Top 15 Oil and Gas Engineering Interview Questions & Answers (With Tips)

Introduction: The oil and gas industry is one of the most challenging yet rewarding sectors for engineers. Whether you're a fresh graduate or a seasoned professional, preparing for an interview requires a clear understanding of technical concepts, industry standards, and safety practices. In this post, we’ll cover the top 15 oil and gas engineering interview questions with sample answers and expert tips.

1. What is the difference between upstream, midstream, and downstream?

• Answer:

  • Upstream: Exploration and production of crude oil and natural gas.

  • Midstream: Transportation and storage of oil and gas.

  • Downstream: Refining and marketing of petroleum products.

• Tip: Use examples like drilling rigs (upstream), pipelines (midstream), and refineries (downstream).

2. What are the common drilling techniques used in the oil and gas industry?

• Answer: Rotary drilling, directional drilling, and horizontal drilling.

• Tip: Mention real-world applications and recent innovations if possible.

3. How do you perform material selection for oil and gas pipelines?

• Answer: Based on temperature, pressure, corrosion resistance, and material strength. Carbon steel is commonly used.

4. What is a P&ID?

• Answer: Piping and Instrumentation Diagram—a detailed diagram showing the piping and related components of a process system.

5. How is safety ensured in oil and gas operations?

• Answer: Through HAZOP studies, regular maintenance, PPE, training, and emergency response plans.

6. What is HAZOP?

• Answer: Hazard and Operability Study—a systematic review to identify and evaluate potential hazards in a system.

7. What are the causes of pipeline corrosion?

• Answer: Moisture, chemicals, microbiological activity, and temperature variations.

8. What is pigging in pipeline maintenance?

• Answer: The process of cleaning and inspecting pipelines using devices called “pigs.”

9. Describe the working of a separator in oil and gas facilities.

• Answer: Separates oil, gas, and water using gravity separation based on fluid densities.

10. What is an FPSO?

• Answer: Floating Production, Storage, and Offloading unit—used offshore to process and store hydrocarbons.

11. What are the types of artificial lift?

• Answer: Rod lift, gas lift, electric submersible pumps, and progressive cavity pumps.

12. How is well integrity monitored?

• Answer: By pressure tests, logging tools, and annular pressure monitoring.

13. What is the role of a choke valve?

• Answer: Controls the flow rate of fluids from the well.

14. Explain the difference between API and ASME standards.

• Answer:

  • API: American Petroleum Institute – Focuses on oil and gas industry standards.

  • ASME: American Society of Mechanical Engineers – Covers broader mechanical standards.

15. What is flare gas and why is it burned?

• Answer: Excess gas released during pressure relief or startup is flared to prevent explosions and reduce emissions.

Final Tips:

• Stay updated on current oil prices and geopolitical factors.

• Practice explaining complex terms in simple language.

• Use the STAR method for behavioral questions.