Wellbore fluids for cement displacement operations

Abstract

A method of cementing a pipe into a wellbore filled with a drilling fluid that includes displacing the drilling fluid with the displacement fluid which includes a base fluid, a micronized weighting agent; suspending a pipe in the wellbore; and pumping cement into the wellbore to substantially fill the annulus formed between the outer surface of the pipe and the wellbore is disclosed.

1 . A method of cementing a pipe into a wellbore filled with a drilling fluid, comprising:
 displacing the drilling fluid with the displacement fluid, comprising:
 a base fluid; and 
 a micronized weighting agent; 
   suspending a pipe in the wellbore; and   pumping cement into the wellbore to substantially fill the annulus formed between the outer surface of the pipe and the wellbore.   
     
     
         2 . The method of  claim 1 , further comprising:
 pumping a spacer fluid into the well prior to pumping the cement.   
     
     
         3 . The method of  claim 1 , further comprising:
 pumping a second displacement fluid into the wellbore to displace the pumped cement into the annulus.   
     
     
         4 . The method of  claim 1 , wherein pumping the cement displaces the displacement fluid from the wellbore. 
     
     
         5 . The method of  claim 1 , further comprising:
 introducing at least one plug into the pipe.   
     
     
         6 . 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. 
     
     
         7 . The method of  claim 1 , wherein the micronized weighting agent is coated with a dispersant made by the method comprising dry blending a micronized weighting agent and a dispersant to form a micronized weighting agent coated with the dispersant. 
     
     
         8 . The method of  claim 1 , wherein the micronized weighting agent comprises colloidal particles having a coating thereon. 
     
     
         9 . The method of  claim 1 , wherein the micronized weighting agent has a particle size d 90  of less than about 20 microns. 
     
     
         10 . The method of  claim 1 , wherein the micronized weighting agent has a particle size d 90  of less than about 10 microns. 
     
     
         11 . The method of  claim 1 , wherein the micronized weighting agent has a particle size d 90  of less than about 5 microns. 
     
     
         12 . The method of  claim 7 , wherein the coating comprises at least one selected from oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpha-olefin sulfonic acids, alkaline earth metal salts thereof, polyacrylate esters, and phospholipids. 
     
     
         13 . The method of  claim 1 , wherein the base fluid is at least one of an oleaginous fluid and a non-oleaginous fluid. 
     
     
         14 . A method of drilling and cementing a wellbore, comprising:
 drilling the wellbore with a drilling fluid;   displacing the drilling fluid with a displacement fluid comprising:
 a base fluid; and 
 a micronized weighting agent; 
   suspending a pipe in the well; and   pumping cement into the well so as to fill the annulus formed between the outer surface of the pipe and the wellbore.   
     
     
         15 . The method of  claim 14 , further comprising:
 pumping a spacer fluid into the well prior to pumping the cement.   
     
     
         16 . The method of  claim 14 , further comprising:
 pumping a second displacement fluid into the wellbore to displace the pumped cement into the annulus.   
     
     
         17 . The method of  claim 14 , wherein pumping the cement displaces the displacement fluid from the wellbore. 
     
     
         18 . The method of  claim 1 , further comprising:
 introducing at least one plug into the pipe.   
     
     
         19 . A method of drilling and cementing a wellbore, comprising:
 drilling the wellbore with a wellbore fluid comprising:
 a base fluid; and 
 a micronized weighting agent; 
   suspending a pipe in the well; and   pumping cement into the well so as to fill the annulus formed between the outer surface of the pipe and the wellbore.   
     
     
         20 . The method of  claim 19 , further comprising:
 pumping a spacer fluid into the well prior to pumping the cement.   
     
     
         21 . The method of  claim 19 , further comprising:
 pumping a displacement fluid into the wellbore to displace the pumped cement into the annulus.   
     
     
         22 . The method of  claim 19 , wherein pumping the cement displaces the drilling fluid from the wellbore. 
     
     
         23 . The method of  claim 19 , further comprising:
 introducing at least one plug into the pipe.