Methods of generating gas in well treating fluids

• US 20040168801A1
• Filed: 03/04/2004
• Published: 09/02/2004
• Est. Priority Date: 05/31/2002
• Status: Active Grant

• Current Assignee: Karen Luke, Krishna M. Ravi, Reddy B. Raghava, Rickey L. Morgan
• Original Assignee: Karen Luke, Krishna M. Ravi, Reddy B. Raghava, Rickey L. Morgan
• Inventors: Ravi, Krishna M., Reddy, B. Raghava, Morgan, Rickey L., Luke, Karen
• Granted Patent: US 6,992,048 B2
• Time in Patent Office: Days
• US Class Current: 166/292
• CPC Class Codes: C04B 14/042 Magnesium silicates, e.g. talc, sepiolite
• CPC Class Codes: C04B 14/047 Zeolites
• CPC Class Codes: C04B 14/06 Quartz; Sand
• CPC Class Codes: C04B 14/08 Diatomaceous earth
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/301 porous or hollow
• CPC Class Codes: C04B 20/10 Coating or impregnating roofing granules E04D7/005
• CPC Class Codes: C04B 20/1025 Fats; Fatty oils; Ester type waxes; Higher fatty acids; Derivatives thereof
• CPC Class Codes: C04B 20/1029 Macromolecular compounds
• CPC Class Codes: C04B 20/1033 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 20/1037 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 20/12 Multiple coating or impregnating
• CPC Class Codes: C04B 20/123 Multiple coatings, for one of the coatings of which at least one alternative is described
• CPC Class Codes: C04B 2103/0067 the ingredients being formed in situ by chemical reactions or conversion of one or more of the compounds of the composition
• CPC Class Codes: C04B 2103/0095 Oxidising agents
• CPC Class Codes: C04B 2103/10 Accelerators; Activators
• CPC Class Codes: C04B 2103/42 Pore formers
• CPC Class Codes: C04B 2103/445 Gelling agents
• CPC Class Codes: C04B 2103/48 Foam stabilisers
• CPC Class Codes: C04B 22/002 Water
• CPC Class Codes: C04B 22/06 : Oxides, Hydroxides C04B22/0013 takes precedence
• CPC Class Codes: C04B 22/068 : Peroxides, e.g. hydrogen peroxide
• CPC Class Codes: C04B 24/12 : Nitrogen containing compounds organic derivatives of hydrazine hydrazine C04B22/00
• CPC Class Codes: C04B 24/129 : Compounds containing one or more nitrogen-to-nitrogen double bonds, e.g. azo-compounds
• CPC Class Codes: C04B 24/383 : Cellulose or derivatives thereof
• CPC Class Codes: C04B 28/02 : containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/04 : Portland cements
• CPC Class Codes: C04B 38/02 : by adding chemical blowing agents
• CPC Class Codes: C04B 40/0633 : Chemical separation of ingredients, e.g. slowly soluble activator
• CPC Class Codes: C09K 8/46 : containing inorganic binders, e.g. Portland cement
• CPC Class Codes: C09K 8/473 : Density reducing additives, e.g. for obtaining foamed cement compositions
• CPC Class Codes: C09K 8/516 : characterised by their form or by the form of their components, e.g. encapsulated material
• CPC Class Codes: C09K 8/518 : Foams
• CPC Class Codes: C09K 8/703 : Foams
• CPC Class Codes: Y10S 507/902 : Controlled release agent

Abstract

The present invention relates to methods of generating gas in and foaming well treating fluids during pumping of the treating fluids or after the treating fluids are placed in a subterranean zone, or both. A method of the present invention provides a method of making a foamed well fluid that comprises a gas comprising the steps of combining an aqueous fluid, a surfactant, an encapsulated activator, and a gas generating chemical, the gas generating chemical being present in an amount in the range of from about 0.1% to 100% of a water component in the aqueous well fluid; and allowing the gas generating chemical and the encapsulated activator to react so that gas is generated in the aqueous fluid to form a foamed well fluid. Methods of cementing, fracturing, cementing compositions, fracturing fluid compositions, and foamed well fluid compositions also are provided.

Claims

1. A method of cementing in a subterranean zone comprising the steps of:

providing a cement composition that comprises a hydraulic cement, a water component, a gas generating chemical, and an encapsulated activator;

placing the cement composition in a subterranean zone;

allowing the gas generating chemical to react so that a gas is generated in the cement composition; and

allowing the cement composition to set in the subterranean zone.

