Ever since the end of the monopoly in 1998, the areas known today as Libra and Mero were thought of as high potential plays. Back then, Petrobras chose to keep them, under the block BS-4. However, no drilling effort was made, and the area was returned to the union in 2003.
In 2004, part of the now Mero and Búzios fields was offered on the 6th Bid Round as the block S-M-421, but there was no interest for the assets.
Only in 2010, after the pre-salt discoveries, ANP made one of the biggest investments in its history financing the drilling of the well 2-ANP-2-RJS. This well finally proved the presence of hydrocarbons and helped ANP establish a new type of bid called Production Share.
The Libra block was offered on the 1st Production Share Bid Round (2013), with estimated reserves of 25 to 40 Bboe. The winner consortium was Petrobras, Shell, Total, CNOOC International, and CNPC.
Nowadays – 7 years after the bid – more than 40 wells were drilled on the original structure, now divided between the Mero field and the Libra block. Two exploration wells with dry results reduced considerably the estimated reserves. Out of the 11 compartments, 6 had positive results, 2 had negative results, and 3 are yet to be tested.