EP2992065A1

EP2992065A1 - Corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks as well as the method of its production

Info

Publication number: EP2992065A1
Application number: EP14729473.0A
Authority: EP
Inventors: Barbara GAZDZIK; Michal PAJDA; Wojciech MAZELA; Leszek Ziemianski; Iwona Skret; Stefan PTAK; Ewa ZEGARMISTRZ; Mieczyslaw SOCHA
Original assignee: Instytut Nafty I Gazu Panstwowy Instytut Badawczy
Current assignee: Instytut Nafty I Gazu Panstwowy Instytut Badawczy
Priority date: 2013-05-02
Filing date: 2014-05-05
Publication date: 2016-03-09
Also published as: RU2641148C2; WO2014178737A1; RU2015150552A; UA117131C2

Abstract

The corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks, which contains: • - component a) produced as a result of the performance of the following processes: • A) - partial neutralization of the new mixture of modified imidazoline derivatives, of general formulas (1) and (2) wherein R₂- C₂-C₁₂ with the possible addition of compound (Γ) wherein R₃: C12-C24 • with an aliphatic and/or an aromatic monocarboxylic acid containing from 1 to 7 carbon atoms per molecule • and B) - further partial neutralization of the obtained intermediate product, with fatty acids containing from 12 to 22 carbon atoms per molecule, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule • - component b), that is oxyethylenated fatty amines containing from 14 to 22 carbon atoms per molecule and from 2 to 22, preferably from 5 to 15, ethoxyl groups per molecule • - component d), that is aliphatic alcohols containing from 1 to 6 carbon atoms per molecule, possibly with the addition of water.

Description

TITLE:

Corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks as well as the method of its production

TECHNICAL FIELD:

The invention relates to a corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks as well as to the method of its production.

BACKGROUND ART: Corrosion inhibitors for protection of crude oil extraction equipment, pipelines, and tanks provide corrosion protection against factors such as: hydrogen sulfide and carbon dioxide found in crude oil and natural gas as well as oxygen and chlorides contained in formation water and drilling fluids.

The phenomenon of corrosion is a serious problem in the crude oil extraction industry and is the result of chemical or electrochemical reactions with the environment.

More than one type of corrosion occurs in gas and oil wells. Drilling fluids are usually aqueous saline solutions that behave as an electrolyte. Extracted crude oil and the produced water accompanying it also contain inorganic salts such as chlorides (sodium, potassium, magnesium), sulfates (sodium, potassium, magnesium), and carbonates. Electrochemical corrosion occurs readily in aqueous systems containing salts. It is caused by the action of galvanic cells forming between the passivated metal surface and a surface that does not possess such a layer. The effect of electrochemical corrosion is mainly pitting corrosion on the surfaces of lifting casings and operational equipment. The most damage to pipe and casing surfaces occurs in saline solutions with concentrations of 7 - 13 %.

Large corrosion damage is caused by the presence of carbon dioxide in the drilled deposit. A characteristic trait of the corrosion resulting from the presence of carbon dioxide is the presence of smooth well edges. Corrosion caused by the presence of carbon dioxide in gas and oil wells is often called "neutral or sweet" corrosion. Carbon dioxide, when dissolved in water, forms H₂C0₃, which then reacts with iron to form iron carbonate FeC0₃, and hydrogen gas ¾ is also formed. When carbon dioxide dissolves in water, it also reduces the pH of water, thus causing an increase of the corrosion rate.

Corrosion resulting from the presence of hydrogen sulfide is just as serious and is referred to as "sour" corrosion. Hydrogen sulfide causes more aggressive corrosion than carbon dioxide. Similarly to carbon dioxide, hydrogen sulfide dissolves in water, reducing pH. As a result of the reaction of hydrogen sulfide with iron, iron sulfide FeS and hydrogen gas ¾ are formed. Iron sulfide forms a coating on metal surfaces, and during the first phase, it inhibits "sour" corrosion, however even slight damage to this coating causes intensive corrosion. "Sour" corrosion causes pits to form and is also often accompanied by cracking of metal coatings caused by the production of hydrogen. Some hydrogen penetrates into steel and becomes the cause of blistering, cracking, and so-called hydrogen embrittlement.

Corrosion processes in oil wells are intensified by Desulfovibrio Desulfuricans sulfate-reducing bacteria, which multiply in the anaerobic conditions of the oil deposit. These bacteria are most active when under the surface of scales formed as a result of sediment deposition.

The rate of corrosion induced by carbon dioxide and hydrogen sulfide increases as the oxygen content in the system increases. Oxygen penetrates into drilling fluids when they pass through machinery servicing wells and tanks. The rate of corrosion is also dependent on temperature; the greater it is, the greater the corrosion rate, which reaches its maximum at a temperature of approx. 70°C. In wells that are not protected with corrosion inhibitors, it may reach from 1 to several mm/year.

The effects of corrosion processes are: reduction of the thickness of lifting casing walls and pipeline walls, deep pitting that may lead to leaks, and severe reduction of their strength properties.

In order to prevent corrosion in oil wells, corrosion inhibitors reducing the corrosive action of extracted crude oil and gas on steel parts of extraction equipment, pipelines, and tanks are used. Corrosion inhibitors of varying chemical nature, most often imidazoline derivatives, are used as corrosion inhibitors. In order for a corrosion inhibitor to be effective, it should dissolve not only in crude oil but, above all, in water. Salts of imidazoline derivatives are usually used for this purpose.

Patent descriptions US 3629104 and US 3758493 present water-soluble corrosion inhibitors containing a carboxylic acid of an imidazoline derivative produced by condensation of dimerized fatty acids with diethylenetriamine.

US Patent 5759485 describes the method of producing the corrosion inhibitor by neutralization of C₂2-tricarboxylic acids and subsequent addition of imidazoline or amidoamine.

Patent application WO 2003/054251 contains a description of the good anti- corrosion properties of ethoxylated fatty alkyl amines, particularly ethoxylated alkyl ether amines.

Patent descriptions PL 61535 and PL 85729 disclose that imidazoline inhibitors are produced in a condensation reaction of diethylenetriamine with fatty acids or naphthenic acids.

Patent descriptions PL 135655 and PL 175452 present production of an inhibitor with increased activity which is a result of condensation of diethylenetriamine with fatty acids and is then modified using hexamethylenetriamine introduced during the final phase of the condensation reaction.

