Hey as Oil and Natural Gas Corporation Limited is an Indian multinational oil and gas company headquartered in Dehradun, Uttarakhand, India

Exam pattern
Duration of Written Test 3 Hrs
There will be no negative marking.
Each objective type question carries one mark.

Here I am giving you some books with content

General English For ONGC Exams Prep Course by GK Publishers
Table of Contents
English Usage
Spotting Errors
Analogy
Sentence Improvement
Selecting Word
Sentence Arrangement
Antonyms
Synonyms
Idioms
Comprehensive
One Word Substitution
Model Papers

Study Guide to General Engineering for ONGC and other Public Sector Examinations

Table of Contents
Fluid Mechanics
Engineering Mechanics
Engineering Materials
Thermodynamics
Strength of Materials
Measurements
Electrons and Photons
Electromagnetic and Magnetic circuits
D.C. Machines
A.C. Basics
Transformers
Synchronous Motors
Induction Motors
Computers Engineering