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1. WO2020153945 - METHOD OF TREATING SUBTERRANEAN FORMATIONS WITH COMPOSITES HAVING ENHANCED STRENGTH

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[ EN ]

CLAIMS

What is claimed is:

1 . A method of treating a subterranean formation penetrated by a well comprising introducing into the well a composite comprising a proppant or sand control particulate core strengthened with a coating covering at least a portion of the proppant or sand control particulate, the coating comprising a hardened reaction product prepared from:

(a) silica or a silicate;

(b) an alkali hydroxide or alkali oxide;

(c) an aluminosilicate; and

(d) at least one member selected from the group consisting of”

(i) aluminum trichloride;

(ii) alkaline earth oxide or hydroxide;

(iii) zinc chloride;

(iv) an oxide of a transition metal; and

(v) weak organic acid, salt or ester thereof.

2. The method of claim 1 , wherein the composite is prepared by etching at least a portion of the surface of the proppant or sand control particulate core prior to introducing any of (a), b), (c) or (d) to the proppant or sand control particulate core.

3. The method of claim 2, wherein the proppant or sand control particulate core is etched with sodium hydroxide and/or sodium silicate.

4. The method of any of claims 1 to 3, wherein the molar ratio of Si02:Al2C>3 in the aluminosilicate is from about 1 :1 to about 30:1.

5. The method of claim 4, wherein the molar ratio of Si02:Al203 in the aluminosilicate is from about 1 :1 to about 6:1 .

6. The method of any of claims 1 to 5, wherein (d) comprises aluminum trichloride.

7. The method of any of claims 1 to 6, wherein (d) comprises an oxide of a transition metal and/or zinc chloride.

8. The method of claim 7, wherein the transition metal oxide is zinc oxide.

9. The method of any of claims 1 to 6, wherein the transition metal of the transition metal containing oxide is selected from the group consisting of a Group III to VI II metal.

10. The method of any of claims 1 to 9, wherein the transition metal of the transition metal oxide is selected from the group consisting of zinc, copper, titanium, zirconium, vanadium, niobium, chromium, molybdenum, tungsten, manganese, cobalt, iron, nickel or palladium.

1 1. The method of any of claims 1 to 10, wherein (d)(v) is at least one member selected from the group consisting of acetic acid, formic acid, citric acid, oxalic acid, malonic acid, succinic acid, malic acid, tartaric acid, lactic acid, fumaric acid, propionic acid, butyric acid, chloroacetic acid, edetatic acid, pentateic acid or a salt, anhydride or ester thereof and as mixtures thereof.

12. The method of any of claims 1 to 5, wherein the composite is prepared by applying a mixture comprising (a), (b) and (c) onto the surface of the core and hardening the mixture in the presence of aluminum trichloride and/or zinc chloride.

13. The method of any of claims 1 to 5, wherein the composite is prepared by applying a mixture comprising (a), (b), (c) and aluminum trichloride and/or zinc chloride onto the surface of the core and then hardening the mixture onto the surface of the core.

14. The method of claim 13, further comprising applying additional aluminum trichloride and/or zinc chloride onto the surface of the core while hardening the mixture.

15. The method of claim 12, wherein the mixture applied onto the core further comprises alkaline earth oxide or hydroxide.

16. The method of claim 15, wherein the coating comprises calcium silicate and sodium silicate and further wherein the calcium silicate is formed from the reaction of the alkaline earth oxide or hydroxide during the hardening of the mixture.

17. The method of claim 15 or 16, further comprising applying additional aluminum trichloride and/or zinc chloride onto the surface of the core while hardening the mixture.

18. The method of any of claims 1 to 5 wherein the composite is prepared by applying a mixture comprising (a), (b), (c) and an oxide of a transition metal and/or zinc chloride onto the surface of the core and hardening the mixture.

19. The method of claim 18, wherein the transition metal is zinc.

20. The method of claim 18 or 19, further comprising applying aluminum trichloride onto the core and hardening the surface mixture onto the surface of the core in the presence of the aluminum trichloride and/or zinc chloride.