According to patent PL 182943, the water-soluble corrosion inhibitor contains a salt of an imidazoline derivative that constitutes the product of condensation of fatty acids with diethylenetriamine and urotropine or formaldehyde as well as low molecular carboxylic acids.

Patent application US 2004/0087448 discloses the use of the product of condensation of C₁₈ unsaturated fatty acid dimmers, containing 1 or 2 double bonds, and diethylenetriamine as a corrosion inhibitor.

In turn, US Patent 6695897 contains a description of a method of producing amidoamine by condensation of N-ethylethylenediamine and fatty acid. The product of the reaction after solubilization with acetic acid may perform the role of a water-soluble corrosion inhibitor.

US patent 7057050 presents a method for producing a water-soluble corrosion inhibitor. The product of the reaction is N-propyl-2-heptadecenyl imidazoline. The obtained product is solubilized to a water-soluble state using acrylic acid.

Patent application WO 2006/078723 contains a description of a method of producing micro-emulsions containing imidazoline derivatives and amidoamines produced in the presence of oleic acid. The micro-emulsion also contains ethoxylated nonylphenols and acetic acid.

Patent description US 5322630 discloses an imidazoline corrosion inhibitor that is the product of the reaction of unsaturated monocarboxylic acids with fatty amines, aminoamides, or fatty imidazol-amines.

Patent description RU 2394941 describes a mixture of imidazoline derivatives modified with aldimines or Schiff bases. According to this patent, the imidazoline derivative is the product of the reaction of polyamines with oleic acid or monocarboxylic acids. The imidazoline derivative is then cyanoethylated with nitriles, acrylic acid, or subjected to oxyalkylation.

An N-ethoxylated imidazoline derivative with unsaturated and saturated fatty acid chains substituted in position 2 is cited as a corrosion inhibitor in American patent description US 5785895.

Patent description GB 2340505 presents a method for producing imidazoline derivatives by the process of condensation of tall oil fatty acids with aminoethylethanolamine. The thus obtained inhibitor is characterized by good anti- corrosion properties, and by forming complexes with mercaptans, it also reduces the characteristic odour of sulfur compounds.

US Patent 5723061 and US patent application 2007/0152191 describe compositions with components including salts that are not products of condensation, produced in a reaction of C₁₀-Ci₂ dicarboxylic acids with polyamines.

Patent literature contains descriptions of condensation of diethylenetriamine with fatty acids containing from 12 to 24 carbon atoms per molecule, with a molar ratio of diethylenetriamine to fatty acids equal to 1 :0.5 - 1.0. Examples of such condensation are known from, among others, American patent descriptions US 2267965, US 2355837, and Polish patent description PL 61535.

Corrosion inhibitors containing bis-amides are described in American patents US 4614600 and US 4344861. US patent 4614600 describes a bis-amide as a product of the reaction of polyamines with fatty acid dimers, and patent US 4344861 described the product of the reaction of polyamines with dicarboxylic acids.

Many available corrosion inhibitors for protection of extraction equipment and pipelines are insufficiently effective and require high doses in order to provide corrosion protection. It has been accepted that the level of corrosion protection at a dosage of 100 mg of corrosion inhibitor per 1 kg of corrosive medium should be greater than 80% (according to standard ASTM NACE ID 182). However, the best inhibitors for oilfield applications should be effective at low doses, below 50 ppm.

The purpose of the invention is to develop a corrosion inhibitor for protection of crude oil extraction equipment, pipelines, and tanks that would provide much better anti-corrosion properties than currently utilized corrosion inhibitors.

SUMMARY OF THE INVENTION

This invention concerns corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks as well as the method of its production.

One aspect the invention is to provide a corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks, which contains: - component a) in the amount from 0.1 5 to 85 % by weight, preferably from 1.55 to 51% by weight, produced by the following processes:

A) - neutralization from 0.1 to 50 % by weight, preferably from 1 to 30 % by weight, of the new mixture of modified imidazoline derivatives, of general formulae (1) and (2),

wherein R\: Ci2-C₂₂ (1)

wherein R₂: C₂-C₁₂ (2), which is the product of condensation of diethylenetriamine with fatty acids containing from 12 to 22 carbon atoms per molecule and aliphatic dicarboxylic acids containing from 2 to 12 carbon atoms per molecule,

with the optional addition of from 0.05 to 20 % by weight of the known product of condensation of diethylenetriamine with fatty acids containing from 12 to 24 carbon atoms per molecule, produced by a known method at a temperature of 180-280°C, preferably 220-260°C, of general formula (Γ)

wherein R₃: C₁₂-C₂₄ with an aliphatic and/or an aromatic monocarboxylic acid containing from 1 to 7 carbon atoms per molecule, used in an amount from 0.025 to 25 % by weight, in which neutralization the mass ratio of the mixture of compounds of general formulae (1), (2), and optionally (Γ) to monocarboxylic acid is 1: 0.15 - 0.70 with obtaining of an intermediate product that is a mixture of compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (1') wherein Rj: C₁₂-C₂₂ (5)

R4: H, C_!-C₆, aromatic radical (C₆H₆)

wherein R₂: C₂-C₁₂ (6)

R4: H, C_!-C₆, aromatic radical (C₆H )

wherein R₃: C₁₂-C₂₄ (5^')

R4: H, C]-C₆, aromatic radical (C₆H₆) and B) - further neutralization of the obtained intermediate product, which is a mixture of the compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (Γ), with fatty acids containing from 12 to 22 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, in which neutralization the mass ratio of the total mass of the mixture of compounds of general formulae (1), (2), and optionally ( ), to fatty acids and/or polymers is 1 : 0.02 - 0.5, with obtaining of a product containing a mixture of compounds of general formulae (7), (8), and optionally (7'),

wherein Rj: C₁₂-C₂₂ (7)

R₅: C₁₂-C₂₂ and/or C₁₈-C₅₄

wherein R₂: C₂-C₁₂ (8)

R₅: C₁₂-C₂₂ and/or C_]8-C₅₄

wherein R₃: Q2-C24 (7^')

R₅: C₁₂-C₂2 and/or C₁₈-C₅₄ and at the end of process B), component a) has a pH = 6.5 - 7.5 and contains a product that is a mixture of compounds of formulae (5), (6), and optionally (5') as well as a product that is a mixture of compounds of formulae (7), (8), and optionally (7');

- component b), that is oxyethylenated fatty amines containing from 14 to 22 carbon atoms per molecule and from 2 to 22, preferably from 5 to 15, ethoxyl groups per molecule, in an amount from 0.01 to 20 % by weight;

