Ultra low density cementitious slurries for use in cementing of oil and gas wells

Abstract

The storable, low-density, hydraulically-active, cementitious slurry of the invention is suitable for cementing within a subterranean formation for oil or gas wells. The low-density slurry comprises a hydraulically-active cementitious material, a set retarder, a plasticizer, glass or ceramic micro-spheres, and a strengthening agent. Further the slurry is substantially free of a suspension agent. The storable, low-density, hydraulically-active, cementitious slurry is made by adding glass or ceramic micro-spheres to a hydraulically-active cementitious material, adding a strengthening agent to the microsphere containing composition, and mixing the resulting composition with water, a set retarder, and a plasticizer to generate a slurry, wherein the set retarder is present in an amount sufficient to allow storage of the slurry.

1 . A storable, low-density, hydraulically-active, cementitious aqueous slurry comprising: 
 (a) a hydraulically-active cementitious material;    (b) a set retarder;    (c) a plasticizer;    (d) glass or ceramic micro-spheres; and    (e) a strengthening agent;    wherein the aqueous slurry is substantially free of a suspension agent.    
     
     
         2 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the set retarder is at least one member selected from the group consisting of hydroxycarboxylic acids, glucoheptonates, lignin sulfonates, gluconates, phosphonates, and sugars.  
     
     
         3 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the plasticizer is at least one member selected from the group consisting of melamine sulfonic acid polymer, sodium polyacrylate, sodium salt of naphthalene sulfonate formaldehyde condensate, napthalene sulfonic acid polymer, and sulfonated styrene maleic anhydride polymer, or a mixture thereof.  
     
     
         4 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 3 , wherein the plasticizer is sodium partially neutralized polyacrylate homopolymer.  
     
     
         5 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the glass or ceramic micro-spheres are of a density and an amount sufficient to effectuate a density to the storable, cementitious aqueous slurry between from about 6 to about 13 lbs/gallon.  
     
     
         6 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the microspheres comprise borosilicate glass.  
     
     
         7 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the microspheres are ceramic.  
     
     
         8 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 1 , wherein the strengthening agent is at least one member selected from the consisting of silica fume, aluminosilicate, fly ash, alumina, aluminum metal powder, manganese oxide fume, ferro-silicon fume, wollastonite, hydrated calcium sulphoaluminate, sodium sulfate, sodium nitrate, sodium chloride, calcium sulfate or potassium sulfate.  
     
     
         9 . The storable, low-density, hydraulically-active, cementitious aqueous slurry of  claim 8 , wherein the strengthening agent is silica fume.  
     
     
         10 . A method of making a storable, low-density, hydraulically-active, cementitious slurry which comprises the steps of: 
 (a) adding glass or ceramic micro-spheres to a hydraulically-active cementitious material;    (b) adding a strengthening agent to the composition of (a); and    (c) mixing composition (b) with water, a set retarder, and a plasticizer to generate a slurry, wherein the set retarder is present in an amount sufficient to allow storage of the slurry    wherein the slurry is substantially free of a suspension agent.    
     
     
         11 . The method of  claim 10 , wherein the set retarder is at least one member selected from the group consisting of hydroxycarboxylic acids, glucoheptonates, lignin sulfonates, gluconates, phosphonates, and sugars.  
     
     
         12 . The method of  claim 10 , wherein the plasticizer is at least one member selected from the group consisting of melamine sulfonic acid polymer, sodium polyacrylate, sodium salt of naphthalene sulfonate formaldehyde condensate, napthalene sulfonic acid polymer, sulfonated styrene maleic anhydride polymer or a mixture thereof.  
     
     
         13 . The method of  claim 12 , wherein the plasticizer is sodium partially neutralized polyacrylate homopolymer.  
     
     
         14 . The method of  claim 10 , wherein the glass or ceramic micro-spheres are present at a density and an amount sufficient to effectuate a density to the slurry between from about 6 to about 13 lbs/gallon.  
     
     
         15 . The method of  claim 10 , wherein the glass or ceramic micro-spheres comprise borosilicate glass.  
     
     
         16 . The method of  claim 10 , wherein the glass or ceramic micro-spheres comprise ceramic.  
     
     
         17 . The method of  claim 10 , wherein the strengthening agent is at least one member selected from the group consisting of silica fume, aluminosilicate, fly ash, alumina, aluminum metal powder, manganese oxide fume, ferro-silicon fume, wollastonite, hydrated calcium sulphoaluminate, sodium sulfate, sodium nitrate, sodium chloride, calcium sulfate or potassium sulfate.  
     
     
         18 . The method of  claim 17 , wherein the strengthening agent is silica fume.  
     
     
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         28 . A storable, low-density, hydraulically-active, cementitious slurry comprising: 
 (a) a hydraulically-active cementitious material;    (b) a set retarder;    (c) a plasticizer;    (d) glass or ceramic micro-spheres;    (e) a strengthening agent; and    (f) water    wherein the slurry is substantially free of a suspension agent and further wherein the density of the slurry is between from about 60 to about 13 lbs/gallon.    
     
     
         29 . The storable, low density, hydraulically-active, cementitious slurry of  claim 1 , wherein the micro-spheres are borosilicate glass.