A flurry of big oil discoveries from Brazil to Sierra Leone undermines those who believe that there are no new oil frontiers to explore but the finds may not be enough to ward off a supply crunch as the world economy recovers.

Anadarko, the US company, announced this week that it had found a whole new oil basin stretching 1,100km from the coast of Ghana to Sierra Leone. That came on the heels of a big find in Brazil, one of the world’s most important future oil exporters. The Brazilian find, which was made by Petrobras and BG, came shortly after BP announced that it had discovered oil in a layer of very deep rock in the Gulf of Mexico, establishing a new geological oil zone.