French oil company Total SA (TTFNF)
said the northwest section of the supergiant Libra offshore oil prospect in Brazil holds 3 to 4 billion barrels of oil, according to a investor presentation on its Web site.
The wells, drilled in the region around the Libra pioneer well, also show "excellent" productivity, Total, which owns 20 percent of Libra, said in the report that accompanied a company presentation to investors in London Sept 22.
The estimate for the northwest region is the first to be made public for Libra since exploration activity began two years ago. The volume would be enough to supply all the oil needs in the United States
, the world's largest petroleum consumer, for nearly seven months.
The northwest part of Libra is close to the original pioneer well in the Libra and represents only about a quarter of the total Libra area.
Total's partners Petroleo Brasileiro SA (Petrobras) holds 40 percent in Libra, while Royal Dutch Shell Plc (RYDAF)
has another 20 percent. China's state-owned CNOOC and CNPC hold 10 percent each.
Petrobras, the field operator, has not released any public estimates for Libra, which the government estimated to have 8 billion to 12 billion boe when it sold rights to the area in 2013.
Petrobras officials were not immediately available for comment.
Total says the Libra partners will begin a 50,000 barrel a day extended well test in 2017, the same year they plan to make a decision to make the financial investment necessary to build the first floating production, storage and loading platform for the Libra area, the report said.
(Reporting by Jeb Blount)