Dispersant coated weighting agents

Abstract

A method of formulating a wellbore fluid that includes providing a base fluid; and adding a sized weighting agent coated with a dispersant made by the method of dry blending a weighting agent and a dispersant to form a sized weighting agent coated with the dispersant is disclosed.

1 . A method of formulating a wellbore fluid comprising:
 providing a base fluid; and   adding a sized weighting agent coated with a dispersant made by the method comprising:   dry blending a weighting agent and a dispersant to form a sized weighting agent coated with the dispersant.   
     
     
         2 . The method of  claim 1 , wherein the weighting agent is at least one selected from barite, calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, manganese oxide, and strontium sulfate. 
     
     
         3 . The method of  claim 1 , wherein the weighting agent is sized by the process of dry blending. 
     
     
         4 . The method of  claim 1 , wherein the dry blending comprises dry blending a sized weighting agent and a dispersant. 
     
     
         5 . The method of  claim 1 , wherein the sized weighting agent has a particle distribution given by d 90  ranging from 2 to 8 μm. 
     
     
         6 . The method of  claim 1 , wherein the sized weighting agent has a particle distribution given by d 50  ranging from 0.5 to 4 μm. 
     
     
         7 . The method of  claim 1 , wherein the dispersant comprises at least one selected from oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpa olefins sulfonic acid, alkaline earth metal salts thereof, and phospholipids. 
     
     
         8 . The method of  claim 1 , wherein the dispersant comprises polyacrylate esters. 
     
     
         9 . The method of  claim 8 , wherein the polyacrylate ester is at least one selected from polymers of stearyl methacrylate, butylacrylate, and acrylic acid. 
     
     
         10 . The method of  claim 1 , wherein the base fluid is one selected from a water-based fluid, an oil-based fluid, and an invert emulsion. 
     
     
         11 . The method of  claim 1 , wherein the wellbore fluid further comprises a colloidal coated weighting agent. 
     
     
         12 . A wellbore fluid comprising:
 a base fluid; and   a sized weighting agent coated with a dispersant made by the method comprising:
 dry blending a weighting agent and a dispersant to form a sized weighting agent coated with the dispersant. 
   
     
     
         13 . The wellbore fluid of  claim 12 , wherein the base fluid is one selected from a water-based fluid, an oil-based fluid, and an invert emulsion. 
     
     
         14 . The wellbore fluid of  claim 12 , wherein the wellbore fluid further comprises: a colloidal coated weighting agent. 
     
     
         15 . The wellbore fluid of  claim 12 , wherein the weighting agent is at least one selected from barite, calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, manganese oxide, and strontium sulfate. 
     
     
         16 . The wellbore fluid of  claim 12 , wherein the sized weighting agent has a particle distribution given by d 90  ranging from 2 to 8 μm. 
     
     
         17 . The wellbore fluid of  claim 12 , wherein the sized weighting agent has a particle distribution given by d 50  ranging from 0.5 to 4 μm. 
     
     
         18 . The wellbore fluid of  claim 12 , wherein the dispersant comprises at least one selected from oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpa olefins sulfonic acid, alkaline earth metal salts thereof, and phospholipids. 
     
     
         19 . The wellbore fluid of  claim 12 , wherein the dispersant comprises polyacrylate esters. 
     
     
         20 . The wellbore fluid of  claim 19 , wherein the polyacrylate ester is at least one selected from polymers of stearyl methacrylate, butylacrylate, and acrylic acid. 
     
     
         21 . The wellbore fluid of  claim 12 , wherein the weighting agent has a particle size distribution selected from at least one of a monomodal, bimodal, or polymodal distribution.