초록

Methods and cement compositions are provided for sealing a subterranean zone penetrated by a wellbore, wherein the cement composition comprises zeolite, cementitious material, and a mixing fluid.

대표청구항 ▼

The invention claimed is: 1. A wellbore sealing low density foamed cement composition comprising: a low density base comprising: at least one cementitious material; a zeolite foam stability agent; and a mixing fluid; and at least one of a foaming agent, a surfactant and air whereby the at least on

The invention claimed is: 1. A wellbore sealing low density foamed cement composition comprising: a low density base comprising: at least one cementitious material; a zeolite foam stability agent; and a mixing fluid; and at least one of a foaming agent, a surfactant and air whereby the at least one of a foaming agent, a surfactant and air foams the low density base to reduce the density of the foamed cement composition to less than the density of a normal weight cement; wherein the low density base comprising a zeolite foam stability agent has an enhanced compressive strength compared to a low density base that does not include the zeolite foam stability agent. 2. The wellbore sealing low density foamed cement composition of claim 1 wherein the zeolite is represented by the formula: description="In-line Formulae" end="lead"Ma/n[(AlO2)a(SiO2)b ]쨌xH2Odescription="In-line Formulae" end="tail" where M represents one or more cations selected from the group consisting of Na, K, Mg, Ca, Sr, Li, Ba, NH4, CH3NH3, (CH3)3NH, (CH3)4N, Ga, Ge and P; n represents the cation valence; the ratio of b:a is in a range from greater than or equal to 1 and less than or equal to 5; and x represents the moles of water entrained into the zeolite framework. 3. The wellbore sealing low density foamed cement composition of claim 1, wherein the zeolite is selected from the group consisting of analcime, bikitaite, brewsterite, chabazite, clinoptilolite, faujasite, harmotome, heulandite, laumontite, mesolite, natrolite, paulingite, phillipsite, scolecite, stellerite, stilbite, and thomsonite. 4. The wellbore sealing low density foamed cement composition of claim 1 wherein the cement composition comprises zeolite in an amount from at least about 30 weight percent. 5. The wellbore sealing low density foamed cement composition of claim 1 wherein the cement composition comprises at least one cementitious material selected from the group consisting of micronized cement, Portland cement, pozzolan cement, gypsum cement, aluminous cement, silica cement, and alkaline cement. 6. The wellbore sealing low density foamed cement composition of claim 1 further comprising at least one additive selected from the group consisting of accelerating additives, lightweight additives, dispersants, fluid loss control additives and surfactants. 7. The wellbore sealing low density foamed cement composition of claim 1 further comprising at least one accelerating additive selected from the group consisting of sodium sulfate, sodium carbonate, calcium sulfate, calcium carbonate, potassium sulfate, and potassium carbonate. 8. The wellbore sealing low density foamed cement composition of claim 1 further comprising at least one accelerating additive selected from the group consisting of sodium sulfate, calcium sulfate, and potassium sulfate; and at least one accelerating additive selected from the group consisting of sodium carbonate, calcium carbonate, and potassium carbonate. 9. The wellbore sealing low density foamed cement composition of claim 1 further comprising a fluid loss control additive selected from the group consisting of anionic water based soluble polymers, hydrophobically modified anionic water based soluble polymers, non-ionic water based soluble polymers and hydrophobically modified non-ionic water based soluble polymers. 10. The wellbore sealing low density foamed cement composition of claim 1 further comprising a fluid loss control additive selected from the group consisting of hydroxyethylcellulose, hydrophobically modified hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, guar, modified guar, polyvinyl alcohol, montmorillonite clay, anhydrous sodium silicate, grafted polymers prepared by the polymerization of monomers or salts of monomers of N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid and acrylonitrile having a lignin or lignite or other backbone, and copolymers or salts of copolymers of N,N-dimethylacrylamide and 2-acrylamido-2-methylpropanesulfonic acid. 11. The wellbore sealing low density foamed cement composition of claim 1 wherein a flow enhancing agent is absorbed on the zeolite. 12. The wellbore sealing low density foamed cement composition of claim 11 wherein the flow enhancing agent is present in an amount of from about 15% to about 25% by weight of the zeolite. 13. The wellbore sealing low density foamed cement composition of claim 1 wherein the zeolite has a mean particle size of about 100 microns or less. 14. The wellbore sealing low density foamed cement composition of claim 1 wherein the zeolite has a mean particle size of from about 3 microns to about 15 microns. 15. The wellbore sealing low density foamed cement composition of claim 1 wherein the at least one cementitious material comprises particles having a size of up to about 30 microns. 16. The wellbore sealing low density foamed cement composition of claim 1 wherein the mixing fluid comprises water. 17. The wellbore sealing low density foamed cement composition of claim 1 further comprising at least one of a defoaming agent and bentonite. 18. The wellbore sealing low density foamed cement composition of claim 1 wherein: the zeolite is present in an amount of from about 35% to about 50% by weight; and the cement composition has a density up to about 13.5 lb/gal. 19. A lightweight cement composition comprising: at least one cementitious material; zeolite in an amount of at least about 15 percent by weight of the cementitious material, wherein: the zeolite is selected from the group consisting of analcime, bikitaite, brewsterite, chabazite, clinoptilolite, faujasite, harmotome, heulandite, laumontite, mesolite, natrolite, paulingite, phillipsite, scolecite, stellerite, stilbite, and thomsonite; and the zeolite has a mean particle size of about 3 to 15 micrometers; and a mixing fluid; wherein the lightweight cement composition has a density of less than 12.5 pounds per gallon. 20. The lightweight cement composition of claim 19 wherein the cement mix comprises zeolite in an amount of at least about 20 percent by weight of the cementitious material. 21. The lightweight cement composition of claim 19 wherein the cement composition comprises at least one cementitious material selected from the group consisting of micronized cement, Portland cement, pozzolan cement, gypsum cement, aluminous cement, silica cement, and alkaline cement. 22. The lightweight cement composition of claim 19 further comprising at least one additive selected from the group consisting of accelerating additives, lightweight additives, dispersants, fluid loss control additives and surfactants. 23. The lightweight cement composition of claim 19 wherein the cementitious material, the zeolite, and the mixing fluid are present in relative amounts sufficient to form a slurry that can be placed in a wellbore penetrating a subterranean zone, and develop compressive strength therein sufficient to seal the subterranean zone. 24. The lightweight cement composition of claim 23 wherein the slurry further comprises at least one of a foaming agent, a surfactant and air. 25. The lightweight cement composition of claim 24 wherein the slurry is foamed. 26. The wellbore sealing low density foamed cement composition of claim 1 wherein the cement composition comprises zeolite in an amount of at least about 40 weight percent. 27. The wellbore sealing low density foamed cement composition of claim 1 wherein the cement composition comprises zeolite in an amount of at least about 50 weight percent. 28. The lightweight cement composition of claim 19 wherein the cement composition comprises zeolite in an amount of at least about 40 weight percent of the weight of the cementitious material. 29. The lightweight cement composition of claim 19 wherein the cement composition comprises zeolite in an amount of at least about 60 weight percent of the weight of the cementitious material.