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The present invention provides improved methods for cementing. The methods are basically comprised of the steps of preparing a cement composition comprised of hydraulic cement, water, gas, surfactants, a cement early strength accelerator and a mildly set retarding cement dispersing agent, placing th

The present invention provides improved methods for cementing. The methods are basically comprised of the steps of preparing a cement composition comprised of hydraulic cement, water, gas, surfactants, a cement early strength accelerator and a mildly set retarding cement dispersing agent, placing the cement composition in the annulus between the casing string and the well bore and allowing the cement composition to set into a hard impermeable mass. The cement composition used can alternatively comprise hydraulic cement, a water reducing additive, a dispersing additive, a set accelerating additive and water. Also, the cement composition can be made environmentally benign by using water reducing and dispersing additives, set retarding additives, and compressive strength and set accelerating additives which are environmentally degradable.

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1. A method of cementing comprising the steps of:preparing a cement composition comprising a hydraulic cement, sufficient water to form a pumpable slurry, a gas present in an amount sufficient to form a foam, a mildly set retarding mixture of cement composition foaming and foam stabilizing surfactan

1. A method of cementing comprising the steps of:preparing a cement composition comprising a hydraulic cement, sufficient water to form a pumpable slurry, a gas present in an amount sufficient to form a foam, a mildly set retarding mixture of cement composition foaming and foam stabilizing surfactant, a cement set and strength accelerating agent, and a mildly set retarding cement dispersing agent, wherein said cement set and strength accelerating agent and said mildly set retarding cement dispersing agent are present in said composition in a weight ratio and an amount such that said cement composition has a thickening time in the range of from about 3 to about 5 hours and develops a compressive strength in the range of from about 400 psi to about 600 psi at a temperature in the range of from about 45° F. to about 55° F. within 24 hours; andallowing said cement composition to set. 2. The method of claim 1 wherein said hydraulic cement in said cement composition is API Class H Portland cement or another cement which is equivalent thereto. 3. The method of claim 1 wherein said water is present in said cement composition in an amount in the range of from about 34% to about 40% by weight of hydraulic cement therein. 4. The method of claim 1 wherein said gas is selected from the group consisting of air and nitrogen. 5. The method of claim 1 wherein said gas is present in said cement composition in an amount sufficient to foam said cement composition and to lower the density thereof to in the range of from about 10 to about 12 pounds per gallon. 6. The method of claim 1 wherein said mildly set retarding mixture of foaming and foam stabilizing surfactants in said cement composition is selected from the group consisting of a mixture of an alcohol ether sulfate ethoxylated with from about 3 to about 10 moles of ethylene oxide and an alkyl or alkene amidopropylbetaine and a mixture of an alcohol ether sulfate ethoxylated with from about 3 to about 10 moles of ethylene oxide, an alkyl or alkene amidopropylbetaine and an alkyl or alkene amidopropyl dimethylamine oxide. 7. The method of claim 6 wherein said mildly set retarding mixture of cement composition foaming and foam stabilizing surfactants is present in an amount in the range of from about 0.5% to about 4% by weight of water in said composition. 8. The method of claim 1 wherein said cement set and strength accelerating agent is selected from the group consisting of calcium chloride, calcium nitrite, calcium formate and other water soluble calcium salts. 9. The method of claim 1 wherein said cement set and strength accelerating agent is added to said cement composition in the form of an aqueous solution wherein said accelerating agent is present therein in an amount of about 33% by weight of said solution. 10. The method of claim 1 wherein said mildly set retarding cement dispersing agent is selected from the group consisting of sulfonated naphthalene formaldehyde condensate and the condensation product of acetone, formaldehyde and sodium bisulfite. 11. The method of claim 10 wherein said mildly set retarding cement dispersing agent is added to said cement composition in the form of an aqueous solution wherein said dispersing agent is present in an amount of about 33% by weight of said solution. 12. The method of claim 1 wherein the weight ratio of said cement set and strength accelerating agent to said mildly set retarding cement dispersing agent in said compositions is in the range of from about 1:1 to about 3:1. 13. The method of claim 12 wherein said cement set and strength accelerating agent and said mildly set retarding cement dispersing agent together are present in an amount in the range of from about 1% to about 3% by weight of cement in said composition. 