Method for resolving emulsions in enhanced oil recovery operations
View Patent ↗Disclosed and claimed is a method of demulsifying a produced emulsion into oil and water by adding a surfactant to the produced emulsion. The surfactant comprises any combination of surfactants having a plurality of hydrophilic groups.
1. A method of demulsifying an emulsion comprising water and oil, the method comprising adding an effective amount of a composition comprising a cationic surfactant to the emulsion to form a mixture and optionally applying heat to the mixture, wherein the cationic surfactant comprises one or more bolaform surfactants, one or more gemini surfactants, or any combination of the foregoing;
wherein the bolaform surfactant is selected from the group consisting of: alkyl-bis(trimethylammonium halide); alkyl-bis(benzyldimethyl ammonium halide); alkyl-bis(amidopropyl-N-benzyl-N,N-dimethylammonium halide); alkyl-bis(amidopropyl-N,N,N-trimethylammonium halide); and any combination thereof, wherein the bolaform surfactant has an average alkyl chain length of C 6 to C 24 ; and
wherein the gemini surfactant is selected from the group consisting of: (C 2 -C 12 )-bis(dimethylalkylammonium halide), (C 2 -C 12 )-bis(methylbenzyl alkylammonium halide), and any combination of thereof, wherein the (C 2 -C 12 )-bis(dimethylalkylammonium halide) and (C 2 -C 12 )-bis(methylbenzyl alkylammonium halide) have an average alkyl chain length of C 6 to C 16 .
2. The method of claim 1 , wherein the halide is selected from the group consisting of: fluoride, chloride, bromide, iodide, astatide, and any combination thereof.
3. The method of claim 1 , wherein the (C 2 -C 12 )-bis(dimethylalkylammonium halide) and (C 2 -C 12 )-bis(methylbenzyl alkylammonium halide) have an average chain length of C 6 to C 10 .
4. The method of claim 1 , wherein the halide is selected from the group consisting of: fluoride, chloride, bromide, iodide, or any combination thereof.
5. The method of claim 1 , wherein the composition comprises from about 30 to about 90 wt % active material of the cationic surfactant.
6. The method of claim 1 , wherein the composition further comprises an organic solvent, water, and any combination thereof.
7. The method of claim 6 , wherein the organic solvent comprises an alcohol, an ether, an aromatic compound, or any combination thereof.
8. The method of claim 1 , wherein the effective amount of the composition comprises from about 50 ppm to about 20,000 ppm, based on actives and total emulsion volume.
9. The method of claim 1 , further comprising adding a polymeric nonionic surfactant to the emulsion.
10. The method of claim 9 , wherein the composition and the polymeric nonionic surfactant are added to the emulsion in a weight ratio of about 9:1 to about 1:1.
11. The method of claim 9 , wherein the polymeric nonionic surfactant and the composition are added about simultaneously to the emulsion.
12. The method of claim 1 , wherein the emulsion is a produced emulsion from an enhanced oil recovery operation.