Análise estratigráfica das seções rifte e pós-rifte offshore na região do Campo de Pescada, Bacia Potiguar, Margem Equatorial Brasileira

Abstract

The Potiguar Basin comprises one of the basins of the Cretaceous Continental Rifts system, an important event that occurred in the implantation of the Brazilian Equatorial Margin in Northeastern Brazil, evincing a noteworthy region of hydrocarbon accumulations. In order to better understand the tectonic-stratigraphic evolution of the Potiguar Basin, this work aims to contribute to the study of sedimentary record of the basin's rift and post-rift sections through the stratigraphic analysis of wells and seismic data. The study area is settled by the post-stack seismic volume 0208_PESCADA, in the Pescada Field region, comprising the wells and seismic lines scrutinized. The first phase of interpretation, the 1D analysis of six exploratory wells, made it possible to characterize the main lithofacies and depositional systems of Pendência, Pescada and Alagamar formations, and also to recognize the main units of sequence stratigraphy, such as cycles, key surfaces and systems tracts, with the definition of three depositional sequences on a regional scale. The 2D interpretation displays a structural arrangement consisting of grabens/semi-grabens, internal highs, and an important fault system of E-W to WNW-ESE trends that affect the layers and gave rise to additional structures of rift context. Furthermore, the stratigraphic framework enabled the identification of the main chronostratigraphic surfaces, seismic facies and seven tectonic system tracts that comprise the rift and post-rift sections and reflect the tectonic progress, from the initial rifting, two stages of high/low tectonic activity and a final stage of low tectonic proportions on the basin installation. The integration of all results reveals the effective application of sequence stratigraphy in the study area and verifies its good response in understanding the Potiguar Basin and Brazilian Equatorial Margin evolution.