Delays that occur outside of the airline control and are considered "extraordinary circumstances" doesn't entitle you to any compensation, I'm not sure whether or not a delay due to a late fuel truck is something controlled by the airline, you can always file a claim with them and see what they say, however all this can only be done after you reach your final destination.

If you are >3hrs and <4hrs delayed, you are potentially looking at 300€ compensation, if more than 4 hours than 600€