GRAVITY DÉCOLLEMENT STRUCTURAL SYSTEM IN OFFSHORE BASINS OF NORTHEAST BRAZIL

The gravity décollement structure is a typical structural style in passive continental margin basins. This paper, based on mechanism analysis of gravity décollement structures, suggests that the gravity décollement structures in Northeast Brazil are mainly distributed in the deepwater area of the Foz do Amazon, Para-maranihao and Barreirinhas Basins. Then, the characteristics of gravity décollement structure were studied to find out the structural and trap types in stretch zone, transition zone and thrust zone. Among the basins in offshore Northeast Brazil, the Foz do Amazon basin has the most typical gravity décollement structure and various trap types. The stretching and thrust structures, which are controlled by gravity gliding since late drift period, are the main trap types. Finally, this paper discussed the roles of gravity décollement structure in hydrocarbon accumulation in the Foz do Amazon basin, and further analyzed the exploration potential of gravity décollement zone in this basin.