Liquid inhibitor composition and a method for its preparation and application as a heavy brine corrosion control

1. A process for inhibiting corrosion in a heavy brine having a density of 1.15 to 2.65 g/cm 3 , comprising the step of adding a composition comprising

at least one amidoamine,

at least one sulfur synergist, and

at least one phosphate ester, to the heavy brine having a density of 1.15 to 2.65 g/cm 3

wherein the at least one amidoamine corresponds to formula IV

wherein

R is —H, —C 2 H 4 NH 2 , —C 2 H 4 OH, —(C 2 H 4 NH) x —C 2 H 4 NH 2 ,

x is a number from 0 to 200

R1 is a C 3 to C 29 aliphatic hydrocarbon group.

2. The process according to claim 1 , wherein R1 is a C 7 to C 21 hydrocarbon group.

3. The process according to claim 1 , wherein R1 is alkyl or alkenyl.

4. The process according to claim 1 , wherein x is 1, 2, 3, 4 or 5.

5. The process according to claim 1 , wherein the at least one sulfur synergist is selected from the group consisting of thioglycolic acid, sodium thiosulfite, ammonium thiosulfite, ammonium thiosulfate, sodium thiosulfate, potassium thiosulfate, potassium thiosulfite, thiourea, sodium thiocyanate, ammonium thiocyanate, and calcium thiocyanate, sodium thioglycolate, ammonium thioglycolate, 1,2-diethylthiourea, propylthiourea, 1,1-diphenylthiourea, thiocarbanilide, 1,2-dibutylthiourea, dithiourea thioacetamide, thionicotimide, or thiobenzamide, 2-Mercpatoethanol, 3-(Methylthio)propanal, thioacetic acid, cyste-amine, 3-Chloro-1-propanethiol, 1-mercapto-2-propanol, 2,3-Dimercapto-1-propanol, 2-Methoxyethane-thiol, 3-Mercapto-1-propanol, 2,3-Dimercapto-1-propanol, 1-Thio-glycerol, 1,3-Propane-dithiol, mercaptosuccinic acid, Cysteine, N-Carbomoyl-L-cysteine, N-Acetylcysteamine, 4-Mercapto-1-butanol, 1-Butanedithiol, 1,4-Butanedithiol, 2,2′-Thiodietanethiol, 4-Cyano-1-butanethiol, Cyclopantanethiol, 1,5-Pentanedithiol, 2-Methyl-1-butanethiol, 2,3,5,6-Tetrafluorobenzenethiophenol, 4-Chlorothiophenol, 2-Mercaptophenol, Thiophenol, Cyclohexylthiol, 4-Mercaptobenzoic acid, Thiosalicylic acid, 2-Ethylhexane thiol and compounds of the formula C n H 2n+1 SH (n=1 to 10).

6. The process according to claim 1 , wherein the at least one phosphate ester is of the formula:

wherein Ra, Rb and Rc are each H or a hydrocarbon group which may contain oxygen or nitrogen atoms with a carbon atom number ranging from 1 to 49.

7. The process according to claim 6 , wherein at least one of Ra, Rb and Rc are ethoxy groups.

8. The process according to claim 6 , wherein the carbon atom number in the hydrocarbon group ranges from 4 to 30.

9. The process according to claim 6 , wherein at least one of Ra, Rb and Rc is selected from the group consisting of alkyl or alkenyl groups.

10. The process according to claim 6 , wherein Ra, Rb and Rc are terminated by a hydrogen, hydroxyl, benzyl or carboxylic acid group.

11. The process according to claim 6 , wherein at least one of Ra, Rb and Rc is substituted with a non-terminal carboxyl, hydroxyl or secondary amine group.

12. The process according to claim 1 , wherein the composition further comprises at least one solvent system wherein the at least one solvent system is selected from the group consisting of water, monohydrate alkyl alcohols with 1 to 8 carbon atoms, dihydric alcohols having 2 to 6 carbon atoms and C 1 to C 6 alkyl ethers of the alcohols.

13. The process according to claim 12 , wherein the solvent system is selected from the group consisting of water, methanol, ethanol, monoethylene glycol, triethylene glycol, 2-butoxyethanol, 2-ethylhexanol, isopropanol, pentanol, butanol and mixtures thereof.

14. The process according to claim 1 , wherein the composition further comprises a bonding surfactant according to the formula

wherein R3 is H, C 1 to C 18 alkyl, C 1 to C 8 alkylamine.

15. The process according to claim 1 , wherein the composition further comprises a bonding surfactant selected from the group consisting of nonyl phenol ethoxylates with 4 to 100 ethoxy groups.

16. The process according to claim 1 , wherein the composition further comprises a bonding surfactant selected from the group consisting of ethoxlated alcohols according to

R4-O-(A-O) x —H

wherein

R4 is an aliphatic C 8 to C 18 hydrocarbon residue,

A is an ethylene group, and

x is a number from 2 to 100.

17. The process according to claim 16 , wherein R4 is alkyl or alkenyl and may either be straight chain or branched.

18. The process according to claim 16 , wherein R4 comprises from 12 to 16 carbon atoms.

19. The process according to claim 16 , wherein x is a number from 7 to 40.

20. The process according to claim 1 , wherein the composition further comprises a bonding surfactant selected from the group consisting of ethoxylated amines having 6 to 18 carbon atoms and 2 to 100 ethoxy groups.

21. The process according to claim 1 , wherein the concentration of the at least one amidoamine is from 1 to 20 wt.-%.

22. The process according to claim 1 , wherein the concentration of the at least one sulfur synergist is from 1 to 10 wt.-%.

23. The process according to claim 1 , wherein the concentration of the at least one phosphate ester is 1 to 30 wt.-%.

24. The process according to claim 14 , wherein the concentration of the at least one bonding surfactant is from 1 to 20 wt.-%.

25. The process according to claim 12 , wherein the concentration of the at least one solvent system is from 20 to 80 wt.-%.

26. The process according to claim 1 , wherein the heavy brine is an aqueous solution comprising at least one salt selected from the group consisting of NaCl, CaCl 2 ), Ca(NO 3 ) 2 , KCl, CaBr 2 , ZnBr, ZnI 2 , and mixtures thereof.

27. The process according to claim 1 , wherein the density of the heavy brine is from 1.4 to 2.65 g/cm 3 .

28. The process according to claim 1 , wherein from 100 to 10,000 mg/L of the composition is added to the heavy brine having a density of 1.15 to 2.65 g/cm 3 .