21. The method of any of claims 1 to 20, wherein the composite is a proppant and the subterranean formation is subjected to fracturing at a pressure sufficient to create or enlarge a fracture in the formation.

22. The method of any of claims 1 to 5 wherein in a first step the core is mixed with an aqueous solution of the silica or sodium silicate and sodium hydroxide to create a uniform wetness on the surface of the core and, in a second step, (ii) introducing to the wet core, a mixture of the aluminosilicate and aluminum trichloride and/or zinc chloride is introduced to the wet core.

23. The method of any of claims 1 to 5, wherein in a first step a mixture of (a), (b), (c) and aluminum trichloride and/or zinc chloride is spread onto the surface of the core and, in a second step, (a), (b) and (c) undergo a sol-gel exothermic reaction.

24. The method of any of claims 1 to 5, wherein a slurry of (a) and (b) are applied onto at least a portion of the core to provide a uniform wetness to the core and then applying a mixture of the aluminosilicate and aluminum trichloride and/or zinc chloride to the core.

25. The method of claim 24, wherein the mixture applied to the wet core further comprises an alkaline earth hydroxide or oxide.

26. The method of claim 25, wherein aluminum trichloride and/or zinc chloride is further applied to the core during hardening.

27. The method of any of claims 1 to 5, wherein a slurry of (a), (b), (c) and the transition metal oxide and/or zinc chloride is spread onto the at least a portion of the core in the reactor and further wherein aluminum chloride is added to the reactor after spreading the slurry onto the core.

28. The method of any of claims 1 to 5, wherein in a first step a sol-gel exothermic reaction occurs between (a) and (c) in the presence of (b) and, in a second step, either (i), (ii), (iii) and/or (iv) is applied onto the core.

29. The method of any of claims 1 to 5, wherein the composite is prepared by a sol-gel exothermic reaction comprising:

(a) combining in a vessel the proppant core with a mixture comprising (i) sodium silicate and/or silica and the alkali hydroxide to wet the sand;

(b) adding to the wet sand a mixture of (i) dehydroxylated kaolin, (ii) alkaline earth hydroxide and/or oxide; (ii) optional aluminum trichloride; and hardening the mixture onto the proppant core;

(c) hardening the mixture onto at least a portion of the surface of the proppant core in the vessel;

(d) applying a liquid solution of aluminum trichloride onto the proppant core during hardening of the mixture;

(e) removing the hardened mixture from the vessel; and

(f) curing the product of step (e).

30. The method of any of claims 1 to 29, wherein the core is heated prior to contacting the core with the silica or silicate.

31. The method of claim 30, where the core is heated to between about 0 and about 300 °C.

32. The method of any of claims 1 to 5, wherein the composite is prepared by a sol-gel exothermic reaction comprising:

(a) combining in a vessel the proppant core with a slurry comprising (i) sodium silicate and/or silica; (ii) zinc oxide and/or an alkaline earth and/or oxide; (iii) alkali hydroxide; and (iv) dehydroxylated kaolin and applying the slurry onto the proppant core and hardening the slurry onto the proppant core;

(b) adding to the product of step (a) dry aluminum chloride;

(c) spraying water onto the core during hardening of the slurry; and

(d) removing the hardened mixture from the vessel; and

(e) curing the product of step (d).

33. A method of treating a subterranean formation penetrated by a well comprising introducing into the well a composite comprising a proppant or sand control particulate core strengthened with a coating covering at least a portion of the proppant, the coating comprising a cured reaction product prepared from:

(a) compound selected from the group consisting of an alkali metal phosphate, a phosphoric acid, ammonium phosphate, and combinations thereof and

(b) a binder selected from the group consisting of a metal oxide, a metal hydroxide, an alkaline earth metal hydroxide, an alkaline earth metal oxide, an aluminosilicate, and combinations thereof;

(c) an alkali hydroxide or alkali oxide; and

(d) at least one member selected from the group consisting of”

(i) aluminum trichloride;

(ii) alkaline earth oxide or hydroxide;

(iii) an oxide of a transition metal; and

(iv) zinc chloride.

