Processes for incorporating inert gas in a cement composition containing spherical beads

Abstract

The present invention provides a process for forming cement in a well bore. In this process, a cement composition is formed that comprises a cement and one or more beads mixed with the cement. The cement composition containing the beads is displaced into the well bore, and an inert gas phase is introduced to the cement composition to control a density of the cement composition. The inert gas phase can be introduced by adding a gas generating material to the cement composition and/or a porous material to the cement composition. In an embodiment, the gas generating material is a nitrogen generating material that may be activated by an oxidizing agent. In another embodiment, the gas generating material is a hydrogen generating material, e.g., an aluminum powder. The present invention further provides a cement composition comprising a cement, one or more beads combined with the cement, and an inert gas phase created by, e.g., a gas generating material and/or a porous material.

1 . A cement composition comprising: 
 a cement;    one or more beads combined with the cement; and    an inert gas phase, wherein the inert gas phase is present in an amount effective to offset an increase in density caused by breakage of a portion of the beads.    
   
   
       2 . The cement composition of  claim 1 , further comprising a mixture of foam and foam stabilizing surfactants.  
   
   
       3 . The cement composition of  claim 1  wherein the beads are selected from the group consisting of cenospheres, glass spheres, ceramic spheres, and combinations thereof.  
   
   
       4 . The cement composition of  claim 1  wherein the cement is a hydraulic cement.  
   
   
       5 . The cement composition of  claim 1 , wherein the cement further comprises and is mixed with: 
 (i) a gas generating material;    (ii) a porous material; or    (iii) combinations of (i) and (ii).    
   
   
       6 . The cement composition of  claim 5  wherein the gas generating material is a nitrogen generating material, and further comprising an oxidizing agent mixed with the cement, the oxidizing agent being capable of activating the nitrogen generating material.  
   
   
       7 . The cement composition of  claim 6  wherein the nitrogen generating material is selected from the group consisting of hydrazine, hydrazine salt of an acid, azodicarbonamide, azobis(isobutyronitrile), p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, p-p′-oxybis(benzenesulfonylhydrazide), carbodihydrazide, and combinations thereof.  
   
   
       8 . The cement composition of  claim 6  wherein the oxidizing agent is selected from the group consisting of ammonium persulfate, sodium persulfate, potassium persulfate, sodium chlorite, sodium perborate, sodium peroxy carbonate, calcium hypochlorite, sodium hypochlorite, sodium bromite, sodium hypobromite, sodium bromate, sodium chlorate, and combinations thereof.  
   
   
       9 . The cement composition of  claim 1  wherein the gas generating material is a hydrogen generating material.  
   
   
       10 . The cement composition of  claim 9  wherein the hydrogen generating material is selected from the group consisting of aluminum, calcium, zinc, magnesium, lithium sodium, and potassium, and combinations thereof.  
   
   
       11 . The cement composition of  claim 9  wherein the hydrogen generating material is an aluminum powder.  
   
   
       12 . The cement composition of  claim 5  wherein the porous material comprises openings in which air is disposed.  
   
   
       13 . The cement composition of  claim 1  wherein the inert gas phase is present in the cement composition in an amount effective to maintain the density of the cement composition in a range of from about 8 to about 23 lb/gal when one or more of the beads break.  
   
   
       14 . A cement composition comprising: 
 a cement;    a plurality of beads combined with the cement; and    an inert gas phase, wherein the inert gas phase is present in an amount effective to offset an increase in density caused by breakage of a portion of the beads and wherein the cement composition has a compressive strength of at least 1,600 pounds per square inch.    
   
   
       15 . The cement composition of  claim 14  wherein the compressive strength of the cement is at least 1,800 pounds per square inch.  
   
   
       16 . The cement composition of  claim 14  wherein the compressive strength of the cement is at least 2,000 pounds per square inch.  
   
   
       17 . A cement composition comprising: 
 a cement;    a plurality of beads combined with the cement; and    an inert gas phase, wherein the inert gas phases decreases the density of the cement, the broken beads increase the density of the cement, and the change in density caused by the inert gas phase compensates for the change in density caused by the broken beads.    
   
   
       18 . The cement compostion of  claim 17  wherein the breakage of the broken beads is caused by the pressure within the wellbore.  
   
   
       19 . The cement composition of  claim 17  wherein the inert gas phase compensates for the broken beads when the cement compostion is positioned in the wellbore.  
   
   
       20 . The cement composition of  claim 17  wherein the cement composition has a compressive strength of at least 1,600 pounds per square inch.