古地理学报 ›› 2024, Vol. 26 ›› Issue (4): 941-961. doi: 10.7605/gdlxb.2024.04.083

所属专题: 深水沉积学专辑

• 深水沉积专题 • 上一篇    下一篇

中国断陷和坳陷湖盆高可容纳空间层序细粒重力流沉积及其页岩油意义*

冯有良1, 邹才能1, 杨智1, 蒋文琦2, 张天舒1, 张洪1, 刘畅1, 王小妮1   

  1. 1 中国石油勘探开发研究院,北京 100083;
    2 北京大学地球与空间科学学院,北京 100871
  • 收稿日期:2023-06-30 修回日期:2024-01-18 出版日期:2024-08-01 发布日期:2024-07-29
  • 作者简介:冯有良,男,1963年生,博士(后),高级工程师,长期从事层序地层学、沉积学和石油地质学研究。E-mail: fyouliang@petroChina.com.cn。
  • 基金资助:
    * 中国石油天然气股份有限公司科技部项目(编号: 2021DJ18,2021DJ1802)资助

Fine-grained gravity flow deposits and their significance for shale oil within high-accommodation sequences in faulted and down-warped lacustrine basins of China

FENG Youliang1, ZOU Caineng1, YANG Zhi1, JIANG Wenqi2, ZHANG Tianshu1, ZHANG Hong1, LIU Chang1, WANG Xiaoni1   

  1. 1 Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;
    2 College of Earth and Space Sciences, Peking University,Beijing 100871,China
  • Received:2023-06-30 Revised:2024-01-18 Online:2024-08-01 Published:2024-07-29
  • About author:FENG Youliang,born in 1963,holds a Ph.D. in geosciences and is a senior engineer at the Department of Petroleum Geology,PetroChina Research Institute of Petroleum Exploration and development. He is mainly engaged in research on sequence stratigraphy,sedimentology,and petroleum geology in lacustrine basins. E-mail: fyouliang@petroChina.com.cn.
  • Supported by:
    Financially supported by PetroChina Science and Technology Projects(Nos. 2021DJ18,2021DJ1802)

摘要: 重力流包括粗粒和细粒重力流,是深湖环境最重要的沉积类型之一,其中,细粒重力流能成为非常规页岩油的“甜点段”。研究该沉积在陆相湖盆层序格架中的分布规律,对页岩油 “甜点段”的预测具有重要意义。作者通过对中国主要湖盆重力流发育与层序格架的系统对比研究发现,重力流沉积体系主要发育在高可容纳空间沉积层序中。断陷湖盆的低位域(LST)湖底扇近端发育粗粒重力流沉积,远端发育薄层细粒重力流沉积,其分布受沟谷和同沉积构造坡折的控制。水进体系域(TST)发育细粒水道—堤—朵叶体系。高位体系域(HST)发育非限定水道湖底扇,细粒重力流沉积分布在扇的远端。坳陷湖盆的水进体系域(TST)主要发育受洪泛影响的大型细粒水道—堤—朵叶体系,而在湖盆挠曲坡折的较陡斜坡发育细粒湖底扇体系。高位域(HST)及低位域(LST)既可形成细粒湖底扇体系,也可发育细粒的水道—堤—朵叶体系。分布在湖底扇远端和水道—堤—朵叶体系的细粒重力流沉积能形成页岩油的“甜点段”。泥流沉积形成页理型“甜点段”,细粒碎屑流、细粒浊流、细粒异重流和细粒过渡流沉积形成纹层型、层理型“甜点段”,细粒浓缩密度流沉积只形成层理型“甜点段”。细粒重力流沉积是页岩油勘探开发的有利 “甜点段”。

关键词: 高可容纳空间层序, 细粒重力流沉积, 陆相盆地, 页岩油, “, 甜点段”

Abstract: Gravity flows,including coarse-grained and fine-grained gravity flows,are the most important sedimentation processes in deep-lake environments. Fine-grained gravity flow sediments hold significant potential as unconventional shale oil “sweet spot intervals”. The distribution characteristics of fine-grained gravity flow sediments within sequence stratigraphic frameworks in lacustrine basins are of great significance to the prediction of shale oil “sweet spot intervals”. Through systematic comparative study of gravity flow deposits and sequence frameworks in major lacustrine basins in China,it is found that gravity flow sedimentary systems are mainly deposited in high accommodation sequences. In the lowstand systems tracts(LST)of the faulted/rifted lacustrine basins,coarse-grained gravity flow deposits are developed at proximal sublauctrine fans and thin fine-grained gravity flow sediments are deposited at distal sublaucustrine fans. The distribution of sublacustine fans is controlled by valley and syn-sedimentary structural slope breaks. Fine-grained channel-levee-lobe systems are developed in transgressive systems tracts(TST). Unconfined-channel sublacustrine fans are developed in highstand systems tracts(HST),and fine gravity flow deposits are distributed in distal sublacustrine fans. Large fine-grained channel-levee-lobe systems influenced by flooding occurred in transgressive systems tracts(TST)of down-warped lacustrine basins. On the steeper slope of syn-depositional flexural breaks,fine-grain sublacustrine fan systems are present. Both fine-grained sublacustrine fan systems and fine-grained channel-levee-lobe systems can be deposited in highstand systems tracts(HST)and lowstand systems tracts(LST). Fine-grained gravity flow deposits at distal sublacustrine fans and channel-levee-lobe systems can form “sweet spot intervals” of shale oil. Mudflow deposits form “sweet spot intervals”of foliation type,fine-grained debris flow,fine-grained turbidity current,fine-grained hyperpycnal flow and fine-grained transition flow deposits form “sweet spot intervals”of lamination type and bedding type,while fine-grained concentrated density flow deposits only form “sweet spot intervals”of bedding type. Fine-grained gravity flow deposits are favorable “sweet spot intervals” for shale oil exploration and development.

Key words: high-accommodation sequence, fine-grained gravity flow deposits, continental basin, shale oil, “sweet spot interval”

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