14. The method of claim 1 wherein except for said single hydraulic cement and said gas, each of the components of said cement composition is added to said composition in liquid form. 15. A method of cementing at a temperature in the range of from about 32° F. to about 80° F. comprising the steps of:preparing a cement composition comprising a hydraulic cement; sufficient water to form a pumpable slurry; a gas present in an amount sufficient to form a foam; an aqueous solution of calcium chloride accelerating agent; and an aqueous solution of sulfonated naphthalene formaldehyde condensate dispersing agent; andvarying the ratio of said accelerating agent to said dispersing agent and the combined amount of said accelerating agent and said dispersing agent present in said composition to vary the thickening time and compressive strength of the composition, wherein said composition has a thickening time in the range of from about 3 to about 5 hours and develops a compressive strength of at least about 400 psi within 24 hours. 16. The method of claim 15 wherein said water is present in said cement composition in an amount in the range of from about 34% to about 40% by weight of hydraulic cement therein. 17. The method of claim 15 wherein said gas is nitrogen present in said cement composition in an amount sufficient to foam said cement composition and lower the density thereof to in the range of from about 10 to about 12 pounds per gallon. 18. The method of claim 15 wherein said mildly set retarding mixture of foaming and foam stabilizing surfactants in said cement composition is a mixture of an alcohol ether sulfate ethoxylated with from about 3 to about 10 moles of ethylene oxide, cocoylamidopropylbetaine and a cocoylamidopropyldimethyl amine oxide and is present in an amount in the range of from about 0.5% to about 4% by weight of water in said composition. 19. The method of claim 15 wherein said aqueous solutions of calcium chloride accelerating agent and sulfonated naphthalene formaldehyde condensate dispersing agent are each 33% by weight solutions. 20. The method of claim 15 wherein the weight ratio of said calcium chloride accelerating agent to said sulfonated naphthalene formaldehyde condensate dispersing agent in said cement composition is in the range of from about 1:1 to about 3:1. 21. The method of claim 20 wherein said calcium chloride accelerating agent and said sulfonated naphthalene formaldehyde condensate dispersing agent together are present in an active amount in the range of from about 1% to about 3% by weight of cement in said composition. 22. The method of claim 15 wherein except for said Portland cement and said gas, each of the components of said cement composition are added to said cement composition in liquid form. 23. A method of cementing comprising the steps of:preparing a cement composition comprising a hydraulic cement, a water reducing additive comprised of a sulfonated naphthalene formaldehyde condensate, a dispersing additive comprised of the condensation product of acetone, formaldehyde and sodium bisulfite, a compressive strength enhancing and set retarding additive comprising a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid, a set accelerating additive and water present in an amount sufficient to form a pumpable slurry; andallowing said cement composition to set. 24. The method of claim 23 wherein said hydraulic cement is a Portland cement. 25. The method of claim 23 wherein said hydraulic cement is selected from the group consisting of API Classes A, C, H and G Portland cements. 26. The method of claim 23 wherein said water reducing additive is present in said composition in an amount in the range of from about 0% to about 3% by weight of said hydraulic cement in said composition. 27. The method of claim 23 wherein said dispersing additive is present in said composition in an amount in the range of from about 0% to about 2% by weight of said hydraulic cement in said composition. 28. The method of claim 23 wherein said compressive strength enhancing and set retarding additive is present in said composition in an amount in the range of from about 0.01% to about 1% by wei ght of said hydraulic cement in said composition. 29. The method of claim 23 wherein said set accelerating additive is a water soluble calcium salt selected from the group consisting of calcium chloride, calcium nitrate and calcium formate. 30. The method of claim 23 wherein said set accelerating additive is calcium chloride. 31. The method of claim 23 wherein said set accelerating additive is present in said composition in an amount in the range of from about 0.1% to about 4% by weight of said hydraulic cement in said composition. 32. The method of claim 23 wherein said cement composition further comprises an additive selected from the group consisting of calcium aluminate and one or more alkali metal aluminates. 33. The method of claim 32 wherein said additive is calcium aluminate present in said composition in an amount in the range of from about 0.5% to about 5% by weight of said hydraulic cement in said composition. 34. The method of claim 23 wherein said cement composition further comprises a gas in an amount sufficient to form a foam and a mixture of cement composition foaming and foam stabilizing surfactants present in an amount sufficient to facilitate the formation of and stabilize said foam. 35. The method of claim 34 wherein said gas is present in an amount sufficient to lower the density of said foam to in the range of from about 10 to about 12 pounds per gallon. 36. The method of claim 35 wherein said mixture of foaming and foam stabilizing surfactants in said cement composition is selected from the group consisting of a mixture of an alcohol ether sulfate ethoxylated with from about 3 to about 10 moles of ethylene oxide and an alkyl or alkene amidopropylbetaine and a mixture of an alcohol ether sulfate ethoxylated with from about 3 to about 10 moles of ethylene oxide, an alkyl or alkene amidopropylbetaine and an alkyl or alkene amidopropyl dimethylamine oxide. 