Enhanced Oil Recovery (EOR) is an advanced petroleum extraction technique that involves injecting industrial gases like carbon diox

ide (CO₂), nitrogen (N₂), or hydrogen (H₂) into depleted or mature oil wells to increase crude oil recovery. By using EOR, oil fields can extract 30–60% more oil from reservoirs that conventional drilling and primary recovery methods cannot reach.

Why is Enhanced Oil Recovery (EOR) Necessary?

• Conventional oil recovery methods (primary and secondary recovery) typically extract only 30–40% of the total available crude oil.

• The remaining oil is trapped in porous rock formations or becomes too thick and viscous to flow to the well.

• EOR injects gases like CO₂ or N₂ to change the physical properties of the trapped oil, making it easier to extract.

Types of Enhanced Oil Recovery (EOR) Using Industrial Gases

Carbon Dioxide Injection – The Most Common Method

Carbon dioxide (CO₂) is injected into oil reservoirs, where it mixes with crude oil and reduces its viscosity, making it less dense and easier to extract. As CO₂ interacts with the oil, it swells and expands, increasing its mobility and allowing it to flow more easily toward production wells. This enhanced movement of oil significantly improves recovery rates from mature or depleted fields. Once the oil-CO₂ mixture is pumped back to the surface, the CO₂ is separated, captured, and re-injected into the well, creating a

continuous cycle that maximizes extraction efficiency while also enabling carbon sequestration, reducing greenhouse gas emissions in the process.

Nitrogen Injection

Nitrogen is injected into oil reservoirs to maintain reservoir pressure and enhance oil recovery by pushing trapped crude toward production wells. It helps prevent gas cap expansion, ensuring consistent pressure levels while also sweeping residual oil from rock pores, improving overall extraction efficiency. This method is particularly ideal for offshore oil fields, where water injection is impractical due to logistical and environmental challenges. Additionally, nitrogen injection helps reduce gas contamination in natural gas-condensate reservoirs, improving the quality and purity of extracted hydrocarbons.