Corrosion inhibitor

Abstract

The use of a compound as a corrosion inhibitor for metallic equipment, where the compound includes (i) a salt of an optionally substituted polycarboxylic acid or an anhydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol and/or an amine, or a salt of the reaction product.

1 . The use of a compound as a corrosion inhibitor for metallic equipment, wherein the compound comprises (i) a salt of an optionally substituted polycarboxylic acid or an anhydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol and/or an amine, or a salt of the reaction product. 
     
     
         2 . A method of preventing or reducing corrosion of metallic equipment, the method comprising contacting at least a portion of the metallic equipment with a compound, wherein the compound comprises (i) a salt of an optionally substituted polycarboxylic acid or an ahydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol and/or an amine, or a salt of the reaction product. 
     
     
         3 . The method according to  claim 2 , wherein the optionally substituted polycarboxylic acid or the anhydride thereof comprises an optionally substituted succinic acid or an optionally substituted succinic anhydride. 
     
     
         4 . The method according to  claim 2 , wherein the optionally substituted polycarboxylic acid or the anhydride thereof is substituted with an alkyl, alkenyl, alkaryl or aralkyl group. 
     
     
         5 . The method according to  claim 4 , wherein the alkyl or alkenyl group has from 2 to 30 carbon atoms. 
     
     
         6 . The method according to  claim 2 , wherein the salt of the optionally substituted polycarboxylic acid or the anhydride thereof or the salt of the reaction product comprises an alkali metal salt and/or an amine salt. 
     
     
         7 . The method according to  claim 6 , wherein the amine salt comprises a tertiary amine salt. 
     
     
         8 . The method according to  claim 2 , wherein the compound comprises a di alkali metal salt of a hydrocarbyl substituted dicarboxylic acid or an anhydride thereof. 
     
     
         9 . The method according to  claim 2 , wherein the compound comprises a mono amine salt of a hydrocarbyl substituted dicarboxylic acid or an anhydride thereof. 
     
     
         10 . The method according to  claim 2 , wherein the alcohol comprises a polyalkylene glycol. 
     
     
         11 . The method according to  claim 10 , wherein the polyalkylene glycol comprises polyethylene glycol having a number average molecular weight of from 60 to 370 or from 400 to 950. 
     
     
         12 . The method according to  claim 2 , wherein the compound comprises a salt of the reaction product of reactants comprising a hydrocarbyl substituted dicarboxylic acid or an anhydride thereof and a polyethylene glycol, wherein the acid/anhydride and the polyethylene glycol are reacted in a molar ratio of from 1.5:1 to 1:1.5. 
     
     
         13 . The method according to  claim 2 , wherein the compound comprises the reaction product of reactants comprising a hydrocarbyl substituted dicarboxylic acid or an anhydride thereof and a polyethylene glycol, wherein the acid/anhydride and the polyethylene glycol are reacted in a molar ratio of from 1.5:1 to 2.5:1. 
     
     
         14 . The method according to  claim 2 , wherein the amine comprises a primary or secondary amine. 
     
     
         15 . The method according to  claim 2 , wherein the amine is substituted with at least one hydroxyalkyl group. 
     
     
         16 . The method according to  claim 2 , wherein the compound comprises a salt of the reaction product of reactants comprising a hydrocarbyl substituted dicarboxylic acid or an anhydride thereof and a dihydroxyalkylamine, wherein the acid/anhydride and the dihydroxyalkylamine are reacted in a molar ratio of from 1.5:1 to 1:1.5. 
     
     
         17 . The method according to  claim 2 , wherein the compound comprises a compound of formula I: 
       
         
           
           
               
               
           
         
         wherein 
         X is a linking group; 
         R 1  is O-M+, O(R 3 O) n R 4 , or NR 5 R 6 ; and 
         R 2  is OH, O-M+, O(R 3 O) n R 4 , or NR 5 R 6 ;
 wherein 
 each M +  is independently a cation; 
 each R 3  is independently an optionally substituted alkylene group; 
 each R 4  is independently hydrogen or an optionally substituted hydrocarbyl group; 
 each R 5  is independently hydrogen or an optionally substituted hydrocarbyl group; 
 each R 6  is independently an optionally substituted hydrocarbyl group; 
 each n is independently 0 or a positive integer, provided that n is not 0 when R 4  is hydrogen. 
 
       
     
     
         18 . The method according to  claim 17 , wherein X is CH 2 CHR or CHRCH 2  wherein R is an optionally substituted hydrocarbyl group. 
     
     
         19 . The method according to  claim 2 , wherein the metallic equipment is metallic oilfield equipment. 
     
     
         20 . The method according to  claim 2 , wherein the metallic equipment is selected from metallic pipelines and temperature control jackets. 
     
     
         21 . The method according to  claim 2 , wherein a surface of the metallic equipment is, or will be, in contact with a corrosive fluid. 
     
     
         22 . The method according to  claim 21 , wherein the corrosive fluid comprises an aqueous fluid, such as brine. 
     
     
         23 . The method according to  claim 21 , wherein the corrosive fluid comprises a fluid produced from an oil or gas well. 
     
     
         24 . The method according to  claim 21 , wherein the method comprises applying the compound to at least a portion of a surface of the metallic equipment and/or adding the compound to the corrosive fluid. 
     
     
         25 . A composition for inhibiting the corrosion of metallic equipment, the composition comprising:
 (a) a compound comprising (i) a salt of an optionally substituted polycarboxylic acid or an anhydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol and/or an amine, or a salt of the reaction product; and   (b) an additive selected from corrosion inhibitors other than compound (a), proppant particulates, fracturing fluids, acids, fluid loss control additives, biocides, surfactants, scale inhibitors, clay control additives, foamers (optionally accompanied with gasses such as air, natural gas, N 2  or CO 2  to form a foam), paraffin inhibitors, gelling agents, pH adjustment additives, buffers, cross-linkers, oxidizing agents, enzymes, oxygen scavengers, hydrogen sulfide scavengers, friction reducers, passivation agents (for example phosphate ester passivation agents), gel degrading agents and additives to control gas hydrate formation.   
     
     
         26 . A use of a compound as a corrosion inhibitor, wherein the compound comprises (i) an alkali metal or amine salt of an optionally substituted polycarboxylic acid or an anhydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and a polyhydric alcohol and/or a secondary amine, or a salt of the reaction product. 
     
     
         27 . A method of preventing or reducing corrosion of a metallic surface, the method comprising contacting at least a portion of the metallic surface with a compound comprising (i) an alkali metal or amine salt of an optionally substituted polycarboxylic acid or an anhydride thereof; and/or (ii) the reaction product of reactants comprising an optionally substituted polycarboxylic acid or an anhydride thereof and a polyhydric alcohol and/or a secondary amine, or a salt of the reaction product.