Polymer compositions

Abstract

Novel polymer compositions are disclosed, along with their use as well service fluids, for example as completion fluids, work-over fluids or drilling fluids, comprising water soluble copolymers having sulfonate groups and carboxylate groups, along with alkali metal salts of carboxylic acid. Exemplary copolymer has 5 to 95 wt. % structural units derived from 2-acrylamido-2-methylpropanesulfonic acid or salt thereof, and 5 to 95 wt. % structural units derived from acrylic acid or salt thereof. A salt of the polymer may be used, such as the sodium, potassium, ammonium and calcium salts. Exemplary alkali metal salts of the polymer composition include sodium, potassium and cesium salts of formic acid and/or acetic acid in amounts suitable to develop high temperature viscosity suitable for such well servicing fluids. The polymer composition is hydrateble/soluble in a brine of sodium and/or potassium and/or cesium salts of formic and/or acetic acid.

1 - 12 . (canceled)  
     
     
         13 . A composition comprising: 
 water soluble copolymer formed as the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound; and    alkali metal salt of carboxylic acid;    wherein the water soluble copolymer comprises from 5 to 95 wt. % structural units derived from 2-acrylamido-2-methylpropanesulfonic acid or salt thereof, and from 5 to 95 wt. % structural units derived from acrylamide, vinylpyrrolidone, acrylic acid or salt thereof, and 0 to 5 wt. % structural units derived from an at least bifunctional cross-linking agent; and wherein the alkali metal salt comprises at least one alkali metal salt of C1 to C3 carboxylic acid.    
     
     
         14 . The composition of  claim 13  wherein the cross-linking agent is N,N′-methylenebis[2-propenamide].  
     
     
         15 - 16 . (canceled)  
     
     
         17 . A composition comprising: 
 water soluble copolymer formed as the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound;    alkali metal salt of carboxylic acid; and    alkali metal salt of at least one halides;    wherein the copolymer is substantially hydrated by water and the alkali metal salt of carboxylic acid is substantially dissolved.    
     
     
         18 . The composition of  claim 17  wherein the alkali metal salt of at least one halide is selected from the sodium, potassium and cesium salts of chloride, bromide and mixtures thereof.  
     
     
         19 . A composition comprising: 
 water soluble copolymer formed as the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound; and    alkali metal salt of carboxylic acid;    wherein the copolymer is substantially hydrated by water and the alkali metal salt of carboxylic acid is substantially dissolved, developing an apparent viscosity of at least 20 cPs., a plastic viscosity of at least 15 cPs, and a yield point of at least 5 lb./100 ft 2  when dissolved in cesium formate brine at a concentration of 2 pounds per barrel and measured at 120 degrees F.    
     
     
         20 . The composition of  claim 19  retaining at least 50 percent of its apparent viscosity after roller aging for 30 days at 375 degrees F. and measured at 120 degrees F.  
     
     
         21 . A process for preparing an aqueous composition comprising: 
 water soluble copolymer formed as the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound; and    alkali metal salt of carboxylic acid wherein the copolymer is substantially hydrated by water and the alkali metal salt of carboxylic acid is substantially dissolved, comprising hydrating the composition.    
     
     
         22 . A process for preparing an aqueous polymer composition according to  claim 21  wherein alkali metal salt of carboxylic acid is dissolved in an aqueous composition containing the water soluble copolymer.  
     
     
         23 . A process for preparing an aqueous polymer composition according to  claim 21  wherein the water soluble copolymer is dissolved in a brine of alkali metal salt of carboxylic acid.  
     
     
         24 . A method of carrying out well-drilling or well-servicing operations comprising the use of an aqueous well service fluid comprising water soluble copolymer having functionality including at least sulfonate groups and carboxylate groups, hydrated in a brine solution.  
     
     
         25 . The method of  claim 24  wherein the water soluble copolymer is substantially fully hydrated in the brine solution.  
     
