ABSTRACT A favorable combination of multiple geological elements in the Lower Cretaceous (Barremian to Aptian), such as organic-rich source rock, porous reservoirs, synrift structures, and very effective evaporite seal, was responsible for forming giant oil accumulations in the pre-salt section of the Santos Basin. The Aptian pre-salt reservoirs, in the Barra Velha Formation (BVF), purpose of this work, consist of layers, which are centimeter-to-decimeter thick of lacustrine carbonates. The sedimentary facies are the products of chemical (e.g., crystal shrubs and spherulites), microbial, and hydrothermal precipitation that commonly appear mixed with reworked grains. Each facies, with greater or lesser presence, depends on the structural framework in which it was deposited. The knowledge of the genesis and geologic history of BVF is essential to understand the formation of the largest deep-water oil reserves in Brazil. The BVF was divided, from base to top, into three cycles: (1) upper-rift, (2) lower-sag, and (3) upper-sag. These cycles make up a second order sequence with flooding-shallowing upward cycles. The association of calcitic spherulites with hydrated talc and stevensite indicates precipitation in an evaporitic-alkaline lake, rich in magnesium and calcium, oversaturated in calcite and with a salinity greater than 3500 ppm but less than 35,000 ppm. The complexity of the facies arrangement in the lake reflects deposition in a proximal environment influenced by evaporation; hydrothermal activity, with complex water chemistry; oscillating groundwater; and frequent lake-level fluctuations. The initial rifting of the Santos Basin was accompanied by extensive volcanic activity that lasted throughout the whole rifting phase, up to the upper-sag phase, influencing both the geological evolution and paleophysiography as well as the chemical characteristics of the lake system.

ABSTRACT The Mero Field is one of the most recent large oil discoveries in the pre-salt play of Brazil, and its original oil in place (OOIP) is estimated at 11.94 bboe. It was discovered 10 years ago by the pioneer well 2-ANP-2A-RJS, drilled by Petrobras in partnership with the National Agency of Petroleum, Natural Gas and Biofuels (ANP). The Mero Field was part of the Libra Block, awarded in the first Brazilian bidding round under a production sharing agreement to Petrobras (operator), Shell, Total, CNOOC, CNPC, and PPSA. Geological and stratigraphic analysis based on public wells drilled in the Mero Field and high-quality 3-D seismic data mapping show wide variation in the facies distribution of microbial carbonate and coquina reservoirs. Thickness variation in coquinas and shale intercalation can be observed in well correlation and are associated with paleo basement highs. Igneous rocks are common in the reservoir. Petrophysical evaluation indicates significant variations in fluid composition between Mero Field and Libra Complex. Although the Mero Field is composed of good-quality oil (29º API), the Libra Complex consists mainly of gas condensate with high carbon dioxide (CO 2 ) content, demonstrating that these structures are disconnected. Petrophysical data also indicate that Mero Field is characterized by two compartments, with different oil–water contacts (OWCs). It can be explained by semipermeable barriers probably because of internal variation in facies distribution. This chapter aims to present a general overview of the geological and petrophysical characteristics of the Mero Field based on data that have just become public.

ABSTRACT The Pre-Salt Polygon was established in 2010, encompassing an area of about 150,000 km 2 offshore southeast Brazil. It covers parts of both the Campos and Santos basins and contains giant and supergiant discoveries found in mid-to-late Aptian reservoirs. Three fiscal regimes coexist within this area: concession, production sharing, and onerous transfer of rights. Pré-Sal Petróleo S.A. (PPSA) is a state-owned company created in 2013 and represents the Brazilian government’s interests within the Pre-Salt Polygon. It has three main objectives: (1) to manage production sharing agreements, (2) to represent the Brazilian government in unitization agreements involving open acreage (noncontracted and strategic areas), and (3) to trade the Brazilian government’s share of oil and natural gas. Unitization is a common feature within the Pre-Salt Polygon, and PPSA is a key player in the process with a portfolio of seven unitization agreements already executed, two under negotiation, and 11 others in early stages of discussion with some of the world’s most important oil companies. This chapter presents a brief description of the Brazilian unitization process with open acreage within the Pre-Salt Polygon, highlighting its peculiarities and challenges, and the important role played by PPSA.

ABSTRACT Although dating back thousands of years, including a brief quote in the Bible, petroleum began its use for industrial purposes only in the last century. In Brazil, the implementation of integrated activities contributed to the progressive development of the hydrocarbon sector based on geological research, predominantly conducted through the use of surface geology analysis, gravimetric and magnetometry data, and drilling of poorly defined prospects. After consolidating some small accumulation discoveries along with new demand growth and the advent of new indirect investigation technologies, unforeseen economic perspectives opened to Brazil and a national company was established to be responsible for managing and running the oil exploration and production activities. Although strengthened by the years of research, possession and control of the oil business monopoly, high investments, and accumulated technical experiences, Petrobras was no longer capable of handling the oil source potential that the Brazilian sedimentary basins could deliver. Therefore, envisioning production beyond the possibilities of only one controlling company, despite being large and technically capable, a law was enacted in 1997, the Petroleum Law, which established the National Agency of Petroleum, Natural Gas and Biofuels (ANP) and opened the Brazilian oil business to foreign capital investments ( ANP, 1988 ). This law unfolded an exploration race in the sector that culminated in the greatest hydrocarbon discoveries ever made in Brazil, the Lula oil field. The new oil business legal framework and the country’s attractive economy brought investments to the Brazilian sedimentary basins, resulting in the collection of six petabytes of technical data and almost 380,000 boxes, of cutting samples and conventional cores, all under ANP custody. By encouraging the use of these data, as well as promoting the acquisition and production of new information from the Brazilian sedimentary basins, the country seeks to reheat the basic research market, implementing policies and investments to enhance exploration and production activities, new data acquisition and reprocessing of existing data libraries, optimizing the cost of technical data access, improving service delivery, and the relationship with regulated agents.

Abstract The Parnaíba Basin is a Paleozoic cratonic basin located in NE Brazil. Despite exploration in the Parnaíba Basin having undergone a long period of stagnation, it is now one of the most prolific natural gas producing basins in Brazil. Production from this basin is c . 5.6 million m 3 day −1 from three established gas fields, with another four fields in development and eight ongoing discovery assessment plans (in January 2017). This success is the result of activity on exploration concessions, both the investments of the Brazilian National Petroleum Agency (ANP) and concessionaires operating in the basin. ANP’s investments were decisive in the definition of the offered areas in the bid rounds and, more importantly, in our understanding of the structural and stratigraphic framework through systematic data acquisition, which helped to define an exploration model for the basin. The Parnaíba Basin received investments of c . US $100 million from ANP and the preliminary results from projects located in the SE of the basin suggest the need for a new exploration model for this area, which was probably affected by the Trans Brazilian Lineament. In this model, the petroleum system would include Ordovician–Silurian components.