Royal Dutch Shell PLC announced Thursday that one of its Brazilian offshore oil fields is commercially viable and that two deep-water areas of the block have been identified for development.
Europe's second-largest oil company did not say when production would begin in the BS-4 block or offer yield estimates, but the field has estimated reserves of about 300 million barrels of very heavy crude.
Shell is the lead operator of the block with a 40 percent stake. Brazil's state-owned Petroleo Brasileiro SA also has a 40 percent stake, and U.S.-based Chevron Corp. holds 20 percent.
The BS-4 field is in the Santos Basin of the Atlantic Ocean about 190 kilometers (120 miles) from Rio de Janeiro, at a depth of 1,550 meters (5,100 feet).
Shell had until the end of this year to declare whether BS-4 was viable or return the block to Brazil's National Petroleum Agency.