Dados da Submissão

Título

PELOTAS BASIN HYDROCARBON EXPLORATORY POTENTIAL

Texto do resumo

The Pelotas Basin is located along the southern margin of the South Atlantic. It records the Gondwana supercontinent break-up and opening of the South Atlantic Ocean. Recently, the basin has heightened attention for hydrocarbon exploration. This interest is driven by significant hydrocarbon discoveries in the Orange Basin (Namibia), where the Venus, Graff, Jonker, La-Rona, Lesedi, and Mopane wells revealed Upper Cretaceous reservoirs. These reservoirs are located in basin floor fan systems, just above the Seaward Dipping Reflectors (SDRs), with predominantly Aptian/Turonian marine shale source rocks. Such discoveries led to the establishment of a new proven petroleum system in the South Atlantic and renewed hydrocarbon exploration investments in the conjugate margin basins, including the Pelotas Basin and Punta del Este. In this context, the present work aims to address the exploratory potential of the Pelotas Basin through the analysis and interpretation of 2D seismic and well data. To do so, we first carried out seismic well-tie, using well data (sonic and density) to enable the positioning of biostratigraphic markers in seismic sections. Then, we did the seismic interpretation aided by seismic attributes and subsequent creation of thickness chronostratigraphic maps of interest intervals. Thickness maps obtained contribute to understanding the depositional history of the basin. This study revealed regions with significant thickness in the Cretaceous interval, such as the northern sector of the Pelotas Basin. This sector is characterized by the highest residual total organic carbon content identified in the basin, reaching almost 4% in the Turonian interval. Cretaceous speculative hydrocarbon plays are identified in the seismic sections. These plays are associated with turbiditic systems, basement volcanic highs, and seismic features similar to those in the Orange Basin. These features comprise high-amplitude reflectors just above the SDRs in the seismic section. The difference lies in the thickness of the Cretaceous package in the Pelotas Basin, which is thinner than in the Orange Basin. On the other hand, the Pelotas Basin has a thick package of SDRs, primarily in the northern portion. These components could imply minor differences in petroleum system evolution. Therefore, the Pelotas Basin presents an important potential for hydrocarbon exploration, which is supported by organic geochemistry data, seismic data interpretation, and hydrocarbon finds in the conjugated margin. These factors reinforce the basin’s potential, which passes through a new exploratory phase.

Palavras Chave

seismic data; speculative prospects; source rocks