The recently discovered Tupi oil field, 290 km off the Brazilian coast, holds between 5 and 8 billion barrels of oil and natural gas.
Analysts estimate that the deposit is worth US $60 billion and that by 2013 will elevate Brazil to the rank of 12th largest oil producer in the world. The discovery is not without its challenges, say Brazilian state oil company, Petrobras.
Tupi is the largest ever oil find in deep waters and Petrobras believes it may be the first of several new fields of over a billion barrels in size, termed "Elephants". This has prompted the Brazilian government to remove over 40 adjacent oil exploration blocks from an upcoming auction and draft new legislation to limit the role of private companies in oil exploitation in the area.
Petrobras has a reputation as one of the world's best at exploiting deep-sea oil deposits; even so the Tupi field poses significant engineering challenges. The oil lies a total of 7km (4.3 miles) beneath the ocean's surface — deeper than Petrobras has ever drilled. The sea bed is 2km (1.2 miles) beneath the surface at this point, and from there lies a further 2km of rock-hard salt, and 3km (1.8 miles) of rock, sand and silt. Much of Brazil's oil production currently comes from deep water, but none yet comes from below the salt layer, which can turn 'sticky' and clog drilling equipment.
"Despite all the difficulties, Petrobras will rise to the challenge," says Marcio Rocha Mello, president of the Brazilian Association of Petroleum Geologists