Compositions for Improving Thermal Conductivity of Cement Systems

Abstract

A method of cementing in a subterranean formation comprises placing a cement composition comprising a non-metallic thermally conductive fiber into the subterranean formation, and allowing the composition to set therein, wherein the non-metallic thermally conductive fiber has a thermal conductivity greater than about 500 W/m.K. Another method of cementing in a subterranean formation comprises providing a cement composition comprising a pitch-based carbon fiber, a hydraulic cement material, and water, placing the cement composition in a formation, and allowing the cement composition to set therein, wherein said pitch-based carbon fiber has a density of from about 2.0 grams/cc to about 2.3 grams/cc. A cement composition comprising a cementitious material, water, and a non-metallic thermally conductive fiber having a thermal conductivity greater than about 500 W/m.K, or a pitch-based carbon fiber having a density of from about 2.0 grams/cc to about 2.3 grams/cc.

1 . A cement composition comprising:
 a cementitious material;   water; and   a non-metallic thermally conductive fiber having a thermal conductivity greater than about 500 W/m.K.   
     
     
         2 . The cement composition of  claim 1  wherein the fiber is a carbon fiber. 
     
     
         3 . The cement composition of  claim 1  wherein the fiber is oriented. 
     
     
         4 . The cement composition of  claim 1  wherein the fiber is discontinuous. 
     
     
         5 . The cement composition of  claim 1  wherein the fiber has a thermal conductivity of greater than about 3000 W/m.K. 
     
     
         6 . The cement composition of  claim 1  wherein the fiber is derived from pitch. 
     
     
         7 . The cement composition of  claim 6  wherein the pitch is mesophase pitch. 
     
     
         8 . The cement composition of  claim 1  wherein the fiber is produced by chemical vapor deposition. 
     
     
         9 . The cement composition of  claim 1  wherein the fiber has a length of from about 20 microns to about 25 mm. 
     
     
         10 . The cement composition of  claim 1  wherein the fiber has a cross-sectional diameter of from about 70 nm to about 20 microns. 
     
     
         11 . The cement composition of  claim 1  where the fiber has an aspect ratio of from about 5 to about 400000. 
     
     
         12 . The cement composition of  claim 1  wherein the fiber has a longitudinal compressive strength of from about 20000 psi to about 100000 psi. 
     
     
         13 . The cement composition of  claim 1  wherein the fiber has a tensile strength of from about 0.2E+6 psi to about 3 E+6 psi. 
     
     
         14 . The cement composition of  claim 1  wherein the fiber has a coefficient of thermal expansion of less than about 1 ppm/° C. 
     
     
         15 . The cement composition of  claim 1  wherein the fiber has a density in the range of from about 2.0 grams/cc to about 2.3 grams/cc. 
     
     
         16 . The cement composition of  claim 1  wherein the fiber is present in the composition in an amount of from about 1 wt. % to about 30 wt. %. 
     
     
         17 . The cement composition of  claim 1  wherein the cement composition comprises a cementitious material selected from the group consisting of: Portland cement, construction cement, pozzolanic cement, gypsum cement, shale cement, acid/base cement, phosphate cement, high alumina content cement, silica cement, high alkalinity cement, magnesia cement, fly ash cement, a zeolite cement system, a cement kiln dust cement system, slag cement, micro-fine cement, metakaolin, Sorel cement, and a combination thereof. 
     
     
         18 . The cement composition of  claim 1  wherein the cementitious material is present in an amount of from about 20 wt. % to about 80 wt. %. 
     
     
         19 . The cement composition of  claim 1  wherein the cement composition comprises water which is present in an amount of from about 20 wt. % to about 180 wt. % by weight of the cementitious material. 
     
     
         20 . The cement composition of  claim 1  wherein the composition has a thermal conductivity of from about 0.75 W/m K to about 15 W/m K.