Defoaming Compositions and Processes for Drilling Fluid Applications

Abstract

Compositions and processes for breaking or reducing foam in a drilling fluid, or improving the disposal of a drilling fluid, or reducing or preventing entrained gas in a drilling fluid. The compositions include a defoaming composition comprising hydrophobic silica and an organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer.

What is claimed is: 
     
         1 . A process of breaking or reducing foam in a drilling fluid, or improving the disposal of a drilling fluid, or reducing or preventing entrained gas in a drilling fluid, the process comprising:
 adding a defoaming composition to a drilling fluid, wherein the defoaming composition comprises hydrophobic silica and an organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer.   
     
     
         2 . The process of  claim 1 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is a condensation reaction product of a polyoxyethylene-polyoxypropylene block copolymer and an organic acid having at least one carboxylic acid group. 
     
     
         3 . The process of  claim 1 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is of the general structure: 
       
         
           
           
               
               
           
         
         wherein R is a linear or branched, saturated or unsaturated alkyl group or alkyl carboxylate group or aryl or aryl carboxylate group having from 3 to 40 carbon atoms, a is 2 to 8 moles and b is 16 to 67 moles. 
       
     
     
         4 . The process of  claim 2 , wherein the organic acid is selected from the group consisting of mono-carboxylic acids, dicarboxylic acids, and multicarboxylic acids. 
     
     
         5 . The process of  claim 1 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer has an average molecular weight of 1000 to 5000 Daltons. 
     
     
         6 . The process of  claim 1 , wherein the acid ester of the polyoxyethylenepolyoxypropylene block copolymer has an acid number less than 15. 
     
     
         7 . The process of  claim 1 , wherein a weight ratio of the hydrophobic silica to the acid ester of the polyoxyethylene-polyoxypropylene block copolymer is between 0.1 to 10 weight percent. 
     
     
         8 . The process of  claim 1 , wherein the hydrophobic silica is hydrophobized silica fume or precipitated silica or a mixture thereof. 
     
     
         9 . The process of  claim 1 , wherein the polyoxyethylene-polyoxypropylene block copolymer is ordered having a polyoxypropylene backbone and polyoxyethylene end groups or a polyoxyethylene backbone and polyoxypropylene end groups. 
     
     
         10 . The process of  claim 1 , wherein the drilling fluid is a drilling mud. 
     
     
         11 . The process of  claim 1 , wherein the organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer is a reaction product of a polyoxyethylene-polyoxypropylene block copolymer and an organic acid selected from the group consisting of oleic acid, stearic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and mixtures thereof; and
 wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is of the general structure:   
       
         
           
           
               
               
           
         
         wherein R is a linear or branched, saturated or unsaturated alkyl group or alkyl carboxylate group or aryl or aryl carboxylate group derived from oleic acid, stearic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid; a is 2 to 8 and b is 16 to 67. 
       
     
     
         12 . A composition comprising a defoaming composition and a drilling fluid, wherein the defoaming composition comprises hydrophobic silica and an organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer. 
     
     
         13 . The composition of  claim 12 , wherein the drilling fluid comprises foam. 
     
     
         14 . The composition of  claim 12 , wherein the drilling fluid is a drilling mud. 
     
     
         15 . The composition of  claim 12 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is a condensation reaction product of a polyoxyethylene-polyoxypropylene block copolymer and an organic acid having at least one carboxylic acid group. 
     
     
         16 . The composition of  claim 12 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is of the general structure: 
       
         
           
           
               
               
           
         
         wherein R is a linear or branched, saturated or unsaturated alkyl group or alkyl carboxylate group or aryl or aryl carboxylate group having from 3 to 40 carbon atoms, a is 2 to 8 moles and b is 16 to 67 moles. 
       
     
     
         17 . The composition of  claim 15 , wherein the organic acid is selected from the group consisting of mono-carboxylic acids, dicarboxylic acids, and multicarboxylic acids. 
     
     
         18 . The composition of  claim 12 , wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer has an average molecular weight of 1000 to 5000 Daltons. 
     
     
         19 . The composition of  claim 12 , wherein the acid ester of the polyoxyethylenepolyoxypropylene block copolymer has an acid number less than 15. 
     
     
         20 . The composition of  claim 12 , wherein a weight ratio of the hydrophobic silica to the acid ester of the polyoxyethylene-polyoxypropylene block copolymer is between 0.1 to 10 weight percent. 
     
     
         21 . The composition of  claim 12 , wherein the hydrophobic silica is hydrophobized silica fume or precipitated silica or a mixture thereof. 
     
     
         22 . The composition of  claim 12 , wherein the polyoxyethylene-polyoxypropylene block copolymer is ordered having a polyoxypropylene backbone and polyoxyethylene end groups or a polyoxyethylene backbone and polyoxypropylene end groups. 
     
     
         23 . The composition of  claim 12 , wherein the organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer is a reaction product of a polyoxyethylene-polyoxypropylene block copolymer and an organic acid selected from the group consisting of oleic acid, stearic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and mixtures thereof; and
 wherein the organic acid ester of the polyoxyethylene-polyoxypropylene block copolymer is of the general structure:   
       
         
           
           
               
               
           
         
         wherein R is a linear or branched, saturated or unsaturated alkyl group or alkyl carboxylate group or aryl or aryl carboxylate group derived from oleic acid, stearic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid; a is 2 to 8 and b is 16 to 67.