Method for resolving emulsions in enhanced oil recovery operations
View Patent ↗Disclosed and claimed is a method of demulsifying an emulsion comprising water and oil. The method comprises adding an effective amount of a composition comprising at least one substantially fully quaternized ammonium adduct of polyephalohydrin that has a molecular weight from about 500 Da to about 2,500 Da.
1. A method of demulsifying a produced emulsion from an enhanced oil recovery flood to give clean water with less than about 300 ppm residual oil and dry oil with less than about 1% total sediment, the method comprising:
adding an effective amount of a composition to the produced emulsion, the composition comprising at least one water soluble quaternary adduct of a tertiary amine and a polyepihalohydrin, said adduct being greater than 99% quaternized and having a weight average molecular weight of from about 500 to about 2,500 Daltons; a solvent comprising an organic solvent, water, or a combination thereof, wherein the produced emulsion comprises water and oil, and the quaternary adduct has the general formula:
wherein each R is independently methyl or ethyl, X − is a halide selected from the group consisting of fluoride, chloride, bromide, iodide, astadide, or a combination thereof, and z ranges from about 4 to about 22.
2. The method of claim 1 , wherein the composition is free of zinc chloride.
3. The method of claim 1 , wherein X is chloride.
4. The method of claim 1 , wherein z is 6.
5. The method of claim 1 , wherein at least one R is methyl.
6. The method of claim 1 , wherein each R is methyl.
7. The method of claim 1 , wherein the composition comprises from about 30 to about 90 wt % active material.
8. The method of claim 1 , wherein the organic solvent comprises an alcohol, an ether, an aromatic compound, or a combination thereof.
9. The method of claim 1 , wherein the effective amount of the quaternary adduct comprises from about 50 ppm to about 20,000 ppm of the quaternary adduct, based on actives and total emulsion volume.
10. The method of claim 9 , wherein the composition comprises from about 200 ppm to about 10,000 ppm of the quaternary adduct, based on actives and total emulsion volume.
11. The method of claim 1 , wherein the produced emulsion further comprises an anionic surfactant.
12. The method of claim 1 , wherein the produced emulsion further comprises a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, or a combination thereof.
13. The method of claim 1 , wherein the enhanced oil recovery flood is an alkaline surfactant-polymer (ASP) flood.
14. The method of claim 3 , wherein z is 6.
15. The method of claim 14 , wherein at least one R is methyl.
16. The method of claim 15 , wherein each R is methyl.
17. The method of claim 16 , wherein the organic solvent comprises an alcohol, an ether, an aromatic compound, or a combination thereof.
18. The method of claim 17 , wherein the effective amount of the quaternary adduct comprises from about 50 ppm to about 20,000 ppm of the quaternary adduct, based on actives and total emulsion volume.
19. The method of claim 18 , wherein the produced emulsion further comprises an anionic surfactant.
20. The method of claim 19 , wherein the enhanced oil recovery flood is an alkaline surfactant-polymer (ASP) flood.