Methods of preparing settable fluids comprising particle-size distribution-adjusting agents, and associated methods

Abstract

Base cement compositions comprising particle-size distribution-adjusting agents, and methods of using such base cement compositions in subterranean operations and surface applications are provided. An example of a method comprises: providing a base cement composition comprising water, a hydraulic cement, a set retarder, and a particle-size distribution-adjusting agent, the base cement composition having a density; adjusting the density of the base cement composition on-the-fly with a density modifying agent to provide a density-adjusted cement; activating the density-adjusted cement composition; placing the density-adjusted cement composition in a subterranean formation; and permitting the density-adjusted cement composition to set in the subterranean formation. Another example of a method comprises: providing a base cement composition comprising water, a hydraulic cement, a set retarder, and a particle-size distribution-adjusting agent, the base cement composition having a density; and adjusting the density of the base cement composition at the job site by variably injecting a density modifier into the base cement composition.

1 . A method of cementing in a subterranean formation, comprising: 
 providing a base cement composition comprising water, a hydraulic cement, a set retarder, and a particle-size distribution-adjusting agent, the base cement composition having a density;    adjusting the density of the base cement composition on-the-fly with a density modifying agent to provide a density-adjusted cement composition;    activating the density-adjusted cement composition;    placing the density-adjusted cement composition in a subterranean formation; and    permitting the density-adjusted cement composition to set in the subterranean formation.    
     
     
         2 . The method of  claim 1  wherein the particle-size distribution-adjusting agent is a cationic polymer.  
     
     
         3 . The method of  claim 2  wherein the cationic polymer is a cationic polyacrylamide, a cationic hydroxyethyl cellulose, a poly(dimethyldiallylammonium chloride), or a cationic starch.  
     
     
         4 . The method of  claim 1  wherein the step of adjusting the density of the base cement composition comprises injecting a density modifier into the base cement composition.  
     
     
         5 . The method of  claim 4  wherein the density modifier comprises a densifier selected from the group consisting of iron oxides, manganese oxides, zinc oxide, zirconium oxide, iron carbonate, aqueous solutions of soluble salts, and mixtures thereof.  
     
     
         6 . The method of  claim 4  wherein the density modifier comprises a densifier which has a specific gravity in the range of from about 3.5 to about 10.  
     
     
         7 . The method of  claim 4  wherein the density modifier comprises a density reducer selected from the group consisting of water, gas, low bulk density inorganic materials containing entrapped air, and microspheres.  
     
     
         8 . The method of  claim 4  wherein the density modifier comprises a density reducer which has a specific gravity in the range of from about 0.1 to about 3.  
     
     
         9 . The method of  claim 1  wherein the step of activating the cement composition comprises adding an activator composition to the cement composition.  
     
     
         10 . The method of  claim 9  wherein the activator composition is a mixture of a trialkanolamine and an alkali or a mixture of a trialkanolamine and an alkaline earth metal hydroxide.  
     
     
         11 . The method of  claim 1  wherein the step of activating the cement composition is performed before, during, or after adjusting the density of the base cement composition.  
     
     
         12 . The method of  claim 1  wherein the step of adjusting the density on-the-fly of the base cement composition comprises injecting a density modifying additive into the base cement composition such that the hydrostatic pressure of the composition does not exceed a fracture gradient of the subterranean formation.  
     
     
         13 . A method of customizing the density of a base cement composition for use at a job site comprising: 
 providing a base cement composition comprising water, a hydraulic cement, a set retarder, and a particle-size distribution-adjusting agent, the base cement composition having a density; and    adjusting the density of the base cement composition at the job site by variably injecting a density modifier into the base cement composition.    
     
     
         14 . The method of  claim 13  wherein the particle-size distribution-adjusting agent is a cationic polymer.  
     
     
         15 . The method of  claim 14  wherein the cationic polymer is selected from the group consisting of cationic polyacrylamides, cationic hydroxyethyl cellulose, poly(dimethyldiallylammonium chloride), and cationic starches.  
     
     
         16 . The method of  claim 13  wherein the step of adjusting the density of the base cement composition at the job site comprises injecting a density modifier into the base cement composition before or during placement of the cement composition within a subterranean formation.  
     
     
         17 . The method of  claim 13  wherein the density modifier comprises a densifier selected from the group consisting of iron oxides, manganese oxides, zinc oxide, zirconium oxide, iron carbonate, aqueous solutions of soluble salts, and mixtures thereof.  
     
     
         18 . The method of  claim 13  wherein the density modifier comprises a densifier which has a specific gravity in the range of from about 3.5 to about 10.  
     
     
         19 . The method of  claim 13  wherein the density modifier comprises a density reducer selected from the group consisting of water, gas, low bulk density inorganic materials containing entrapped air, and microspheres.  
     
     
         20 . The method of  claim 13  wherein the density modifier comprises a density reducer which has a specific gravity in the range of from about 0.1 to about 3.  
     
     
         21 . The method of  claim 13  wherein the step of adjusting the density of the base cement composition at the job site comprises variably injecting a density modifying additive into the base cement composition in response to hydrostatic pressure of the composition in a subterranean formation.  
     
     
         22 . The method of  claim 13  wherein the step of adjusting the density of the base cement composition at the job site comprises variably injecting a density modifying additive into the base cement composition to counter cement circulation loss into a subterranean formation.