Polymer-microemulsion complexes for the enhanced recovery of oil

• US 4,353,806 A
• Filed: 04/03/1980
• Issued: 10/12/1982
• Est. Priority Date: 04/03/1980
• Status: Expired due to Term

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Robbins, Max L., Canter, Nathan H., Baker, Edward G.
• Primary Examiner(s): Guynn, Herbert B.
• Application Number:
  US06/136,936
• Time in Patent Office: 922 Days
• Field of Search: 252/8.55 D, 166/274, 166/275
• US Class Current: 507/229
• CPC Class Codes: C08J 3/02 Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
• CPC Class Codes: C09K 23/00 Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
• CPC Class Codes: C09K 23/04 Sulfonates or sulfuric acid ester salts derived from polyhydric alcohols or amino alcohols or derivatives thereof sulfated or sulfonated fatty oils C09K23/08
• CPC Class Codes: C09K 23/42 Ethers, e.g. polyglycol ethers of alcohols or phenols
• CPC Class Codes: C09K 8/584 characterised by the use of specific surfactants
• CPC Class Codes: C09K 8/588 characterised by the use of specific polymers polymeric surfactants C09K8/584
• CPC Class Codes: Y10S 507/938 with microemulsion

Abstract

A polymer-microemulsion complex useful for the enhanced recovery of crude oil is disclosed. The polymer is polyethylene oxide or polyvinyl pyrrolidone and interacts with the surfactant of the microemulsion to form a physical association. The resulting complex is characterized by a complexation energy of at least 2 Kcal/mole. The polymer microemulsion complexes are stable at high salinity, reduce adsorption and retention by the formation, lower interfacial tension, achieve retentions as low as 0.1 mg surfactant/gm sand at high salinity and provide for early banking, as well as high recovery of oil.

Claims

1. A stabilized microemulsion system containing a polymer-microemulsion complex which comprises:

(a) a microemulsion, said microemulsion including as components

(1) an oil

(2) water having up to 25% by weight of dissolved

inorganic salts and

(3) 0.2 to 15 wt.%, based on the microemulsion, of at least one anionic surfactant balanced to form the microemulsion, and

(b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer has a molecular weight of from 4,000 to 5,000,000 and is selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, the polymermicroemulsion complex being characterized by a complexation energy of at least 2 Kcal/mole.

2. The microemulsion system of claim 1 wherein the complexation energy is from about 5 to 15 Kcal/mole.

3. The microemulsion system of claim 1 wherein component (2) contains from about 1 to 14 wt.% based on water of dissolved inorganic salts.

4. The microemulsion system of claim 1 wherein component (1) is a sweet or sour crude;

synthetic crude;

refined fraction such as kerosene, diesel oil, lube oil, aromatic naphtha or white oil boiling at from 80°

to 345°

C.;

C₆ to C₂₂ aliphatic hydrocarbon;

aromatic hydrocarbon boiling at from 80°

to 300°

C.;

or mixtures thereof.

5. The microemulsion system of claim 1 wherein component (3) is a mixture of an anionic surfactant with at least one other anionic, nonionic or cationic cosurfactant.

6. The microemulsion system of claim 5 wherein the anionic surfactant or anionic cosurfactant is a sulfonate or sulfate.

7. The microemulsion system of claim 6 wherein the sulfonate has the formula

8. The microemulsion system of claim 6 wherein the sulfate has the formula

9. The microemulsion system of claim 5 wherein the mixture contains dodecylxylene sulfonate or dodecylbenzene sulfonate as the anionic surfactant.

10. The microemulsion system of claim 5 or 9 wherein the nonionic cosurfactant is an ethoxylated C₈ to C₂₅ alkanol or an ethoxylated phenol of the formula

11. The microemulsion system of claim 9 wherein the nonionic cosurfactant is an ethoxylated C₈ to C₂₄ alkylphenol.

12. The microemulsion system of claim 9 wherein the nonionic cosurfactant is an ethoxylated octyl, nonyl or -dodecyl phenol containing 8 to 24 --CH₂ CH₂ O-- groups, or an ethoxylated dinonyl phenol containing 8 to 50 --CH₂ CH₂ O-- groups.

13. The microemulsion system of claim 9 wherein the anionic cosurfactant is a sulfated ethoxylated C₁₂ -C₁₆ alkanol or sulfonated ethoxylated C₈ -C₂₆ alkyl phenol.

14. The microemulsion system of claim 9 wherein the anionic cosurfactant is a sulfonated ethoxylated dinonyl phenol containing 8 to 50 --CH₂ CH₂ O-- groups.

15. The microemulsion system of claim 5 or 9 wherein the nonionic or cationic cosurfactant is a C₈ to C₃₀ alkylamine, C₈ to C₃₀ ethoxylated alkylamine or the respective quaternary ammonium salts thereof.

16. The microemulsion system of claim 9 wherein the nonionic or cationic cosurfactant has the formula ##STR14## where m is from 8 to 25 and the sum of u+v is from 2 to 20.

17. The microemulsion system of claim 5 wherein the anionic surfactant and cosurfactant have hydrophilic and lipophilic properties which are balanced.

18. A micellar formulation suitable for recovering crude oil by chemically enhanced recovery techniques which comprises

(a) 0.3 to 98 wt.% of oil,

(b) 1 to 99 wt.% of water containing up to 25% dissolved inorganic salts,

(c) 0.2 to 15 wt.% of at least one anionic surfactant,

(d) 0.1 to 10 wt.% of a polar polymer capable of forming a polymer-surfactant complex wherein the polar polymer has a molecular weight of from 4,000 to 5,000,000 and is selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, and

(e) 0 to 15 wt.% of cosurfactant, wherein the polar polymer and surfactant form a polymer-surfactant complex characterized by a complexation energy of at least 2 Kcal/mole.

19. The micellar formulation of claim 18 wherein the amounts of components (a) to (c) are from 0.3 to 30 wt.%, 50 to 99 wt.% and 0.2 to 10 wt.%, respectively.

20. The micellar formulation of claim 18 wherein component (c) is an anionic surfactant and component (e) is an anionic, cationic or nonionic cosurfactant.

21. The micellar formulation of claim 18 wherein component (c) is a sulfate or sulfonate surfactant.

22. The micellar formulation of claim 18 wherein the formulation is anisotropic and birefringent.

23. The micellar formulation of claim 18 wherein the formulation is a microemulsion.