This type of tertiary recovery method involves injecting air into the formation and igniting the oil.

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

Answer: (A)

Fire Flood is a thermal enhanced oil recovery method where air is injected into the formation and the oil is ignited in place. The burning front travels through the reservoir, heating nearby oil and lowering its viscosity, which helps mobilize the oil and push it toward production wells. The heat and combustion gases further aid displacement, making heavy or thick oil easier to recover. This approach is unique because it relies on ignition of oil in situ, unlike the other methods that use injected fluids or foams without combustion. Gas flood injects gas to push oil but does not ignite; water flood uses water for displacement; foam flood introduces foam to improve sweep without burning. So the described method is Fire Flood.