关键词: 隐蔽油气藏, 勘探潜力, 油气地质, 坎普斯盆地, 巴西

Abstract:

In recent years,Brazil offshore has become one of the hot areas atracting international investments.In order to lower exploration risk,we studied the basic elements of total petroleum system in Campos Basin,including source rocks,reservoir rocks,traps and seals by integrating geophysical prospecting and well data,analyzed four kinds of typical subtle traps discovered in this basin,and proposed that subtle traps have large exploration potentials in this basin.Since the formation of the basin in the Early Cretaceous,it has experienced three evolution stages,including rifting,early drifting and late drifting stages,and developed three megasequences of non-marine,transitional and marine facies respectively.Three sets of source rocks possibly occur in the strata from the Lower Cretaceous to the Neogene in Campos Basin and the most important source rocks is the Lower Cretaceous Lagoa Feia Formation,from which all the discovered oil/gas in the basin were sourced.Various oil/gas reservoirs have been discovered in all the formations from the Lower Cretaceous to the Miocene,including fractured basalt in the basement,bioclastics in the Lagoa Feia Formation,carbonates in the Maca? Formation,clastic reservoirs and marine turbidites in the Upper Cretaceous-Oligocene.Subtle traps are very important in the basin and are dominated by stratigraphic traps including overlap traps,buried-hill traps and unconformity traps.More attention should be paid to the exploration of subtle traps,especially lithologic traps and fractured subtle traps.

Key words: subtle trap, exploration potential, petroleum geology, Campos Basin, Brazil