{"title":"琼东南盆地原油的生物起源与沉积环境:分子生物标志物和全油碳同位素的启示","authors":"","doi":"10.1016/j.petsci.2024.05.026","DOIUrl":null,"url":null,"abstract":"<div><div>Molecular biomarker and whole oil carbon isotope (<em>δ</em><sup>13</sup>C<sub>oil</sub>) analyses were conducted on eleven typical crude oils from the Qiongdongnan Basin to investigate their biological sources and depositional environments. Saturated hydrocarbon biomarkers in most samples are characterized by angiosperm-derived compounds, with aromatic compounds dominated by the naphthalene, phenanthrene, biphenyl, and fluorene series. The related source rocks of these oils were mainly deposited under oxic condition, but a subanoxic–suboxic and enclosed water column condition in the Central Depression during Oligocene. The identification of simonellite and related compounds in the aromatic fractions provides reliable evidence for the input of coniferous gymnosperms. Cadalene may also have a potential association with gymnosperms since it shows a strong positive correlation with simonellite. Evidence from density, n-alkanes, short-chain alkylbenzenes and secondary brine inclusions indicates that the unique crude oil B13-1 may have suffered from thermal alteration. These crude oils (excluding B13-1) can be classified into four types based on the <em>δ</em><sup>13</sup>C<sub>oil</sub> values and molecular biomarkers. Type A oil (solely S34-3) is characterized by non-angiosperm plants, with minor dinoflagellates and increasing contribution from conifer gymnosperms than others. Type B oils (L17-2, L18-1, L25-1, and L25-1W) show heavy <em>δ</em><sup>13</sup>C<sub>oil</sub> (−24 ‰ to −25 ‰) and mixed contributions from both angiosperms and marine algae, with the marine algae contribution increasing. Type C oils (L13-2 and B21-1) share similar biological sources with Type B, but the moderately <em>δ</em><sup>13</sup>Coil (−25‰ to −26‰) and high level of terrestrial biomarkers suggesting a predominant contribution of angiosperms. Type D oils (Y13-1a, Y13-1b, and Y13-4) possess the lightest <em>δ</em><sup>13</sup>C<sub>oil</sub> (mainly below −26‰) and are primarily derived from angiosperms, with mangrove vegetation playing an important role. Spearman correlation analysis among 14 source biomarker parameters with <em>δ</em><sup>13</sup>C<sub>oil</sub> and geological setting of related source rocks implied that the marine algae should be responsible for the heavy <em>δ</em><sup>13</sup>C<sub>oil</sub> in the Type B. The contribution of marine algae in the Central Depression may have been neglected in the past, as it is usually covered by remarkable angiosperm biomarkers.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"21 5","pages":"Pages 3029-3046"},"PeriodicalIF":6.0000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Biological origin and depositional environment of crude oils in the Qiongdongnan Basin: Insights from molecular biomarkers and whole oil carbon isotope\",\"authors\":\"\",\"doi\":\"10.1016/j.petsci.2024.05.026\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Molecular biomarker and whole oil carbon isotope (<em>δ</em><sup>13</sup>C<sub>oil</sub>) analyses were conducted on eleven typical crude oils from the Qiongdongnan Basin to investigate their biological sources and depositional environments. Saturated hydrocarbon biomarkers in most samples are characterized by angiosperm-derived compounds, with aromatic compounds dominated by the naphthalene, phenanthrene, biphenyl, and fluorene series. The related source rocks of these oils were mainly deposited under oxic condition, but a subanoxic–suboxic and enclosed water column condition in the Central Depression during Oligocene. The identification of simonellite and related compounds in the aromatic fractions provides reliable evidence for the input of coniferous gymnosperms. Cadalene may also have a potential association with gymnosperms since it shows a strong positive correlation with simonellite. Evidence from density, n-alkanes, short-chain alkylbenzenes and secondary brine inclusions indicates that the unique crude oil B13-1 may have suffered from thermal alteration. These crude oils (excluding B13-1) can be classified into four types based on the <em>δ</em><sup>13</sup>C<sub>oil</sub> values and molecular biomarkers. Type A oil (solely S34-3) is characterized by non-angiosperm plants, with minor dinoflagellates and increasing contribution from conifer gymnosperms than others. Type B oils (L17-2, L18-1, L25-1, and L25-1W) show heavy <em>δ</em><sup>13</sup>C<sub>oil</sub> (−24 ‰ to −25 ‰) and mixed contributions from