Polyelectrolyte complexes for oil and gas applications

1. A composition for controlling the release of an oil and gas field chemical comprising:

a polyanion and a polycation forming a polyelectrolyte complex, said polyelectrolyte complex having a polymeric core and polymeric shell, and an oil and gas field chemical associated with said polyelectrolyte complex, wherein said composition is injected into an oil and gas well for the controlled release of the oil and gas field chemical from said complex,

and wherein said oil and gas field chemical is selected from the group consisting of a scale inhibitor;

which is selected from the group consisting polyvinyl sulphonic acid, hexamethylene diamine tetrakis (methylene phosphonic acid), diethylene triamine tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid), bis-hexamethylene triamine pentakis (methylene phosphonic acid), phosphino carboxylic acid, diglycol amine phosphonate, 1-hydroxyethylidene, 1,1-diphosphonate, and bisaminoethylether phosphonate; and their alkali metal salts;

and wherein said polyelectrolyte complex is a nanoparticle having a particle size less than about 5000 nm.

2. The composition of claim 1 wherein said polycation is selected from the group consisting of chitosan, polyethylenimine, poly-L-lysine and said polyanion comprises dextran sulfate.

3. The composition of claim 1 further comprising a monovalent or bivalent cation selected from the group consisting of sodium ion or calcium ion.

4. The composition of claim 1 further comprising an anion selected from the group consisting of triphosphate ion, chloride ion, or sulfate ion.

5. The composition of claim 1 wherein said polyelectrolyte complex is a nanoparticle with a particle size of about 100 to 300 nm in diameter.

6. A method for producing a composition for the delayed release of an oil and gas field chemical comprising:

mixing a polyanion, a polycation, and an oil and gas field chemical together in solution;

ceasing mixing to form a composition comprising a polyelectrolyte complex having a polymeric core and polymeric shell, said polyelectrolyte complex comprising said polyanion and said polycation and said oil and gas field chemical associated with said polyelectrolyte complex; for the delayed release of the oil and gas field chemical from said complex,

and wherein said oil and gas field chemical is selected from the group consisting of a scale inhibitor;

which is selected from the group polyvinyl sulphonic acid, hexamethylene diamine tetrakis (methylene phosphonic acid), diethylene triamine tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid), bis-hexamethylene triamine pentakis (methylene phosphonic acid), phosphino carboxylic acid, diglycol amine phosphonate, 1-hydroxyethylidene, 1,1-diphosphonate, and bisaminoethylether phosphonate; and their alkali metal salts;

and wherein said polyelectrolyte complex is a nanoparticle having a particle size less than about 5000 nm.

7. The method of claim 6 wherein said polyanion and polycation are first mixed together separately prior to adding the oil and gas field chemical.

8. The method of claim 6 wherein said polycation and oil and gas field chemical are first mixed together separately prior to adding the polyanion.

9. The method of claim 6 wherein said polyanion and oil and gas field chemical are first mixed together separately prior to adding the polycation.

10. The method of claim 6 further comprising dialyzing said polyelectrolyte complex solution to isolate a polyelectrolyte nanoparticle having said oil and gas field chemical associated therewith.

11. The method of claim 6 wherein said polycation is selected from the group consisting of chitosan, polyethylenimine, poly-L-lysine and said polyanion comprises dextran sulfate.

12. The method of claim 6 further comprising the step of adding a cation selected from the group consisting of sodium ion or calcium ion.

13. The method of claim 6 further comprising the step of adding an anion selected from the group consisting of triphosphate ion, chloride ion, or sulfate ion.

14. The method of claim 6 wherein said complex is a nanoparticle ranging from about 100 to 300 nm in diameter.

15. The composition of claim 1 wherein said polyelectrolyte complex is a nanoparticle with a particle size of about 50 to 500 nm.

16. The method of claim 6 wherein said polyelectrolyte complex is a nanoparticle with a particle size of about 50 to 500 nm.

17. The composition of claim 1 wherein said polyelectrolyte complex is a nanoparticle with a particle size less than about 2000 nm.

