What type of EOR method uses the flooding of the oil reservoir from the top of the reservoir or from an updip location in order to push the oil towards a producing well?

What type of EOR method uses the flooding of the oil reservoir from the top of the reservoir or from an updip location in order to push the oil towards a producing well?

• A. Water Flood
• B. Gas Flood
• C. Chemical Flood
• D. Foam Flood

Answer: (B)

This description hinges on buoyancy-driven displacement. Injecting a gas into the reservoir creates a gas cap that sits at the top or updip region because gas is lighter than oil. As the gas pushes against the oil, it moves upward and outward, sweeping oil toward the producing well. That top-down, gravity-assisted sweep is the key feature of a gas flood. Water floods rely on a piston-like push from water, not on buoyancy of a gas cap, and chemical or foam floods modify interfacial properties rather than rely on buoyant displacement.

This description hinges on buoyancy-driven displacement. Injecting a gas into the reservoir creates a gas cap that sits at the top or updip region because gas is lighter than oil. As the gas pushes against the oil, it moves upward and outward, sweeping oil toward the producing well. That top-down, gravity-assisted sweep is the key feature of a gas flood. Water floods rely on a piston-like push from water, not on buoyancy of a gas cap, and chemical or foam floods modify interfacial properties rather than rely on buoyant displacement.