BP has announced its largest oil and gas discovery in more than two decades after drilling a successful well in Brazil’s Santos Basin, marking a significant milestone as the company doubles down on fossil fuels.

The Bumerangue field, located around 400 kilometers off the coast of Rio de Janeiro, spans over 300 square kilometers — an area roughly five times the size of Manhattan. BP said the find is its biggest since the 1999 discovery of Shah Deniz in the Caspian Sea.

“This significant discovery is the largest BP has made in 25 years,” Gordon Birrell, BP’s head of oil production, said in a stock exchange statement on Monday. Shares in BP rose 1.7% following the announcement.

The discovery comes amid a strategic pivot by BP to ramp up oil and gas exploration, scaling back its previous ambitions to transition aggressively towards renewables. Earlier this year, CEO Murray Auchincloss announced plans to increase annual investment in oil and gas projects to $10 billion, about 20% more than previously budgeted.

While the company described the Bumerangue find as containing a mix of gas, condensate, and oil, it stressed that it is too early to determine the size or commercial viability of the reserves. BP also noted elevated levels of carbon dioxide in the field, which could complicate extraction and increase costs.

Analysts have urged caution, pointing to past experiences with similar deepwater discoveries. In the same basin, Brazil’s state oil company Petrobras faced setbacks when a promising initial discovery at the Libra field yielded a far smaller economically viable area after further appraisal.

Nonetheless, a successful development of Bumerangue would be a boost for Brazil, which is looking to offset an expected decline in production after 2031. The Santos Basin has produced over 7 billion barrels of oil and gas in the past 14 years, playing a key role in Brazil’s rise as a major oil producer.

BP holds full ownership of the Bumerangue license, acquired in a 2022 auction under terms considered highly favorable. After recovering its investment, the company will pay 5.9% of profits to the Brazilian government.

This is BP’s 10th oil and gas discovery of 2025, following successful drilling campaigns in Trinidad, Egypt, Libya, the Gulf of Mexico, and other regions.