The Mexican government has announced plans for an auction of exploration and shared-production rights on 15 blocks of potential oil fields in the shallow waters of the Gulf of Mexico.

The blocks cover 3,440 square miles (8,908 square kilometers) and contain potential reserves of up to 1.58 billion barrels of crude equivalent.

The Energy Department said Tuesday the blocks will be put for bid on a shared-production basis with an initial exploratory period. The contracts would run for 30 years. The bidding is scheduled for March 2017.

Mexico is offering the contracts under a 2014 law change that ended seven decades of state monopoly on the oil business.

Mexico produces 2.2 million barrels of oil a day, down from a peak of 3.4 million barrels in 2004.