古地理学报 ›› 2025, Vol. 27 ›› Issue (4): 1064-1080. doi: 10.7605/gdlxb.2025.047

• 古地理学及矿产资源 • 上一篇    

中始新世气候演化与页岩有机质富集: 以东营凹陷为例*

郑凯1(), 孔祥鑫1(), 姜在兴1, 蒋龙2, 葛涛元1, 杨叶芃3, 王成1, 彭艳霞2   

  1. 1 中国地质大学(北京)能源学院,北京 100083
    2 中国石化胜利油田分公司勘探开发研究院,山东东营 257015
    3 中国石油勘探开发研究院,北京 100083
  • 收稿日期:2024-04-14 修回日期:2024-08-22 出版日期:2025-08-01 发布日期:2025-07-30
  • 通讯作者: 孔祥鑫,男,1990年生,副教授,主要从事细粒沉积学与非常规油气储集层研究。E-mail: kongxx@cugb.edu.cn。
  • 作者简介:

    郑凯,男,1999年生,硕士研究生,主要从事沉积学研究。E-mail:

  • 基金资助:
    *国家自然科学基金(42402114); 中央高校基本科研业务费专项基金(2652022035)

Climate evolution and shale organic matter enrichment during the Middle Eocene: a case study of Dongying sag

ZHENG Kai1(), KONG Xiangxin1(), JIANG Zaixing1, JIANG Long2, GE Taoyuan1, YANG Yepeng3, WANG Cheng1, PENG Yanxia2   

  1. 1 School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China
    2 Petroleum Exploration and Production Research Institute,Shengli Oil field Company,Sinopec,Shandong Dongying 257015,China
    3 Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China
  • Received:2024-04-14 Revised:2024-08-22 Online:2025-08-01 Published:2025-07-30
  • Contact: KONG Xiangxin,born in 1990, is an associate professor, and specializes in fine⁃grained sedimentology and unconventional oil and gas reservoirs. E⁃mail: kongxx@cugb.edu.cn.
  • About author:

    ZHENG Kai,born in 1999,is a master’s degree candidate primarily engaged in the study of sedimentology. E-mail:

  • Supported by:
    Co-funded by the National Natural Science Foundation of China(42402114); Fundamental Research Funds for the Central Universities(2652022035)

摘要:

渤海湾盆地东营凹陷牛庄洼陷沙河街组四段上亚段(沙四上亚段)发育数百米厚富有机质页岩,该页岩发育时期正处于东亚地区中始新世气候波动的关键阶段,但页岩沉积演化及其有机质富集对气候演化的响应尚有待研究。通过岩心和薄片观察、有机和元素地球化学分析,探讨在气候演化约束下有机质富集机制。根据岩相组合和地化参数,将沙四上亚段分为3个阶段: 第1阶段气候相对干冷,TOC均值为2.52%,发育中有机质韵律型纹层状云质细粒沉积岩和高有机质韵律型纹层状混合细粒沉积岩; 第2阶段气候相对暖湿,TOC均值为3.29%,发育高有机质韵律型纹层状含石英灰质细粒沉积岩和高有机质韵律型纹层状混合细粒沉积岩; 第3阶段气候暖湿,TOC均值为2.78%,发育高有机质非韵律型纹层状混合细粒沉积岩和中高有机质韵律型纹层状含石英灰质细粒沉积岩。根据岩相组合和沉积环境变化趋势,建立牛庄洼陷沙四上亚段纯上段沉积模式。在相对暖湿气候下,适量的陆源输入会给湖盆带来陆源碎屑有机质和营养物质,利于有机质富集; 在相对干冷气候下浅水高盐的环境会抑制水生生物的生长和繁殖,在暖湿气候下过强的陆源输入稀释水体有机质含量并带来的大量氧气,均不利于有机质富集。本次研究可为中国东部陆相断陷湖盆富有机制页岩地质甜点分析提供借鉴意义。

关键词: 沉积环境, 细粒沉积, 有机质富集, 中始新世, 东营凹陷

Abstract:

Several hundred meters of organic-rich shale are developed in the upper 4th Member of the Shahejie Formation in the Niuzhuang sub-sag of the Dongying sag,Bohai Bay Basin. This shale formation occurred during a critical period of climate fluctuations in the Middle Eocene in East Asia. However,the sedimentary evolution of this shale and its organic matter enrichment mechanisms in response to climate changes remain insufficiently studied. Through core and thin section observations,as well as organic and elemental geochemical analyses,we explore the mechanisms of organic matter enrichment under climatic constraints. Based on lithofacies assemblages and geochemical parameters,the study interval is divided into three stages: The first stage was characterized by a relatively dry and cold climate,with an average Total Organic Carbon(TOC)content of 2.52%. This stage featured rhythmically layered,dolomitic,fine-grained sedimentary rocks with moderate organic matter content and high-organic-matter rhythmic layered mixed fine-grained sedimentary rocks. The second stage experienced a relatively warm and humid climate,with an average TOC of 3.29%. It was marked by the development of high-organic-matter rhythmically layered quartz-containing calcareous fine-grained sedimentary rocks and high-organic-matter rhythmically layered mixed fine-grained sedimentary rocks. The third stage was a warm and humid period,with an average TOC of 2.78%. This stage was characterized by the development of high-organic-matter non-rhythmically layered mixed fine-grained sedimentary rocks and medium-to high-organic-matter rhythmically layered quartz-containing fine-grained calcareous sedimentary rocks. A sedimentary model for the Upper Fourth Member of the Shahejie Formation in the Niuzhuang sub-sag has been established based on lithofacies assemblages and trends in sedimentary environment changes. Under relatively warm and humid climates,moderate terrestrial input can bring terrestrial detrital organic matter and nutrients to the lake basin,which is beneficial for organic matter enrichment. Conversely,under relatively dry and cold climates,shallow water with high salinity can inhibit the growth and reproduction of aquatic organisms. Under warm and humid climates,excessive terrestrial input can dilute the organic matter concentration in water and introduce large amounts of oxygen,both of which are unfavorable for organic matter enrichment. This study provides valuable insights into the analysis of geological sweet spot analysis of organic-rich shale in continental faulted lake basins in eastern China.

Key words: depositional environment, fine-grained sedimentary rocks, organic matter enrichment, Middle Eocene, Dongying sag

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