Oil has been seeping from the ocean floor since Nov. 8, near where Chevron was drilling an exploratory well. But until now, the company has been slow to acknowledge that the spill was directly related to the drilling, saying instead that the well was "suspected to be contributing" to seepage.
On Saturday evening, however, Chevron spokesman Kurt Glaubitz said, "The drilling was responsible for the seepage."
The Brazilian Petroleum Agency said that between 200 and 330 barrels of oil per day leaked between Nov. 8 and Nov. 15. Chevron said the oil seeps have been reduced to "infrequent droplets."
"The situation is largely resolved," the company said in a statement Saturday, adding that it will conduct an internal investigation and comply with Brazilian agencies investigating the spill.
"We want to fully understand what happened -- and share that information -- in order to prevent a similar situation from occurring" in Brazil's offshore oil fields, the company said. It plans to hold a press conference in Rio on Sunday.
Controversy over the spill is rising in Brazil, which could become a critical problem for Chevron, one of the world's top deep-water drillers. The second-largest U.S. oil company pins a major part of its hopes for near and medium-term growth on its ability to extract oil from the oceans' depths through technically complex projects that cost billions of dollars to develop.
Brazil is only one of many places where the company drills deep-water wells, but is one of the most promising, because some of the world's largest oil reservoirs have been found in its offshore.
The leak is in the Frade field, about 230 miles northeast of Rio de Janeiro, which produces 79,000 barrels of oil and its equivalent in natural gas a day -- or about 3% of the company's total production.
Chevron is also developing a neighboring field called Papa-Terra, which it estimates to be even larger and will become the company's biggest investment in Brazil when it is completed.
The mishap also comes a year after Chevron, along with Exxon Mobil Corp, Royal Dutch Shell and other big oil companies, sought to distance itself from BP PLC during the Deepwater Horizon oil spill, maintaining that deep-water drilling was safe when properly performed.
Chevron began plugging the Brazil well with cement this week. On Friday, the ANP said in a statement that the plugging process is "presenting positive results, with a substantial reduction of the spill," according to images captured by remote-operated vehicles.
Also, after a flyover by experts from Brazil's environmental regulator, the ANP said that "a decrease was observed in the slick, which continues moving away from the coast."
Most of the oil that has leaked is floating about three feet below the ocean's surface, the agency said.