2. The method of claim 1 wherein the gas generating chemical reacts so that the gas is generated in the cement composition during the step of placing the cement composition in the subterranean zone.

3. The method of claim 1 wherein the gas generating chemical reacts so that the gas is generated in the cement composition after the step of placing the cement composition in the subterranean zone.

4. The method of claim 1 wherein the gas generating chemical reacts so that the gas is generated in the cement composition during a cement transition time period.

5. The method of claim 1 wherein the gas generating chemical comprises a hydrazine or an azo group.

6. The method of claim 1 wherein the gas generating chemical comprises azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, carbohydrazide, p-p′

-oxybis(benzenesulfonylhydrazide), an ammonium salt of an organic acid, an ammonium salt of an inorganic acid, hydroxylamine sulfate, carbamide, or a mixture thereof.

7. The method of claim 1 wherein the gas generating chemical is present in the cement composition in an amount in the range of from about 0. 1% to about 10% by weight of the cement composition.

8. The method of claim 1 wherein the gas generating chemical is present in the cement composition in an amount in the range of from about 0.3% to about 8% by weight of the cement composition.

9. The method of claim 1 wherein the gas generating chemical is present in the cement composition in an amount in the range of about 4%.

10. The method of claim 1 wherein the encapsulated activator comprises an alkaline material or an oxidizing agent.

11. The method of claim 1 wherein the encapsulated activator comprises a carbonate, a hydroxide salt of an alkali earth metal, a hydroxide salt of an alkaline earth metal, an oxide salt of an alkali earth metal, an oxide salt of an alkaline earth metal, an alkali earth metal salt of a peroxide, an alkali earth metal salt of a persulfate, an alkali earth metal salt of a perborate, an alkali earth metal salt of a hypochlorite, an alkali earth metal salt of a hypobromite, an alkaline earth metal salt of a peroxide, an alkaline earth metal salt of a persulfate, an alkaline earth metal salt of a perborate, an alkaline earth metal salt of a hypochlorite, an alkaline earth metal salt of a hypobromite, ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium chlorate, hydrogen peroxide, sodium perborate, or sodium peroxy carbonate.

12. The method of claim 1 wherein the encapsulated activator comprises a coating material.

13. The method of claim 12 wherein the coating comprises a wax, a drying oil, a polyurethane, a polyacrylic, or styrene butadiene.

14. The method of claim 12 wherein the encapsulated activator further comprises an undercoating.

15. The method of claim 14 wherein the undercoating comprises styrene butadiene.

16. The method of claim 1 wherein the encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

17. The method of claim 16 wherein the membrane comprises a partially hydrolyzed acrylic cross-linked with an aziridine prepolymer or a carbodiimide.

18. The method of claim 1 wherein at least a portion of the encapsulated activator is in the form of an aqueous solution on porous solid particulates.

19. The method of claim 18 wherein the porous solid particulates comprise a diatomaceous earth material, a zeolite, silica, alumina, a metal salt of an alumino-silicate, a clay, hydrotalcite, a styrene-divinylbenzene based material, a cross-linked polyalkylacrylate ester, or a cross-linked modified starch.

20. The method of claim 18 wherein the portion of the encapsulated activator that is in the form of an aqueous solution on porous solid particulates further comprises a polymeric external coating.

21. The method of claim 20 wherein the polymeric external coating comprises a EDPM rubber, a polyvinyldichloride, a nylon, a wax, a polyurethane, or a cross-linked partially hydrolyzed acrylic.

22. The method of claim 1 wherein the cement composition further comprises a gas production rate enhancing chemical.

23. The method of claim 22 wherein the gas production rate enhancing chemical comprises a copper salt, a complex of a copper salt, an iron salt, or ethylene diamine tetraacetic acid.

24. The method of claim 22 wherein at least a portion of the gas production rate enhancing chemical is encapsulated.

25. The method of claim 1 wherein the cement composition further comprises a surfactant.

26. The method of claim 25 wherein the surfactant comprises an ethoxylated alcohol ether sulfate surfactant, an aklyl amidopropylbetaine surfactant, an alkene amidopropylbetaine surfactant, an alkyl amidopropyldimethylamine oxide surfactant, or an alkene amidopropyldimethylamine oxide surfactant.

27. The method of claim 1 wherein the hydraulic cement comprises calcium, aluminum, silicon, oxygen, or sulfur.

28. The method of claim 1 wherein the hydraulic cement comprises a Portland cement, a pozzolana cement, a gypsum cement, an aluminous cement, or a silica cement.

