Aqueous ampholyte polymer containing solutions for subterranean applications

Abstract

A aqueous solution that includes water, from 100,000 to 300,000 ppm of dissolved solids, from 0.5 to 3 gallons per thousand gallons of a water-in-oil emulsion, and an inverting surfactant. The water-in oil emulsion includes an oil phase and an aqueous phase where the oil phase is a continuous phase comprising an inert hydrophobic liquid and the aqueous phase is present as dispersed distinct particles in the oil phase. The aqueous phase contains water, a water soluble polymer, and surfactants. The water soluble polymer includes 30 to 50 weight percent of a non-ionic monomer, 5 to 15 weight percent of a sulfonic acid containing monomer, and 40 to 60 weight percent of a cationic monomer. The water soluble polymer makes up from 10 to 35 weight percent of the water-in-oil emulsion.

We claim: 
     
         1 . An aqueous solution comprising:
 water;   from 100,000 to 300,000 ppm of dissolved solids;   from 0.5 to 3 gallons per thousand gallons of a water-in-oil emulsion comprising an oil phase (O) and an aqueous phase (A) at an O/A ratio of from about 1:8 to about 10:1, wherein the oil phase is a continuous phase comprising an inert hydrophobic liquid;
 wherein the aqueous phase is present as dispersed distinct particles in the oil phase and comprises water, a water soluble polymer, and surfactants; 
 wherein the water soluble polymer comprises 30 to 50 weight percent of a non-ionic monomer, 5 to 15 weight percent of a sulfonic acid containing monomer, and 40 to 60 weight percent of a cationic monomer; and 
 wherein the water soluble polymer comprises from 10 to 35 weight percent of the water-in-oil emulsion; and 
   an inverting surfactant.   
     
     
         2 . The aqueous solution according to  claim 1 , wherein the cationic monomer is methacrylamidopropyltrimethyl ammonium chloride or acryloyloxyethyltrimethyl ammonium chloride. 
     
     
         3 . The aqueous solution according to  claim 1 , wherein the nonionic monomer is acrylamide. 
     
     
         4 . The aqueous solution according to  claim 1 , wherein the sulfonic acid containing monomer is 2-acrylamido-2-methylpropane sulfonic acid. 
     
     
         5 . The aqueous solution according to  claim 1 , wherein the dissolved solids comprise 30 to 39 weight percent sodium, 0 to 9 weight percent calcium, 0 to 3 weight percent magnesium and 58 to 62 weight percent chloride. 
     
     
         6 . The aqueous solution according to  claim 1 , wherein the water soluble polymer has a molecular weight in the range of from about 7,500,000 to about 20,000,000. 
     
     
         7 . The aqueous solution according to  claim 1 , wherein the water soluble polymer has a reduced viscosity, as determined in a Ubbelhhde Capillary Viscometer at 0.05% by weight concentration of the polymer in 1M NaCl solution, at 30° C., pH 7, of from about 10 to about 40 dl/g. 
     
     
         8 . The aqueous solution according to  claim 1 , wherein the water-in-oil emulsion comprises at least one of an inhibitor, a salt, or an inverting surfactant. 
     
     
         9 . The aqueous solution according to  claim 1 , wherein the water-in-oil emulsion comprises an ammonium salt. 
     
     
         10 . The aqueous solution according to  claim 1 , wherein the water-in-oil emulsion comprises 4-methoxyphenol. 
     
     
         11 . The aqueous solution according to  claim 1 , wherein the inverting surfactant is one or more selected from the group consisting of polyoxyethylene alkyl phenol; polyoxyethylene (10 mole) cetyl ether; polyoxyethylene alkyl-aryl ether; N-cetyl-N-ethyl morpholinium ethosulfate; sodium lauryl sulfate; condensation products of higher fatty alcohols with ethylene oxide, condensation products of alkylphenols and ethylene oxide, condensation products of higher fatty acid amines with five, or more, ethylene oxide units; ethylene oxide condensation products of polyhydric alcohol partial higher fatty esters, and their inner anhydrides. 
     
     
         12 . The aqueous solution according to  claim 1 , wherein the inverting surfactant comprises one or more ethoxylated C 12 -C 16  alcohols. 
     
     
         13 . The aqueous solution according to  claim 1 , wherein the inert hydrophobic liquid comprises a mixture of paraffinic hydrocarbons and napthenic hydrocarbons. 
     
     
         14 . The aqueous solution according to  claim 1 , wherein the surfactants comprise a tall oil fatty acid diethanol amine, a polyoxyethylene (5) sorbitan monooleate, and a sorbitan monooleate. 
     
     
         15 . The aqueous solution according to  claim 1 , wherein the aqueous solution demonstrates better friction reduction properties than an aqueous solution containing the same level of dissolved solids and the same amount of a similarly prepared water soluble polymer that contains only the same non-ionic monomers and cationic monomers, but no sulfonic acid containing monomers. 
     
     
         16 . An aqueous solution comprising:
 water;   from 150,000 to 250,000 ppm of dissolved solids;   from 0.5 to 3 gallons per thousand gallons of a water-in-oil emulsion comprising an oil phase (O) and an aqueous phase (A) at an O/A ratio of from about 1:8 to about 10:1, wherein the oil phase is a continuous phase comprising an inert hydrophobic liquid;
 wherein the aqueous phase is present as dispersed distinct particles in the oil phase and comprises water, a water soluble polymer, and surfactants; 
 wherein the water soluble polymer comprises 35 to 45 weight percent of a non-ionic monomer, 5 to 15 weight percent of a sulfonic acid containing monomer, and 45 to 55 weight percent of a cationic monomer; and 
 wherein the water soluble polymer comprises from 10 to 35 weight percent of the water-in-oil emulsion; and 
   an inverting surfactant.   
     
     
         17 . The aqueous solution according to  claim 16 , wherein the non-ionic monomer comprises acrylamide, the sulfonic acid containing monomer comprises sodium AMPSA, and the cationic monomer comprises AETAC. 
     
     
         18 . A water-in-oil emulsion comprising an oil phase (O) and an aqueous phase (A) at an O/A ratio of from about 1:8 to about 10:1,
 wherein the oil phase is a continuous phase comprising an inert hydrophobic liquid;   wherein the aqueous phase is present as dispersed distinct particles in the oil phase and comprises water, a water soluble polymer, and surfactants;
 wherein the water soluble polymer comprises 35 to 45 weight percent of a non-ionic monomer, 5 to 15 weight percent of a sulfonic acid containing monomer, and 45 to 55 weight percent of a cationic monomer; and 
 wherein the water soluble polymer comprises from 10 to 35 weight percent of the water-in-oil emulsion; and 
   an inverting surfactant.   
     
     
         19 . The water-in-oil emulsion according to  claim 18 , wherein the non-ionic monomer comprises acrylamide, the sulfonic acid containing monomer comprises sodium AMPSA, and the cationic monomer comprises AETAC. 
     
     
         20 . The water-in-oil emulsion according to  claim 18 , wherein the surfactants comprise a tall oil fatty acid diethanol amine, a polyoxyethylene (5) sorbitan monooleate, and a sorbitan monooleate; the inert hydrophobic liquid comprises a mixture of paraffinic hydrocarbons and napthenic hydrocarbons; and the inverting surfactant comprises one or more ethoxylated C 12 -C 16  alcohols.