both angiosperms and marine algae, with the marine algae contribution increasing. Type C oils (L13-2 and B21-1) share similar biological sources with Type B, but the moderately <em>δ</em><sup>13</sup>Coil (−25‰ to −26‰) and high level of terrestrial biomarkers suggesting a predominant contribution of angiosperms. Type D oils (Y13-1a, Y13-1b, and Y13-4) possess the lightest <em>δ</em><sup>13</sup>C<sub>oil</sub> (mainly below −26‰) and are primarily derived from angiosperms, with mangrove vegetation playing an important role. Spearman correlation analysis among 14 source biomarker parameters with <em>δ</em><sup>13</sup>C<sub>oil</sub> and geological setting of related source rocks implied that the marine algae should be responsible for the heavy <em>δ</em><sup>13</sup>C<sub>oil</sub> in the Type B. The contribution of marine algae in the Central Depression may have been neglected in the past, as it is usually covered by remarkable angiosperm biomarkers.</div></div>\",\"PeriodicalId\":19938,\"journal\":{\"name\":\"Petroleum Science\",\"volume\":\"21 5\",\"pages\":\"Pages 3029-3046\"},\"PeriodicalIF\":6.0000,\"publicationDate\":\"2024-10-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Petroleum Science\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1995822624001560\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Petroleum Science","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1995822624001560","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
Biological origin and depositional environment of crude oils in the Qiongdongnan Basin: Insights from molecular biomarkers and whole oil carbon isotope
Molecular biomarker and whole oil carbon isotope (δ13Coil) analyses were conducted on eleven typical crude oils from the Qiongdongnan Basin to investigate their biological sources and depositional environments. Saturated hydrocarbon biomarkers in most samples are characterized by angiosperm-derived compounds, with aromatic compounds dominated by the naphthalene, phenanthrene, biphenyl, and fluorene series. The related source rocks of these oils were mainly deposited under oxic condition, but a subanoxic–suboxic and enclosed water column condition in the Central Depression during Oligocene. The identification of simonellite and related compounds in the aromatic fractions provides reliable evidence for the input of coniferous gymnosperms. Cadalene may also have a potential association with gymnosperms since it shows a strong positive correlation with simonellite. Evidence from density, n-alkanes, short-chain alkylbenzenes and secondary brine inclusions indicates that the unique crude oil B13-1 may have suffered from thermal alteration. These crude oils (excluding B13-1) can be classified into four types based on the δ13Coil values and molecular biomarkers. Type A oil (solely S34-3) is characterized by non-angiosperm plants, with minor dinoflagellates and increasing contribution from conifer gymnosperms than others. Type B oils (L17-2, L18-1, L25-1, and L25-1W) show heavy δ13Coil (−24 ‰ to −25 ‰) and mixed contributions from both angiosperms and marine algae, with the marine algae contribution increasing. Type C oils (L13-2 and B21-1) share similar biological sources with Type B, but the moderately δ13Coil (−25‰ to −26‰) and high level of terrestrial biomarkers suggesting a predominant contribution of angiosperms. Type D oils (Y13-1a, Y13-1b, and Y13-4) possess the lightest δ13Coil (mainly below −26‰) and are primarily derived from angiosperms, with mangrove vegetation playing an important role. Spearman correlation analysis among 14 source biomarker parameters with δ13Coil and geological setting of related source rocks implied that the marine algae should be responsible for the heavy δ13Coil in the Type B. The contribution of marine algae in the Central Depression may have been neglected in the past, as it is usually covered by remarkable angiosperm biomarkers.
期刊介绍:
Petroleum Science is the only English journal in China on petroleum science and technology that is intended for professionals engaged in petroleum science research and technical applications all over the world, as well as the managerial personnel of oil companies. It covers petroleum geology, petroleum geophysics, petroleum engineering, petrochemistry & chemical engineering, petroleum mechanics, and economic management. It aims to introduce the latest results in oil industry research in China, promote cooperation in petroleum science research between China and the rest of the world, and build a bridge for scientific communication between China and the world.