Gas pre-injection for chemically enhanced oil recovery
AssigneeExxon Research & Engineering Co.
InventorsEdward G. Baker, John S. Huang
Life of this patent
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Abstract
A method for the chemically enhanced recovery of oil in which a gas is injected into the oil-bearing formation prior to the commencement of any surfactant flood. The pre-injection of gas allows the chemical flood to function more effectively and also permits the use of unthickened pushers and smaller surfactant banks.
Claims10
A process for the chemically enhanced recovery of oil from an oil-bearing formation which consists essentially of the steps of
- injecting nitrogen, flue gas or exhaust gas into the formation in an amount sufficient to attain trapped gas phase saturation,
- injecting a fluid containing an effective amount of surfactant to displace oil,
- driving the fluid through the formation with an aqueous pusher, and
- recovering the displaced oil.
A process for the chemically enhanced recovery of oil from an oil-bearing formation which consists essentially of the steps of
- injecting nitrogen, flue gas or exhaust gas into the formation in an amount sufficient to attain trapped gas phase saturation,
- injecting a fluid containing an effective amount of a microemulsion to displace oil,
- driving the fluid through the formation, with an aqueous pusher, and
- recovering the displaced oil.
A process for the chemically enhanced recovery of oil from an oil-bearing formation which consists essentially of the steps of
- injecting nitrogen, flue gas or exhaust gas into the formation in an amount sufficient to attain trapped gas phase saturation,
- injecting a fluid containing an effective amount of a microemulsion to displace oil,
- driving the fluid through the formation with an unthickened water or brine, and
- recovering the displaced oil.
Dependencies are inferred from the claim text.