     
         26 . An aqueous well service fluid comprising: 
 water soluble copolymer having functionality including at least sulfonate groups and carboxylate groups, hydrated in a brine solution.    
     
     
         27 . The aqueous well servicing fluid of  claim 26  wherein the water soluble copolymer is soluble in a brine of alkali metal salt of carboxylic acid.  
     
     
         28 . The aqueous well servicing fluid of  claim 26  wherein the water soluble copolymer is substantially fully hydrated in the brine solution.  
     
     
         29 . Water soluble copolymer having functionality including at least sulfonate groups and carboxylate groups, which has a weight average molecular weight of at least 1,000,000 and develops an apparent viscosity of at least 20 cPs., a plastic viscosity of at least 15 cPs, and a yield point of at least 5 lb./100 ft 2  when substantially fully hydrated in cesium formate brine at a concentration of 2 pounds per barrel and measured at 120 degrees F.  
     
     
         30 . Water soluble copolymer of  claim 29  having weight average molecular weight between 1,000,000 and 5,000,000.  
     
     
         31 . Water soluble copolymer of  claim 29  soluble in an amount of at least 4 lbs/bbl in a substantially saturated brine of alkali metal carboxylate selected from sodium, potassium and cesium salts of acetic and formic acids.  
     
     
         32 . Water soluble copolymer of  claim 29  which retains at least 50 percent of its apparent viscosity after roller aging for 30 days at 375 degrees F. and measured at 120 degrees F.  
     
     
         33 . Water soluble copolymer of  claim 29  hydrated in a brine solution.  
     
     
         34 . Water soluble copolymer comprising the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound, having weight average molecular weight of at least 1,000,000 and developing an apparent viscosity of at least 20 cPs., a plastic viscosity of at least cPs, and a yield point of at least 5 lbs./100 ft2 when substantially fully hydrated in cesium formate brine at a concentration of 2 pounds per barrel and measured at 120 degrees F.  
     
     
         35 . Water soluble copolymer of  claim 34  wherein the acrylamidomethylpropanesulfonic acid or salt thereof is 2-acrylamido-2-methylpropanesulfonic acid or salt thereof.  
     
     
         36 . Water soluble copolymer of  claim 34  wherein the acrylamidomethylpropanesulfonic acid or salt thereof is 2-methyl-2[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid or salt thereof.  
     
     
         37 . Water soluble copolymer of  claim 34  having a 5 to 95 wt. % structural units derived from 2-methyl-2[(-oxo-2-propenyl)amino]-1-propanesulfonic acid or salt thereof, and 5 to 95 wt. % structural units derived from 2-propanoic acid or salt thereof.  
     
     
         38 . Water soluble copolymer of  claim 34  having 40 to 80 wt. % structural units derived from 2-acrylamido-2-methylpropanesulfonic acid or salt thereof and 20 to 60 wt. % structural units derived from acrylamide, vinylpyrrolidone, acrylic acid or salt thereof.  
     
     
         39 . Water soluble copolymer of  claim 38  having 0 to 5 wt. % structural units derived from at least bifunctional cross-linking agent.  
     
     
         37 . (canceled)  
     
     
         38 . (canceled)  
     
     
         39 . (canceled)  
     
     
         40 . A composition comprising: 
 water soluble copolymer formed as the polymerization reaction product of acrylamidomethylpropanesulfonic acid or salt thereof and alpha, beta-unsaturated carbonyl compound; and    alkali metal salt of carboxylic acid;    wherein the water soluble copolymer has 5 to 95 wt. % structural units derived from 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid or salt thereof, and 5 to 95 wt. % structural units derived from 2-propanoic acid or salt thereof.    
     
     
         41 . The composition of  claim 26  further comprising sodium salt of a carboxylic acid.  
     
     
         42 . The composition of  claim 26  further comprising potassium salt of a carboxylic acid.  
     
     
         43 . The composition of  claim 26  further comprising sodium salt of a carboxylic acid and potassium salt of a carboxylic acid.