Methods of generating gas in well treating fluids

• US 20050126781A1
• Filed: 01/31/2005
• Published: 06/16/2005
• Est. Priority Date: 05/31/2002
• Status: Abandoned Application

• 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
• Application Number:
  US11/048,293
• Publication Number:
  US 20050126781A1
• 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 treating a subterranean zone comprising the steps of providing a well treating fluid that comprises a water component, a gas generating chemical, and an encapsulated activator, placing the well treating fluid in a subterranean zone, and allowing the gas generating chemical to react so that a gas is generated in the cement composition. Methods of cementing, fracturing, cementing compositions, fracturing fluid compositions, and foamed well fluid compositions also are provided.

Claims

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

providing a well treating fluid that comprises a water component, a gas generating chemical, and an encapsulated activator;

placing the well treating fluid in a subterranean zone; and

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

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

3. The method of claim 1 wherein the gas generating chemical is present in the well treating fluid in an amount in the range of from about 0.1% to about 10% by weight of the well treating fluid.

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

5. The method of claim 1 wherein the encapsulated activator comprises at least one of the following:

a coating material, an undercoating, or a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

6. The method of claim 5 wherein the coating material comprises a wax, a drying oil, a polyurethane, a polyacrylic, or styrene butadiene.

7. The method of claim 5 wherein the undercoating comprises styrene butadiene.

8. The method of claim 5 wherein the membrane comprises a partially hydrolyzed acrylic cross-linked with an aziridine prepolymer or a carbodiimide.

9. 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.

10. The method of claim 9 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.

11. The method of claim 1 wherein the well treating fluid further comprises a gas production rate enhancing chemical.

12. The method of claim 11 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.

13. 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.

14. The method of claim 13 wherein the gelling agent comprises a cross-linked gelling agent.

15. The method of claim 13 wherein the fracturing fluid further comprises a crosslinking agent.

16. The method of claim 13 wherein the fracturing fluid further comprises a delayed gel breaker.

17. The method of claim 13 wherein the encapsulated activator comprises at least one of the following:

a coating material, an undercoating, or a membrane that has at least one imperfection through which an aqueous fluid may diffuse.

18. 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.

19. The method of claim 18 wherein the hydraulic cement comprises a Portland cement, a pozzolana cement, a gypsum cement, an aluminous cement, or a silica cement.

20. The method of claim 18 wherein the encapsulated activator comprises at least one of the following:

a coating material, an undercoating, or a membrane that has at least one imperfection through which an aqueous fluid may diffuse.