The study area is located in Tupi field in Santos Basin. It is one of the largest Brazilian maritime basins. They were formed during the Neocomian period as a result of the process of separation of the supercontinent Gondwana. Detailed description work was carried out on plug samples from the five wells in the Tupi oil field to understand carbonate facies and their distribution better. The samples were obtained from the Exploration and Production Database (BDEP/ANP). The facies analysis followed the classification standards proposed by Gomes et al. (2020). The results showed the diversity of facies, with significant variability along the depth of each well, which are related to different depositional environments. In situ, facies with a higher proportion of mud indicate conditions with lower flow energy. At the same time, a greater abundance of spherulites and shrubs may signal shallow water environments, providing carbonate precipitation for forming these structures. Reworked facies indicate environmental conditions with high flow energy, wave and wind action.
The study area is located in Tupi field in Santos Basin, in the southeastern part of the Brazilian continental margin, occupying an area of nearly 352,000 km2 and water depths of up to 3,000 m. It is one of the largest maritime basins in Brazil, and, being situated approximately 230 km from the Brazilian coast, it extends along the coasts of the states of Rio de Janeiro, São Paulo, Paraná and Santa Catarina (Moreira et al., 2007) (Fig. 1).
The formation process of Brazilian marginal basins had its origins during the rupture of the Gondwana Supercontinent in the Neocomian period, approximately 135 Ma. ago, and the supercontinent rifting resulted in the separation of the African and South American continents and the opening of the South Atlantic Ocean. During the evolution of Brazilian marginal basins, large lacustrine carbonate deposits were covered by an extensive evaporite layer that served as a trap for significant quantities of hydrocarbons, known as the Pre-salt section. The carbonate deposits received worldwide attention and became relevant due to the economic discovery of this considerable accumulation of oil in the Santos Basin and the confirmation of the exploratory viability of these new oil reservoirs.
