The communist dictator of Venezuela, from which we do receive significant amounts of refined and unrefined oil, has declared that he would cut shipments to the US if we attack Iran.
To build specialized refineries for it, or to re-tool an existing refinery to handle it is no small matter. Without St. Croix and Trinidad, Chavez oil is not really all that a red hot commodity. The CHICOM may build Chavez a refinery or two, but until that happens, the fat dog can howl all he wants... or all his oncologist lets him.