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MEXICO CITY, April 27 (Reuters) - The board of Mexico's state-owned oil company Pemex on Thursday approved its second-ever deep water joint venture covering the Nobilis-Maximino block in the country's territorial Gulf waters.

Pemex, which is looking for a partner to develop the block, estimates it to hold reserves of some 500 million barrels of oil equivalent (boe) based on data gathered from five wells drilled in the past, the company said in a statement.

The potentially-lucrative project lies just south of Mexico's maritime border with the United States in the Perdido Fold Belt, where dozens of successful projects have been developed on the U.S. side of the same basin in recent decades.

Pemex said production could reach 300,000 barrels per day in its Perdido Fold Belt developments by 2025.

Reuters revealed details of the Nobilis-Maximino plan last week, with an auction being eyed for December.

The area covers some 588 square miles (1,524 sq km) and at a water depth of around 9,840 feet (3,000 meters).

Late last year, Mexico inked its first-ever deep water joint venture for Pemex's Trion block after Australian mining and oil giant BHP Billiton won the rights.

Nobilis-Maximino is located due east of Trion, which could eventually provide "operational synergies," Pemex said.

BHP Billiton was selected at a competitive auction managed by Mexico's National Hydrocarbons Commission, or CNH, in a process that will be repeated for the second deep water tie-up later this year.

The joint venture partnerships are fruit of a sweeping sector overhaul finalized in 2014 that ended Pemex's decades-long monopoly and for the first times allowed joint ventures in exploration and production of oil and gas with equity partners. (Reporting by David Alire Garcia; Editing by Marguerita Choy)