Water-soluble polymers for oil recovery

Abstract

The present invention refers to the use of anionic water-soluble polymers being partially or totally neutralized with an organic counter-ion for oil filed application, especially tertiary oil recovery steps.

1 - 12 . (canceled) 
     
     
         13 . A method for treating a subterranean formation comprising the steps:
 a) providing a water-soluble polymer, wherein the water-soluble polymer is anionic, is partially or totally neutralized with at least one organic counter-ion, is obtainable from a polymerization mixture containing at least one non-ionic monomer and at least one anionic monomer, wherein more than 1% of the anionic groups present in the polymer are neutralized said organic counter-ions and wherein the organic counter-ion is added before or during the polymerization of the polymerization mixture,   b) preparing an aqueous solution from the water-soluble anionic polymer, and   c) employing the aqueous solution obtained in step b) in the secondary or tertiary recovery of oil from said formation.   
     
     
         14 . The method according to  claim 13 , wherein the water-soluble anionic polymer is provided in the form of a powder or an inverse emulsion. 
     
     
         15 . The method according to  claim 13 , wherein the water-soluble anionic polymer is contained in the solution in an amount of between 10 ppm to 7500 ppm of the total weight of the solution. 
     
     
         16 . The method according to  claim 13 , wherein the at least one organic counter-ion is selected from organic amines in the protonated form with the general formula  + NHR 1 ,R 2 ,R 3 , wherein R 1  and R 2  independently from each other are selected from the group consisting of H, substituted or unsubstituted C1-C10alkyl, substituted or unsubstituted C3-C8cycloalkyl, substituted or unsubstituted C6-C14aryl, substituted or unsubstituted heteroaryl and polyoxyethylene-moieties, and R 3  is selected from the group consisting of substituted or unsubstituted C1-C10alkyl, substituted or unsubstituted C3-C8cycloalkyl, substituted or unsubstituted C6-C14aryl, substituted or unsubstituted heteroaryl and polyoxyethylene-moieties. 
     
     
         17 . The method according to  claim 13 , wherein the at least one organic counter-ion is selected from the group consisting of  + NH 3 (CH 3 ),  + NH 2 (CH 3 ) 2 ,  + NH(CH 3 ) 3 ,  + NH 3 (CH 2 CH 3 ),  + NH 2 (CH 2 CH 3 ) 2 ,  + NH(CH 2 CH 3 ) 3 ,  + NH 3 (CH 2 CH 2 OH),  + NH 2 (CH 2 CH 2 OH) 2 ,  + NH(CH 2 CH 2 OH) 3 , methylbis(polyoxyethylene (15)) octadecyl quaternary ammonium, cations derived from N,N-Diethanolamine, N,N,N-triethanolamine, N-ethanolamine, N,N-di-isopropylamine, N,N-diethylamine, N,N-dipropylamine, N,N-dimethylaminopropylamine (DMAPA), N-propylamine, N-isopropylamine, N-isobutylamine, N,N-di-isobutylamine, N,N-dibutylamine and N-butylamine. 
     
     
         18 . The method according to  claim 13 , wherein the at least one non-ionic monomer is a water-soluble vinylmonomer, preferably selected from the group consisting of acrylamide and methacrylamide, N-isopropyacrylamide, N,N-dimethylacrylamide, diacetone acrylamide, N-vinylformamide, N-vinyl acetamide, N-vinylpyridine, N-vinyl caprolactone and N-vinylpyrrolidone. 
     
     
         19 . The method according to  claim 13 , wherein the at least one anionic monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinylsulfonic acid, vinylphosphonic acid, (meth)allylsulfonic acid, (meth)allylphosphonic acid, acrylamido methyl butanoic acid, acrylamido tertiary butyl sulfonic acid and water-soluble salts of the foregoing substances. 
     
     
         20 . The method according to  claim 13 , wherein the polymerization mixture contains at least one cationic monomer, preferably a cationic monomer being derived from a non ionic monomer being protonated, more preferably a cationic monomer being derived from a non ionic monomer having a tertiary amine function including dimethylaminoethyl acrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEMA), dimethylaminopropyl acrylate (DMAPA) and dimethylaminopropyl methacrylate (DMAPMA). 
     
     
         21 . The method according to  claim 13 , wherein the anionic water-soluble polymer is hydrophobically modified. 
     
     
         22 . The method according to  claim 13 , wherein the polymerization mixture contains at least one branching agent, preferably at least one branching agent selected from the group consisting of methylene bisacrylamide (MBA), ethylene glycol diacrylate, polyethylene glycol dimethacrylate, vinyloxyethylacrylate or methacrylate, triallylamine, pentaerythritol triallyl ether, glycidylethers including diglycidylether, and epoxides. 
     
     
         23 . The method according to  claim 13 , wherein the water-soluble anionic polymer in aqueous solution provides a filter ratio of not more than 1.5. 
     
     
         24 . The method according to  claim 13 , wherein the water-soluble anionic polymer in aqueous solution provides a filter ratio of not more than 1.3. 
     
     
         25 . The method according to  claim 13 , wherein the water-soluble anionic polymer in aqueous solution provides a filter ratio of not more than 1.1. 
     
     
         26 . The method according to  claim 13 , wherein the anionicity of the water-soluble anionic polymer is less than 70 mol-%. 
     
     
         27 . The method according to  claim 13 , wherein the weight average molecular weight of the water-soluble anionic polymer is more than 1 million and less than 20 million. 
     
     
         28 . The method according to  claim 13 , wherein the oil field application is enhanced oil recovery, drilling, drag reduction, hydraulic fracturing, water shut-off and conformance control or mining.