Hello Ankit

Definitely petroleum engineering is much easier than electrical engineering. In petroleum engineering you have to learn subject like petroleum chemistry, subject deals with chemical, environmental as a subject. While in electrical engineering you have to deals with lots of circuit problems. You have to learn subject like electrical circuit analysis, basic of electronic engineering, network synthesis analysis which are difficult in comparison to petroleum engineering. While subject like engineering mathematics, introduction to computer programming and physics is common in both branch in first year and second year.

Good luck for your future :)

Feel free to ask if you have any further queries.