A kilogram of fuel will have the same amount of specific energy as another kilogram
Yep, it's not the volume of fuel that's important in terms of the energy a given volume contains, it's the number of "fuel molecules"..which is related to density.
Putting it another very simplistic way, it might need the energy contained in 10 billion billion molecules of fuel to fly from XXX to YYY....those 10 billion billion molecules will have a total mass - so as long as I can get that mass into the tanks I'll have the right number of molecules for the flight and from a range POV it doesn't matter if the fuel occupies a volume of e.g.1000 litres or 10,000 litres.
Of course in some circumstances the fuel is so warm you can't get your 10 billion billion molecules in the tanks - then you've got a problem...
(Edit to add: Before the Physicists and planners pile in :Yes, yes it's first approximation answer given in the context of the question)