南美洲被动大陆边缘盆地的油气地质特征

南美洲被动大陆边缘盆地是目前世界油气勘探最活跃的地区之一。南美洲被动大陆边缘盆地形成于晚侏罗世-早白垩世冈瓦纳大陆的裂解，经历了前裂谷期、同裂谷期、过渡期、后漂移期4个阶段，发育了多套生储盖组合。其中同裂谷期的湖相源岩为最重要的生油岩，过渡期发育的盐岩层对油气的成藏起着关键作用。近年来，发现的大油气田均位于盐下同裂谷期的陆相碎屑岩和湖相碳酸盐岩储层中。南美东部被动大陆边缘盆地可以按油气潜力分为3类，最有潜力区位于巴西东海岸的中南部盆地群。随着油气勘探技术的进步，在本区进行油气藏勘探具有广阔的前景。

Geologic Characteristic of Hydrocarbon in the Passive Continental Marginal Basins of South America

The passive continental marginal basins of South America have developed into one of the most active regions for petroleum exploration. The passive continental marginal basins of South America formed in Late Jurassic-Early Cretaceous as Gondwana land splitting, underwent pre-rift stage, syn-rift stage, transitional period and drift episode, formed sets of generating rock and reservoir-cover rock compages. Lacustrine generating rock of syn-rift periods is the most important oil source rock. Salt rock of transitional period dominated hydrocarbon reservoirs generation. Almost major fields were found in recent years, situated in continental clastic container rock and lacustrine carbonate rock. The passive continental marginal basins of South America were classified into three levels by hydrocarbon potential. The largest petroleum accumulations are situated in central south offshore of Brazil. Along with exploration technical progress, it presents well feasibility in this area to prospect reservoirs.