Methods of formulating a cement composition

Abstract

A method of cementing a wellbore in a subterranean formation comprising formulating a non-Portland base cement composition that may be suitable for long-term zonal isolation, preparing the non-Portland base cement composition, determining a density of the non-Portland base cement composition and adjusting the density as needed to within an optimized density range to form a first optimized cement composition, determining the percentage of tensile strength relative to compressive strength of the cement composition, and placing the optimized cement composition in the wellbore.

1 . A method of cementing a wellbore in a subterranean formation, comprising:
 formulating a non-Portland base cement composition that may be suitable for long-term zonal isolation;   preparing the non-Portland base cement composition;   determining a density of the non-Portland base cement composition and adjusting the density as needed to within an optimized density range to form a first optimized cement composition;   determining the percentage of tensile strength relative to compressive strength of the first optimized cement composition;   adjusting the percentage of tensile strength relative to compressive strength of the first optimized cement composition as needed to within an optimized percentage of tensile strength relative to compressive strength range to produce an optimized cement composition; and   placing the optimized cement composition in the wellbore.   
     
     
         2 . The method of  claim 1  wherein the optimized density range is from about 5 ppg to about 22 ppg. 
     
     
         3 . The method of  claim 1  wherein the adjusting the density comprises adding weighting agent, barite, hematite, hausmannite, calcium carbonate, siderite, ilmenite, or combinations thereof. 
     
     
         4 . The method of  claim 1  further comprising:
 determining a Young's modulus of the non-Portland base cement composition; and   adjusting the Young's modulus as needed to within an optimized Young's modulus range to form an adjusted first optimized cement composition.   
     
     
         5 . The method of  claim 4  wherein the optimized Young's modulus range is from about 1,000 psi to about 3,000,000 psi. 
     
     
         6 . The method of  claim 4  wherein the adjusting the Young's modulus comprises adding an elastomer, a rubber, or combinations thereof. 
     
     
         7 . The method of  claim 4  wherein the adjusting the Young's modulus comprises adding polyisoprene; polybutadiene; polyisobutylene; polyether; polyester; polystyrene; poly(methacrylate); isotactic polypropylene; polyurethane; natural rubber; styrene/butadiene rubber; cis-1,4-polybutadiene rubber; high styrene resin; butyl rubber; ethylene/propylene rubbers; neoprene rubber; nitrile rubber; cis-1,4-polyisoprene rubber; silicone rubber; chlorosulfonated rubber; polyethylene rubber; epichlorohydrin rubber; fluorocarbon rubber; fluorosilicone rubber; polyurethane rubber; polyacrylic rubber; polysulfide rubber; or combinations thereof. 
     
     
         8 . The method of  claim 4  wherein the density and Young's modulus are repeatedly adjusted as needed until the density is within an optimized density range, and Young's modulus is within an optimized Young's modulus range to form a second optimized cement composition. 
     
     
         9 . The method of  claim 8  further comprising:
 determining a Poisson's ratio of the non-Portland base cement composition; and   adjusting the Poisson's ratio as needed to within an optimized Poisson's ratio range.   
     
     
         10 . The method of  claim 9  wherein the optimized Poisson's ratio range is from about 0.05 to about 0.40. 
     
     
         11 . The method of  claim 9  wherein adjusting the Poisson's ratio comprises adding flexible compressible beads, a resilient material, gas, resilient graphite, natural rubber, styrofoam beads, styrene-butadiene copolymer, neoprene, synthetic rubbers, vinyl plastisol thermoplastics, nitrile rubber, butyl rubber, polysulfide rubber, EPDM rubber, silicone rubber, polyurethane rubber, or combinations thereof. 
     
     
         12 . The method of  claim 9  wherein the density, Young's modulus, and Poisson's ratio are repeatedly adjusted as needed until the density is within an optimized density range, Young's modulus is within an optimized Young's modulus range and Poisson's ratio is within an optimized Poisson's ratio range to form a third optimized cement composition. 
     
     
         13 . The method of  claim 1  wherein the optimized percentage of tensile strength relative to compressive strength range is from about 2% to about 20%. 
     
     
         14 . The method of  claim 1  wherein the adjusting the percentage of tensile strength relative to compressive strength comprises adding fibers, plastic fibers, carbon fibers, glass fibers, or combinations thereof. 
     
     
         15 . The method of  claim 12  wherein the density, Young's modulus, Poisson's ratio, and percentage of tensile strength relative to compressive strength are repeatedly adjusted as needed until the density is within an optimized density range, Young's modulus is within an optimized Young's modulus range, Poisson's ratio is within an optimized Poisson's ratio range and the optimized percentage of tensile strength relative to compressive strength is within an optimized percentage of tensile strength relative to compressive strength range to form a fourth optimized cement composition. 
     
     
         16 . The method of  claim 1  wherein the optimized cement composition develops a compressive strength of 50 psi within a time period of equal to or less than about 4 hours. 
     
     
         17 . The method of  claim 1  wherein the optimized cement composition develops a compressive strength of 500 psi within a time period of equal to or less than about 12 hours. 
     
     
         18 . The method of  claim 1  wherein the optimized cement composition has a density variation allowance of from about 0.01 ppg to about 1 ppg. 
     
     
         19 . The method of  claim 1  wherein the optimized cement composition has a thickening time of from about 30 minutes to about 10 hours. 
     
     
         20 . The method of  claim 1  wherein the optimized cement composition has a zero gel time of from about 5 minutes to about  110  minutes. 
     
     
         21 . The method of  claim 1  wherein the optimized cement composition has a transition time of from about 2 minutes to about 30 minutes. 
     
     
         22 . The method of  claim 1  wherein the optimized cement composition has a linear expansion of from about 1% to about 10%. 
     
     
         23 . The method of  claim 1  wherein the non-Portland cement composition comprises a metal oxide, a soluble chloride or phosphate salt, and water.