I applied through my university's internship program, but online on Suncor's website. Got a call from HR requesting a phone interview one week after job posting closed, also asked some pre-sreening questions (nothing big, just things like how long you are available for, willing to relocate, etc); interview was two days after and offer came within 24 hours. Interviewed with engineers that I would be working with, no HR. Not much behavioral questions, it was really a get to know the company and the role and for them to get to know me, asked questions about experience and skills listed on my resume (just to throw more light on them), asked about projects I had worked on that were listed on my resume.
I think the main thing was being able to communicate the passion and desire to work with the company, to learn (very important) and just the general motivation. Phone interviews can be tricky because of the absence of facial expression, etc, but if you prepare and smile your way (its in your voice), you'd be fine