The main job opportunity is as an Engineer in a Petroleum refinery. There are number of Private as well as Government refineries. One may apply for the post of an Engineer after graduation. Some big Petroleum Refineries in India are- Reliance Refinery (Jamnagar), Essar (Jamnagar), Cochin Refinery etc. One may also become an Engineer in Government enterprises such as ONGC and OIL!

Some common job posts available in front of Graduates after completing B.Tech. Petroleum Engineering are-

Petroleum Engineer
Product Testing Engineer
Exploration Engineer
Marketing Head
Refinery Manager
Production Manager
Transport and Storage specialist

All the Best!!