State-controlled oil giant Petrobras plans to provide Chevron Corp. with assistance from its legal department to help the U.S.-based supermajor continue to operate in Brazil after a judge ordered the company to halt operations at the end of this month, a high-level executive said.

Legal assistance will also be provided to Transocean, a contractor for Chevron in Brazil, that was ordered to suspend its operations, Petrobras exploration and production director Jose Formigli said.

The two companies are the subjects of legal proceedings over a spill of 3,700 barrels of crude last year off the coast of Rio de Janeiro state.

"We are going to help Transocean and we are going to help Chevron with this task of showing the legal system that, in our opinion, there is no reason for the embargo (on the companies' activities) here in Brazil," Formigli said.

Petrobras is helping the companies because it has eight Transocean rigs under contract in deepwater areas, Formigli said.

A suspension of Transocean's operations would harm Petrobras becaause it would not be able to operate the rigs, the executive said.

"Paralyzing these rigs that we use in petroleum exploration would obviously have on impact on Petrobras. That is why our legal department is working with Transocean and, to the extent possible, with the National Petroleum Agency," which regulates the industry, Formigli said.

Petrobras will assist the two companies in appealing the ruling to a higher court, the executive said.

The National Petroleum Agency said last month that Chevron would be fined nearly 50 million reais ($24.7 million) for the spill at the Frade field last November.

Some 3,700 barrels of crude leaked from the Frade field, located 120 kilometers (75 miles) off the coast of Rio de Janeiro state, the agency, known by the acronym ANP, said.

The San Ramon, California-based multinational is the operator of the field with a 51.74 percent stake, while Petrobras and Japan's Frade Japao Petroleo have 30 percent and 18.26 percent interests, respectively.

Frade lies in the Campos basin, where nearly 90 percent of Brazil's oil and gas is produced.

Formigli also discussed Petrobras's investment strategy for its vast pre-salt reserves.

The pre-salt layer, which is found beneath the sea bottom and contains a gel-like deposit of salt that could be up to two kilometers (1.24 miles) deep, is estimated to contain billions of barrels of oil equivalent and could potentially transform Brazil into a major crude exporter.

Some 51 percent of Petrobras's exploration and production investment will go into the pre-salt reserves, Formigli said. EFE