- optionally component c), that is aliphatic polyols in an amount from 0.1 to 50 % by weight;

- component d), that is aliphatic alcohols containing from 1 to 6 carbon atoms per molecule, optionally with the addition of water, in an amount from 15.0 to 99.6 % by weight,

- optionally component e), that is an anti-foaming agent, in an amount from 0.01 to 2 % by weight. Another aspect of the present invention is to provide the method of production of corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks, which contains the following stages:

I) production of component a) in a reaction medium containing component d), that is aliphatic alcohols containing from 1 to 6 carbon atoms per molecule, optionally with the addition of water, in an amount from 15 to 99.6 % by weight, which comprises the following processes: A) - neutralization of the new mixture of modified imidazoline derivatives, of general formulae (1) and (2), which is the product of condensation of diethylenetriamine with fatty acids containing from 12 to 22 carbon atoms per molecule and aliphatic dicarboxylic acids containing from 2 to 12 carbon atoms per molecule,

wherein

wherein R₂: C2-Q2 (2) used in an amount from 0.1 to 50 % by weight, preferably from 1 to 30 % by weight, with the optional addition of 0.05 to 20 % by weight of the known product of condensation of diethylenetriamine with fatty acids containing from 12 to 24 carbon atoms per molecule, produced by a known method at a temperature of 180-280°C, preferably 220-260°C, of general formula (Γ),

wherein R₃: C₁₂-C₂₄ with an aliphatic and/or an aromatic monocarboxylic acid containing from 1 to 7 carbon atoms per molecule, used in an amount from 0.025 to 25 % by weight, where the mass ratio of the mixture of compounds of general formulae (1), (2), and optionally (Γ) to monocarboxylic acid is 1 : 0.15 - 0.70, with obtaining of an intermediate product, that is a mixture of compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (Γ)

wherein Ri: C₁₂-C₂₂ (5)

R4: H, CrC₆, aromatic radical (C₆H₆)

wherein R₂: C₂-C₁₂ (6)

4: H, C!-C₆, aromatic radical (C6¾) wherein R₃: C]2-C₂₄ (5^')

R₄: H, Q-C₆, aromatic radical (C H₆);

and B) - further neutralization of the resulting intermediate product, containing a mixture of the compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally ( ), with fatty acids containing from 12 to 22 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, in which neutralization the mass ratio of the total mass of the mixture of compounds used in the process, of general formulae (1), (2), and optionally (Γ), to fatty acids and/or polymers is 1 : 0.02 - 0.5, with obtaining of a product containing a mixture of compounds of general formulae (7), (8), and optionally (7'), with the process B) being performed until the reaction mixture attains pH = 6.5 - 7.5 and component a) containing a product that is a mixture of compounds of formulae (5), (6), and optionally (5') as well as a product that is a mixture of compounds of formulae (7), (8), and optionally (7'), is obtained;

wherein C₁₂-C₂₂ (7) R₅: C₁₂-C₂2 and/or C₁₈-C₅₄

wherein R₂: C₂-Ci₂ (8)

R₅: C₁₂-C₂₂ and/or C

wherein R₃: C₁₂-C₂ (T)

R₅: C₁₂-C₂₂ and/or C₁₈-C₅₄

II) introduction to component a), in an amount from 0.155 to 85 % by weight, preferably from 1.55 to 51 % by weight, and to the mentioned component d), of further inhibitor components:

component b), that is oxyethylenated fatty amines containing from 14 to 22 carbon atoms per molecule and from 2 to 22, preferably from 5 to 15, ethoxyl groups per molecule, in an amount from 0.01 to 20 % by weight, and optionally component c), that is aliphatic polyols in an amount from 0.1 to 50 % by weight,

and finally, optionally component e), that is an anti-foaming agent in an amount from 0.01 to 2 % by weight. DESCRIPTION OF THE PREFERRED EMBODIMENTS

It was unexpectedly noted that the application of a component in the composition of the corrosion inhibitor based on a new mixture of modified imidazoline derivatives, which constitutes a mixture of compounds that are products of the condensation of diethylenetriamine with fatty acids containing from 12 to 22 carbon atoms per molecule and aliphatic dicarboxylic acids containing from 2 to 12 carbon atoms per molecule, by means of neutralization of this mixture of modified imidazoline derivatives with aliphatic and/or aromatic carboxylic acid containing from 1 to 7 carbon atoms per molecule, and after that, by neutralization with fatty acids containing from 12 to 22 carbon atoms per molecule, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule and after that, through introduction into the composition of the inhibitor of oxyethylenated fatty amines containing from 14 to 22 carbon atoms per molecule and from 2 to 22, preferably from 5 to 15 ethoxyl groups per molecule, and optionally, of an anti-foaming agent, that is a siloxane derivative, provided anti- corrosion protection that is more efficient than that of a corrosion inhibitor containing only a known imidazoline derivative produced by a known method in the process of condensation of diethylenetriamine with oleic acid/tall oil acids.

In this invention, a new mixture of modified imidazoline derivatives of general formulae (1) and (2) is used,

wherein (1)

which is obtainable in such a way, that condensation of diethylenetriamine is performed with fatty acids containing 12-22 carbon atoms per molecule and aliphatic dicarboxylic acids containing 2-12 carbon atoms per molecule, where the molar ratio of diethylenetriamine to fatty acids and to aliphatic dicarboxylic acids is 1:0,5-0,99: 0.01- 0.5, at a temperature of at least 140°C, preferably 150°C, with the formation of an aminoamide mixture of general formulae (3) and (4),

wherein Ci₂-C₂₂ ( 3)

wherein R₂: C₂-C₁₂ ( 4) with acid number < 10 mg KOH/g, and next, the temperature is raised to above 180 °C, preferably to 220 °C, and the condensation reaction is performed further until a mixture of compounds of general formulae (1) and (2) is obtained

wherein Rj: C₁₂-C

wherein R₂: C₂-C₁₂ (2) with acid number < 1 mg KOH/g.

There can be many embodiments of the invention depending on variants of its components and the ways they are combined. The preferred embodiments of the invention concerning components a), e), d), c) are listed below.

