I applied online. The process took 2 months. I interviewed at Indian Oil (Neu-Delhi) in Jul 2017
Interview
The interview process involves 2 rounds:
1) GD ( It's simple , one must present his point of view on the topic and keep it simple)
2) Technical and HR Interview: 5-10 technical questions, very basics and finally few HR personal questions.
Just keep it simple is the key.
Technical interview mainly pertaining to various aspects of refinery operations along with a general idea on how equipments work.Majority of the questions were quite basic in nature pertaining to distillations ,pumps etc.
I applied through college or university. The process took 3 weeks. I interviewed at Indian Oil (Neu-Delhi) in Jan 2013
Interview
Not so hard. It was a good experience to share the things that you were taught at undergraduate school and then answering the counter questions.It was a interview organised on my undergraduate school campus. Entire process took 1 day and was notified spot on. I would classify the entire interview being a technical one.