ABSTRACT As the operator of several exploratory blocks in ultradeep waters, Petrobras was responsible for many presalt oil discoveries in Santos Basin such as Tupi, Carioca, Guará, and Iara. In partnership with the National Petroleum, Natural Gas and Biofuels Agency (ANP), Petrobras drilled well 2-ANP-2A, which resulted in the Libra discovery. In 2013, Libra was offered in the first bidding round executed by the Brazilian government under the new Production Sharing Contract for presalt areas. The winning consortium is comprised of Petrobras (operator), Shell, Total, CNOOC (China National Offshore Oil Corporation), CNPC (China National Petroleum Corporation), and PPSA (Pré-Sal Petróleo S.A.). The Libra discovery is sitting over a structural trap of about 550 km 2 (212 mi 2 ) closure at the Aptian top reservoirs level presenting a maximum oil column that can reach up to 900 m (2953 ft). The main reservoirs are lacustrine carbonates, deposited from the Neobarremian until the Aptian. Preliminary estimates indicate a volume of oil in place between 8 and 12 billion BOE. The development proposed for Libra started with Phase 0, in 2014, and is focused on information gathering, including appraisal wells, extended well tests (EWT), early production systems (EPS), and a pilot project. Phase 1 encompasses the definitive production systems and is expected to start in 2022 and finish in 2030.