China Petroleum Exploration ›› 2020, Vol. 25 ›› Issue (4): 43-51.DOI: 10.3969/j.issn.1672-7703.2020.04.005

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Types of rift basins in Africa and their hydrocarbon accumulation characteristics

Zhang Guangya1, Yu Zhaohua1,2, Huang Tongfei1, Cheng Dingsheng1, Chen Zhongmin1, Chen Xi1, Liu Hong1, Song Chengpeng1   

  1. 1 PetroChina Research Institute of Petroleum Exploration & Development; 2 China National Oil and Gas Exploration and Development Corporation Ltd.
  • Online:2020-07-14 Published:2020-07-14
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Abstract: Rift basins in Africa are of many types, are in many stages of geological development, and often possess rich oil and gas resources. In order to guide oil and gas exploration and strategic selection of favorable areas, this study analyzes the types and formation stages of rift basins in Africa. The hydrocarbon accumulation characteristics of a number of key rift basins are also described. The results show that: (1) there are three principal stages of rift basins in Africa: Paleozoic, Mesozoic, and Cenozoic. A number of rift systems are formed: the Karoo rift system, the intracontinental rift system in West and Central Africa, the continental margin rift system in North Africa, and the Red Sea-Gulf of Aden-East African rift system. Prototype basins can be divided into active rift basins and passive rift basins according to genesis type. Active basins are related to thermal-uplift and tension and passive basins are related to strike slip or regional extensional stress fields. Basins can be divided into intracontinental rift basins, intercontinental rift basins, aulacogen rift basins, and continental margin rift basins according to structural position and basement characteristics. (2) The basins have different petroleum geological characteristics and hydrocarbon enrichment laws as a result of variations in tectonic evolution, sedimentary filling, and structure. In North Africa, high-quality marine source rocks are developed in continental margin rift basins. The dominant petroleum system is a Mesozoic-Cenozoic system. Oil and gas are primarily accumulated in faulted horst areas formed by differential subsidence. In Central and West Africa, multi-stage superimposed rifts are developed in intracontinental rift basins with a variety of major plays. Oil and gas are distributed in Paleogene, Upper Cretaceous, and Lower Cretaceous formations. In East Africa, intracontinental rift basins formed late and are dominated by a Cenozoic petroleum system.

 

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