It all depends on where the freezing was occurring. Sean said that the water was freezing in the tanks so wrapping the pipes would not prevent this, but then I have to ask have we removed the water that was in the tanks from before the weather hit? If not then wouldn't this water freeze and the crystals crack the tanks as he said? With the right amount of voltage applied to the heat trace concentrated on the highest possible freezing areas, with good insulation blankets wrapped correctly I would say 10 to 20' of the pipe would solve the pipe issue. As for the tanks that is another story but there is still the water that is already in the tanks. If we are using a treater to help separate this heavy oil from this water which I am sure has some emulsion so we would almost have to have a treater, this would help with the freezing in the tanks, not hurt.