The oil market actually has sub markets that break down by region and the type of crude that is being traded. Not all crude is created equal and there are different types of refineries that are designed to refine the different types of crude.

For example, a refinery that refines light / sweet crude won’t take the heavy stuff. Which is why places like North America export a lot of their domestic stuff. North America has a lot refineries looking for light crude, but pulls a lot of heavy stuff out of the ground.