摘要： 北非地区古生代位于冈瓦纳大陆北缘,经历古生代冈瓦纳和中新生代特提斯2大裂谷—拗陷—前陆盆地演化旋回,是世界范围内重要的油气富集区之一。基于公开地质资料和油气勘探数据的综合分析,指出北非地区含油气盆地存在克拉通叠加拗陷、裂谷和被动陆缘3种盆地类型,盆地演化经历冈瓦纳期和特提斯期2大成盆旋回,明确了区域构造演化对含油气盆地类型、盆地结构和生储盖发育规律的控制作用。受全球板块构造演化影响,北非地区经历了5期构造演化阶段: (1)晚元古代—早寒武世基底拼合和裂谷发育阶段; (2)寒武纪—早石炭世克拉通内拗陷发育阶段; (3)晚石炭世—早二叠世海西造山阶段; (4)晚二叠世—早白垩世裂谷盆地发育阶段; (5)晚白垩世—现今阿尔卑斯造山阶段。以海西造山作用为标志,形成古生代冈瓦纳期成盆旋回和中新生代特提斯期成盆旋回。北非西部盆地演化以古生代冈瓦纳期旋回占主导,在霍加尔地盾周边形成克拉通拗陷叠加盆地; 东部盆地演化以中新生代特提斯旋回占主导,形成中新生代裂谷盆地和被动陆缘盆地。受盆地发育特征控制,西部克拉通拗陷叠加盆地烃源岩以志留系、泥盆系泥岩为主,储集层包括古生界和三叠系,区域盖层为志留系页岩和上三叠统—下侏罗统蒸发岩; 东部裂谷盆地烃源岩以白垩系、古近系、新近系为主,储集层包括裂谷前古生界和裂谷期中生界、新生界,区域盖层为中新生代裂谷晚期蒸发岩。总的来看,北非地区差异构造演化控制了其含油气盆地形成机制差异和源储盖发育规律。

关键词: 北非油气地质, 冈瓦纳大陆, 特提斯洋, 被动陆缘, 构造演化, 盆地形成

Abstract: North Africa,located on the northern margin of the Gondwana continent in Paleozoic era,is one of the important oil and gas enrichment areas worldwide,experiencing two rift-sag-foreland basin evolution cycles,namely the Paleozoic Gondwana and the Mesozoic Cenozoic Tethys. Based on a comprehensive analysis of publicly available geological data and oil and gas exploration data,this article identified three types of petroliferous basins in the North African region: cratonic superimposed sags,rifts,and passive margin related basins;summarized two basin evolution cycles: Gondwana and Tethyan basin-forming cycle;clarified the controlling role of tectonic evolution on basin types,basin structures,and the development of source,reservoir,and cap rocks. Under the influence of the global plate tectonic evolution,different regions in North Africa have gone through five stages of tectonic evolution: (1)late Proterozoic-early Cambrian basement assembly and rift stage;(2)Cambrian-Early Carboniferous intra-cratonic sag stage;(3)Late Carboniferous-Early Permian Hercynian orogenic stage;(4)Late Permian-Early Cretaceous rift stage; and (5)Late Cretaceous-Present Alpine orogenic stage. Marked by the Hercynian orogeny,the basin features cycles that consist of the Paleozoic Gondwana Cycle and the Mesozoic-Cenozoic Tethyan Cycle. The evolution of the basins in western North Africa are dominated both by the Gondwana and Tethyan cycles,forming superimposed sag basins, while the evolution of the eastern basins are dominated by the Mesozoic and Cenozoic Tethyan cycle,forming the Mesozoic and Cenozoic rift basins and passive continental margin basins. Controlled by the development differences of basins,the source rocks of the western superimposed sag basins are developed mainly in Silurian and Devonian,with including the Paleozoic and Triassic reservoirs. The regional cap rocks are Silurian shale and Upper Triassic-Lower Jurassic evaporate. In comparison the source rocks of the eastern rift basins developed in Cretaceous,Paleogene,and Neogene,with pre-rift Paleozoic and syn-rift Mesozoic and Cenozoic reservoirs. The regional caprocks include the Late Mesozoic and Cenozoic evaporites rocks deposited in the rifting stages. Overall,the differential tectonic evolution in the North African controls the formation mechanism of petroliferous basins and the distribution of source,reservoir,and cap rocks.

Key words: North African petroleum geology, Gondwana, Tethys, passive margin, tectonic evolution, basin formation

中图分类号: 

• P618.130.2