US 4,396,530 A · Mineral acid demulsification of surfactant-containing emulsion

Abstract

Oil is recovered simultaneously from all phases of a surfactant-produced crude oil or simultaneously from the middle and upper phases of such an emulsion by acidizing the emulsion with a mineral acid, preferably nitric acid. Following the acidation step, the oil is rendered relatively noncorrosive by the use of a neutralization step which incorporates a demulsifier to prevent the reformation of subsequent emulsions. Polyalkyloxyamines are particularly useful as both neutralizers and demulsifiers. The process of the present invention is useful in the demulsification of crude oil emulsions produced by surfactant floods utilized in secondary and tertiary oil recovery techniques. The invention is particularly beneficial in the treatment of such emulsions produced by micellar or micellar-polymer flooding of oil reservoirs.

Claims11

Dependent claims

A process for the demulsification of emulsions contained in a surfactant produced crude oil emulsion comprising:

contacting the surfactant produced crude oil emulsion for a time period of from about 0.01 to about 10 hours at a temperature of between about 37.degree. C. to about 94.degree. C. with an amount of nitric acid sufficient to give the mixture a pH of less than about 6 to cause the demulsification of the crude oil emulsion.

A process for the demulsification of emulsion phases contained in a surfactant produced crude oil emulsion comprising:

(a) contacting the surfactant produced crude oil emulsion for a time period of from about 0.01 to about 10 hours at a temperature of between about 37.degree. C. to about 94.degree. C. with a mineral acid selected from the group consisting of nitric acid, sulfuric acid and hydrochloric acid in an amount sufficient to give the mixture a pH of less than about 6;
(b) separating the oil phase from the phases caused by the demulsification of step (a);
and
(c) neutralizing the oil phase by contacting the oil phase with an inorganic base selected from the group consisting of sodium bicarbonate and alkali metal hydroxides or a non-ionic, water-soluble amine base in an amount sufficient to raise the pH to at least about 7, and wherein the base utilized for neutralization does not have demulsifying properties, conducting the neutralization step in the presence of an amine-containing demulsifier;
(d) allowing the mixture of step (c) to separate into at least two phases, one of which is an oil phase;
and
(e) separating the oil phase from the other phases present.

4 more elements

Dependencies are inferred from the claim text.

Mineral acid demulsification of surfactant-containing emulsion

Life of this patent

Mineral acid demulsification of surfactant-containing emulsion

Life of this patent

Abstract

Claims11