First off, are you just interested in Petroleum engineering in general or is there a specific component? I'm asking this because there are opportunities for all streams of engineering to work in the petroleum line.
For example,
Chemical - Processing, Mixtures (Most flexible for the petroleum industry)
Aero/mech - Fluids, mechanical design (machines and stuff)
Civil - Geo-technical, Surveying
Electrical/Mechatronics - Automation, robotics etc.
Also, if you are dead set on working in that industry, I would recommend university located in WA, think University of Western Australia or Curtin University. 90% of internships/companies in the petroleum industry in Australia is located over there, and you do need to be exceptional to secure a position as an interstate student.
A chemical engineering degree with a specialization in petroleum engineering would be pretty relevant.
P.S. Yes they pay extremely well. Large companies pays interns up to 15k for a 3 months period + super and accommodations etc. so you can imagine the money in it. The industry is a little slow now but it's cyclical so if you're really intent on doing it, it's a really good pathway with good opportunities (relative to other streams anyway)