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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 compri

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.

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What is claimed is: 1. A method of making a foamed well fluid that comprises a gas comprising the steps of: combining an aqueous fluid, a surfactant, a delayed encapsulated activator, a proppant material, and a gas generating chemical, the gas generating chemical being present in an amount in the r

What is claimed is: 1. A method of making a foamed well fluid that comprises a gas comprising the steps of: combining an aqueous fluid, a surfactant, a delayed encapsulated activator, a proppant material, 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 delayed encapsulated activator to react so that gas is generated in the aqueous fluid to form a foamed well fluid. 2. The method of claim 1 wherein the aqueous fluid is a viscous alkaline fluid. 3. The method of claim 1 wherein the aqueous fluid is an acidic fluid. 4. The method of claim 1 further comprising the step of using the foamed well fluid in a subterranean operation. 5. The method of claim 4 wherein the subterranean operation involves cementing or fracturing a chosen subterranean zone. 6. A well treatment fluid that comprises a water component, a gelling agent, a proppant material, a gas generating chemical, and a delayed encapsulated activator. 7. The well treatment fluid of claim 6 wherein the gelling agent comprises a cross-linked gelling agent. 8. The well treatment fluid of claim 6 wherein the gelling agent comprises a retarded crosslinking composition that comprises a solvent, an organotitanate chelate, and a borate ion producing compound. 9. The well treatment fluid of claim 6 wherein the well treatment fluid further comprises a crosslinking agent. 10. The well treatment fluid of claim 6 wherein the gelling agent comprises a galactomannan gelling agent. 11. The well treatment fluid of claim 6 wherein the gelling agent comprises hydroxyethylguar, hydroxypropylguar, carboxymethylguar, carboxymethylhydroxyethylguar, or carboxymethylhydroxypropylguar. 12. The well treatment fluid of claim 6 wherein the well treatment fluid further comprises a delayed gel breaker. 13. The well treatment fluid of claim 6 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. 14. The well treatment fluid of claim 6 wherein the gas generating chemical is present in the well treatment fluid in an amount in the range of from about 0.1% to about 10% by weight of the well treatment fluid. 15. The well treatment fluid of claim 6 wherein the delayed 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. 16. The well treatment fluid of claim 6 wherein the delayed encapsulated activator comprises a coating material that comprises a wax, a drying oil, or a polymeric material. 17. The well treatment fluid of claim 6 wherein the delayed encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse. 18. The well treatment fluid of claim 6 wherein at least a portion of the delayed 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. 19. The well treatment fluid of claim 6 wherein the well treatment fluid further comprises a gas production rate enhancing chemical. 20. The well treatment fluid of claim 6 wherein the water comprises fresh water, salt water, or, brine. 21. A foamed well fluid comprising a proppant material and a gas, the gas being generated by a reaction of a gas generating chemical and a delayed encapsulated activator. 22. The foamed well fluid of claim 21 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. 23. The foamed well fluid of claim 21 wherein the delayed 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. 24. The foamed well fluid of claim 21 wherein the delayed encapsulated activator comprises a coating material that comprises a wax, a drying oil, or a polymeric material. 25. The foamed well fluid of claim 21 wherein the delayed encapsulated activator comprises a membrane that has at least one imperfection through which an aqueous fluid may diffuse. 26. The foamed well fluid of claim 21 wherein at least a portion of the delayed 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. 27. The foamed well fluid of claim 21 wherein the foamed well fluid is a cement composition. 28. The foamed well fluid of claim 21 wherein the foamed well fluid is a fracturing fluid.