In the preferred embodiment of the invention, the corrosion inhibitor contains as component a) a product formed by neutralization with acetic acid and/or benzoic acid of the following imidazoline derivatives :

i) the new mixture of modified imidazoline derivatives, which is condensation product of diethylenetriamine with fatty acids containing 12-22 carbon atoms per molecule and aliphatic dicarboxylic acids containing 6-10 carbon atoms per molecule, where the molar ratio of diethylenetriamine to fatty acids and to aliphatic dicarboxylic acids is 1 : 0,5-0,99: 0.01-0.5, at a temperature of at least 140°C, preferably 150°C, with the formation of an aminoamide mixture of general formulae (3) and (4),

wherein Rj: C₁₂-C22

wherein R₂: C₆-C₁₀ ( 4) with acid number < 10 mg KOH/g, and next, the temperature of the reaction is raised to above 180 °C, preferably to 220 °C, and the condensation reaction is performed further until a mixture of compounds of general formulae (1) and (2) are obtained

with acid number < 1 mg KOH/g,

ii) optionally added, the known product of condensation of diethylenetriamine with fatty acids,

and neutralization of the resultant intermediate product with fatty acids, with acid number from 180 to 210 mg KOH/g, saponification number from 180 to 210 mg KOH/g and iodine number from 80 to 130 g J2 /100 g, in which the main component is oleic acid C₁₈H₃₄0₂ and or fatty acid polymers containing dimers as their main component, with acid number from 190 to 197 mg KOH/g. In more preferred embodiment of the invention the corrosion inhibitor contains, as component a), a product formed by neutralization of the new mixture of modified imidazoline derivatives, with the optional addition of the known product of condensation of diethylenetriamine with fatty acids produced by a known method, using first glacial acetic acid, and after that, neutralization of the resultant intermediate product with fatty acids in which the main ingredient is oleic acid C₁₈H₃₄0₂ and/or fatty acid polymers containing fatty acid dimers as their main component.

In the preferred embodiment of the invention the corrosion inhibitor contains methanol, isopropanol, ethanol, optionally added water or their mixtures as component d).

In the preferred embodiment of the invention the corrosion inhibitor contains aliphatic polyols, preferably ethylene glycol, glycerin, propylene glycol, dipropylene glycol, tripropylene glycol, or their mixtures as component c).

In the preferred embodiment of the invention the corrosion inhibitor contains a siloxane derivative, most preferably branched siloxane polymers as component e).

The composition of the corrosion inhibitor according to the invention has been given in percentages by weight calculated in reference to the total mass of the inhibitor.

In the preferred embodiment of the invention, concerning the method of production of corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks, neutralization with acetic acid and/or benzoic acid of the following imidazoline derivatives is carried out in a process A): i) the new mixture of modified imidazoline derivatives, which is condensation product of diethylenetriamine with fatty acids containing 12-22 carbon atoms per molecule and aliphatic dicarboxylic acids containing 2-12 carbon atoms per molecule, where the molar ratio of diethylenetriamine to fatty acids and to aliphatic dicarboxylic acids is 1 : 0,5-0,99: 0.01-0.5, at a temperature of at least 140°C, preferably 150°C, with the formation of an aminoamide mixture of general formulae (3) and (4),

wherein Ri: C₁₂-C₂₂ (3)

wherein R₂: C6-C₁₀ (4) with acid number < 10 mg KOH/g, after which the temperature of the reaction is raised to above 180 °C, preferably to 220 °C, and as a result of the reaction, a mixture of compounds of general formulae (1) and (2) is obtained

wherein R\ : C₁₂-C22 (1)

H₂N NH₂

wherein R₂: C -C₁₀ (2) with acid number < 1 mg KOH/g ii) optionally added the known product of condensation of diethylenetriamine with fatty acids produced by a known method, and then neutralization is carried out in a process B), of the resultant intermediate product, with fatty acids with acid number from 180 to 210 mg KOH/g, saponification number from 180 to 210 mg KOH/g and iodine number from 80 to 130 g J₂ /100 g, in which the main component is oleic acid C₁₈H₃₄0₂ and/or fatty acid polymers containing dimers as their main component, with acid number from 190 to 197 mg KOH/g.

In the more preferred embodiment of the invention, concerning the method of production of corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines, and crude oil tanks, neutralization of the new mixture of modified imidazoline derivatives with the optional addition of the known product of condensation of diethylenetriamine with fatty acids is performed using glacial acetic acid, and after that, the obtained intermediate product is neutralized with fatty acids, in which the main component is oleic acid C₁₈H₃₄0₂, and/or fatty acid polymers containing dimers as their main component. In the case where high transparency of the inhibitor that is the subject of this invention is required during long-term storage under winter conditions at a temperature below -30 °C, it is preferably to introduce, besides the new mixture of modified imidazoline derivatives, a known imidazoline derivative into the composition of the inhibitor, the addition of which causes the inhibitor according to this invention to be completely transparent at low temperatures.

In the case where high transparency of the inhibitor according to this invention is required during long-term storage at a temperature below - 0°C, aliphatic polyols, preferably ethylene glycol, glycerin, propylene glycol, dipropylene glycol, tripropylene glycol, or their mixtures, can be applied as solubilizers in an amount from 0.1 to 50 % by weight, and possibly alcohols other than methanol, isopropanol, and ethanol.

The percentages of components used to produce the corrosion inhibitor using the method according to the invention have been given as percentages by weight calculated in reference to the total mass of the inhibitor.

The corrosion inhibitor produced using the base of the mixture of modified imidazoline derivatives is characterized by better anti-corrosion and hydrophilic properties as compared to inhibitors containing known imidazoline derivatives.

The best corrosion inhibitors used in oil and gas wells are those that are very well soluble in water while leaving a persisting film of the corrosion inhibitor on metal surfaces. A corrosion inhibitor should provide protection for a pipeline/installation for at least 24 h from an emergency stop of the dosing pump.

Many available corrosion inhibitors for protection of crude oil bore-holes and transmission pipelines are insufficiently effective and require high doses in order to provide corrosion protection. Many of them form an inhomogenous liquid after being mixed with formation water, with release of sediments and precipitation of a part of the inhibitor. This results in insufficient corrosion protection and may also be the cause of occurrence of dangerous pitting corrosion. The inhibitor according to this invention forms homogenous fluids with formation water containing up to 30 % salt, and even at a temperature of 80°C, no precipitation of the inhibitor from these fluids is observed. The exceptional compatibility of the inhibitor that is the subject of this invention with formation water of varying salinity increases its anti-corrosion properties in the entire oil-gas-water or oil-water system. Many available corrosion inhibitors for protection of crude oil wells and pipelines contain dispersants derived from nonylphenol among their components. Phenol groups are particularly harmful to the natural environment due to their very low biodegradation. The application of a surfactant from the group of oxyethylenated, hydrogenated, tall oil amines in the composition of the corrosion inhibitor according to this invention, which have a very high degree of biodegradation, had a favorable impact on the biocompatibility of the corrosion inhibitor according to this invention.

