More than you want to know, perhaps, but most Saudi oil is contracted, rather than sold on the spot market. Another reason that the Saudis are refining is that it allows them to sell to countries that do not have oil refining capabilities--

Oil refining does two things that will have a significant impact on the Saudis--it creates an increased demand for skilled labor, and it increases the overhead costs of oil production significantly.

This means that their population of immigrant workers will jump, that more of the oil money will have to be reinvested and expended in the oil business itself, and that fluctuations in the price of oil will have ever greater impact on the fabric of their society than it does now. It will be worth watching.