巴西陆上盆地类型及油气地质特征

Types and Petroleum Geology Characteristics of Onshore Basins in Brazil

基于巴西陆上沉积盆地基础地质条件,以石油地质理论为指导,运用分析、类比的方法划分盆地类型,并对各类盆地生储盖组合及油气成藏特征进行了研究。分析认为,南美地台经历复杂的构造演化,在巴西境内形成元古宙叠合、显生宙克拉通和中生代萎缩裂谷3大类盆地。元古宙盆地以地层年代久远、构造演化复杂、烃源岩热演化漫长为特征。显生宙克拉通盆地呈现"先断后坳"的演化特征,主体地层序列形成于古生代,有一套普遍发育且受侵入岩影响的烃源岩。中生代萎缩裂谷盆地基础及油气地质两方面均呈现断陷湖盆的特征。通过对巴西陆上盆地区域演化、类型划分、地层及构造特征、生储盖层和成藏特征等方面的探讨,可为中国海外油气区域优选提供一定参考。

Based on basic geological conditions of onshore basins in Brazil and the theory of petroleum geology, basin types are classified and petroleum geological characteristics of different types of basins are studied with methods of analogy and analysis. South America platform underwent a complex tectonic evolution history, and three types of basins formed in Brazil, including Proterozoic superimposed basin, Phanerozoic craton basins, and Mesozoic failed rift basins. Proterozoic superimposed basin is characterized by its ancient strata, complex tectonic evolution history, Proterozoic source-reservoir-cap assemblages, and long thermal evolution history of source rocks. The similarities of the Phanerozoic craton basins are the evolution of ＂from rift to depression＂, Paleozoic main sequences, one set of widespread source rock, and the generation and expulsion both influenced by intrusive rocks. In Mesozoic failed rift basins, both basic and petroleum geology are characterized by the fea- tures of rifted lacustrine basins. Through the research in regional evolution, classification, strata and tectonic characteristics, source rocks, reservoirs, cap rocks, and petroleum accumulation of these onshore basins, we hope the information mentioned above can be a reference in the nation＇s oversea targeting strategies.