Brazilian state oil company Petrobras has cut estimated production costs in the offshore subsalt fields by 50% over one year, a Petrobras director said.

Petrobras exploration and production director Guilherme Estrella said a company working group created to study subsalt production costs has “managed to cut the cost of extraction in half”.

“We’re going to continue working in that direction,” he told reporters after an event in Rio de Janeiro, Brazil.

“The challenge of the subsalt region is not technology … It’s a question of looking at the wells, the concept of the floating production unit, the number of wells … it requires a new way of looking at things,” he said.

The massive subsalt region off the coast of Brazil is believed to hold tens of billion of barrels, miles below the ocean’s surface beneath a thick salt layer.