correlation
文献类型：期刊论文
| 作者 | Liu, Xiaodong2,3,4; Jia, Wanglu1,3,4; Wang, Qiang3,4; Wu, Jinxiang2,3,4; Chen, Jian3,4; Peng, Ping'an2,3,4 |
| 刊名 | MARINE AND PETROLEUM GEOLOGY
 |
| 出版日期 | 2024-05-01 |
| 卷号 | 163页码:12 |
| 关键词 | Source rock Expelled oil Nitrogen isotopes Thermal maturity Redox condition Oil -source correlation |
| ISSN号 | 0264-8172 |
| DOI | 10.1016/j.marpetgeo.2024.106796 |
| 英文摘要 | Sedimentary nitrogen isotopes have been widely used to reconstruct the nitrogen cycling and redox characteristics of ancient oceans, but they also have important value in the study of oil genesis, such as oil classification. However, the thermal evolution of nitrogen isotopes in the source rock and associated oil is currently unclear. In this study, the thermal evolution (from the oil generation to the dry gas stage) of three types of low-maturity source rock was simulated. And the content and isotope composition of total organic carbon (TOC) and total nitrogen (TN) of the pyrolyzed source rock, expelled oil and retained oil were measured. In combination with weight-quantitative analyses, the following conclusions can be drawn: (1) During the main oil and gas generation stage, the pyrolyzed source rocks lost 15.1-28.3% of TN, which is much lower than the loss of TOC (26.2-46.1%). This difference may be related to the fact that the TOC content of the generated oil and gas is two orders of magnitude higher than the TN. In addition, TOC loss occurred mainly within the oil generationexpulsion stage, whereas TN loss occurred mainly in the dry gas stage and higher maturity stage. (2) The nitrogen isotope compositions of three types of source rocks and associated kerogens became heavier by 0.5-1.5%o as thermal maturity increased, which is similar to the change of organic carbon isotope compositions. The delta 15N values of pyrolyzed source rocks generally have poor relationships with either the amount of expelled oil and gas or the TN loss, which is different from the delta 13Corg values. The delta 15N fluctuations may be attributed to three processes: oil generation-expulsion, N2 gas generation-expulsion, and inorganic N (like NH4+) expulsion. The bulk nitrogen isotope composition of source rocks is only slightly affected by thermal maturity and can be used to indicate the nitrogen biogeochemical cycle and water redox conditions during the deposition. (3) Similar to delta 13Corg values, delta 15N values of both expelled oil and retained oil increased gradually with enhanced thermal maturity, implying a control of kinetic isotope effect. Among the three types of source rock, two of them having relatively light nitrogen isotope compositions (delta 15N value of -2.5%o) generated and expelled oils with similar nitrogen isotope compositions, while the third type, which has heavy nitrogen isotope composition (delta 15N value of -13.0%o), generated and expelled oils with much lighter nitrogen isotope compositions (by 3-6%o). This finding shows that there may be significant nitrogen isotope fractionation during the generation and primary migration of oil from source rocks. The nitrogen isotopes should be used in oil-source correlation with caution, even though related mechanisms need to be further studied. Nevertheless, using a combination of organic carbon and nitrogen isotopes, the oil generated and expelled by the three types of source rocks could be distinguished. Therefore, the use of nitrogen isotopes for oil-source correlation under geological conditions should be combined with other isotope and molecular indicators. |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:001220755800001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/77037]  |
| 专题 | 有机地球化学国家重点实验室 |
| 通讯作者 | Jia, Wanglu |
| 作者单位 | 1.Chinese Acad Sci, Guangzhou Inst Geochem, 511 Kehua St, Tianhe Dist, Guangzhou 510640, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.CAS Ctr Excellence Deep Earth Sci, Guangzhou 510640, Peoples R China 4.Chinese Acad Sci, State Key Lab Organ Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China |
| 推荐引用方式 GB/T 7714 | Liu, Xiaodong,Jia, Wanglu,Wang, Qiang,et al. Experimental simulation of thermal evolution of nitrogen content and isotopes in source rocks: Implications for nitrogen cycling characterization and oil-source correlation[J]. MARINE AND PETROLEUM GEOLOGY,2024,163:12. |
| APA | Liu, Xiaodong,Jia, Wanglu,Wang, Qiang,Wu, Jinxiang,Chen, Jian,&Peng, Ping'an.(2024).Experimental simulation of thermal evolution of nitrogen content and isotopes in source rocks: Implications for nitrogen cycling characterization and oil-source correlation.MARINE AND PETROLEUM GEOLOGY,163,12. |
| MLA | Liu, Xiaodong,et al."Experimental simulation of thermal evolution of nitrogen content and isotopes in source rocks: Implications for nitrogen cycling characterization and oil-source correlation".MARINE AND PETROLEUM GEOLOGY 163(2024):12. |
入库方式： OAI收割
来源：广州地球化学研究所
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