TA are usually for those with industry experience. Are you sure it's a TA and not an SI (usually fresh grad undergoes SI). As for the second question. You're kidding right? Petronas is one of the largest company in Malaysia, even the guys working in Petronas won't be able to answer that question.

case study role play etc are for SI and not for TA. For TA, they will ask you technical questions.

What is your degree? Most likely they will ask some technical questions regarding the courses you have taken.

What do you mean no majoring? Your major is Petroleum Engineering la.

Be prepared to answer question abour reservoir pressure and how you use information regarding reservoir pressure to determine contact (Oil Gradient vs Water Gradient vs Gas Gradient). They may also ask abou PVT, RFT etc etc and also ask you about the 9 spot development concept etc. Also be prepared to answer questions regarding reservoir development like natural depletion, water drive, gas cap drive etc etc.

Err, I think you misunderstood me, I went to a US University and when we say major, it means that's the area you are studying for a degree. So if you have a degree in PE, then your major is PE, my Major or my degree was in Geology etc etc ....

Just be frank and honest about it. If you have a gf/wife/foreveralone. Working offshore does not need you to sell your soul by giving up all luxury of life to work. Very common people working offshore have their own families. If a company expects that you can't have a gf don't work for that company as it is a slave driver company.

To me the main reason they ask is see if there is a conflict of interest. Like your wife or family members work in Petronas and you work in Shell. Beside that probably just want to create some conversation and get to know you better.