This is an on-site interview for a PhD level research Engineer in Hydrocarbon R&D group. I got this opportunity from an employee referral. The process started with a 45-60 min long presentation on my own graduate research, followed by 6-7 1:1 interviews with the research scientists/engineers. It also included a dinner the night before, a lunch during the interview, a lab tour and an HR wrap-up. The whole process was from 8AM to 3:30PM.