hmm.. for utp intake, i think petronas does not offers scholarship (the term they use is "Pinjaman Boleh Ubah"). They will convert it to scholarship if you grad in 1st class honor (2nd class upper you have to pay 10%, and the value you have to pay increases as you grads at lower classes)
For utp programmes (5 years) the amount of loan will reach 100K.
For engineering students, in their final year petronas will conduct an interview to select candidates to fill in vacant position in the company.
the interview itself (conducted by petronas senior managers and above) will determine whether you can enter petronas or not. (the result will be "Recommended" or "Not reccomended")

Not recommended = no job in petronas, pay the loan according to your result

Recommended =
1) Wait for vacancies, serve according to years of sponsorship (1 year sponsor 2 years bonded), no need to pay loan, no deduction in salary to pay loan or
2) if no vancancies, they will release u from the bond, no need to pay loan

but there are cases where "not recommended" are also accepted in though..

sadfully for IT or IS students.. petronas no longer conducted interview for them.. so i can say almost 0% chances to enter petronas unless u have "connection"

As for petronas scholars overseas, the process is also the same but the interview will be conducted by higher level staff (general managers and above) so expect tougher interview..

so if u wanted to join petronas, u will need to know the workforce market by the time you grads.. for now petronas are after those who have Petroleum Engineering and Geologist background...