Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China
Organic matter (OM) and carbonate are the important organic and inorganic components, respectively, in the shales of the upper fourth member of the Eocene Shahejie Formation, Dongying Depression, Eastern China. Their enrichment affects the hydrocarbon generation capacity and reservoir development of...
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Wiley
2022-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2022/7929351 |
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| author | Jing Wu Wei Li Wenjin Li Wei Chen |
| author_facet | Jing Wu Wei Li Wenjin Li Wei Chen |
| author_sort | Jing Wu |
| collection | DOAJ |
| description | Organic matter (OM) and carbonate are the important organic and inorganic components, respectively, in the shales of the upper fourth member of the Eocene Shahejie Formation, Dongying Depression, Eastern China. Their enrichment affects the hydrocarbon generation capacity and reservoir development of shales. The development mechanism of sequence stratigraphy and the influence of sequence stratigraphy on OM enrichment and carbonate deposition are investigated in this study. Based on the petrological, mineralogical, and geochemical analyses, a third-order sequence is recognized, including the lowstand systems tract (LST), transgressive systems tract (TST), and highstand systems tract (HST). The total organic carbon (TOC) content is 0.11–9.05 wt% (average 2.2 wt%), and the carbonate content is 3–95 wt% (average 51 wt%). Organic matter and carbonate are enriched in TST and gradually reduced in HST and LST. The decrease in the relative lake level in LST results in the deposition of abundant siltstone, leading to both poor OM preservation and carbonate precipitation. The rapid rise in the relative lake level in TST may be triggered by marine transgression, promoting OM enrichment in terms of both production and preservation. Seawater input brought abundant Ca2+ and Mg2+, which facilitated the precipitation of carbonates. The enrichment of OM and carbonate improves the capacity of hydrocarbon generation and reservoir performance of shales in the TST. The decrease in the relative lake level in HST causes a slight increase in the terrigenous clastic content, which, on the one hand, accelerates the sedimentation rate and OM deposition and, on the other hand, reduces carbonate precipitation. This study not only explains the differential distribution of OM and carbonate but also helps to improve the accuracy of the evaluation of shale oil sweet spots. |
| format | Article |
| id | doaj-art-83429680361f4f2ab0f17107b8fa7004 |
| institution | Kabale University |
| issn | 1468-8123 |
| language | English |
| publishDate | 2022-01-01 |
| publisher | Wiley |
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| series | Geofluids |
| spelling | doaj-art-83429680361f4f2ab0f17107b8fa70042025-02-03T05:53:34ZengWileyGeofluids1468-81232022-01-01202210.1155/2022/7929351Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern ChinaJing Wu0Wei Li1Wenjin Li2Wei Chen3School of Earth Science and EngineeringSchool of Earth Science and EngineeringSchool of Earth Science and EngineeringSchool of Earth Science and EngineeringOrganic matter (OM) and carbonate are the important organic and inorganic components, respectively, in the shales of the upper fourth member of the Eocene Shahejie Formation, Dongying Depression, Eastern China. Their enrichment affects the hydrocarbon generation capacity and reservoir development of shales. The development mechanism of sequence stratigraphy and the influence of sequence stratigraphy on OM enrichment and carbonate deposition are investigated in this study. Based on the petrological, mineralogical, and geochemical analyses, a third-order sequence is recognized, including the lowstand systems tract (LST), transgressive systems tract (TST), and highstand systems tract (HST). The total organic carbon (TOC) content is 0.11–9.05 wt% (average 2.2 wt%), and the carbonate content is 3–95 wt% (average 51 wt%). Organic matter and carbonate are enriched in TST and gradually reduced in HST and LST. The decrease in the relative lake level in LST results in the deposition of abundant siltstone, leading to both poor OM preservation and carbonate precipitation. The rapid rise in the relative lake level in TST may be triggered by marine transgression, promoting OM enrichment in terms of both production and preservation. Seawater input brought abundant Ca2+ and Mg2+, which facilitated the precipitation of carbonates. The enrichment of OM and carbonate improves the capacity of hydrocarbon generation and reservoir performance of shales in the TST. The decrease in the relative lake level in HST causes a slight increase in the terrigenous clastic content, which, on the one hand, accelerates the sedimentation rate and OM deposition and, on the other hand, reduces carbonate precipitation. This study not only explains the differential distribution of OM and carbonate but also helps to improve the accuracy of the evaluation of shale oil sweet spots.http://dx.doi.org/10.1155/2022/7929351 |
| spellingShingle | Jing Wu Wei Li Wenjin Li Wei Chen Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China Geofluids |
| title | Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China |
| title_full | Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China |
| title_fullStr | Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China |
| title_full_unstemmed | Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China |
| title_short | Sequence Stratigraphy Variation and Its Implication in Shale Oil Exploration: A Case Study of the Eocene Dongying Depression, Eastern China |
| title_sort | sequence stratigraphy variation and its implication in shale oil exploration a case study of the eocene dongying depression eastern china |
| url | http://dx.doi.org/10.1155/2022/7929351 |
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