Isn't the price difference between the prices due to the fact that cushing, ok is the spot of settlement for all that oil. My understanding is that as of this summer the pipelines that run from Cushing to the gulf coast will switch directions to allow the fuel from North Dakota to Cushing to the gulf coast. this should alleviate the price differential.
No idea on why Hess is getting a premium other than the fact that brokers would rather make 1 phone call vs 10. Up in ND they are now opening up new barge runs to rails to get the price out as the pipelines are full and even after the increased costs (barge + rail) to refineries on east and gulf coasts its worth the price difference.
Here's a decent article explaining the price differences.
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