37. The method of claim 36 wherein said mixture of cement composition foaming and foam stabilizing surfactants is present in an amount in the range of from about 0.1% to about 3% by weight of water in said composition. 38. The method of claim 37 wherein said cement composition further comprises an additive selected from the group consisting of calcium aluminate and one or more alkali metal aluminates. 39. A method of cementing comprising the steps of:preparing a cement composition comprising a hydraulic cement, sufficient water to form a pumpable slurry, an environmentally degradable water reducing and dispersing additive, an environmentally degradable set retarding additive selected from the group consisting of sodium lignosulfonate, calcium lignosulfonate and ammonium lignosulfonate, said set retarding additive being present in an amount in the range of from about 0.0165% to about 0.165% by weight of cement in said composition, and an environmentally degradable compressive strength and set accelerating additive; andallowing said cement composition to set. 40. The method of claim 39 wherein said hydraulic cement is a Portland cement. 41. The method of claim 39 wherein said hydraulic cement is selected from the group consisting of API Classes A, C, H and G Portland cements. 42. The method of claim 39 wherein said water is selected from the group consisting of fresh water and salt water present in an amount in the range of from about 30% to about 45% by weight of cement in said composition. 43. The method of claim 39 wherein said water reducing and dispersing additive is polyaspartic acid present in an amount in the range of from about 0.2% to about 2% by weight of cement in said composition. 44. The method of claim 39 wherein said set retarding additive is sodium lignosulfonate. 45. The method of claim 39 wherein said compressive strength and set accelerating additive is selected from the group of calcium chloride, calcium nitrite and calcium formate and is present in an amount in the range of from about 0.33% to about 4% by weight of cement in said compos ition. 46. The method of claim 39 wherein said water reducing and dispersing additive, said set retarding additive and said compressive strength and set accelerating additive are present in amounts such that said cement composition has a thickening time in the range of from about 3 to about 5 hours, and a compressive strength from about 400 psi to about 600 psi at a temperature in the range of from about 45° F. to about 55° F. in 24 hours or less. 47. A method of cementing comprising the steps of:preparing a composition comprised of a single hydraulic cement, sufficient water to form a pumpable slurry, a gas present in an amount sufficient to form a foam, an environmentally degradable foaming and foam stabilizing additive, an environmentally degradable water reducing and dispersing additive, an environmentally degradable set retarding additive and an environmentally degradable compressive strength and set accelerating additive; andallowing said cement composition to set. 48. The method of claim 47 wherein said hydraulic cement is a Portland or equivalent cement. 49. The method of claim 47 wherein said hydraulic cement is selected from the group consisting of API Classes A, C, H and G Portland cements. 50. The method of claim 47 wherein said water is selected from the group consisting of fresh water and salt water present in an amount in the range of from about 30% to about 45% by weight of cement in said composition. 51. The method of claim 47 wherein said gas is selected from the group of air and nitrogen present in an amount sufficient to foam the cement composition to a density in the range of from about 10 to about 12 pounds per gallon. 52. The method of claim 47 wherein said foaming and foam stabilizing additive is selected from the group consisting of hydrolyzed keratin and a mixture of 63.3 parts by weight of ethoxylated alcohol ether sulfate, 31.7 parts by weight of cocoylamidopropyl betaine and 5 parts by weight of cocoylamidopropyl dimethylamine oxide present in an amount in the range of from about 1% to about 5% by weight of water in said composition. 53. The method of claim 47 wherein said water reducing and dispersing additive is polyaspartic acid present in an amount in the range of from about 0.2% to about 2% by weight of cement in said composition. 54. The method of claim 47 wherein said set retarding additive is selected from the group consisting of sodium lignosulfonate, calcium lignosulfonate and ammonium lignosulfonate and is present in an amount in the range of from about 0.0165% to about 0.165% by weight of the cement in said composition. 55. The method of claim 54 wherein said set retarding additive is sodium lignosulfonate. 56. The method of claim 47 wherein said compressive strength and set accelerating additive is selected from the group of calcium chloride, calcium nitrite and calcium formate and is present in an amount in the range of from about 0.33% to about 4% by weight of cement in said composition. 57. The method of claim 47 wherein said water reducing and dispersing additive, said set retarding additive and said compressive strength and set accelerating additive are present in amount such that said cement composition has a thickening time in the range of from about 3 to about 5 hours, and a compressive strength from about 400 psi to about 600 psi at a temperature in the range of from about 45° F. to about 55° F. in 24 hours or less.