AAAAAAHHHHHHHHHHHHHHHHHHH BOOTS ON THE GROUND, ARMY OF THE WILLING- WE ARE SO FUCKED, THIS IS IT-ITS NEVER BEEN MORE JOEVER, WERE ALL GOING TO DIIIIIIIEEEEEEEEEEEEEEEEEEEEEEE
The Australian continent spent a lot of time at the south pole before drifting to its current position, and if you buy the dinosaurs and ferns theory for petroleum genesis (how'd they all get on the moon, Titan?), those were never optimal conditions for the sort of high-turnover forestry that created the hydrocarbon deposits.
If you're more open to the abiogenic theory for hydrocarbon genesis, it does seem a bit odd, but that would still depend on deep Earth topology, conditions, etc, whatever allows the burny-liquid and gasses to seep up to accessible depths.