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Enhanced Oil Recovery Secondary Methods

Introduction

Did you know that primary oil recovery methods only extract 15-20% of the oil in a reservoir? The remaining oil requires advanced techniques known as Enhanced Oil Recovery (EOR) or secondary recovery methods. In this blog, we’ll explore how water injection and gas injection help maximize oil production, especially in ONGC’s onshore and offshore fields.

Why Secondary Oil Recovery?

When natural reservoir pressure drops, primary methods become ineffective. That’s when EOR techniques come into play, helping recover more oil efficiently.

A.  Enhanced Oil Recovery (EOR): Water Injection Well Boosting Oil Production Sustainably

Water Injection Well

Water injection wells are a key secondary oil recovery method, enhancing crude oil extraction by maintaining reservoir pressure and displacing trapped oil. By injecting water into the reservoir, this technique improves sweep efficiency, extending the life of mature oil fields and increasing recovery rates by 20-40%. It’s a cost-effective and environmentally sustainable approach compared to tertiary EOR methods, making it a preferred choice for maximizing output in declining wells. Properly managed waterflooding reduces waste, optimizes resource use, and supports long-term energy production.

How Water Injection Wells Work in Enhanced Oil Recovery (EOR)

Water injection wells boost oil production by flushing trapped oil toward production wells. High-pressure water is pumped into the reservoir, displacing oil and maintaining pressure to prevent decline. Over time, this improves sweep efficiency, recovering additional oil that primary methods leave behind. Advanced monitoring ensures optimal injection rates, preventing water breakthrough and maximizing recovery.

🔹 How It Works:

Water is injected under high pressure (150-250 bar) into the reservoir.

Since water is denser than oil, it pushes the oil towards production wells.

🔹 Key Factors for Success:

✅ Mobility ratio (how easily oil and water flow)

✅ Reservoir geology (rock permeability and structure)

#OilRecovery #WaterFlooding #EOR

🔹 Where It’s Used:

Most oil companies implement this technique in depleted wells to enhance oil recovery, pushing trapped crude toward the production well.

B.  Enhanced Oil Recovery (EOR): Gas Injection Well Maximizing Oil Recovery Efficiently

Gas Injection Well

Gas injection wells are a vital secondary oil recovery method, enhancing production by injecting natural gas, nitrogen, or CO₂ into reservoirs. This technique maintains reservoir pressure and improves oil displacement, pushing trapped crude toward production wells. It’s particularly effective in high-pressure, high-permeability reservoirs, often increasing recovery rates by 20-30%. Gas injection is cost-efficient and environmentally adaptable, especially when using CO₂ for carbon storage benefits.

🔹 How It Works:

Gas is injected into the reservoir, where it expands and displaces oil, driving it toward production wells. Depending on the gas type, it may also mix with oil (miscible flooding), reducing viscosity for easier extraction. Advanced monitoring ensures optimal injection rates and sweep efficiency, maximizing recovery while minimizing gas breakthrough.

Natural gas, nitrogen, or CO₂ is injected into the reservoir.

Unlike water injection, gas is usually injected into the gas cap (upper part of the reservoir).

#GasInjection #EOR #OilAndGas

🔹 Benefits:

✔ Maintains reservoir pressure

✔ Helps displace oil towards production wells

🔹 Where It’s Used:

Most oil companies implement this technique in depleted wells to enhance oil recovery, pushing trapped crude toward the production well.

Conclusion

Secondary recovery methods such as water injection and gas injection are critical for maximizing oil production. Companies like ONGC and other major oil producers extensively apply these techniques to enhance oil recovery (EOR), ensuring efficient extraction from depleting reservoirs.

#EnhancedOilRecovery #ONGC #OilProduction #EnergySolutions