«Geology, geophysics and development of oil and gas fields»

PROSPECTS FOR OIL AND GAS POTENTIAL OF THE CAMPOS BASIN IN THE SOUTH-EAST OF BRAZIL

UDC: 553.98(81)
DOI: 10.33285/2413-5011-2021-7(355)-13-19

Authors:

¹ P.P. Shirshov Institute of Oceanology Russian Academy of Sciences, Moscow, Russian Federation

Keywords: oil, GaS, basin, continental slope, subsalt, post-salt

Annotation:

Analysis of more than 50 big hydrocarbon fields, mainly oily in the deep-water part of the Campos basin, revealed the tendency of these large fields lying in the productive belt of oil-pay, extending in the limit of sea depth from 400 till 2500 m (possibly 3000 m and more), in the system of external depressions, which are stretching along the lower part of the continental slope. This belt perhaps is spreading to the north. All the fields of this belt, judging by their reserves, are estimated as large and gigantic ones. The exploration works have already been conducted in this belt for the last 10...15 years in the subsalt formation: 21 fields were discovered in the Campos basin. It should be noted that 48 % of the total hydrocarbon production of the country is formed by the subsalt carbonate deposits of the Aptian age, located on the continental slope, 44 % of post-salt rocks are partially found on the continental slope and shelf and only 8 % of hydrocarbons produced on land. The deepwater sub-salt Aptian formations in Brazil are essentially unique in the world. The giant hydrocarbons accumulations have been discovered in them for the last decades, which nearly doubled the country’s oil and gas reserves, bringing the total recoverable reserves of oil and gas to more than 3 billion t and 4.7 trillion m3 correspondingly. The geology of sub-salt formations is closely related with the tectonic movements which occurred during the breakup of Gondwana super continent into the South American and the African continents. This took place 150 million years ago in the Early Cretaceous time. The salt of the Aptian formation is an excellent cap rock. The sub-salt reservoirs by their characteristics are simply super, oil is light, sweet and the source rocks are enriched by an organic matter. The Aaptian salt thickness spreading is limited, changing from the basin to the basin, the widest part of the salt is concentrated in the Santos basin - 400 km long and 2000 m thick. Further on, in the north direction, the thickness decreases and the width narrows down, and in the Sergipi Alagoas basin it already reaches 100 m.

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