有机物氢化产生的碳氢化合物气体的 C/H 同位素分馏：热液实验的启示

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Organic Geochemistry Pub Date : 2024-11-19 DOI:10.1016/j.orggeochem.2024.104884

Kun He , Xiaomei Wang , Chunlong Yang , Linfeng Xie , Shuichang Zhang

{"title":"有机物氢化产生的碳氢化合物气体的 C/H 同位素分馏：热液实验的启示","authors":"Kun He , Xiaomei Wang , Chunlong Yang , Linfeng Xie , Shuichang Zhang","doi":"10.1016/j.orggeochem.2024.104884","DOIUrl":null,"url":null,"abstract":"<div><div>It is widely accepted that organic–inorganic interactions involving hydrogen-rich fluids (H2O and H2) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H2O/H2 on C/H isotope fractionation remain poorly understood. This study investigates these effects through a series of pyrolysis experiments conducted at 330–420 °C and 50 MPa, encompassing three groups: (1) anhydrous pyrolysis with kerogen only (Group 1), (2) kerogen and H2O (Group 2), and (3) kerogen, H2O, and Fe1-xS (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H2O and H2, respectively. Results show that HC gas yields in Group 3 experiments are 1.8 to 3.2 times of those in Group 1, while yields in Group 2 are lower than Group 1. Moreover, hydrogenation by H2 produces HC gases with smaller 13C fractionation and more negative δ2H values compared to hydrogenation by H2O. These findings suggest distinct mechanisms for HC gas generation during H2-OM and H2O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs 13C and 2H isotope fractionation during hydrogenation of OM by H2. Importantly, the EIE for 2H isotope fractionation of H2O-H2, CH4-H2, and OM-H2 is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H2 on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H2 in organic-rich shales.</div></div>","PeriodicalId":400,"journal":{"name":"Organic Geochemistry","volume":"199 ","pages":"Article 104884"},"PeriodicalIF":2.6000,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"C/H isotope fractionation of hydrocarbon gases from hydrogenation of organic matter: Insights from hydrothermal experiments\",\"authors\":\"Kun He , Xiaomei Wang , Chunlong Yang , Linfeng Xie , Shuichang Zhang\",\"doi\":\"10.1016/j.orggeochem.2024.104884\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>It is widely accepted that organic–inorganic interactions involving hydrogen-rich fluids (H2O and H2) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H2O/H2 on C/H isotope fractionation remain poorly understood. This study investigates these effects through a series of pyrolysis experiments conducted at 330–420 °C and 50 MPa, encompassing three groups: (1) anhydrous pyrolysis with kerogen only (Group 1), (2) kerogen and H2O (Group 2), and (3) kerogen, H2O, and Fe1-xS (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H2O and H2, respectively. Results show that HC gas yields in Group 3 experiments are 1.8 to 3.2 times of those in Group 1, while yields in Group 2 are lower than Group 1. Moreover, hydrogenation by H2 produces HC gases with smaller 13C fractionation and more negative δ2H values compared to hydrogenation by H2O. These findings suggest distinct mechanisms for HC gas generation during H2-OM and H2O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs 13C and 2H isotope fractionation during hydrogenation of OM by H2. Importantly, the EIE for 2H isotope fractionation of H2O-H2, CH4-H2, and OM-H2 is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H2 on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H2 in organic-rich shales.</div></div>\",\"PeriodicalId\":400,\"journal\":{\"name\":\"Organic Geochemistry\",\"volume\":\"199 \",\"pages\":\"Article 104884\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-11-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Organic Geochemistry\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0146638024001499\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic Geochemistry","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0146638024001499","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}

