Table of Contents
ISRN Geophysics
Volume 2014, Article ID 384752, 19 pages
http://dx.doi.org/10.1155/2014/384752
Research Article

Heat Flow in the Campos Sedimentary Basin and Thermal History of the Continental Margin of Southeast Brazil

1Observatório Nacional-ON/MCT, Rio de Janeiro, Brazil
2Superintendence for Petroleum and Gas/DPG, Empresa de Pesquisa Energética (EPE), Rio de Janeiro, Brazil

Received 21 February 2014; Accepted 27 March 2014; Published 27 April 2014

Academic Editors: E. Liu and A. Tzanis

Copyright © 2014 Roberta A. Cardoso and Valiya M. Hamza. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Bottom-hole temperatures and physical properties derived from geophysical logs of deep oil wells have been employed in assessment of the geothermal field of the Campos basin, situated in the continental margin of southeast Brazil. The results indicate geothermal gradients in the range of 24 to 41°C/km and crustal heat flow in the range of 30 to 100 mW/m2 within the study area. Maps of the regional distributions of these parameters point to arc-shaped northeast-southwest trending belts of relatively high gradients and heat flow in the central part of the Campos basin. This anomalous geothermal belt is coincident with the areas of occurrences of oil deposits. The present study also reports progress obtained in reconstructing the subsidence history of sedimentary strata at six localities within the Campos basin. The results point to episodes of crustal extension with magnitudes of 1.3 to 2, while extensions of subcrustal layers are in the range of 2 to 3. Thermal models indicate high heat flow during the initial stages of basin evolution. Maturation indices point to depths of oil generation greater than 3 km. The age of peak oil generation, allowing for variable time scales for cooling of the extended lithosphere, is found to be less than 40 Ma.