I would stay away from any kind of oil as a means of sealing an egg. I know that Canada Goose control involves oiling goose eggs so the embryos die and then return the eggs to the nest so they don't lay another clutch but the eggs will never hatch.
I never had one that bad but when I dropped an egg that was covered with cracks, I used liquid bandage and coated all the cracks with it. The chick hatched fine but mine didn't have shell parts missing.