U.K. oil giant BP announced with great fanfare today its entry into Brazil's offshore--the world's hottest new oil basin--following the purchase of assets from U.S.-based Devon Energy.

The deal gives BP seven exploration blocks in Brazil's Campos basin, which is a very promising oil basin in its own right, home to a number of significant producing oil fields.

However, when you compare Campos to the Santos basin farther south, where the largest oil discoveries for at least a decade have been made, you can't help feeling that BP is arriving late to the party, only to find the prom queen has already gone home with the captain of the other team.

The Tupi field in the Santos basin alone contains an estimated 8 billion barrels of recoverable oil. A number of smaller fields in the block neighboring Tupi could contain 6 billion barrels in total, according to Spain's Repsol, which has a stake in the fields.

In contrast, Devon estimated the possible resources in all seven of its Campos basin licenses at between 2 billion and 4 billion barrels.