Structural geology and deformation analysis in the Búzios-Itapu area, Santos Basin — offshore Brazil

Abstract

Despite their proximity, the Búzios and Itapu oil fields in the Santos Basin have different structural configurations. The study of the deformation pattern of the area and the relationship of the observed structures with the tectonic evolution of the basement is important to understand the geologic setting and evolution of the studied oil fields. In this work, a 3D PSDM seismic volume calibrated with well data was used to characterize the different types of structures, the distinct structural domains that occur in the Pre-Salt of the Búzios and Itapu fields, and the relationship between the basement trends and the structures in the sedimentary section. The Búzios field is formed by a series of half-grabens and horsts elongated in the NE-SW and NW-SE trends. Over the structural highs, a wide carbonate platform was developed. The Itapu field is a structural high related to a single elongated half-graben with a N-S main trend. The main structural pattern in the area is defined by normal faults that indicate an extensional process, typical of rift evolution. However, there are several structures that show indication of oblique-like deformation with strike-slip displacements, throughout the studied area. A very important issue is the discussion of the hierarchy of the observed structures, both rift extensional structures, and the oblique-like ones.