The Lower Congo Basin is one of the most prolific basins in the world, with over 30 billion barrels of recoverable oil discovered to date. The basin is mature, but recent well results show it still has significant potential.
The Lower Congo is part of the greater South Atlantic salt basin, with multiple proven plays throughout its stratigraphic section. Initial exploration in shelfal regions from the 1960s through to the 1980s concentrated on the post-salt Albian Pinda carbonate and Vermelha sandstone plays, with multi-billion barrel volumes discovered in raft structures. Additional success was also observed in the pre-salt and Tertiary sections of the shelfal domain, demonstrating the multitude of prospective reservoirs for explorers in the basin.
As seismic and drilling technology advanced in the 1990s, the deep-water Oligo-Miocene plays of the Congo Fan were opened, and these high-quality deep-water slope channel reservoirs have continued to be targets of focus since.
Agência Nacional de Petróleo, Gas e Biocombustíveis (ANPG) was established in 2019 as the state regulator, when production was declining steeply and exploration activity was limited. Today, blocks in both mature and frontier areas are being licensed again under flexible and favorable fiscal terms. Exploration drilling is now at its highest level in recent years.
With more than sixty years of exploration history, the Lower Congo Basin might be considered a mature basin with limited potential remaining. Recent drilling through 2026 suggests otherwise, with established plays continuing to deliver new opportunities.
The Albian Pinda carbonate play has been tested by two wells recently, namely 105-4X and Pacassa 416 (Figure 1). Both have found significant hydrocarbons in targets that have largely been overlooked in the recent past, reinvigorated through legislative changes that provide incentives for further exploration in development leases, marginal field developments and gas monetization.
Well 105-4X, operated by Chevron in the shallow water Block 0, found an oil and gas column of over 600m in an Pinda raft structure, close to the Bomboco (oil) and Sanha (gas-condensate) fields. The discovery is reported to be under evaluation for a potential tie-back development.
The Sonangol P&P operated PAC 416 well, testing a previously undrilled structure at the southwestern extent of the Pacassa Field, proved a hydrocarbon bearing interval with 136m net pay, also in the Albian-aged Pinda Formation carbonates. The well is to be completed as a producer and connected to the existing Pacassa Field infrastructure, with first oil expected in Q3 2026.
ANPG’s objective is to maintain oil production at over 1 million bopd, and these wells are examples of the remaining potential existing near-field, that can support rapid development and the nation’s goal.
In the deep-water Congo Fan setting, three further successes have been drilled in 2026. Algaita-01 on Block 15/06, discovered oil in the Upper Miocene, with initial estimates of ~500 million barrels in place. This is the 22nd discovery made since 2006 on the block, an area that was relinquished in 2003. This demonstrates that significant opportunities exist in overlooked and previously disregarded parts of the basin. Whilst many successes in this area of the Lower Congo Basin appear to be contained in slope channel systems draped over deeper structure, the Algaita-01 well looks to have tested a downthrown section in a trough beside a large raft structure (Figure 2). Regional data over the basin reveals many more situations similar to this (for example in Figure 3), along with large undrilled raft structures, providing numerous opportunities to test and extend proven plays in alternative trapping geometries.