BP Plc said it has made its largest oil and gas discovery in a quarter-century after drilling the 1-BP-13-SPS exploration well at the Bumerangue block in Brazil’s deep-water Santos Basin. The company intercepted an estimated 500-metre column of hydrocarbons in high-quality pre-salt carbonate reservoirs, describing the result as its biggest find since Azerbaijan’s Shah Deniz field in 1999. The well is located about 400 kilometres off Rio de Janeiro in 2,372 metres of water and reached a total depth of 5,855 metres. BP estimates the areal extent of the accumulation at more than 300 square kilometres but has yet to disclose resource volumes, saying further appraisal is required. Early tests show elevated carbon-dioxide levels that will be factored into development studies. BP holds 100% of the block and plans to assess whether Bumerangue can underpin a new production hub in Brazil, where the company operates four of eight offshore licences. The discovery is BP’s tenth so far in 2025 and aligns with Chief Executive Murray Auchincloss’s decision to refocus on fossil fuels after a period of tepid returns from low-carbon investments. Investors welcomed the news, lifting BP shares about 1.3% in London trading, outperforming the wider European energy index. Bernstein analyst Irene Himona said the find could prolong the company’s upstream portfolio “well into the 2030s and 2040s,” while rival majors, including Shell, are also expanding in the Santos Basin.