In certain wells, the formation water accompanying the crude oil is characterized by low mineralization level, which favors foaming of the inhibitor in the water. Foaming is also fostered by a large amount of formation water relative to the extracted crude oil. In such a case, it is advantageous to introduce an anti-foaming agent, preferably a siloxane derivative, into the composition of the inhibitor.

The corrosion inhibitor according to this invention is characterized by high anti- corrosion properties under conditions of crude oil extraction at low inhibitor doses in crude oil production installations. The corrosion inhibitor produced using the method according to the invention is a clear liquid with low viscosity. It is easily soluble in formation water and exhibits high stability under operating conditions, even up to very high temperatures above 80°C. It protects metal surfaces against corrosion well, even in the case of a periodical failure of the dosing system.

One of the numerous versions of the corrosion inhibitor according to this invention contains benzoic acid, which may act as a bactericide.

In practice corrosion inhibitor for protection of crude oil extraction equipment, crude oil pipelines and crude oil tanks, according to the invention, is added to the crude oil or crude oil - water or crude oil-water-gas, preferably it is added to the fluid: crude oil or crude oil - water or crude oil-water-gas continuously.

Corrosion inhibitor according to the invention, in general, is added to the fluid in amount from about 0,01 to 5000 ppm, preferably from about 1 to 500 ppm, the most preferably from about 10 to 30 ppm. The examples given below illustrate the invention while not limiting its scope.

Exemples from 1 to 5 concern the production of new mixture of modified imidazoline derivatives, and examples from 6 to 11 concern the production of the corrosion inhibitor according to the invention.

Example 1.

The following components were introduced into a reactor: 103.16 kg (1 mole) diethylenetriamine, 141.23 kg (0.5 mole) distilled olein, in which the main component is oleic acid C₁₈H₃40₂, and 45.02 kg (0.5 mole) oxalic acid. The content was heated while being mixed constantly with a mechanical stirrer and nitrogen barbotage was additionally applied in order to remove the water forming during the reaction. After a temperature of 150°C was achieved, it was maintained for 3 hours until an acid number of 3.51 mg KOH/g was obtained, and after that, further heating was applied until the temperature of 220°C was achieved. The reaction was performed for 4 hours while the temperature was maintained constant at 220°C and while nitrogen barbotage was applied for the purpose of removing water from the reaction. 226 kg of product -mixture of modified imidazoline derivatives - with acid number 0.25 mg KOH/g were obtained.

Example 2.

The following components were introduced into a reactor: 103.16 kg (1 mole) diethylenetriamine, 279.64 kg (0.99 mole) oleic acid, and 1.88 kg (0.01 mole) azelaic acid. The content was heated while being mixed constantly with a mechanical stirrer and nitrogen barbotage was additionally applied in order to remove the water forming during the reaction. After a temperature of 150°C was achieved, it was maintained for 3 hours (acid number 4.32 mg KOH/g was obtained), and after that, further heating was applied until the temperature of 220°C was achieved. The reaction was performed for 5 hours while the temperature was maintained constant at 220°C and while nitrogen barbotage was applied for the purpose of removing water from the reaction. 317 kg of product (mixture of modified imidazoline derivatives) with acid number = 0.38 mg KOH/g were obtained. Example 3.

The following components were introduced into a reactor: 103.16 kg (1 mole) diethylenetriamine, 264.10 kg (0.95 mole) tall oil fatty acids, and 10.11 kg (0.05 mole) sebacic acid. The content was heated while being mixed constantly with a mechanical stirrer, and nitrogen barbotage was additionally applied in order to remove the water forming during the reaction. After a temperature of 150°C was achieved, it was maintained for 3 hours (acid number 5.1 mg KOH/g was obtained), and after that, further heating was applied until the temperature of 220°C was achieved. The reaction was performed for 5 hours while the temperature was maintained constant at 220°C and while nitrogen barbotage was applied for the purpose of removing water from the reaction. 308 kg of product (mixture of modified imidazoline derivatives) with acid number 0.7 mg KOH/g were obtained.

Example 4.

The following components were introduced into a reactor: 103.16 kg (1 mole) diethylenetriamine, 268.34 kg (0.95 mole) distilled olein, in which the main component is oleic acid C₁₈H₃₄02, and 5.90 kg (0.05 mole) succinic acid. The content was heated while being mixed constantly with a mechanical stirrer, and nitrogen barbotage was additionally applied in order to remove the water forming during the reaction. After a temperature of 150°C was achieved, it was maintained for 3 hours (acid number 3.94 mg KOH/g was obtained), and after that, further heating was applied until the temperature of 210°C was achieved. The reaction was performed for 5 hours while the temperature was maintained constant at 210°C and while nitrogen barbotage was applied for the purpose of removing water from the reaction. 312 kg of product (mixture of modified imidazoline derivatives) with acid number 0.24 mg KOH/g were obtained. Example 5.

The following components were introduced into a reactor: 103.16 kg (1 mole) diethylenetriamine, 268.34 kg (0.95 mole) distilled olein, in which the main component is oleic acid C₁₈H₃402, and 7.67 kg (0.05 mole) adipic acid. The content was heated while being mixed continuously with a mechanical stirrer, and at the same time, a 100 mm Hg vacuum was applied in order to remove water from the reaction. After a temperature of 150°C was achieved, it was maintained for 3 hours (acid number 4.72 mg KOH/g was obtained), and after that, further heating was applied until the temperature of 220°C was achieved. The reaction was performed for 5 hours while the temperature was maintained constant at 220°C and while a 100 mmHg vacuum was applied for the purpose of removing water from the reaction. 299 kg of product (mixture of modified imidazoline derivatives) with acid number 0.33 mg KOH/g were obtained.

Example 6.

The following components were introduced into a reactor: 694 kg (69.4 % by weight) of isopropyl alcohol, and then 200 kg (20 % by weight) of the product of condensation of diethylenetriamine with distilled olein (instead of tall oil fatty acids) and sebacic acid, produced according to example 3, with acid number 0.7 mg KOH/g.

After complete dissolution, 45 kg (4.5 % by weight) of glacial acetic acid were added.

