{"title":"鄂尔多斯盆地中段上三叠统延长构造长-9原油与潜在源岩的相关性:长-9油层原油与潜在源岩的相关性","authors":"Yan Liu, Han Yue, Rongxi Li, Xuefeng Liu","doi":"10.1155/2024/4861384","DOIUrl":null,"url":null,"abstract":"<p>The Chang 9 oil layer deposits within Ansai District, Ordos Basin, yield considerable reserves of crude oil, yet their source remains ambiguous. This research endeavor was designed to characterize the Chang 9 crude oil and the Chang 7 and Chang 9 source rocks (SRs) of the Yan-Chang Formation via organic geochemical analysis. The results indicate that the Chang 9 crude oil exhibits a Pr/Ph ratio of 0.84–2.29 and Ga/C<sub>30</sub>H less than 0.1, implying formed in a weak reduction to weak oxidation freshwater environment. The regular sterane C<sub>27</sub>-C<sub>28</sub>-C<sub>29</sub> configuration assumes an inversed “L” type, reflecting mixed sources and dominant terrestrial plant input. Ratios such as C<sub>29</sub>20<i>S</i>/(20<i>S</i> + 20<i>R</i>) (0.54–0.6) and C<sub>29</sub><i>β</i><i>β</i>/(<i>β</i><i>β</i> + <i>α</i><i>α</i>) (0.44–0.58) indicate a mature oil stage. The depositional environment of the C7 and C9 SRs is similar, with weak oxidation to reduction conditions, and consists mainly of Type I and II organics, with a relatively higher maturity of the C9 SRs. A difference in C<sub>19</sub>/C<sub>23</sub>TT and C<sub>30</sub>D/C<sub>30</sub>H was found between the C7 and C9 SRs. The results show that the C9 crude oils have a similar C<sub>19</sub>/C<sub>23</sub>TT with the C9 SRs and similar diahopanes distribution with Class II SRs (C7 and part of the C9 SRs). Thus, the C9 crude oils most likely originate from the C9 SR mixed with the C7 SRs.</p>","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":"2024 1","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1155/2024/4861384","citationCount":"0","resultStr":"{\"title\":\"Correlation Between Chang-9 Crude Oil and Potential Source Rocks, Upper Triassic Yan-Chang Formation, Middle Area of Ordos Basin: Correlation Between Crude Oil in the Chang-9 Member and Potential Source Rocks\",\"authors\":\"Yan Liu, Han Yue, Rongxi Li, Xuefeng Liu\",\"doi\":\"10.1155/2024/4861384\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The Chang 9 oil layer deposits within Ansai District, Ordos Basin, yield considerable reserves of crude oil, yet their source remains ambiguous. This research endeavor was designed to characterize the Chang 9 crude oil and the Chang 7 and Chang 9 source rocks (SRs) of the Yan-Chang Formation via organic geochemical analysis. The results indicate that the Chang 9 crude oil exhibits a Pr/Ph ratio of 0.84–2.29 and Ga/C<sub>30</sub>H less than 0.1, implying formed in a weak reduction to weak oxidation freshwater environment. The regular sterane C<sub>27</sub>-C<sub>28</sub>-C<sub>29</sub> configuration assumes an inversed “L” type, reflecting mixed sources and dominant terrestrial plant input. Ratios such as C<sub>29</sub>20<i>S</i>/(20<i>S</i> + 20<i>R</i>) (0.54–0.6) and C<sub>29</sub><i>β</i><i>β</i>/(<i>β</i><i>β</i> + <i>α</i><i>α</i>) (0.44–0.58) indicate a mature oil stage. The depositional environment of the C7 and C9 SRs is similar, with weak oxidation to reduction conditions, and consists mainly of Type I and II organics, with a relatively higher maturity of the C9 SRs. A difference in C<sub>19</sub>/C<sub>23</sub>TT and C<sub>30</sub>D/C<sub>30</sub>H was found between the C7 and C9 SRs. The results show that the C9 crude oils have a similar C<sub>19</sub>/C<sub>23</sub>TT with the C9 SRs and similar diahopanes distribution with Class II SRs (C7 and part of the C9 SRs). Thus, the C9 crude oils most likely originate from the C9 SR mixed with the C7 SRs.</p>\",\"PeriodicalId\":12512,\"journal\":{\"name\":\"Geofluids\",\"volume\":\"2024 1\",\"pages\":\"\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2024-09-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1155/2024/4861384\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geofluids\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1155/2024/4861384\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geofluids","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1155/2024/4861384","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Correlation Between Chang-9 Crude Oil and Potential Source Rocks, Upper Triassic Yan-Chang Formation, Middle Area of Ordos Basin: Correlation Between Crude Oil in the Chang-9 Member and Potential Source Rocks
The Chang 9 oil layer deposits within Ansai District, Ordos Basin, yield considerable reserves of crude oil, yet their source remains ambiguous. This research endeavor was designed to characterize the Chang 9 crude oil and the Chang 7 and Chang 9 source rocks (SRs) of the Yan-Chang Formation via organic geochemical analysis. The results indicate that the Chang 9 crude oil exhibits a Pr/Ph ratio of 0.84–2.29 and Ga/C30H less than 0.1, implying formed in a weak reduction to weak oxidation freshwater environment. The regular sterane C27-C28-C29 configuration assumes an inversed “L” type, reflecting mixed sources and dominant terrestrial plant input. Ratios such as C2920S/(20S + 20R) (0.54–0.6) and C29ββ/(ββ + αα) (0.44–0.58) indicate a mature oil stage. The depositional environment of the C7 and C9 SRs is similar, with weak oxidation to reduction conditions, and consists mainly of Type I and II organics, with a relatively higher maturity of the C9 SRs. A difference in C19/C23TT and C30D/C30H was found between the C7 and C9 SRs. The results show that the C9 crude oils have a similar C19/C23TT with the C9 SRs and similar diahopanes distribution with Class II SRs (C7 and part of the C9 SRs). Thus, the C9 crude oils most likely originate from the C9 SR mixed with the C7 SRs.
期刊介绍:
Geofluids is a peer-reviewed, Open Access journal that provides a forum for original research and reviews relating to the role of fluids in mineralogical, chemical, and structural evolution of the Earth’s crust. Its explicit aim is to disseminate ideas across the range of sub-disciplines in which Geofluids research is carried out. To this end, authors are encouraged to stress the transdisciplinary relevance and international ramifications of their research. Authors are also encouraged to make their work as accessible as possible to readers from other sub-disciplines.
Geofluids emphasizes chemical, microbial, and physical aspects of subsurface fluids throughout the Earth’s crust. Geofluids spans studies of groundwater, terrestrial or submarine geothermal fluids, basinal brines, petroleum, metamorphic waters or magmatic fluids.