how much does a well really cost?, page-8

Mandurah,

TPT free carried and total well cost is around $30m. They've got a budget of $33.5m for a bit of overshoot. Water depths are 200m.

PVD are drilling into depths of around 2000m and are carried on two wells at a maximum of $215m, so around $100m each. The difference between deep water and shallow is huge.

Onshore is even cheaper again. Your best bet would be to ring the company and actually ask what a drill might cost in this area, obviously giving or taking up to $5m so they'll actually give a figure.