29. The method of claim 1 wherein the water component comprises fresh water, an unsaturated salt solution, or a saturated salt solution.

30. The method of claim 1 wherein the cement composition further comprises a set retarding agent, a fluid loss control agent, a dispersing agent, a set accelerating agent, or a formation conditioning agent.

31. A method of fracturing a subterranean zone comprising the steps of:

providing a fracturing fluid that comprises a water component, a gelling agent, a gas generating chemical, and an encapsulated activator;

contacting the subterranean zone with the fracturing fluid at a pressure sufficient to create or enhance at least one fracture therein; and

allowing the gas generating chemical to react so that generated gas is incorporated in the fracturing fluid; and

reducing the viscosity of the fracturing fluid so as to produce a reduced viscosity fracturing fluid.

32. The method of claim 31 further comprising the step of recovering the reduced viscosity fracturing fluid from the subterranean zone.

33. The method of claim 31 wherein the gelling agent comprises a cross-linked gelling agent.

34. The method of claim 31 wherein the gelling agent comprises a retarded crosslinking composition that comprises a solvent, an organotitanate chelate, and a borate ion producing compound.

35. The method of claim 31 wherein the fracturing fluid further comprises a crosslinking agent.

36. The method of claim 31 wherein the gelling agent comprises a galactomannan gelling agent.

37. The method of claim 31 wherein the gelling agent comprises a derivative of guar, locust bean gum, tara gum, honey locust gum, tamarind gum, karaya gum, tragacanth gum, carrageenen, or succinoglycan.

38. The method of claim 31 wherein the gelling agent comprises hydroxyethylguar, hydroxypropylguar, carboxymethylguar, carboxymethylhydroxyethylguar, or carboxymethylhydroxypropylguar.

39. The method of claim 31 wherein the fracturing fluid further comprises a delayed gel breaker.

40. The method of claim 39 wherein the delayed gel breaker comprises a mixture of calcium hypochlorite, an alkali metal chlorite, or hypochlorite.

41. The method of claim 39 wherein the delayed gel breaker further comprises an activator.

42. The method of claim 39 wherein the viscosity of the fracturing fluid is reduced by an interaction between the delayed gel breaker and the gelling agent.

43. The method of claim 31 wherein the gas generating chemical comprises a hydrazine or an azo group, azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, carbohydrazide, p-p′

-oxybis(benzenesulfonylhydrazide), an ammonium salt of an organic acid, an ammonium salt of an inorganic acid, hydroxylamine sulfate, carbamide, or a mixture thereof.

44. The method of claim 31 wherein the gas generating chemical is present in the cement composition in an amount in the range of from about 0.1% to about 10% by weight of the cement composition.

45. The method of claim 31 wherein the encapsulated activator comprises an alkaline material, an oxidizing agent, a carbonate, a hydroxide salt of an alkali earth metal, a hydroxide salt of an alkaline earth metal, an oxide salt of an alkali earth metal, an oxide salt of an alkaline earth metal, an alkali earth metal salt of a peroxide, an alkali earth metal salt of a persulfate, an alkali earth metal salt of a perborate, an alkali earth metal salt of a hypochlorite, an alkali earth metal salt of a hypobromite, an alkaline earth metal salt of a peroxide, an alkaline earth metal salt of a persulfate, an alkaline earth metal salt of a perborate, an alkaline earth metal salt of a hypochlorite, an alkaline earth metal salt of a hypobromite, ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium chlorate, hydrogen peroxide, sodium perborate, or sodium peroxy carbonate.

46. The method of claim 31 wherein the encapsulated activator comprises a coating material that comprises a wax, a drying oil, or a polymeric material.

47. The method of claim 31 wherein the encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

48. The method of claim 31 wherein at least a portion of the encapsulated activator is in the form of an aqueous solution on porous solid particulates that comprise a diatomaceous earth material, a zeolite, silica, alumina, a metal salt of an alumino-silicate, a clay, hydrotalcite, a styrene-divinylbenzene based material, a cross-linked polyalkylacrylate ester, or a cross-linked modified starch.

