Invert emulsion based completion and displacement fluid and method of use

Abstract

A method of cleaning a wellbore prior to the production of oil or gas, wherein the wellbore has been drilled with an invert emulsion drilling mud that forms an invert emulsion filter cake is disclosed. The method may include circulating a breaker fluid into the wellbore, where the breaker fluid includes a non-oleaginous internal phase and an oleaginous external phase, where the non-oleaginous phase includes a water soluble polar organic solvent, a hydrolysable ester of a carboxylic acid, and a weighting agent, and the oleaginous external phase includes an oleaginous fluid and an emulsifier, and where the hydrolysable ester is selected so that upon hydrolysis an organic acid is released and the invert emulsion of the filter cake breaks.

1 . A method of cleaning a wellbore, wherein the wellbore has been drilled with an invert emulsion drilling mud that forms an invert emulsion filter cake, the method comprising: circulating a breaker fluid into the wellbore, the breaker fluid comprising: 
 a non-oleaginous internal phase; and    an oleaginous external phase, wherein the non-oleaginous phase comprises:    a water soluble polar organic solvent;    a hydrolysable ester of a carboxylic acid; and    a weighting agent; and    wherein the oleaginous external phase comprises: 
 an oleaginous fluid; and  
 an emulsifier;  
 wherein the hydrolysable ester is selected so that upon hydrolysis an organic acid is released and the invert emulsion of the filter cake breaks.  
   
   
   
       2 . The method of  claim 1 , wherein the water soluble polar organic solvent is a glycol or glycol ether.  
   
   
       3 . The method of  claim 2 , wherein the water soluble polar organic solvent is ethylene glycol mono-butyl ether.  
   
   
       4 . The method of  claim 1 , wherein the hydrolysable ester of the carboxylic acid is a formic acid ester of a C4 to C30 alcohol.  
   
   
       5 . The method of  claim 1 , further comprising: displacing the broken invert emulsion filter cake.  
   
   
       6 . The method of  claim 1 , further comprising: removing the broken invert emulsion filter cake from the wellbore.  
   
   
       7 . A method of producing a hydrocarbon from a formation, the method comprising: 
 drilling the formation with an invert emulsion drilling mud;    performing at least one completion operation in the wellbore;    emplacing a breaker fluid in the wellbore, the breaker fluid comprising: 
 a non-oleaginous internal phase; and  
 an oleaginous external phase,  
 wherein the non-oleaginous phase comprises: 
 a water soluble polar organic solvent;  
 a hydrolysable ester of a carboxylic acid; and  
 a weighting agent; and  
 
 wherein the oleaginous external phase comprises: 
 an oleaginous fluid; and  
 an emulsifier; and  
 
   shutting the well for a predetermined time to allow the hydrolysis of the ester and the breaking of the invert emulsion of the filter cake.    
   
   
       8 . The method of  claim 7 , further comprising: allowing the formation fluids to enter into the well; and producing fluids from the well.  
   
   
       9 . The method of  claim 8 , wherein the emplacing the breaker fluid occurs after producing the fluids from the well.  
   
   
       10 . The method of  claim 7 , wherein the emplacing the breaker fluid occurs simultaneous as performing the at least one completion operation.  
   
   
       11 . The method of  claim 7 , wherein the emplacing the breaker fluid occurs after performing the at least one completion operation.  
   
   
       12 . The method of  claim 7 , wherein the completed wellbore contains at least one of a slotted liner, a predrilled liner, a wire wrapped screen, an expandable screen, a sand screen filter, a open hole gravel pack, and casing.  
   
   
       13 . The method of  claim 7 , wherein the water soluble polar organic solvent is a glycol or glycol ether.  
   
   
       14 . The method of  claim 13 , wherein the water soluble polar organic solvent is ethylene glycol mono-butyl ether.  
   
   
       15 . The method of  claim 7 , wherein the hydrolysable ester of the carboxylic acid is a formic acid ester of a C4 to C30 alcohol.  
   
   
       16 . A solution, comprising: 
 a non-oleaginous internal phase; and    an oleaginous external phase,    wherein the non-oleaginous phase comprises: 
 a water soluble polar organic solvent;  
 a hydrolysable ester of a carboxylic acid; and  
 a weighting agent; and  
   wherein the oleaginous external phase comprises: 
 an oleaginous fluid; and  
 an emulsifier.  
   
   
   
       17 . The solution of  claim 16 , wherein the water soluble polar organic solvent is a glycol or glycol ether.  
   
   
       18 . The solution of  claim 17 , wherein the water soluble polar organic solvent is ethylene glycol mono-butyl ether.  
   
   
       19 . The solution of  claim 16 , wherein the hydrolysable ester of the carboxylic acid is a formic acid ester of a C4 to C30 alcohol.  
   
   
       20 . The solution of  claim 16 , further comprising: at least one selected from a wetting agent, a cleaning agent, a thinner, and a viscosifying agent.  
   
   
       21 . The solution of  claim 16 , wherein the weighting agent is a brine comprising freshwater or seawater that contains halide or formate salts of alkali and alkaline earth metals.  
   
   
       22 . The solution of  claim 21 , wherein the cleaning agent is d-limonene.  
   
   
       23 . The solution of  claim 16 , wherein the hydrolysable ester of the carboxylic acid comprises from about 20 to about 60 volume percent of the solution.