委内瑞拉马拉开波盆地构造演化对油气的控制

委内瑞拉马拉开波盆地自中生代以来经历了裂谷、被动大陆边缘、前陆盆地和马拉开波向斜4个演化阶段,对油气的生成运移聚集起到了重要的控制作用。从石油地质条件对构造作用的地质响应出发,探讨了构造演化对盆地烃源岩、储层、圈闭类型以及油气运聚的控制作用。受构造作用影响,烃源岩发育南薄北厚,沉积中心也发生迁移,形成3个向不同方向增厚的碎屑岩楔体,构成了马拉开波盆地的主要储层,并引起烃源岩埋深的变化,导致生烃条件的多期变化。同时,构造作用还控制了不同层系主要的圈闭类型,而早期与裂谷作用相关的断层在后期构造作用下的复活或反转,为油气提供了主要的运移通道。此外,盆地区域性的倾斜也为油气的运移提供了大的构造格局。

Controlling of Tectonic Evolution on Hydrocarbon Occurrence of Maracaibo Basin, Venezuela

Maracaibo Basin has experienced four tectonic phases including rifting,passive continental margin,foreland basin and Maracaibo syncline since Mesozoic,which played a significant role in the controlling of oil generation,migration and accumulation.Based on the response of hydrocarbon geologic condition to tectonic events,the author discussed the controlling of tectonic evolution on the formation of source rock,reservoir,traps as well as oil migration and accumulation.Impacted by tectonic activities,the thickness of source rock interval varied,with thicker to the north and thinner to the south.Depocentre transferred as well,formed three clastic wedges thickening in different directions,which comprised the major reservoirs of Maracaibo Basin.Besides,the change of buried depth led to the multi-phase oil generation of source rock.Also,tectonic activities controlled the trap types of different layers.The revival and reversal of faults related to early rifting during the later tectonic activities offered the main pathway for oil migration.In addition,regional tilt of the layers set up a basinal structural framework for the oil migration.