UPES

Yes,
UPES is a good college with best faculty and best placements. Visit the below Shiksha link to know about colleges in Uttarakhand. https://www.shiksha.com/engineering/colleges/ph-d-colleges-Uttarakhand
Visit the below Shiksha link to know about best colleges in India for Ph.D.
https://www.shiksha.com/humanities-social-sciences/colleges/ph-d-colleges-india.

Christ is highly reputed. It's name has a Goodwill Nationwide spread.

Hello Daniel, You have declared that you are doing a post graduate Diploma in petroleum engineering. However you have not mention as to the institute from where you are doing this. Be that as it may, but in India it is next to impossible to shift institutes after getting admission. You have to start the process afresh completely to get admission in another place where you want it now. But I would advise you to continue in the same place since you are already into the programme and must have been well-set in the place for studies as well as other essential things. Best wishes.

Here is the direct link. It will cost you 1.64 lakhs per semester. But check it out for yourself in the given link:
https://www.upes.ac.in/course/btech-applied-petroleum-engineering-with-specialization-in-upstream.

Yes,it is easy to clear UPES entrance exam level of paper is moderate.

It generally starts from month of November to first week of March.

Dear,
The average package was approximately INR. 2.7 lacs and the highest was INR. 4 lacs per annum.

Admission in UPES for MBA is not easy you have to get a good score in CAT exam.

UPES is the best college in all of the colleges you have mentioned above, as this college is best in class for the placements, infrastructure and faculty.