{"title":"中国东部渤海湾盆地渤中沙砾不同面相渐新世源岩的地球化学特征及分类","authors":"","doi":"10.1016/j.jseaes.2024.106304","DOIUrl":null,"url":null,"abstract":"<div><p>There have been many studies conducted on the Eocene source rocks (Shahejie Formation Mbrs 1 and 3) (E<sub>2</sub>s<sub>1</sub> and E<sub>2</sub>s<sub>3</sub>) of the Bozhong Sag, Bohai Bay Basin in East China. However, Oligocene source rocks (Dongying Formation Mbrs 2 and 3) (E<sub>3</sub>d<sub>2</sub> and E<sub>3</sub>d<sub>3</sub>) have also made significant contributions to petroleum accumulations in this region. Their organic matter (OM) enrichment mechanisms, environmental and ecological variations, and laterally variable facies remain subjects of debate, particularly in the lower Dongying Formation Mbrs 2 (E<sub>3</sub>d<sub>2</sub><sup>L</sup>). Thus, we investigated the geochemical properties, depositional environments, and OM origins of E<sub>3</sub>d<sub>2</sub><sup>L</sup> and E<sub>3</sub>d<sub>3</sub> source rocks from seven prospecting wells in southwestern Bozhong Sag. Our findings indicate that E<sub>3</sub>d<sub>2</sub><sup>L</sup> source rocks are of poor-to-medium quality, whereas E<sub>3</sub>d<sub>3</sub> source rocks are classified as good-to-excellent quality. Notable differences in the geochemical characteristics between E<sub>3</sub>d<sub>2</sub><sup>L</sup> and E<sub>3</sub>d<sub>3</sub> source rocks were observed. Hierarchical cluster analysis identified five genetic organic facies. The E<sub>3</sub>d<sub>2</sub><sup>L</sup> source rocks comprises facies D2-Ⅰ, D2-Ⅱ, D2-Ⅲ, and D2–D3, whereas E<sub>3</sub>d<sub>3</sub> contains facies D3 and D2–D3, with D2–D3 being common to both source rocks. Additionally, an integrated OM enrichment model was established to evaluate Oligocene source rocks. The five genetic organic facies exhibit distinctive differences and some similarities regarding redox conditions, water salinity, and OM origins. Their geochemical characteristics within the same intervals display pronounced lateral heterogeneity from deep source rocks deposits to more marginal water depths. The established model provides guidance for the prediction and exploration of effective Oligocene source rocks in the Bohai Sea and research on the Paleogene and Neogene petroleum systems. Moreover, the integration of biomarkers and hierarchical cluster analysis methods for organic facies analysis has significant implications for predicting of source-rock heterogeneity in other lacustrine rift basins.</p></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":null,"pages":null},"PeriodicalIF":2.7000,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Geochemical characteristics and classification of Oligocene source rocks with different facies in Bozhong Sag, Bohai Bay Basin, East China\",\"authors\":\"\",\"doi\":\"10.1016/j.jseaes.2024.106304\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>There have been many studies conducted on the Eocene source rocks (Shahejie Formation Mbrs 1 and 3) (E<sub>2</sub>s<sub>1</sub> and E<sub>2</sub>s<sub>3</sub>) of the Bozhong Sag, Bohai Bay Basin in East China. However, Oligocene source rocks (Dongying Formation Mbrs 2 and 3) (E<sub>3</sub>d<sub>2</sub> and E<sub>3</sub>d<sub>3</sub>) have also made significant contributions to petroleum accumulations in this region. Their organic matter (OM) enrichment mechanisms, environmental and ecological variations, and laterally variable facies remain subjects of debate, particularly in the lower Dongying Formation Mbrs 2 (E<sub>3</sub>d<sub>2</sub><sup>L</sup>). Thus, we investigated the geochemical properties, depositional environments, and OM origins of E<sub>3</sub>d<sub>2</sub><sup>L</sup> and E<sub>3</sub>d<sub>3</sub> source rocks from seven prospecting wells in southwestern Bozhong Sag. Our findings indicate that E<sub>3</sub>d<sub>2</sub><sup>L</sup> source rocks are of poor-to-medium quality, whereas E<sub>3</sub>d<sub>3</sub> source rocks are classified as good-to-excellent quality. Notable differences in the geochemical characteristics between E<sub>3</sub>d<sub>2</sub><sup>L</sup> and E<sub>3</sub>d<sub>3</sub> source rocks were observed. Hierarchical cluster analysis identified five genetic organic facies. The E<sub>3</sub>d<sub>2</sub><sup>L</sup> source rocks comprises facies D2-Ⅰ, D2-Ⅱ, D2-Ⅲ, and D2–D3, whereas E<sub>3</sub>d<sub>3</sub> contains facies D3 and D2–D3, with D2–D3 being common to both source rocks. Additionally, an integrated OM enrichment model was established to evaluate Oligocene source rocks. The five genetic organic facies exhibit distinctive differences and some similarities regarding redox conditions, water salinity, and OM origins. Their geochemical characteristics within the same intervals display pronounced lateral heterogeneity from deep source rocks deposits to more marginal water depths. The established model provides guidance for the prediction and exploration of effective Oligocene source rocks in the Bohai Sea and research on the Paleogene and Neogene petroleum systems. Moreover, the integration of biomarkers and hierarchical cluster analysis methods for organic facies analysis has significant implications for predicting of source-rock heterogeneity in other lacustrine rift basins.