49. The method of claim 31 wherein the fracturing fluid further comprises a gas production rate enhancing chemical.

50. The method of claim 31 wherein the water comprises fresh water, salt water, or a brine.

51. A method of making a foamed well fluid that comprises a gas comprising the steps of:

combining an aqueous fluid, a surfactant, an encapsulated activator, and a gas generating chemical, the gas generating chemical being present in an amount in the range of from about 0.1% to 100% of a water component in the aqueous fluid; and

allowing the gas generating chemical and the encapsulated activator to react so that gas is generated in the aqueous fluid to form a foamed well fluid.

52. The method of claim 51 wherein the aqueous fluid is a viscous alkaline fluid.

53. The method of claim 51 wherein the aqueous fluid is an acidic fluid.

54. The method of claim 51 further comprising the step of using the foamed well fluid in a subterranean operation.

55. The method of claim 54 wherein the subterranean operation involves cementing or fracturing a chosen subterranean zone.

56. A foamed well fluid made by the method of claim 51.

57. A cement composition that comprises a hydraulic cement, a water component, a gas generating chemical, and an encapsulated activator.

58. The cement composition of claim 57 wherein the gas generating chemical comprises a hydrazine, azo group, azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, carbohydrazide, p-p′

-oxybis(benzenesulfonylhydrazide), an ammonium salt of an organic acid, an ammonium salt of an inorganic acid, hydroxylamine sulfate, carbamide, or a mixture thereof.

59. The cement composition of claim 57 wherein the gas generating chemical is present in the cement composition in an amount in the range of from about 0.1% to about 10% by weight of the cement composition.

60. The cement composition of claim 57 wherein the encapsulated activator comprises an alkaline material, an oxidizing agent, a carbonate, a hydroxide salt of an alkali earth metal, a hydroxide salt of an alkaline earth metal, an oxide salt of an alkali earth metal, an oxide salt of an alkaline earth metal, an alkali earth metal salt of a peroxide, an alkali earth metal salt of a persulfate, an alkali earth metal salt of a perborate, an alkali earth metal salt of a hypochlorite, an alkali earth metal salt of a hypobromite, an alkaline earth metal salt of a peroxide, an alkaline earth metal salt of a persulfate, an alkaline earth metal salt of a perborate, an alkaline earth metal salt of a hypochlorite, an alkaline earth metal salt of a hypobromite, ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium chlorate, hydrogen peroxide, sodium perborate, or sodium peroxy carbonate.

61. The cement composition of claim 57 wherein the encapsulated activator comprises a coating material the comprises a wax, a drying oil, or a polymeric material.

62. The cement composition of claim 61 wherein the encapsulated activator further comprises an undercoating.

63. The cement composition of claim 62 wherein the undercoating comprises styrene butadiene.

64. The cement composition of claim 57 wherein the encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

65. The cement composition of claim 57 wherein at least a portion of the encapsulated activator is in the form of an aqueous solution on porous solid particulates, the porous solid particulates comprising a diatomaceous earth material, a zeolite, silica, alumina, a metal salt of an alumino-silicate, a clay, hydrotalcite, a styrene-divinylbenzene based material, a cross-linked polyalkylacrylate ester, or a cross-linked modified starch.

66. The cement composition of claim 57 wherein the cement composition further comprises a gas production rate enhancing chemical.

67. The cement composition of claim 66 wherein at least a portion of the gas production rate enhancing chemical is encapsulated.

68. The cement composition of claim 57 wherein the cement composition further comprises a surfactant.

69. The cement composition of claim 57 wherein the hydraulic cement comprises calcium, aluminum, silicon, oxygen, or sulfur.

70. The cement composition of claim 57 wherein the hydraulic cement comprises a Portland cement, a pozzolana cement, a gypsum cement, an aluminous cement, or a silica cement.

71. The cement composition of claim 57 wherein the water component comprises fresh water, an unsaturated salt solution, or a saturated salt solution.

72. The cement composition of claim 57 wherein the cement composition further comprises a set retarding agent, a fluid loss control agent, a dispersing agent, a set accelerating agent, or a formation conditioning agent.

73. A fracturing fluid that comprises a water component, a gelling agent, a gas generating chemical, and an encapsulated activator.

74. The fracturing fluid of claim 73 wherein the gelling agent comprises a cross-linked gelling agent.

75. The fracturing fluid of claim 73 wherein the gelling agent comprises a retarded crosslinking composition that comprises a solvent, an organotitanate chelate, and a borate ion producing compound.