After the glacial acetic acid completely underwent the reaction, 10 kg (1 % by weight) of C₁₈ fatty acid polymer with 79 % by weight dimer and 19 % by weight trimer content, with acid number 190 mg KOH/g, was introduced. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 28 kg (2.8 % by weight) of oxyethylenated C₁₈ fatty amine containing 8 ethoxyl groups per molecule, 20 kg (2 % by weight) of ethylene glycol, and then 3 kg (0.3 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Munzing company, were added. After complete dissolution, 1000 kg (100% by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point below - 60 °C and a kinematic viscosity of 3.9 mm²/s at a temperature of 20°C.

Example 7.

The following components were introduced into a reactor: 229.5 kg (22.95 % by weight) of isopropyl alcohol, and then 500 kg (50 % by weight) of the product of condensation of diethylenetriamine with oleic acid and azelaic acid, produced according to example 2, with acid number 0.38 mg KOH/g.

After complete dissolution, 240 kg (24 % by weight) of glacial acetic acid were added. After the glacial acetic acid completely underwent the reaction, 10 kg (1 % by weight) of oleic acid, with acid number 198 mg KOH/g, saponification number 200 mg KOH/g, and iodine number 100 g J₂/100g, were added. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 0.5 kg (0.05 % by weight) of oxyethylenated C₁₈ fatty amine containing 20 ethoxyl groups per molecule and 20 kg (2 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Miinzing company, were added. After complete dissolution, 1000 kg (100 % by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point below - 42 °C and a kinematic viscosity of 90 mm /s at a temperature of 40°C. Example 8.

The following components were introduced into a reactor: 425 kg (42.5 % by weight) of isopropyl alcohol, 10 kg (1 % by weight) of ethanol, 100 kg (10 % by weight) of water, and then 100 kg (10 % by weight) of the product of condensation of diethylenetriamine with distilled olein, in which the main component is oleic acid C₁₈H3₄0₂ and with adipic acid, produced according to example 5, with acid number 0.33 mg KOH/g.

After complete dissolution, 25 kg (2.5 % by weight) of benzoic acid were introduced. After the benzoic acid completely underwent the reaction, 30 kg (3 % by weight) of oleic acid, with acid number 198 mg KOH/g, saponification number 200 mg KOH/g, and iodine number 100 g J₂/100g, were added. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 20 kg (2 % by weight) of oxyethylenated C₁₈ fatty amine containing 2 ethoxyl groups per molecule, 100 kg (10 % by weight) of dipropylene glycol, and 10 kg (1 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Miinzing company, were added. After complete dissolution, 1000 kg (100 % by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point of - 12 °C and a kinematic viscosity of 12 mm²/s at a temperature of 20°C.

Example 9.

The following components were introduced into a reactor: 335 kg (33.5 % by weight) of methyl alcohol, 143 kg (14.3 % by weight) of isopropyl alcohol, and then 300 kg (30 % by weight) of the product of condensation of diethylenetriamine with distilled olein, in which the main component is oleic acid C₁₈H340₂ and with succinic acid, produced according to example 4, with acid number 0.24 mg KOH/g.

After complete dissolution, 50 kg (5 % by weight) of glacial acetic acid were introduced. After the glacial acetic acid completely underwent the reaction, 80 kg (8 % by weight) of C₁₈ fatty acid polymer with 79 % by weight dimer and 19 % by weight trimer content, with acid number 195 mg KOH/g, were introduced. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 50 kg (5 % by weight) of oxyethylenated C₁₈ fatty amine containing 8 ethoxyl groups per molecule, 40 kg (4 % by weight) of dipropylene glycol, and 2 kg (0.2 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Munzing company, were added. After complete dissolution, 1000 kg (100% by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point below - 54 °C and a kinematic viscosity of 15.2 mm²/s at a temperature of 20°C. Example 10.

The following components were introduced into a reactor: 335 kg (33.5 % by weight) of methyl alcohol, 143 kg (14.3 % by weight) of isopropyl alcohol, and then 180 kg (18 % by weight) of the product of condensation of diethylenetriamine with distilled olein, in which the main component is oleic acid C₁₈H₃₄0₂ and oxalic acid, produced according to example 1, with acid number 0.25 mg KOH/g, as well as 20 kg (2 % by weight) of the known product of condensation of diethylenetriamine with tall oil acids, with water content below 2% by weight and pH of a 5 % by volume alcohol water solution equal to 11.2. After complete dissolution, 45 kg (4.5 % by weight) of glacial acetic acid were introduced. After the glacial acetic acid completely underwent the reaction, 10 kg (1 % by weight) of C₁₈ fatty acid polymer with 79 % by weight dimer and 19 % by weight trimer content, with acid number 190 mg KOH/g, was introduced. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 45 kg (4.5 % by weight) of oxyethylenated C₁₈ fatty amine containing 5 ethoxyl groups per molecule, 50 kg (5 % by weight) of tripropylene glycol, and 6 kg (0.6 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Munzing company, were added. After complete dissolution, 1000 kg (100% by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point below - 60 °C, high transparency during long-term storage at a temperature of - 40 degrees Celsius, and a kinematic viscosity of 5.9 mm²/s at a temperature of 20°C. Example 11.

The following components were introduced into a reactor: 994.25 kg (99.425 % by weight) of isopropyl alcohol, 0.1 kg (0.01 % by weight) of ethanol, 1 kg (0.1 % by weight) of water, and then 1 kg (0.1 % by weight) of the product of condensation of diethylenetriamine with distilled olein, in which the main component is oleic acid C₁₈H₃₄0₂ and with adipic acid, produced according to example 5, with acid number 0.33 mg KOH/g.

After complete dissolution, 0.25 kg (0.025 % by weight) of benzoic acid were introduced. After the benzoic acid completely underwent the reaction, 0.3 kg (0.03 % by weight) of oleic acid, with acid number 198 mg KOH/g, saponification number 200 mg KOH/g, and iodine number 100 g J₂/100g, were added. Both neutralization reactions were performed at a temperature not exceeding 40°C.

Next, 2 kg (0.2 % by weight) of oxyethylenated Ci₈ fatty amine containing 8 ethoxyl groups per molecule, 1 kg (0.1 % by weight) of dipropylene glycol, and 0.1 kg (0.01 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Miinzing company, were added. After complete dissolution, 1000 kg (100% by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point below - 60 °C and a kinematic viscosity of 2.1 mm²/s at a temperature of 20°C.

