地学前缘 ›› 2018, Vol. 25 ›› Issue (2): 24-32.DOI: 10.13745/j.esf.2018.02.003

• 油气勘探新领域 • 上一篇    下一篇

东非被动大陆边缘盆地演化及大气田形成主控因素:以鲁武马盆地为例

张光亚,刘小兵,赵健,温志新,张荻萩,王兆明,张磊,马锋,陈曦   

  1. 1. 中国石油勘探开发研究院, 北京 100083
    2. 中国石油经济技术研究院, 北京 100724
  • 收稿日期:2017-09-10 修回日期:2017-10-20 出版日期:2018-03-15 发布日期:2018-03-15
  • 作者简介:张光亚(1962—),男,博士,教授级高级工程师,主要从事盆地构造分析和石油地质综合研究工作。E-mail:zgy@petrochina.com.cn
  • 基金资助:
    国家科技重大专项“大型油气田及煤层气开发”(2011ZX05028);中国石油天然气股份有限公司重大科技专项“全球油气资源评价与利用研究”(2013E0501);中国石油天然气集团有限公司重大科技项目“苏丹Muglad盆地精细勘探领域评价与目标优选”(2015D-0909)

Passive continental margin basin evolution of East Africa and the main controlling factors of giant gas fields: an example from the Rovuma Basin.

ZHANG Guangya,LIU Xiaobing,ZHAO Jian,WEN Zhixin,ZHANG Diqiu,WANG Zhaoming,ZHANG Lei,MA Feng,CHEN Xi   

  1. 1. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China
    2. CNPC Economics & Technology Research Institute, Beijing 100724, China
  • Received:2017-09-10 Revised:2017-10-20 Online:2018-03-15 Published:2018-03-15

摘要: 东非被动大陆边缘盆地近年来发现了一系列大气田,主要分布于鲁武马盆地,其可采储量达3.8×1012 m3。盆地经历了卡鲁裂谷期、马达加斯加裂谷期和马达加斯加漂移期等3期构造演化。其中,马达加斯加裂谷期形成下侏罗统—中侏罗统湖相滨浅海相烃源岩,于早白垩世进入生油门限,晚白垩世达到生油高峰,渐新世进入生气窗。受马达加斯加漂移期东非陆上断裂系统活动影响,大量富砂沉积物以块体搬运和深海滑塌方式向深水区堆积,形成了盆地内面积广、厚度大、岩性相对均一且物性良好的超大型深水重力流沉积砂体;漂移期海相泥页岩则为良好的区域性盖层。东非陆上早期隆升和三角洲进积作用使鲁武马盆地形成重力滑动和盐底辟构造,渐新统—上新统内形成东非被动陆缘正断层带(EANFZ)和逆冲断层带(EATFZ),下伏中—下侏罗统烃源岩生成油气沿正断层和深水区逆冲断层向上运移,聚集于构造岩性地层、构造圈闭中,形成大气田。

关键词: 盐底辟, Davie断裂带(DFZ), 卡鲁裂谷期, 马达加斯加裂谷期, 马达加斯加漂移期, 东非被动陆缘正断层带(EANFZ), 东非被动陆缘逆冲断层带(EATFZ)

Abstract: Many giant gas fields, concentrated in the Rovuma Basin of the East Africa passive margin basins, were discovered in recent years with a total recoverable reserves up to 3.8 trillion cubic meters. The Rovuma Basin has gone through three stages of tectonic evolution, i.e. the Karoo rift, Madagascar rift and Madagascar drift. The LowerMiddle Jurassic lacustrine and shallow sea source rocks formed in the Madagascar rift period, and came to the oil window, the peak of oil generation and the gas window, in the Early Cretaceous, the Late Cretaceous and the Oligocene, respectively. Affected by the East Africa onshore faults during the Madagascar drift period, massive sandrich sediments accumulated towards the deep water region by way of block transport and deep water sliding. It formed a super giant deepwatergravityflow sandbody, wide and thick, with relatively uniform lithology and favorable physical property within the basin. The marine mudstone during the Madagascar drift period provided a good regional overlying strata. The early uplift onshore East Africa and delta progradation led to the formation of gravity sliding and salt diapir within the Rovuma Basin, and subsequently the East Africa normal fault zone (EANFZ) and the East Africa thrust fault zone (EATFZ), between the Oligocene and Pliocene. As a result, hydrocarbons from the underlying LowerMiddle Jurassic source rocks migrated upward along the normal and deep water thrust faults, accumulating in the structurallithologicalstratigraphy and structural traps to form the giant gas fields.

Key words: salt diapir, Davie Fault Zone (DFZ), Karoo rift, Madagascar rift, Madagascar drift, East Africa normal fault zone (EANFZ), East Africa thrust fault zone (EATFZ)

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