This mod effectively adds 2 empty barrels to the nauvis core fragment processing recipe,
the output chances for the fluid barrels are: 64% + 32% + 32% + 8% + 64% = 200%
(oil, mineral water, water, pyroflux & empty barrels respectively)

If playing without Krastorio 2 installed the numbers will be different but will still match their original fluid values.
Mods that chance barrel amounts should also be compatible with this, though i have not thourugly tested it myself.

This mod exists because hooking up 4 fluids at weird positions was just not fun for me, so yay for barrels.

Why does the recipe return empty barrels too? Well item ingredients can only be full numbers, so it's rounded up and you get the leftovers back.