BP (NYSE: BP) has discovered a "giant" new oil deposit in the Gulf of Mexico, the company announced in a press release on Sept. 3. The deposit, the Tiber field, has an estimated 3 billion barrels of oil equivalent, about one-sixth of which is thought to be extractable. It is located in the Keathley Canyon area, where BP discovered another major field, the Kaskida, in the deep lower Tertiary layer of rocks in 2006. The Tiber deposit is a boon for U.S. domestic oil production in the Gulf, which was thought to be in decline until a number of recent major discoveries (such as this latest one) and technological advances created new hopes.

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Yet producing oil at the Tiber field poses significant challenges — it is at the very brink or possibly beyond what is possible with present technology. The deposit is in relatively deep water (about 4,100 feet) and the well is one of the deepest oil wells ever drilled at 35,055 feet (with salt and layers of rock intervening). High pressure and temperatures at that depth will create problems, and it is uncertain how accessible the formation is and what quality the crude will be. The whole endeavor promises to be expensive — it is not yet known at what price the project will be commercially viable, but it will certainly not be low — and is certain to tax the capabilities of one of the world’s most expert energy supermajors.

All of this will take time. BP hopes the first oil from the field will come forth in the latter half of the next decade; 2015 would be the most optimistic date for beginning production and 2018 would be reasonable, but unforeseen delays are likely. Part of the timing issue is that the deposit is also located about 250 miles offshore from Houston, well away from existing pipeline infrastructure. This will further delay getting production up and running, as either pipelines or perhaps even independent loading platforms will have to be built. And of course, as with all Gulf oil infrastructure, the Tiber development will be subject to the risk of damaging tropical storms.

Geopolitically, the discovery will somewhat offset the decline in U.S. domestic oil production — if estimates are correct, Tiber’s extractable oil will equal more than a year’s worth of U.S. production in the Gulf, and nearly one-fourth of U.S. annual production. It will also inspire further exploration in the Gulf. All of this benefits the United States at a time when it is striving to increase its energy security.

But the geopolitical effects are not limited to the United States. It so happens that Petroleo Brasileiro (Petrobras) (NYSE: PZE), Brazil’s state-run energy company, has a 20 percent stake in the consortium that will be developing the field (ConocoPhilips (NYSE: COP) has the other stake, with 18 percent). This discovery adds to a long string of good news for Petrobras, which has made several big offshore discoveries of its own recently. Though Petrobras is technologically adept already, it can still gain from working with BP as it attempts to become a global leader, specifically in deep water production techniques necessary both for Tiber and its own daunting ultra-deep super-fields. Participating in Tiber’s production alongside BP will give Petrobras a serious learning opportunity just as it prepares to set to work on some of its own discoveries.