@n0m, Your lack of knowledge is amazing, ALL crude is impure regardles if its shale in PA, sands in Canda or the Persian Gulf, it all gets refined and the sold on the world market, including Keystone.
@Yackov Doe, the wholesale price of gas is either spot market or options with two benchmarks West Texas Intermediate or Brent [North Sea] The majors have a slight markup of the wholesale price but majority of the price is driven by the market and more supplies equals lower prices