The main reason PDVSA bought Citgo in the first place was that Citgo's refineries here in the US could process the heavy crude and it gave Venezuela a ready customer for their output. I guess they are going to cut off their own refineries in the US?
There is a lot of air in Hugo's threat. You are correct about the Venz sulfur content but their crude oil is the source for the world's best asphalt for shingles (and for which they could set their own price, an industry from which they've mostly withdrawn from. Their stupidity simply amazes me.