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现代地质 ›› 2023, Vol. 37 ›› Issue (05): 1155-1168.DOI: 10.19657/j.geoscience.1000-8527.2023.006

• 沉积学 • 上一篇    下一篇

塔里木盆地东北缘下寒武统页岩岩相特征与沉积模式

刘旺威1,2,3(), 李一凡2,3(), 高志前2,3, 樊太亮2,3, 张坦4, 匡明志4   

  1. 1.中国石化石油勘探开发研究院无锡石油地质研究所,江苏 无锡 214126
    2.中国地质大学(北京)能源学院,北京 100083
    3.中国地质大学(北京)教育部海相储层演化与油气富集机理重点实验室,北京 100083
    4.成都理工大学能源学院,四川 成都 610059
  • 收稿日期:2022-09-22 修回日期:2023-01-06 出版日期:2023-10-10 发布日期:2023-11-14
  • 通讯作者: 李一凡,男,博士,副教授,1987年出生,矿产普查与勘探专业,主要从事沉积地球化学及非常规油气勘探研究。Email: liyifan@cugb.edu.cn
  • 作者简介:刘旺威,男,硕士,1994年出生,矿产普查与勘探专业,主要从事沉积学研究。Email:ww.syky@sinopec.com
  • 基金资助:
    国家自然科学基金项目(U19B6003-01-02);国家自然科学基金项目(41802155)

Lithofacies Characteristics and Sedimentary Model of the Lower Cambrian Shale in the Northeastern Margin of Tarim Basin

LIU Wangwei1,2,3(), LI Yifan2,3(), GAO Zhiqian2,3, FAN Tailiang2,3, ZHANG Tan4, KUANG Mingzhi4   

  1. 1. Wuxi Research Institute of Petroleum Geology, Petroleum Exploration and Production Research Institute, SINOPEC, Wuxi, Jiangsu 214126, China
    2. School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China
    3. Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism, Ministry of Education, China University of Geosciences (Beijing), Beijing 100083, China
    4. School of Energy, Chengdu University of Technology, Chengdu, Sichuan 610059, China
  • Received:2022-09-22 Revised:2023-01-06 Online:2023-10-10 Published:2023-11-14

摘要:

研究页岩岩相特征和沉积模式有助于把握细粒烃源岩的特征和分布。通过野外露头描述、薄片观察和有机质含量测定等手段,对塔里木盆地东北缘(塔东北地区)下寒武统页岩的岩相、岩相组合和沉积演化模式进行了分析。塔东北地区早寒武世水体表现为快速海侵-持续变深-迅速变浅,海平面的变化直接影响页岩的发育。研究区下寒武统自下而上发育6种岩相和3种岩相组合:(1)半深水陆棚岩相组合,包括硅质页岩相、硅质黏土质混合页岩相和磷质页岩相;(2)深水陆棚岩相组合,包括硅质页岩相和黏土质页岩相;(3)浅水陆棚岩相组合,包括钙质页岩相和硅质钙质页岩相。寒武纪初期塔东北地区处于半深水陆棚环境,且拉张作用强烈,热液活动频繁,热液活动对有机质富集具有双重作用,不利于半深水陆棚环境中硅质页岩相中有机质的富集,有利于半深水陆棚环境中磷质页岩相中有机质的富集。随着水体持续变深,构造活动和热液活动减弱,深水陆棚岩相组合开始沉积,这一时期有机质保存条件好、沉积速率慢、古生产力较高,页岩中TOC含量相对较高。在西大山组沉积时期整体为浅水陆棚环境,这一时期沉积物中硅质矿物含量减少,钙质矿物含量增加,有机质保存条件较差,沉积速率较快,页岩中TOC含量相对较低。总体认为塔东北地区下寒武统的磷质页岩相和深水陆棚岩相组合为有利层段。

关键词: 塔里木盆地, 下寒武统, 页岩岩相, 沉积模式

Abstract:

The study of shale facies characteristics and sedimentary model can help to reveal the characteristics and distribution of fine-grained source rocks.The lithofacies assemblage and sedimentary model of the Lower Cambrian shale in the northeastern margin of the Tarim Basin are analyzed by means of outcrop description, thin-section petrographic observation and organic matter content measurement.The sea-level of the Lower Cambrian in northeastern Tarim Basin was characterized by rapid transgression, continuous deepening and rapid shallowing.The sea-level change may have directly affected the shale development.Six lithofacies and three lithofacies assemblages are developed from bottom to top in the Lower Cambrian in the study area: (1)the semi deep-water shelf lithofacies assemblage includes siliceous shale facies, siliceous clay-shale mixed facies and phosphorous shale facies; (2)the deep-water shelf lithofacies assemblage includes siliceous shale facies and clayey shale facies; (3)the shallow water shelf lithofacies assemblage includes calcareous shale facies and siliceous calcareous shale facies.In the Early Cambrian, the northeastern Tarim region was likely in a semi-deep-water shelf environment, with strong extension and frequent hydrothermal activity.The hydrothermal activity has a dual role in the enrichment of organic matter, which is not conducive to organic matter enrichment in the siliceous shale in the semi-deep-water shelf environment, and to the organic matter enrichment in the phosphorous shale in the semi-deep-water shelf environment.With the continuous sea-level rise, tectonic activity and hydrothermal activity decreased, and the deep-water shelf lithofacies assemblages began to develop.During this period, the organic matter was well preserved.The sedimentation rate was slow, and the paleoproductivity was high.The total organic carbon (TOC) content in the shale was relatively high.During the sedimentation of the Xidashan Formation, the environment was generally of shallow water shelf.During this period, the content of silicic minerals in the sediments decreased, while that of calcareous minerals increased.The preservation conditions of organic matter were poor, the sedimentation rate was high, and the TOC content in the shale was relatively low.We considered that Lower Cambrian phosphorous shale facies and the deep-water shelf lithofacies assemblage in the northeastern Tarim basin represent favorable intervals.

Key words: Tarim Basin, Lower Cambrian, shale lithofacies, sedimentary model

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