Cellulose nanofibers in extended cement systems

Abstract

Methods herein may include injecting a cement slurry having an aqueous base fluid, a cement, and a plurality of cellulose nanofibers dispersed in the aqueous base fluid. The plurality of cellulose nanofibers may be present in the slurry in an amount effective to provide a slurry density of not higher than 15 lb/gal.

1 . A cement slurry for treating a wellbore, comprising:
 an aqueous base fluid;   a cement; and   a plurality of cellulose nanofibers dispersed in the aqueous base fluid; and   wherein the plurality of cellulose nanofibers is present in the slurry in an amount effective to provide a slurry density of not higher than 15 lb/gal,   an anti-foaming agent.   
     
     
         2 . The slurry of  claim 1 , wherein the density of the cement slurry ranges from about 6 to about 15 lb/gal. 
     
     
         3 . The slurry of  claim 1 , wherein the plurality of cellulose nanofibers further increases a slurry yield by 1 to 3 feet cubed per sack depending on the density of the slurry. 
     
     
         4 . The slurry of  claim 1 , wherein the plurality of cellulose nanofibers is present in the cement slurry in a concentration ranging from about 0.03 to about 6% by weight of a blend, where the blend refers to all solid materials in the slurry including cement. 
     
     
         5 . The slurry of  claim 1 , wherein the cellulose nanofibers are selected from the group of cellulose nanofibrils and cellulose nanocrystals. 
     
     
         6 . The slurry of  claim 5 , wherein the cellulose nanofibers are cellulose nanofibrils present in the slurry in a concentration ranging from about 0.03 to about 2.5% by weight of a blend, where the blend refers to all solid materials in the slurry including cement. 
     
     
         7 . The slurry of  claim 5 , wherein the cellulose nanofibers are cellulose nanocrystals present in the slurry in a concentration ranging from about 0.2 to about 6% by weight of a blend, where the blend refers to all solid materials in the slurry including cement. 
     
     
         8 . The slurry of  claim 1 , wherein the cellulose nanofibers have a length ranging from about 100 nm to about 3 mm. 
     
     
         9 . The slurry of  claim 1 , wherein the cellulose nanofibers have a diameter ranging from about 4 nm to about 20 μm. 
     
     
         10 . The slurry of  claim 1 , further comprising at least an additive selected from the group of fly ash, silica, cenospheres, a dispersant, a fluid loss control additive or a combination thereof. 
     
     
         11 . The slurry of  claim 1 , further comprising gas bubbles and a foaming agent. 
     
     
         12 . A method for treating a subterranean formation penetrated by a wellbore, the method comprising:
 injecting a cement slurry into the wellbore, the slurry comprising:   an aqueous base fluid;   a cement; and   a plurality of cellulose nanofibers dispersed in the aqueous base fluid;   wherein the plurality of cellulose nanofibers is present in the slurry in an amount effective to provide a slurry density of not higher than 15 lb/gal; and   allowing the cement slurry to set.   
     
     
         13 . The method of  claim 12 , further comprising: performing a downhole operation. 
     
     
         14 . The method of  claim 12 , wherein the injecting comprises pumping the cement slurry through the wellbore and into an annulus formed between the wellbore and a casing. 
     
     
         15 . The method of  claim 12 , wherein the density of the cement slurry ranges from about 6 to about 15 lb/gal. 
     
     
         16 . The method of  claim 12 , wherein the plurality of cellulose nanofibers further increases a slurry yield by 1 to 3 feet cubed per sack depending on the density of the slurry. 
     
     
         17 . The method of  claim 12 , wherein the plurality of cellulose nanofibers is present in the cement slurry in a concentration ranging from about 0.03 to about 6% by weight of the blend. 
     
     
         18 . The method of  claim 12 , wherein the cellulose nanofibers are selected from the group of cellulose nanofibrils and cellulose nanocrystals. 
     
     
         19 . The method of  claim 12 , wherein the cellulose nanofibers have a length ranging from about 100 nm to about 3 mm. 
     
     
         20 . The method of  claim 12 , wherein the cellulose nanofibers have a diameter ranging from about 4 nm to about 20 μm.