I think oxygen is the only fuel that methane can use, but I could definetly be wrong. I’m no chemistry expert.

methane is CH4 which contains no oxygen so when burnt it has to be burnt in air with the reaction
CH4 + 2O2 → CO2 + 2H2O
as you can see methane and oxygen react to make carbon dioxide and water
a basic hydrocarbon reaction.
taken from wikipedia

if you were to puncture the pipes, either by penetration with a foreign object or rupturing the pipe itself through internal pressure, you would be ultimately introducing oxygen.