Seismic characteristics and distribution of hydrothermal vent complexes in the Cretaceous offshore rift section of the Campos Basin, offshore Brazil

Abstract

Hydrothermal vents are structures that occur close to volcanically active areas. Their occurrence can have considerable impacts on the evaluation of the oil reserves of a basin. In the Campos Basin, eastern Brazilian continental margin, no hydrothermal vents have been previously recognized and related with magmatic events on seismic sections. This work aims to map the hydrothemal vents, ducts and associated intrusive bodies observed in the rifte section. With the use of 2D seismic data and a well with lithologic information, the occurrence of ten hydrothermal vents and seven ducts were mapped and the interval with volcanic intrusive rocks was characterized. The identification of intrusive rocks in seismic data is given by reflectors with high amplitude and disk or half-moon geometry with abrupt endings. The vent geometries shows dome and eye-shaped types and the ducts are fault-related, downward-tapering cone type. This study highlights new geological elements that can influence the petroleum systems of the Campos Basin, such as the identification of hydrothermal vents in seismic sections and the correlation with regional tectono-magmatic events.