Wellbore fluids for casing drilling

Abstract

A method of drilling a subterranean hole that includes mixing a base fluid and a micronized weighting agent having a particle size d 90 of less than about 50 microns to form a wellbore fluid; providing a drilling assembly that includes a casing as at least a portion of a drill string; and a drill bit attached at the distal end of the drill string; and drilling said subterranean hole with the drilling assembly using the wellbore fluid is disclosed.

1 . A method of drilling a subterranean hole, comprising:
 mixing a base fluid and a micronized weighting agent having a particle size d 90  of less than about 50 microns to form a wellbore fluid;   providing a drilling assembly comprising:
 a casing as at least a portion of a drill string; and 
 a drill bit attached at the distal end of the drill string; and 
   drilling said subterranean hole with the drilling assembly using the wellbore fluid.   
   
   
       2 . The method of  claim 1 , wherein the micronized weighting agent is at least one selected from barite, calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, hausmannite, and strontium sulfate. 
   
   
       3 . The method of  claim 1 , wherein the micronized weighting agent comprises a coating thereon. 
   
   
       4 . The method of  claim 3 , wherein the dispersant comprises at least one selected from oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpha olefins sulfonic acid, alkaline earth metal salts thereof, and phospholipids. 
   
   
       5 . The method of  claim 3 , wherein the dispersant comprises polyacrylate esters. 
   
   
       6 . The method of  claim 5 , wherein the polyacrylate ester is at least one selected from polymers of stearyl methacrylate, butylacrylate, and acrylic acid. 
   
   
       7 . The method of  claim 3 , wherein the micronized weighting agent comprises colloidal particles having a coating thereon. 
   
   
       8 . The method of  claim 1 , wherein the micronized weighting agent has a particle size d 90  of less than about 10 microns. 
   
   
       9 . The method of  claim 4 , wherein the micronized weighting agent has a particle size d 90  of less than about 5 microns. 
   
   
       10 . The method of  claim 1 , wherein the base fluid comprises at least one of an oleaginous fluid and a non-oleaginous fluid. 
   
   
       11 . A method of drilling a subterranean hole, comprising:
 mixing an oleaginous fluid, a non-oleaginous fluid, and a micronized weighting agent having a particle size d 90  of less than about 50 microns to form an invert emulsion drilling fluid;   providing a drilling assembly comprising:
 a casing as at least a portion of a drill string; and 
 a drill bit attached at the distal end of the drill string; and 
   drilling said subterranean hole with the drilling assembly using the invert emulsion drilling fluid.   
   
   
       12 . The method of  claim 11 , wherein the oleaginous fluid is selected from the group consisting of diesel oil, mineral oil, synthetic oil such as polyolefins or isomerized polyolefins, ester oils, glycerides of fatty acids, aliphatic esters, aliphatic ethers, aliphatic acetals, and combinations thereof. 
   
   
       13 . The method of  claim 11 , wherein the non-oleaginous fluid is selected from the group consisting of fresh water, seawater, brine containing inorganic or organic dissolved salts, aqueous solutions containing water-miscible organic compounds and combinations thereof. 
   
   
       14 . The method of  claim 11 , wherein the micronized weighting agent is at least one selected from barite, calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, hausmannite, and strontium sulfate. 
   
   
       15 . The method of  claim 11 , wherein the micronized weighting agent has a particle size d 90  of less than about 10 microns. 
   
   
       16 . The method of  claim 15 , wherein the micronized weighting agent has a particle size d 90  of less than about 5 microns. 
   
   
       17 . A method of drilling a subterranean hole, comprising:
 mixing an aqueous fluid and a micronized weighting agent having a particle size d 90  of less than about 50 microns to form a water-based wellbore fluid;   providing a drilling assembly comprising:
 a casing as at least a portion of a drill string; and 
 a drill bit attached at the distal end of the drill string; and 
   drilling said subterranean hole with the drilling assembly using the water-based wellbore fluid.   
   
   
       18 . The method of  claim 17 , wherein the aqueous fluid is selected from the group consisting of least one of fresh water, sea water, brine, mixtures of water and water-soluble organic compounds and mixtures thereof. 
   
   
       19 . The method of  claim 17 , wherein the micronized weighting agent is at least one selected from barite, calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, hausmannite, and strontium sulfate. 
   
   
       20 . The method of  claim 17 , wherein the micronized weighting agent has a particle size d 90  of less than about 10 microns. 
   
   
       21 . The method of  claim 20 , wherein the micronized weighting agent has a particle size d 90  of less than about 5 microns.