Petroleum Engineering

Hi Prakhar,
The oil and gas industry is usually divided into three major sectors: upstream, midstream and downstream. The upstream oil sector is also commonly known as the exploration and production (E&P) sector.
The upstream sector includes searching for potential underground or underwater crude oil and natural gas fields, drilling exploratory wells, and subsequently drilling and operating the wells that recover and bring the crude oil and/or raw natural gas to the surface. There has been a significant shift toward including unconventional gas as a part of the upstream sector, and corresponding developments in liquefied natural gas (LNG) processing and transport.
The midstream sector involves the transportation (by pipeline, rail, barge, oil tanker or truck), storage, and wholesale marketing of crude or refined petroleum products. Pipelines and other transport systems can be used to move crude oil from production sites to refineries and deliver the various refined products to downstream distributors. Natural gas pipeline networks aggregate gas from natural gas purification plants and deliver it to downstream customers, such as local utilities. The midstream operations are often taken to include some elements of the upstream and downstream sectors. For example, the midstream sector may include natural gas processing plants that purify the raw natural gas as well as removing and producing elemental sulfur and natural gas liquids (NGL) as finished end-products.
The downstream sector commonly refers to the refining of petroleum crude oil and the processing and purifying of raw natural gas,[1] as well as the marketing and distribution of products derived from crude oil and natural gas. The downstream sector reaches consumers through products such as gasoline or petrol, kerosene, jet fuel, diesel oil, heating oil, fuel oils, lubricants, waxes, asphalt, natural gas, and liquefied petroleum gas (LPG) as well as hundreds of petrochemicals.
Please feel free to discuss more.
Wish you luck.

Definitely, CSE will give you better chances of higher salary. In CSE, you can get into companies like a Google, Microsoft etc.
I will suggest you University of Engineering & Management (UEM) under IEM group.
Students passing out from IEM and UEM are all having 1-2 join offers. They are working all over the world in top positions. They are working in Microsoft, Google, Oracle, Honeywell, IBM research, INTEL and all top multinational companies.
Govt of India, MHRD, NIRF
has ranked IEM group as 3rd in Bengal after IIT Kharagpur and NIT Durgapur. The top 4 of Bengal within 100 in order are:-
1) IIT Kharagpur
2) NIT Durgapur
3) IEM Kolkata
4) IIEST Shibpur (Formerly BESU)