Secondary oil recovery by waterflooding with extracted petroleum acids

Claim 2

IN THE RECOVERY OF OIL FROM A SUBTERRANEAN OIL RESERVOIRPENETRATED BY SPACED INJECTION SYSTEMS, THE METHOD COMPRISING: A. CONTACTING A PETROLEUM OIL WITH AN AQUEOUS ALKALINE SOLUTION TO EXTRACT NEUTRALIZED ORGANIC AIDS FROM SAID OIL IN SAID AQUEOUS MEDIUM, B. SEPARATING THE RESULTING AQUEOUS SOLUTION OF NEUTRALIZED ORGANIC AIDS FROM SAID OIL, C. INJECTING SAID AQUEOUS SOLUTION OF NEUTRALIZED ORGANIC ACIDS INTO SAID RESERVOIR VIA SAID INJECTION SYSTEM D. THEREAFTER INTRODUCING INTO SAID RESERVOIR VIA SAID INJECTION SYSTEM AN AQUEOUS FLOODING MEDIUM TO DISPLACE OIL TO SAID PRODUCTION SYSTEM, AND E. RECOVERING FROM SAID PRODUCTION SYSTEM.

Claim 3

The method of claim 1 wherein said petroleum oil is a crude oil fraction exhibiting an API gravity within the range of 10* to 25*. 3. The method of claim 1 wherein said aqueous solution of neutralized organic acids contains dispersed oil in an amount within the range of 2 to 10 percent by volume.

Claim 4

The method of claim 1 further comprising the step of adding a monovalent salt to said aqueous solution of neutralized organic acids prior to injection thereof.

Claim 5

The method of claim 1 further comprising the step of adding an alkaline agent to said aqueous solution of neutralized organic acids prior to the injection thereof.

Claim 6

The method of claim 1 wherein at least a portion of the injected aqueous fluid comprises a thickening agent.

Claim 7

In a method of recovering oil from a subterranean reservoir penetrated by spaced injection and production systems and located in an oil field, the steps comprising: a. mixing water from a source of water in the field in which said reservoir is located with an alkaline agent to form an aqueous alkaline solution, b. contacting a petroleum oil produced in said field with said aqueous alkaline solution in an extraction zone to extract neutralized organic acids from said oil, c. withdrawing from said extraction zone a first effluent comprising oil and a second effluent comprising a mixture of an aqueous solution of neutralized acids and oil, d. passing said second effluent mixture to a separation zone in which at least a portion of the oil in said mixture is separated therefrom, e. returning said oil to said first effluent, f. withdrawing said aqueous solution of neutralized acids from said separation zone and introducing said solution into said reservoir via said injection system, g. thereafter introducing into said reservoir via said injection system an aqueous flooding medium to displace oil to said production system, and h. recovering oil from said production system.

Claim 8

In a method of recovering oil from a subterranean reservoir penetrated by spaced injection and production systems and located in an oil field, the steps comprising: a. mixing water from a source of water in the field in which said reservoir is located with an alkaline agent to form an aqueous alkaline solution, b. contacting a petroleum oil produced in said field with said aqueous alkaline solution in an extraction zone to extract neutralized organic acids from said oil, c. withdrawing from said extraction zone a first effluent comprising oil and a second effluent comprising a mixture of an aqueous solution of neutralized acids and oil, d. passing said second effluent mixture to a separation zone in which at least a portion of the oil in said mixture is separated therefrom, e. returning said oil to said first effluent, f. withdrawing said aqueous solution of neutralized acids from said separation zone and introducing said solution into said reservoir via said injection system, g. thereafter introducing into said reservoir via said injection system an aqueous flooding medium to displace oil to said production system, and h. recovering oil from said production system.

Claim 9

The method of claim 7 wherein the aqueous solution of neutralized acids withdrawn from said separation zone contains dispersed oil in an amount within the range of 2 to 20 percent by volume.

Claim 10

The method of claim 7 further comprising the step of heating the second effluent from said extraction zone prior to introducing said mixture into said separation zone.

Claim 11

The method of claim 7 wherein water from said field source is circulated in countercurrent flow with said first oil effluent in order to remove alkaline agents entrained in said oil.