There is a move coming where, at considerable expense, WTI oil transfers will find there way to the Brent market. Given the $22+ premium in doing so, this is actually a profitable move. If gold in Europe sold for $2000 but you could buy it here in the USA for $1600, people would fill that gap almost instantly.
With oil it much harder, but there is profit to be made and all the profit can be locked in, in advance. This spread cannot endure, especially with Libya cooling off and getting back online.