</p></div>\",\"PeriodicalId\":50253,\"journal\":{\"name\":\"Journal of Asian Earth Sciences\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.7000,\"publicationDate\":\"2024-08-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Asian Earth Sciences\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1367912024002992\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Asian Earth Sciences","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1367912024002992","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
对中国东部渤海湾盆地渤中相始新世源岩(沙河街地层第1和第3层)(E2s1和E2s3)进行了许多研究。然而,渐新世源岩(东营地层 Mbrs 2 和 3)(E3d2 和 E3d3)也对该地区的石油积聚做出了重要贡献。它们的有机质(OM)富集机制、环境和生态变化以及侧向变异面仍是争论的主题,尤其是在东营地层下部 Mbrs 2(E3d2L)。因此,我们研究了渤中相西南部七口探井中 E3d2L 和 E3d3 源岩的地球化学性质、沉积环境和 OM 来源。我们的研究结果表明,E3d2L源岩的质量从差到中等,而E3d3源岩的质量从好到优。E3d2L和E3d3源岩的地球化学特征存在明显差异。层次聚类分析确定了五个遗传有机层。E3d2L源岩包括D2-Ⅰ、D2-Ⅱ、D2-Ⅲ和D2-D3面,而E3d3源岩则包括D3和D2-D3面,其中D2-D3面是两个源岩的共同面。此外,还建立了一个综合有机质富集模型来评估渐新世源岩。五个遗传有机层在氧化还原条件、水盐度和 OM 来源方面表现出明显的差异和一些相似之处。它们在同一区间内的地球化学特征显示出明显的横向异质性,从深源岩沉积到更边缘的水深。所建立的模型为渤海新近纪有效源岩的预测和勘探以及古近纪和新近纪石油系统的研究提供了指导。此外,将生物标志物与分层聚类分析方法相结合进行有机面分析,对预测其他湖相裂谷盆地的源岩异质性具有重要意义。
Geochemical characteristics and classification of Oligocene source rocks with different facies in Bozhong Sag, Bohai Bay Basin, East China
There have been many studies conducted on the Eocene source rocks (Shahejie Formation Mbrs 1 and 3) (E2s1 and E2s3) of the Bozhong Sag, Bohai Bay Basin in East China. However, Oligocene source rocks (Dongying Formation Mbrs 2 and 3) (E3d2 and E3d3) have also made significant contributions to petroleum accumulations in this region. Their organic matter (OM) enrichment mechanisms, environmental and ecological variations, and laterally variable facies remain subjects of debate, particularly in the lower Dongying Formation Mbrs 2 (E3d2L). Thus, we investigated the geochemical properties, depositional environments, and OM origins of E3d2L and E3d3 source rocks from seven prospecting wells in southwestern Bozhong Sag. Our findings indicate that E3d2L source rocks are of poor-to-medium quality, whereas E3d3 source rocks are classified as good-to-excellent quality. Notable differences in the geochemical characteristics between E3d2L and E3d3 source rocks were observed. Hierarchical cluster analysis identified five genetic organic facies. The E3d2L source rocks comprises facies D2-Ⅰ, D2-Ⅱ, D2-Ⅲ, and D2–D3, whereas E3d3 contains facies D3 and D2–D3, with D2–D3 being common to both source rocks. Additionally, an integrated OM enrichment model was established to evaluate Oligocene source rocks. The five genetic organic facies exhibit distinctive differences and some similarities regarding redox conditions, water salinity, and OM origins. Their geochemical characteristics within the same intervals display pronounced lateral heterogeneity from deep source rocks deposits to more marginal water depths. The established model provides guidance for the prediction and exploration of effective Oligocene source rocks in the Bohai Sea and research on the Paleogene and Neogene petroleum systems. Moreover, the integration of biomarkers and hierarchical cluster analysis methods for organic facies analysis has significant implications for predicting of source-rock heterogeneity in other lacustrine rift basins.
期刊介绍:
Journal of Asian Earth Sciences has an open access mirror journal Journal of Asian Earth Sciences: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review.
The Journal of Asian Earth Sciences is an international interdisciplinary journal devoted to all aspects of research related to the solid Earth Sciences of Asia. The Journal publishes high quality, peer-reviewed scientific papers on the regional geology, tectonics, geochemistry and geophysics of Asia. It will be devoted primarily to research papers but short communications relating to new developments of broad interest, reviews and book reviews will also be included. Papers must have international appeal and should present work of more than local significance.
The scope includes deep processes of the Asian continent and its adjacent oceans; seismology and earthquakes; orogeny, magmatism, metamorphism and volcanism; growth, deformation and destruction of the Asian crust; crust-mantle interaction; evolution of life (early life, biostratigraphy, biogeography and mass-extinction); fluids, fluxes and reservoirs of mineral and energy resources; surface processes (weathering, erosion, transport and deposition of sediments) and resulting geomorphology; and the response of the Earth to global climate change as viewed within the Asian continent and surrounding oceans.