Petrobras takes 75% and operatorship of Block 3 offshore São Tomé and Príncipe

Petrobras assumes control of Block 3

Petrobras has completed the acquisition of a 75% interest and operatorship in Block 3, an exploration asset offshore São Tomé and Príncipe. The Brazilian company announced the closing on July 9, 2026, following the agreement disclosed on April 17, 2026.

The transaction changes the ownership structure of the block. Petrobras is now the operator with 75%, Nigerian company Oranto Petroleum retains 15%, and the National Petroleum Agency of São Tomé and Príncipe, or ANP-STP, holds 10%. Before the deal, Oranto operated the block with a 90% interest, alongside ANP-STP with 10%.

ANP-STP said Petrobras acquired its interest from Oranto Petroleum. The agency formalized the change through a second amendment to the Block 3 production-sharing contract, signed on July 9. The amendment establishes Petrobras as operator and records the consortium’s new ownership structure.

A broader African exploration portfolio

Block 3 adds an operated asset to a São Tomé and Príncipe portfolio that Petrobras has been building since its return to African exploration in 2024. That year, the company acquired 45% interests in Blocks 10 and 13 and a 25% interest in Block 11. Those transactions marked its resumption of exploration activity on the continent.

Petrobras expanded the portfolio again in September 2025 by completing the acquisition of 27.5% of Block 4. Shell operates that asset with 30%, while Galp and Petrobras each hold 27.5% and ANP-STP holds 15%. Block 3 therefore differs from the earlier acquisitions because Petrobras will control operating decisions through its 75% stake.

The company has not disclosed the purchase price, resource estimates, drilling timetable or planned investment for Block 3. The acquisition concerns exploration acreage rather than producing fields, so it does not immediately add oil or gas output. Its commercial value will depend on geological studies, future drilling and any discoveries that can be developed economically.

Reserve replacement drives the transaction

Petrobras said the acquisition supports its strategy of replenishing oil and gas reserves by exploring new frontiers in Brazil and abroad. It also described international exploration as a way to diversify its portfolio and sustain the business over the long term. The agreement followed the company’s internal governance procedures and is aligned with its 2026-2030 Business Plan.

For São Tomé and Príncipe, the entry of a large offshore operator gives Block 3 a new lead investor while preserving national participation through ANP-STP. Oranto remains exposed to any exploration success through its 15% interest but has transferred control and most of its economic stake to Petrobras.

The immediate significance is portfolio positioning rather than new supply. No production volumes, reserves or development approval were announced with the closing. Petrobras has nevertheless assembled interests in Blocks 3, 4, 10, 11 and 13, giving the company several opportunities to test the offshore potential of São Tomé and Príncipe while spreading exploration risk across multiple licenses and partners.