南美洲含油气盆地和油气分布综述

南美洲是世界上的主要油气产区之一,近年来取得了一系列重大勘探突破。2007年以来,桑托斯盆地盐下一系列巨型油气田的发现表明南美洲,特别是被动陆缘盆地深水盐下层系有着巨大的勘探潜力。以获取的最新油气田储量资料为基础,探讨了南美洲的油气资源在不同类型盆地、不同地区和不同层系的分布特征。统计分析表明前陆盆地油气最富集,其次是被动陆缘盆地。南美洲的前陆盆地沿安第斯山展布,南段和北段为新生代前陆盆地,中段为古生代前陆盆地。南段、中段和北段前陆盆地的主要储集层分别为侏罗系—白垩系、石炭系和白垩系—新近系。经历了被动陆缘演化阶段的前陆盆地是南美洲油气最富集的盆地,典型的代表为东委内瑞拉盆地和马拉开波盆地。被动陆缘盆地分布于南美洲大陆的东部沿海区,油气主要聚集于白垩系、古近系和新近系。在被动陆缘盆地中,发育有蒸发岩的盆地油气更为富集,坎波斯盆地和桑托斯盆地是这类盆地的典型代表。

Synopsis of Petroliferous Basins and Petroleum Distribution in South America

South America is one of the major oil and gas producing regions.It has recorded a number of significant exploration breakthroughs recently.Since 2007,several giant fields have been discovered in the sub-salt sequences in the Santos Basin,which indicates the promising exploration potential of sedimentary basins in South America,particularly deep water sub-salt play in the passive margin basins.Based on the up to date reserve data of oil and gas fields,this paper documents the oil and gas distribution features in terms of basin type.It also characterizes the areal and stratigraphic distribution of discovered oil and gas reserves.In South America,the foreland basin is the basin type with the richest oil and gas resources,followed by the passive margin basin.The foreland basins are located along the Andes Mountains.The ones in the northern and southern sectors are Cenozoic foreland basins and those in the middle sector Paleozoic foreland basins.The foreland basins which evolved from a proceeding passive margin basin development stage are the most prolific oil and gas-bearing basins.They are represented by the East Venezuela and Maracaibo Basins.Along the Andes foreland basins,the main reservoir intervals vary from the Jurassic-Cretaceous in the south,through the Carboniferous in the middle,to the Cretaceous-Tertiary in the north.The passive margin basins lie along the South Atlantic margin.In this type of basins,oil and gas are mainly concentrated in the Cretaceous-Tertiary.Of them,the ones with evaporites tend to be richer in oil and gas and they are represented by Campos and Santos Basins.