76. The fracturing fluid of claim 73 wherein the fracturing fluid further comprises a crosslinking agent.

77. The fracturing fluid of claim 73 wherein the gelling agent comprises a galactomannan gelling agent.

78. The fracturing fluid of claim 73 wherein the gelling agent comprises hydroxyethylguar, hydroxypropylguar, carboxymethylguar, carboxymethylhydroxyethylguar, or carboxymethylhydroxypropylguar.

79. The fracturing fluid of claim 73 wherein the fracturing fluid further comprises a delayed gel breaker.

80. The fracturing fluid of claim 73 wherein the gas generating chemical comprises a hydrazine or an azo group, azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, carbohydrazide, p-p′

-oxybis(benzenesulfonylhydrazide), an ammonium salt of an organic acid, an ammonium salt of an inorganic acid, hydroxylamine sulfate, carbamide, or a mixture thereof.

81. The fracturing fluid of claim 73 wherein the gas generating chemical is present in the fracturing fluid in an amount in the range of from about 0.1% to about 10% by weight of the cement composition.

82. The fracturing fluid of claim 73 wherein the encapsulated activator comprises an alkaline material, an oxidizing agent, a carbonate, a hydroxide salt of an alkali earth metal, a hydroxide salt of an alkaline earth metal, an oxide salt of an alkali earth metal, an oxide salt of an alkaline earth metal, an alkali earth metal salt of a peroxide, an alkali earth metal salt of a persulfate, an alkali earth metal salt of a perborate, an alkali earth metal salt of a hypochlorite, an alkali earth metal salt of a hypobromite, an alkaline earth metal salt of a peroxide, an alkaline earth metal salt of a persulfate, an alkaline earth metal salt of a perborate, an alkaline earth metal salt of a hypochlorite, an alkaline earth metal salt of a hypobromite, ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium chlorate, hydrogen peroxide, sodium perborate, or sodium peroxy carbonate.

83. The fracturing fluid of claim 73 wherein the encapsulated activator comprises a coating material that comprises a wax, a drying oil, or a polymeric material.

84. The fracturing fluid of claim 73 wherein the encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

85. The fracturing fluid of claim 73 wherein at least a portion of the encapsulated activator is in the form of an aqueous solution on porous solid particulates that comprise a diatomaceous earth material, a zeolite, silica, alumina, a metal salt of an alumino-silicate, a clay, hydrotalcite, a styrene-divinylbenzene based material, a cross-linked polyalkylacrylate ester, or a cross-linked modified starch.

86. The fracturing fluid of claim 73 wherein the fracturing fluid further comprises a gas production rate enhancing chemical.

87. The fracturing fluid of claim 73 wherein the water comprises fresh water, salt water, or, brine.

88. A foamed well fluid comprising a gas, the gas being generated by a reaction of a gas generating chemical and an encapsulated activator.

89. The foamed well fluid of claim 88 wherein the gas generating chemical comprises a hydrazine or an azo group, azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, carbohydrazide, p-p′

-oxybis(benzenesulfonylhydrazide), an ammonium salt of an organic acid, an ammonium salt of an inorganic acid, hydroxylamine sulfate, carbamide, or a mixture thereof.

90. The foamed well fluid of claim 88 wherein the encapsulated activator comprises an alkaline material, an oxidizing agent, a carbonate, a hydroxide salt of an alkali earth metal, a hydroxide salt of an alkaline earth metal, an oxide salt of an alkali earth metal, an oxide salt of an alkaline earth metal, an alkali earth metal salt of a peroxide, an alkali earth metal salt of a persulfate, an alkali earth metal salt of a perborate, an alkali earth metal salt of a hypochlorite, an alkali earth metal salt of a hypobromite, an alkaline earth metal salt of a peroxide, an alkaline earth metal salt of a persulfate, an alkaline earth metal salt of a perborate, an alkaline earth metal salt of a hypochlorite, an alkaline earth metal salt of a hypobromite, ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium chlorate, hydrogen peroxide, sodium perborate, or sodium peroxy carbonate.

91. The foamed well fluid of claim 88 wherein the encapsulated activator comprises a coating material that comprises a wax, a drying oil, or a polymeric material.

92. The foamed well fluid of claim 88 wherein the encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

93. The foamed well fluid of claim 88 wherein at least a portion of the encapsulated activator is in the form of an aqueous solution on porous solid particulates that comprise a diatomaceous earth material, a zeolite, silica, alumina, a metal salt of an alumino-silicate, a clay, hydrotalcite, a styrene-divinylbenzene based material, a cross-linked polyalkylacrylate ester, or a cross-linked modified starch.