Brazil's environmental regulator Ibama last week granted state-owned oil company Petrobras permission to drill three additional wells in the block where the company made an oil discovery earlier this year.

Ibama amended the licence for Petrobras' pioneering Morpho well, in Block FZA-M-59 of the Foz do Amazonas Basin off Amapá state, to allow three new exploratory wells named Manga, Crotalus and Morpho Extensão. These are known as contingent wells, drilled only under certain conditions depending on the results of the main well.

The regulator has also authorised use of the Amaralina Star drilling rig, but only after Petrobras has proved that adjustments have been made relating to gravel removal from the seabed. The rig will need to undergo an inspection to demonstrate that it has met Ibama’s conditions.

Ibama has barred the simultaneous use of two rigs, meaning Petrobras can operate only the NS-42 or the NS-43 vessel. As a licensing condition, the company must also establish two wildlife centres in Belém and Oiapoque available to receive and rehabilitate manatees in the event of a spill.

The additional wells are expected to help assess the scale of the Morpho discovery, according to industry experts cited by Valor.

The Brazilian Institute of Petroleum, Gas and Biofuels’ president, Roberto Ardenghy, said the licence would help Petrobras delineate the reservoir. Petrobras needs to establish the deposit's width and depth in order to calculate recoverable volumes.

Oil and gas regulator the National Agency of Petroleum, Natural Gas and Biofuels’ (ANP) former director-general, David Zylbersztajn, said the additional drilling was a natural step in evaluating the area, while the ANP’s former director, Allan Kardec, said measuring oil volumes required at least three data points rather than one.

Prosecutors from the Federal Public Prosecutor's Office in Pará and Amapá had sought clarification from Ibama over the requests, arguing in an official letter that authorising new drilling through amended permits ignored cumulative environmental impacts, Valor reported.

Block FZA-M-59 lies about 175 km off the Amapá coast in a region that regulators consider environmentally sensitive. The original licence for the Morpho well took more than 10 years to secure and followed an appeal after Ibama's initial refusal in 2023.

The ANP estimates potential oil and gas resources in the wider Equatorial Margin at around 30bn barrels of oil equivalent (boe), with at least 6.2bn barrels considered recoverable in the Amazon River Mouth Basin alone.

Petrobras said it would begin planning further exploratory activities in the block following the authorisation. It has been reported that the company could begin drilling new wells at the mouth of the Amazon within three months.

Meanwhile, a source with knowledge of the matter told newspaper O Globo that preliminary analysis of oil samples from the Morpho well indicated crude with an API gravity of 35-40. This would place the find among the lightest ever discovered in Brazil and comparable to oil produced in neighbouring Guyana.

Final results are expected within weeks, according to the source, who said Petrobras had not yet completed its characterisation of the discovery.

Samples are being examined at Petrobras' Research, Development and Innovation Centre (Cenpes) in Rio de Janeiro, having travelled more than 2,000 km by sea from the coast of Amapá. The material could not be transported by air without compromising its original density and composition, O Globo reported.

API gravity is an inverse measure of crude density: the higher the number, the lighter the oil, and lighter crudes typically require less processing into products such as petrol, diesel and jet fuel.

ExxonMobil's main Guyanese grades carry an API of roughly 32-34, according to company data, while Brazil's pre-salt oils are generally heavier, with the Tupi field at about 28 and Búzios close to 28.5.

Brazilian President Luiz Inacio Lula da Silva, visiting Petrobras' operations in Amapá last month, said of the samples: "It seems to be refined already, it's so light. We have a chance to have some very high-quality oil."

This comes amid a larger push by Brazil to expand its oil and gas output further still. Also last week, the ANP approved the designation of 24 new exploration blocks in the onshore portion of the Potiguar Basin, according to a report by Estadão.

The board decided the blocks could be included in future cycles of the Permanent Concession Offer, though they will only become available for bidding after the sixth cycle, scheduled for October 7, the agency said.

Among the areas identified is block POT-T-551, covering the region of Tabuleiro do Norte in Ceará state, where the presence of petroleum has already been confirmed by the ANP's Centre for Technological Research and Analysis, Estadão reported.

The approved blocks still require further steps, including environmental analysis, a joint statement from the Ministry of Mines and Energy and the Ministry of Environment and Climate, and a public hearing, before they can be offered for bidding.