In oil wells equipped with high-output dosing pumps, a corrosion inhibitor with low kinematic and dynamic viscosity over a wide temperature range is required, and thus, a low content of active components is also required. Required inhibitor dosages may be 1000, 2000, or 3000 mg/kg. The corrosion inhibitor according to example 6 is destined for such dosing pumps. Example 12 - comparative.

The following components were introduced into a reactor: 694 kg (69.4 % by weight) of isopropyl alcohol, followed by 200 kg (20 % by weight) of the known product of condensation of diethylenetriamine with distilled olein according to formula (Γ), with acid number 0.9 mg KOH/g, produced by the known method. After complete dissolution, 45 kg (4.5 % by weight) of glacial acetic acid were added. After the glacial acetic acid completely underwent the reaction, with formation of the product with formula (5') and containing an unreacted product with formula (Γ), 10 kg (1 % by weight) of C₁₈ fatty acid polymer with 79 % by weight dimer and 19 % by weight trimer content, with acid number 190 mg KOH/g, was introduced. Both neutralization reactions were performed at a temperature not exceeding 40°C. A final product containing a mixture of compounds with formulas (5') and (7') was obtained.

Next, 28 kg (2.8 % by weight) of oxyethylenated C₁₈ fatty amine containing 8 ethoxyl groups per molecule, 20 kg (2 % by weight) of ethylene glycol, and then 3 kg (0.3 % by weight) of a siloxane derivative with the commercial name Foam Ban HP 732, from the Miinzing company, were added. After complete dissolution, 1000 kg (100% by weight) of corrosion inhibitor were obtained, which is a clear liquid with a poor point of - 60 °C and a kinematic viscosity of 3.5 mm /s at a temperature of 20°C.

Example 13.

Tests of the anti-corrosion properties of the corrosion inhibitor for protection of crude oil extraction equipment, pipelines, and tanks according to this invention were performed according to the Wheel Test in accordance with standard ASTM NACE 1 D 182 "Wheel test method used for evaluation of film-persistent corrosion inhibitors for Oilfield applications". This is a conventional method of testing mass decrement, used to evaluate the effectiveness of an inhibitor through simulation of continuous flow of a corrosive medium.

A. Preparation of corrosive water: corrosive water was prepared according to the following composition: 9.62 % by weight NaCl and 0.305 % by weight CaCl₂ and 0.186 % by weight MgCl₂-6H₂0 and 89.89 % by weight distilled water. The water was subjected to nitrogen barbotage for 30 minutes, and then to carbon dioxide barbotage for approx. 10 minutes until the achievement of corrosive water pH within the range of 4.4 to 4.8. B. Preparation of paraffin oil (mixture of isoparaffinic hydrocarbons): oil was homogenized at a temperature of 62°C, and then poured into test bottles.

C. Preparation of metal samples: metal plates of„Sand blasted mild steel Shim stock" type, with dimensions of 0.13x12.7x76 mm were rinsed with acetone, dried with a dry cloth, weighed, and stored in a desiccator.

90 ml corrosive water and 10 ml paraffin oil were added into bottled with a capacity of 200 ml from which air had been removed earlier. Next, the inhibitor according to the invention was introduced in the amount of 10, 20, and 30 ppm by weight, and in the case of the inhibitor according to example 11, in the amount of 1000, 2000, and 3000 ppm by weight, into the corrosive medium. The metal plates described in point C) were introduced into the thus prepared bottles. Carbon dioxide was once again dosed into the bottles over a time of approx. 30 s, and bottles were hermetically closed. The bottles were placed in a thermostat at a temperature of 65.5°C, in a rotating apparatus that rotated with a speed of 15 rotations/minute. The test was performed for a period of 72 hours. After the test, metal samples were removed from bottles, rinsed with isopropyl alcohol, and subjected to the action of a 10% hydrochloric acid solution for a period of 10 - 15 seconds. Metal samples were then rinsed with water, acetone, and alcohol, after which they were weighed with an accuracy to 0.1 mg. The mass decrement of metal samples was assessed, and the possible presence of pitting corrosion was also assessed. The percentage of protection against corrosion was calculated from the mass decrement of the metal sample in the presence of the inhibitor W(inhib) and without the inhibitor W(0).

Percentage of protection, % P = W (0) - W(inhib) / W(0) x 100% The results of testing of the anti-corrosion properties of corrosion inhibitors according to examples 6, 7, 8, 9, 10, and 11, containing a neutralized new mixture of modified imidazoline derivatives according to the invention, containing compounds with formulae (5), (6), and optionally (5') as well as (7), (8), and optionally (7'), as compared to the corrosion inhibitor produced according to example 12 (comparative), containing a neutralized known product produced using a known method in a condensation reaction of diethylenetriamine with oleic acid according to formulae (5') and (7'), instead of the neutralized mixture of modified imidazoline derivatives according to formulae (5), (6), and optionally (5'), as well as (7), (8), and optionally (7'), are presented in the table below.

INDUSTRIAL APPLICABILITY

The above examples proved that the corrosion inhibitor for protection of extraction equipment, crude oil pipelines and crude oil tanks as well as the method of its production according to this invention creates the possibility of industrial application.

Claims

1. Corrosion inhibitor for protection of crude oil extraction equipment, pipelines, and tanks, containing imidazoline derivatives, oxyethylenated fatty monoamines, and alcohol solvents, characterized in that it contains:

- component a) in the amount from 0.155 to 85 % by weight, preferably from 1.55 to 51% by weight, produced by the following processes:

A) - neutralization from 0.1 to 50 % by weight, favorably from 1 to 30 % by weight, of the new mixture of modified imidazoline derivatives, of general formulae (1) and (2),

wherein R₂: C₂-C₁₂

which is the product of condensation of diethylenetriamine with fatty acids containing from 12 to 22 carbon atoms per molecule and aliphatic dicarboxylic acids containing from 2 to 12 carbon atoms per molecule,

wherein R₃: C₁₂-C₂₄ with an aliphatic and/or aromatic monocarboxylic acid containing from 1 to 7 carbon atoms per molecule, used in an amount from 0.025 to 25% by weight, in which neutralization the mass ratio of the mixture of substances of general formulae (1), (2), and optionally (Γ) to monocarboxylic acid is 1 : 0.15 - 0.70 with obtaining of an intermediate product that is a mixture of compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (1')

wherein Ri: C₁₂-C₂₂ (5)

