According to the incoming Secretary of Oil and Gas at Brazil’s Ministry of Energy, Marcio Felix, the Brazilian government has announced its plans to hold its second auction of four sub-salt exploration and production areas by mid 2017, reported Marine Technology News. The sub-salt is a region near Rio where about 100b barrels of oil are trapped deep beneath the seabed by a layer of mineral salts.

Felix added that the areas, which will be sold under production-sharing agreements, will include four blocks adjacent to four large existing oil discoveries near Rio de Janeiro: Carcara, Sapinhoa, Gato do Mato, and Tartaruga Mestica.

According to Reuters, the area that will be adjacent to the giant Carcara prospect in the BM-S-8 block in Brazil’s offshore Santos Basin, is said to rival one of the world’s largest oil discoveries in four decades, Brazil’s 8b barrel Lula field. The field is believed to contain enough oil to supply all the world’s needs for almost three months.

Petrobras, the state run oil company, is considered to be the lead partner and operator of Carcara, as it owns 66% of BM-S-8 block. Galp owns 14% and Barra and QGEP each own 10%. All four partners have invested more than $2b in the Carcara prospect to date, but will have to wait until at least 2020, two decades after rights to the area were first sold, for collecting their return on investments.