Frank Okon

Brazil’s state-controlled oil major Petrobras has agreed to acquire a 75% operating stake in offshore Block 3 in São Tomé and Príncipe from Nigerian independent Oranto Petroleum Limited, in a move that deepens its renewed push into African exploration.

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The transaction will significantly reshape the ownership structure of the block. Oranto, which currently holds a 90% operating interest, will reduce its stake to 15%, while the National Petroleum Agency of São Tomé and Príncipe will retain its 10% interest. Upon completion, Petrobras will assume operatorship with a controlling 75% stake, effectively taking the lead role in developing the asset.

The deal marks a strategic shift for Oranto and its founder, Arthur Eze, as the company transitions from operator to minority partner in the block. For Petrobras, the acquisition reinforces its broader strategy of expanding its upstream footprint across Africa after resuming activities on the continent in 2024.

The Block 3 entry comes alongside a series of recent moves by Petrobras to build a diversified exploration portfolio in São Tomé and Príncipe. The company recently finalized agreements to join consortia in three additional offshore blocks — 10, 11, and 13 — through transactions with Shell plc.

Under those arrangements, Shell remains operator of all three blocks with a 40% stake. In Block 10, Petrobras holds 45% alongside ANP-STP’s 15%. In Block 11, Petrobras has 25%, partnering with Galp (20%) and ANP-STP (15%). In Block 13, Petrobras again holds 45%, with ANP-STP retaining 15%.

Petrobras has framed its re-entry into Africa as part of a long-term strategy to rebuild reserves and diversify exploration opportunities. In a February statement, the company said the investments are aimed at “restoring oil and gas reserves by exploring new frontiers and working in partnership.”

The groundwork for this expansion was laid in 2023. Petrobras’ board approved operations in São Tomé and Príncipe in December of that year, following a memorandum of understanding signed in March 2023 with Shell to identify upstream collaboration opportunities.

Shell itself has steadily expanded its presence in the island nation. The company entered São Tomé and Príncipe in 2019 through the acquisition of interests in offshore Blocks 6 and 11. It later deepened its position by acquiring KE STP Co., gaining additional stakes in Blocks 6, 10, 11, and 13. That transaction closed in December 2020, bringing the assets into Shell’s global portfolio.

Taken together, Petrobras’ latest acquisition from Oranto and its earlier deals with Shell signal a coordinated effort to establish a strong foothold in one of Africa’s underexplored offshore basins. The shift also underscores a broader trend of international oil companies returning to frontier markets in search of new reserves as competition for established assets intensifies.