BP announced on Wednesday it had struck a ‘giant’ oil-field nearly 11 kilometres under the waters of the Gulf of Mexico, a region of increasing importance in the oil world. The find underlines the impressive – or, as you could see it, desperate – depths to which oil producers are now drilling to find black gold.

“We believe it’s the deepest well ever drilled by the oil and gas industry,” the Wall Street Journal quotes a BP spokesman of the find. “It says we’re seeing that improved technology is unlocking resources that were before either undiscovered or too costly to exploit because of economics,” says Chris Ruppel, an energy analyst at London investment bank Execution LLC (New York Times).

The term ‘giant’ indicates merely that the find is greater than 500 million barrels of oil. The world runs through about a billion barrels of oil every two weeks. BP reckons the field holds more than 3 billion barrels, and a spokesperson said they would be ‘doing well’ to get 20-30% of that out of the ground. BP has a 62% stake in the project, making its potential entitlement “nice, but no game-changer,” according to Richard Griffith, an analyst at Evolution Securities Ltd in London (Bloomberg).

Bigger oil discoveries have been announced recently in other parts of the world: off the shores of Brazil, in Uganda, Kurdistan, and off the coast of Ghana, for example, says Andrew Latham, a vice president of global exploration services for consultant Wood Mackenzie (Wall Street Journal). Iran announced an 8.8 billion barrel discovery just a fortnight ago. But these more promising fields are off limits: governments restrict access. So the deepwater offshore southern United States, though risky to exploit, looks much more attractive for international oil companies.

The oil BP found lies in the rocks of the lower tertiary or Paleogene, which date back between 38 million and 68 million years. Around 10 other discoveries have been made at that level in the Gulf (Washington Post), and the first lower tertiary oil from the region will be produced in the next few months, by Shell and Chevron.

BP’s find won’t produce anything until at least the second half of next decade, even if further exploratory work runs smoothly. New technologies will be needed to get the oil out, a spokesperson said, given the temperatures (250°C) and pressures at these depths. BP’s Thunder Horse oilfield – the biggest producer in the Gulf, churning out 300,000 barrels a day – was first drilled in 1999 but didn’t produce for a decade.