34. The method of any of claims 1 to 33, wherein the composite is introduced into the well in a slurry, wherein the pH of the slurry is between from about 4.0 to about 12.0.

35. The method of any of claims 1 to 34, wherein the proppant or sand control particulate core is selected from the group consisting of sand, ceramic beads, glass beads, bauxite grains, sintered bauxite, sized calcium carbonate, walnut shell fragments, aluminum pellets, nylon pellets, nut shells, gravel, resinous particles, alumina, minerals, polymeric particles, and combinations thereof

36. The method of claim 34, wherein the proppant or sand control particulate core is sand.

37. The method of any of claims 1 to 36, wherein the proppant or sand control particulate core is etched with sodium hydroxide and/or sodium silicate.

38. The method of any of claims 1 to 37, wherein the compressive strength of the composite is between from about 34 to about 130 MPA.

39. The method of any of claims 1 to 38, wherein the surface of the composite is hydrophobic or oleophobic.

40. The method of any of claims 1 to 38, further comprising, prior to introducing particulates of the composite into a fracture, treating the surface of the composite with a surface modifying treatment agent to render the composite hydrophobic or oleophobic.

41. The method of any of claims 1 to 38 further comprising modifying the surface of the composite by applying onto the surface a treatment agent and hardening the treatment agent onto the surface of the core.

42. The method of claim 40 or 41 , wherein the treatment agent imparts at least one of the following properties to the composite:

(a) magnetism;

(b) isolator;

(c) wettability alteration;

(d) paramagnetic; or

(e) electrical conductivity

43. The method of claim 42, wherein the treatment agent comprises nanoparticles.

44. The method of any of claims 1 to 43, wherein apparent density of the core is less than or equal to 2.25 g/cc.

45. The method of claim 44, wherein the apparent density of the core is less than or equal to 2.0 g/cc.

46. The method of claim 45, wherein the apparent density of the core is less than or equal to 1 .75 g/cc.

47. The method of claim 46, wherein the apparent density of the core is less than or equal to 1 .5 g/cc.

48. The method of claim 47, wherein the apparent density of the core is less than or equal to 1 .25 g/cc.

49. The method of any of claims 1 to 48, wherein the apparent density of the composite is less than the apparent density of the core.

50. The method of any of claims 1 to 49, wherein the Krumbein sphericity of the composite is at least 0.5, API-RP-19C, and the roundness of the composite is at least 0.5 (on the Sloss Chart).

51. The method of claim 50, wherein the Krumbein sphericity of the composite is at least 0.6 and the roundness of the composite is at least 0.6 (on the Sloss Chart).

52. The method of any of claims 1 to 51 , wherein the core is heated prior to applying the coating onto the surface of the core.

53. The method of claim 52, wherein the core is heated to between 0 to about 300 °C.

54. The method any of claims 1 to 51 , wherein the core and the coating are mixed in a pre-heated reactor.

55. The method of claim 54, wherein the core reactor is pre-heated to between 0 to about 300 °C.

56. The method of any of claims 1 to 55, where the composite further comprises one or more fillers selected from the group consisting of silica sand, Kevlar fibers, fly ash, sludges, slags, waste paper, rice husks, saw dust, volcanic aggregates, expanded perlite, pumice, scoria, obsidian, minerals, diatomaceous earth, mica, borosilicates, clays, metal oxides, metal fluorides, plant and animal remains, sea shells, coral, hemp fibers, manufactured fillers, silica, mineral fibers, mineral mats, chopped fiberglass, woven fiberglass, metal wools, turnings, shavings, wollastonite, nanoclays, carbon nanotubes, carbon fibers and nanofibers, graphene oxide, graphite, and combinations thereof.