Corrosion inhibitor composition for use in the oil and gas industry
A corrosion inhibitor composition is described. The corrosion inhibitor composition includes 1 to 15 weight percentage (wt. %) of a polymer having at least one vinylpyrrolidone unit and at least one vinyl acetate unit, 0.1 to 1 wt. % of a thioamide having 2 to 20 carbon atoms, 1 to 5 wt. % of a thioalcohol having 2 to 8 carbon atoms, 1 to 3 wt. % of a surfactant, 0 to 15 wt. % of an aliphatic alcohol having 1 to 8 carbon atoms, 30 to 60 wt. % of a solvent, and each wt. % based on a total weight of the corrosion inhibitor composition. The present disclosure also describes a method for inhibiting corrosion of a metal with the corrosion inhibitor composition of the present disclosure.
1 . A method for inhibiting corrosion of a metal in contact with a corrosive fluid, the method comprising:
adding to a corrosive fluid the corrosion inhibitor composition in an amount of 10 to 1000 ppm based on a total number of parts by weight of the corrosive fluid,
wherein the corrosive fluid comprises carbon dioxide and/or halides in an amount of at least 0.5 g carbon dioxide and/or halides per kg of the corrosive fluid, and
wherein the corrosion inhibitor composition comprises:
1 to 15 wt % of a polymer having at least one vinylpyrrolidone unit and at least one vinyl acetate unit;
0.1 to 1 wt % of a thioamide having 2 to 20 carbon atoms;
1 to 5 wt % of a thioalcohol having 2 to 8 carbon atoms;
1 to 3 wt % of a surfactant;
0 to 15 wt % of an aliphatic alcohol having 1 to 8 carbon atoms; and
30 to 60 wt % of a solvent, each wt % based on a total weight of the corrosion inhibitor composition.
2 . The method of claim 1 , wherein the corrosion inhibitor composition, the polymer is a poly(1-vinylpyrolidone-co-vinylacetate).
3 . The method of claim 2 , wherein the poly(1-vinylpyrolidone-co-vinylacetate) has a formula (I)
wherein:
m is an integer of from 1 to 600 inclusive; and
n is an integer of from 1 to 600 inclusive.
4 . The method of claim 1 , wherein the corrosion inhibitor composition, the thioamide is thiobenzamide.
5 . The method of claim 1 , wherein the corrosion inhibitor composition, the thioalcohol is 2-mercaptoethanol.
6 . The method of claim 1 , wherein the corrosion inhibitor composition, the surfactant is a non-ionic surfactant of formula (II)
wherein:
R is selected from the group consisting of a hydrocarbon chain having 8 to 22 carbon atoms, an optionally substituted alkyl, and an optionally substituted cycloalkyl;
each of w, x, y, and z is an integer of from 1 to 20 inclusive; and
w+x+y+z=20.
7 . The method of claim 6 , wherein the non-ionic surfactant is polyoxyethylene (20) sorbitan monooleate, in which R is an 8-heptadecene group having 17 carbon atoms.
8 . The method of claim 1 , wherein the corrosion inhibitor composition, the aliphatic alcohol is methanol.
9 . The method of claim 1 , wherein the corrosion inhibitor composition, the solvent is water.
10 . The method of claim 1 , wherein the corrosive fluid is an aqueous solution.
11 . The method of claim 10 , wherein the halides are in the form of an alkali metal halide salt.
12 . The method of claim 11 , wherein the alkali metal halide salt is present in an amount of 1 to 5 wt % based on a total weight of the corrosive fluid.
13 . The method of claim 11 , wherein the alkali metal halide salt is sodium chloride.
14 . The method of claim 1 , wherein the metal is a steel.
15 . The method of claim 14 , wherein the steel is a carbon steel.
16 . The method of claim 1 , wherein the metal is in contact with the corrosive fluid at 25 to 100° C.
17 . The method of claim 1 , wherein the metal is part of a casing, a pipe, a pump, a screen, a valve, or a fitting of an oil or gas well.
18 . The method of claim 1 , which has an inhibition efficiency of greater than 90% when the metal is in contact with the corrosive fluid at 25 to 75° C. for 10 to 480 minutes by following ASTM G59 standard test method.