石油与天然气地质 ›› 2017, Vol. 38 ›› Issue (1): 39-48,143.doi: 10.11743/ogg20170105

• 油气地质 • 上一篇    下一篇

早始新世极热气候时期湖盆水体性质及生烃环境——以东营凹陷古近系孔店组为例

刘萍1, 谭先锋2,3, 陈青2,3, 王佳2,3, 梁迈3, 王萍3, 王伟庆4   

  1. 1. 成都理工大学 沉积地质研究院, 四川 成都 610059;
    2. 复杂油气田勘探开发重庆市重点实验室, 重庆 401331;
    3. 重庆科技学院 石油与天然气工程学院, 重庆 401331;
    4. 中国石化 胜利油田分公司 地质科学研究院, 山东 东营 257015
  • 收稿日期:2016-11-27 修回日期:2016-12-20 出版日期:2017-02-28 发布日期:2017-02-27
  • 通讯作者: 谭先锋(1982-),男,博士、副教授,沉积地质与古环境。E-mail:xianfengtan8299@163.com。 E-mail:xianfengtan8299@163.com
  • 第一作者简介:刘萍(1978-),男,博士研究生,沉积地质与古环境。E-mail:liuping@cdut.edu.cn。
  • 基金项目:

    国家自然科学基金项目(41202043);中国石油科技创新基金项目(2014D-5006-0108);重庆市基础科学与前沿技术研究项目(cstc2016jcyjA0606)。

Water redox conditions and environment for source rock deposition in lacustrine during the Initial Eocene Thermal Maximum(IETM): A case study on the Paleogene Kongdian Formation in the Dongying Sag

Liu Ping1, Tan Xianfeng2,3, Chen Qing2,3, Wang Jia2,3, Liang Mai3, Wang Ping3, Wang Weiqing4   

  1. 1. Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu, Sichuan 610059, China;
    2. Chongqing Key Laboratory of Complex Oil and Gas Exploration and Development, Chongqing 401331, China;
    3. Chongqing University of Science and Technology, Chongqing 401331, China;
    4. Geological Scientific Research Institute of Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257015, China
  • Received:2016-11-27 Revised:2016-12-20 Online:2017-02-28 Published:2017-02-27

摘要:

早始新世极热气候(IETM)事件严重影响了海洋和湖泊的水体性质和生物活动。依据钻井岩心、元素分析、有机碳同位素与有机碳含量等实验结果,研究了东营断陷湖盆早始新世时期的湖泊水体氧化还原变化和古生产力条件,发现湖盆早期出现了较强的还原性,之后逐步恢复其氧化性。极热气候事件引起的湖水氧化还原界面的波动变化改变了其氧化还原格局,造成氧化还原环境与湖水深度变化的“不协调性”。湖盆早期具有较高的生产力,随后迅速降低之后逐渐增高,生产力的最低时期与极热气候(IETM)事件发生时期比较一致。由此证实了湖泊的时空波动演化经历了古新世-始新世时期的极热气候(IETM)事件,该事件具有明显的沉积记录和生物地球化学响应,决定了原始湖盆的水体氧化还原性质和生命活动过程,改变了整个湖盆的氧化还原结构。极热气候引起的湖水缺氧咸化造成了湖泊生产力的短暂降低,而随着恢复期的增氧作用的加强,生产力得到了极大的恢复,尤其是沙河街组四段有机碳含量较高,具有较高的生产力,成为主要的生油层和致密油气产层。

关键词: 氧化还原, 古生产力, 极热气候, 早始新世, 孔店组, 东营凹陷

Abstract:

The Initial Eocene Thermal Maximum(IETM) has seriously affected the water quality and biological activities of sea and lake.Based on the experimental results of drilling cores,elemental analysis,organic carbon isotope and TOC,the lakewater oxidation-reduction conditions and paleoproductivity of Dongying terrestrial fault basin during early Eocene has been studied in this paper.It turned out that the lacustrine was strongly reductive but resumed oxidation environment afterward.The fluctuations of redox interface caused by the extreme climate events changed the lacustrine redox pattern,which resulted in the "disharmony" of the oxidation-reduction variation along the water depth.The productivity of the lacustrine was high in the early time,followed by a rapid decrease but increased progressively again.The lowest productivity period is basically consistent with the IETM.It has confirmed that the Initial Eocene Thermal Maximum (IETM) has affected the spatial and temporal fluctuation of the lacustrine.This event has obvious sedimentary record and biogeochemical response,which determines water oxidation-reduction and the bio-mass activities of the original basin.The hypoxia of lacustrine caused by thermal maximum resulted in the temporary decrease in productivity.However,productivity has been greatly restored with the sufficient oxygen supply after the event.This is especially demonstrated in the No.four section of Shahejie Formation with the higher TOC content and the productivity,and thus becomes the main reservoir of tight oil and gas production.

Key words: redox, paleoproductivity, IETM, Early Eocene, Kongdian Formation, Dongying Sag

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