18. The method of claim 6 wherein said polyelectrolyte complex is a nanoparticle with a particle size less than about 2000 nm.

19. The composition of claim 1 wherein said scale inhibitor is selected from the group consisting of polyvinyl sulphonic acid and its alkali metal salts.

20. The composition of claim 1 wherein said scale inhibitor is selected from the group consisting of hexamethylene diamine tetrakis (methylene phosphonic acid), diethylene triamine tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid), bis-hexamethylene triamine pentakis (methylene phosphonic acid), phosphino carboxylic acid, diglycol amine phosphonate, and 1-hydroxyethylidene 1,1-diphosphonate, bisaminoethylether phosphonate and their alkali metal salts.

21. A composition for controlling the release of an oil and gas field chemical comprising:

a polyanion and a polycation forming a polyelectrolyte complex, said polyelectrolyte complex having a polymeric core and polymeric shell, and an oil and gas field chemical associated with said polyelectrolyte complex, wherein said composition is injected into an oil and gas well for the controlled release of the oil and gas field chemical from said complex,

wherein said oil and gas field chemical is a gel-forming agent, and wherein said gel-forming agent is a chromium containing compound selected from the group consisting of chromium nitrate, chromium chloride, chromium citrate, chromium acetate, and chromium propionate; and wherein said polyelectrolyte complex is a nanoparticle having a particle size less than about 5000 nm.

22. The composition of claim 21 wherein said polycation is selected from the group consisting of chitosan, polyethylenimine, poly-L-lysine and said polyanion comprises dextran sulfate.

23. The composition of claim 21 further comprising a monovalent or bivalent cation selected from the group consisting of sodium ion or calcium ion.

24. The composition of claim 21 further comprising an anion selected from the group consisting of triphosphate ion, chloride ion, or sulfate ion.

25. The composition of claim 21 wherein said complex is a nanoparticle ranging from about 100 to 300 nm in diameter.

26. The composition of claim 21 wherein said complex is a nanoparticle ranging from about 50 to 500 nm in diameter.

27. The composition of claim 21 wherein said polyelectrolyte complex is a nanoparticle with a particle size less than about 2000 nm.

28. A method for producing a composition for the delayed release of an oil and gas field chemical comprising:

mixing a polyanion, a polycation, and an oil and gas field chemical together in solution;

ceasing mixing to form a composition comprising a polyelectrolyte complex having a polymeric core and polymeric shell, said polyelectrolyte complex comprising said polyanion and said polycation and said oil and gas field chemical associated with said polyelectrolyte complex;

and wherein said oil and gas field chemical is a gel forming agent which is a chromium containing compound selected from the group consisting of chromium nitrate, chromium chloride, chromium citrate, chromium acetate, and chromium propionate;

and wherein said polyelectrolyte complex is a nanoparticle having a particle size less than about 5000 nm.

29. The method of claim 28 wherein said polyanion and polycation are first mixed together separately prior to adding the oil and gas field chemical.

30. The method of claim 28 wherein said polycation and oil and gas field chemical are first mixed together separately prior to adding the polyanion.

31. The method of claim 28 wherein said polyanion and oil and gas field chemical are first mixed together separately prior to adding the polycation.

32. The method of claim 28 further comprising dialyzing said polyelectrolyte complex solution to isolate a polyelectrolyte nanoparticle having said oil and gas field chemical associated therewith.

33. The method of claim 28 further comprising the step of adding a cation selected from the group consisting of sodium ion or calcium ion.

34. The method of claim 28 further comprising the step of adding an anion selected from the group consisting of triphosphate ion, chloride ion, or sulfate ion.

35. The method of claim 28 wherein said complex is a nanoparticle ranging from about 100 to 300 nm in diameter.

36. The method of claim 28 wherein said polyelectrolyte complex is a nanoparticle with a particle size of about 50 to 500 nm.

37. The method of claim 28 wherein said polyelectrolyte complex is a nanoparticle with a particle size less than about 2000 nm.