引用次数: 0

摘要

人们普遍认为，富氢流体（H2O 和 H2）参与的有机-无机相互作用在沉积盆地的碳氢化合物（HC）生成过程中发挥着重要作用，而 H2O/H2 对有机质（OM）的氢化作用对 C/H 同位素分馏的影响仍鲜为人知。本研究通过在 330-420 °C 和 50 兆帕下进行的一系列热解实验研究了这些影响，实验包括三组：(1) 仅含角质的无水热解（第 1 组），(2) 角质和 H2O（第 2 组），以及 (3) 角质、H2O 和 Fe1-xS（第 3 组）。第 2 组和第 3 组分别用于模拟 H2O 和 H2 对 OM 的氢化作用。结果表明，第 3 组实验的碳氢化合物气体产率是第 1 组的 1.8 至 3.2 倍，而第 2 组的产率低于第 1 组。此外，与 H2O 加氢相比，H2 加氢产生的碳氢化合物气体的 13C 分馏率更小，δ2H 值更负。这些发现表明，H2-OM 和 H2O-OM 反应过程中产生 HC 气体的机制不同。进一步的分析表明，在 H2 对 OM 的氢化过程中，平衡同位素效应（EIE）控制着 13C 和 2H 的同位素分馏。重要的是，在实验和地质条件下对 H2O-H2、CH4-H2 和 OM-H2 的 2H 同位素分馏的 EIE 进行了评估。这项研究为了解 H2 对 OM 的氢化作用对 HC 气体的生成和 C/H 同位素分馏的重要影响，以及 H2 在富含有机物的页岩中的演化和保存提供了重要见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

查看原文本刊更多论文

C/H isotope fractionation of hydrocarbon gases from hydrogenation of organic matter: Insights from hydrothermal experiments

It is widely accepted that organic–inorganic interactions involving hydrogen-rich fluids (H₂O and H₂) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H₂O/H₂ on C/H isotope fractionation remain poorly understood. This study investigates these effects through a series of pyrolysis experiments conducted at 330–420 °C and 50 MPa, encompassing three groups: (1) anhydrous pyrolysis with kerogen only (Group 1), (2) kerogen and H₂O (Group 2), and (3) kerogen, H₂O, and Fe_1-_xS (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H₂O and H₂, respectively. Results show that HC gas yields in Group 3 experiments are 1.8 to 3.2 times of those in Group 1, while yields in Group 2 are lower than Group 1. Moreover, hydrogenation by H₂ produces HC gases with smaller ¹³C fractionation and more negative δ²H values compared to hydrogenation by H₂O. These findings suggest distinct mechanisms for HC gas generation during H₂-OM and H₂O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs ¹³C and ²H isotope fractionation during hydrogenation of OM by H₂. Importantly, the EIE for ²H isotope fractionation of H₂O-H₂, CH₄-H₂, and OM-H₂ is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H₂ on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H₂ in organic-rich shales.

求助全文

通过发布文献求助，成功后即可免费获取论文全文。去求助

来源期刊

Organic Geochemistry 地学-地球化学与地球物理

CiteScore

5.50

自引率

6.70%

发文量

100

审稿时长

61 days

期刊介绍： Organic Geochemistry serves as the only dedicated medium for the publication of peer-reviewed research on all phases of geochemistry in which organic compounds play a major role. The Editors welcome contributions covering a wide spectrum of subjects in the geosciences broadly based on organic chemistry (including molecular and isotopic geochemistry), and involving geology, biogeochemistry, environmental geochemistry, chemical oceanography and hydrology. The scope of the journal includes research involving petroleum (including natural gas), coal, organic matter in the aqueous environment and recent sediments, organic-rich rocks and soils and the role of organics in the geochemical cycling of the elements. Sedimentological, paleontological and organic petrographic studies will also be considered for publication, provided that they are geochemically oriented. Papers cover the full range of research activities in organic geochemistry, and include comprehensive review articles, technical communications, discussion/reply correspondence and short technical notes. Peer-reviews organised through three Chief Editors and a staff of Associate Editors, are conducted by well known, respected scientists from academia, government and industry. The journal also publishes reviews of books, announcements of important conferences and meetings and other matters of direct interest to the organic geochemical community.