Colombia-based Ecopetrol SA announced Dec. 20 that it was awarded a 10% stake in the Saturno block by Shell and Chevron, expanding its stake in Brazil's pre-salt region in the Santos basin.

The agreement was signed in Rio de Janeiro and is still subject to approval by Brazil's Ministry of Mines and Energy and the Brazilian National Agency of Petroleum, Natural Gas and Biofuels, or ANP.

The block was assigned to Royal Dutch Shell plc and Chevron Corp. during the fifth pre-salt round held by ANP on Sept. 28. Both firms hold a 45% stake in the block, which covers 1,100 square kilometers and is off the coast of Sao Paulo and Rio de Janeiro.

Ecopetrol also holds a 20% stake in the Pau-Brasil exploratory block located in the Santos basin, along with oil major BP p.l.c. with a 50% stake, and CNOOC Ltd. which holds 30%.

Ecopetrol holds five blocks in the Santos, Foz de Amazonas, Potiguar and Ceara basins in Brazil.