Precipitated weighting agents for use in wellbore fluids

Abstract

A method of formulating a wellbore fluid that includes precipitating a weighting agent from a solution; and adding the precipitated weighting agent to a base fluid to form a wellbore fluid is disclosed. Fluids and methods of formulating wellbore fluids that contain dispersant coated precipitated weighting agents are also disclosed.

1 - 25 . (canceled) 
     
     
         26 . A wellbore fluid, comprising:
 a base fluid;   a precipitated weighting agent comprising at least one of barium sulfate, calcium carbonate, magnesium carbonate, calcium magnesium carbonate, iron oxide, magnesium silicate, iron silicate, iron carbonate, and strontium sulfate and formed by precipitating a weighting agent from a solution in the presence of a dispersant to have a d 50  of of less than 1 micron; and   at least one selected from the group consisting of wetting agents, organophilic clays, viscosifiers, fluid loss control agents, surfactants, dispersants, interfacial tension reducers, pH buffers, mutual solvents, thinners, thinning agents, and cleaning agents.   
     
     
         27 . The wellbore fluid of  claim 26 , wherein the precipitated weighting agent has a d 50  of less than 700 nanometers. 
     
     
         28 . The wellbore fluid of  claim 26  wherein the precipitated weighting agent has a d 50  of at least 5 nanometers. 
     
     
         29 . The wellbore fluid of  claim 26 , wherein the base fluid is one selected from a water-based fluid, an oil-based fluid, and an invert emulsion. 
     
     
         30 . The wellbore fluid of  claim 26 , 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. 
     
     
         31 . The wellbore fluid of  claim 26 , wherein the dispersant comprises polyacrylate esters. 
     
     
         32 . The wellbore fluid of  claim 31 , wherein the polyacrylate ester is at least one selected from polymers of stearyl methacrylate, butylacrylate, and acrylic acid. 
     
     
         33 . The wellbore fluid of  claim 26 , wherein the dispersant comprises a homopolymer or copolymer of one or more monomers selected from acrylic acid, itaconic acid, maleic acid or anhydride, hydroxypropyl acrylate vinylsulphonic acid, acrylamido 2-propane sulphonic acid, acrylamide, styrene sulphonic acid, acrylic phosphate esters, methyl vinyl ether or vinyl acetate or salts thereof. 
     
     
         34 . A wellbore fluid, comprising:
 a base fluid;   a precipitated weighting agent comprising at least one of barium sulfate, calcium carbonate, magnesium carbonate, calcium magnesium carbonate, iron oxide, magnesium silicate, iron silicate, iron carbonate, and strontium sulfate and formed by:
 precipitating a weighting agent from a solution; 
 controlling the particle size of the precipitated weighting agent to d 50  of less than 700 nanometers and dispersing the precipitated weighting agent; and 
   at least one selected from the group consisting of wetting agents, organophilic clays, viscosifiers, fluid loss control agents, surfactants, dispersants, interfacial tension reducers, pH buffers, mutual solvents, thinners, thinning agents, and cleaning agents.   
     
     
         35 . The wellbore fluid of  claim 34 , wherein the controlling comprises adding a dispersant to the solution during the precipitating. 
     
     
         36 . The wellbore fluid of  claim 34 , wherein the controlling comprises precipitating in the presence of at least one of a stirred tank reactor, a rotor-stator mixer, impinging jets, micro-channel mixers, a Taylor-Couette reactor, or ultrasonication. 
     
     
         37 . The wellbore fluid of  claim 34  wherein the precipitated weighting agent has a d 50  of at least 5 nanometers. 
     
     
         38 . The wellbore fluid of  claim 34 , wherein the base fluid is one selected from a water-based fluid, an oil-based fluid, and an invert emulsion. 
     
     
         39 . The wellbore fluid of  claim 35 , 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. 
     
     
         40 . The wellbore fluid of  claim 35 , wherein the dispersant comprises polyacrylate esters. 
     
     
         41 . The wellbore fluid of  claim 40 , wherein the polyacrylate ester is at least one selected from polymers of stearyl methacrylate, butylacrylate, and acrylic acid. 
     
     
         42 . The wellbore fluid of  claim 35 , wherein the dispersant comprises a homopolymer or copolymer of one or more monomers selected from acrylic acid, itaconic acid, maleic acid or anhydride, hydroxypropyl acrylate vinylsulphonic acid, acrylamido 2-propane sulphonic acid, acrylamide, styrene sulphonic acid, acrylic phosphate esters, methyl vinyl ether or vinyl acetate or salts thereof. 
     
     
         43 . The wellbore fluid of  claim 34 , wherein the precipitated weighting agent has an average particle size of less than 500 mm. 
     
     
         44 . The wellbore fluid of  claim 43 , wherein the precipitated weighting agent has an average particle size of less than 100 nm. 
     
     
         45 . A wellbore fluid, comprising:
 a base fluid;   a precipitated weighting agent comprising at least one of barium sulfate, calcium carbonate, magnesium carbonate, calcium magnesium carbonate, iron oxide, magnesium silicate, iron silicate, iron carbonate, and strontium sulfate and formed by:
 dispersing and precipitating a weighting agent from a solution in the presence of at least one of a stirred tank reactor, a rotor-stator mixer, impinging jets, micro-channel mixers, a Taylor-Couette reactor, or ultrasonication; and 
   at least one selected from the group consisting of wetting agents, organophilic clays, viscosifiers, fluid loss control agents, surfactants, dispersants, interfacial tension reducers, pH buffers, mutual solvents, thinners, thinning agents, and cleaning agents.   
     
     
         46 . The wellbore fluid of  claim 45 , wherein the precipitated weighting agent has an average particle size of less than 700 mm. 
     
     
         47 . The wellbore fluid of  claim 46 , wherein the precipitated weighting agent has an average particle size of less than 500 nm.