R₄: H, C!-C₆, aromatic radical (C₆H₆)

wherein R₃: C₁₂-C₂₄

R4: H, Ci-Ce, aromatic radical (C₆H₆); and B) - further neutralization of the obtained intermediate product, which is a mixture of the compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (Γ), with fatty acids containing from 12 to 22 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule, used in an amount from 0.03 to 10 % by weight, in which neutralization the mass ratio of the total mass of the mixture of compounds of general formulae (1), (2), and optionally (Γ), to fatty acids and/or polymers is 1 : 0.02 - 0.5, with obtaining of a product containing a mixture of compounds of general formulae (7), (8), and optionally (7'),

wherein C₁₂-C22 (7)

R₅: C₁₂-C₂₂ and/or Ci₈-C₅₄

wherein R₂: C2-C! 2 (8)

R₅: Q2-C22 and/or C₁₈-C₅₄

wherein R₃: C₁₂-C2₄ (7^')

R₅: C₁₂-C₂₂ and/or C₁₈-C₅₄ and at the end of process B), component a) has a pH = 6.5 - 7.5 and contains a product that is a mixture of compounds with formulae (5), (6), and optionally (5') as well as a product that is a mixture of compounds with formulae (7), (8), and- optionally (7');

and

- optionally component e), that is an anti-foaming agent, in an amount from 0.01 to 2 % by weight

2. The corrosion inhibitor according to claim 1, characterized in that, it contains, as component a) a product formed by neutralization with acetic acid and/or benzoic acid of the following imidazoline derivatives:

i) the new mixture of modified imidazoline derivatives, which is condensation product of diethylenetriamine with fatty acids containing 12-22 carbon atoms per molecule and aliphatic dicarboxylic acids containing 6-10 carbon atoms per molecule, where the molar ratio of diethylenetriamine to fatty acids and to aliphatic carboxylic acids is 1: 0,5-0,99: 0.01-0.5, at a temperature of at least 140°C, preferably 150°C, with the formation of an aminoamide mixture of general formulae (3) and (4),

with acid number < 10 mg KOH/g, and next, the temperature of the reaction is raised to above 180°C, preferably to 220°C, and the condensation reaction is performed further, until a mixture of compounds of general formulae (1) and (2) is obtained

wherein

wherein R₂: C₆-C₁₀ (2) with acid number < 1 mg KOH/g, ii) optionally added, the known product of condensation of diethylenetriamine with fatty acids, produced by a known method, and neutralization of the resultant intermediate product with fatty acids, with acid number from 180 to 210 mg KOH/g, saponification number from 180 to 210 mg KOH/g and iodine number from 80 to 130 g J₂ /100 g, in which the main component is oleic acid C18H34O2 and/or fatty acid polymers containing dimers as their main component with acid number from 190 to 197 mg KOH/g.

3. The corrosion inhibitor according to claim 2, characterized in that it contains, as component a), a product formed by neutralization of the new mixture of modified imidazoline derivatives, with the optional addition of the known product of condensation of diethylenetriamine with fatty acids produced by a known method, using first glacial acetic acid, and after that neutralization of the resultant intermediate product with fatty acids in which the main component is oleic acid C₁₈H₃₄0₂ and/or fatty acid polymers containing fatty acid dimers as their main component.

4. The corrosion inhibitor according to claim 1 or 2 or 3, characterized in that it contains: methanol, isopropanol, ethanol, optionally added water or their mixtures, as component d).

5. The corrosion inhibitor according to claim 1 or 2 or 3, characterized in that it contains: ethylene glycol, glycerin, propylene glycol, dipropylene glycol, tripropylene glycol, or their mixtures, as component c).

6. The corrosion inhibitor according to claim 1 or 2 or 3, characterized in that it contains: branched siloxane polymers as component e).

7. The method of production of the corrosion inhibitor for protection of crude oil extraction equipment, pipelines, and tanks encompassing neutralization of the imidazoline derivatives and addition of further inhibitor components, characterized in that it contains the following stages: I) production of component a) in a reaction medium containing component d), that is aliphatic alcohols containing from 1 to 6 carbon atoms per molecule, optionally with the addition of water, in an amount from 15 to 90.6 % by weight, which comprises the following processes:

A) - neutralization of the new mixture of modified imidazoline derivatives, of general formulae (1) and (2), which is the product of condensation of diethylenetriamine with fatty acids containing from 12 to 22 carbon atoms per molecule and aliphatic dicarboxylic acids containing from 2 to 12 carbon atoms per molecule,

wherein Ri: C₁₂-C₂₂ (1)

used in an amount from 0.1 to 50 % by weight, preferably from 1 to 30 % by weight, with the optional addition of 0.05 to 20 % by weight of the known product of condensation of diethylenetriamine with fatty acids containing from 12 to 24 carbon atoms per molecule, produced by a known method at a temperature of 180-280°C, preferably 220-260°C, of general formula (Γ),

wherein R₃: C₁₂-C₂₄ (Γ) with an aliphatic and/or aromatic monocarboxylic acid containing from 1 to 7 carbon atoms per molecule, used in an amount from 0.025 to 25 % by weight, where the mass ratio of the mixture of compounds of general formulae (1), (2), and optionally ( ) to monocarboxylic acid is 1: 0.15 - 0.70 with obtaining of an intermediate product, containing a mixture of compounds of general formulae (5), (6), and optionally (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally (Γ)

wherein Ri: Q2-C2₂ ( 5)

R4: H, C!-C₆, aromatic radical (C₆H₆)

wherein R₃ : C ₁₂-C₂4 ( 5 ^Λ )

R4: H, C Q, aromatic radical (C₆H₆)

and B) - further neutralization of the resulting intermediate product, containing a mixture of the compounds of general formulas (5), (6), and possibly (5') as well as a mixture of non-neutralized compounds of general formulae (1), (2), and optionally ( ), with fatty acids containing from 12 to 22 carbon atoms per molecule, used in an amount from 0.03 to 10% by weight, and/or fatty acid polymers containing from 18 to 54 carbon atoms per molecule, used in an amount from 0.03 to 10% by weight, in which neutralization the mass ratio of the total mass of the mixture of compounds used in the process of general formulae (1), (2), and optionally (Γ), to fatty acids and/or polymers is 1: 0.02 - 0.5, with obtaining of a product containing a mixture of compounds of general formulae (7), (8), and optionally (7'), with the process B) being performed until the reaction mixture attains pH = 6.5 - 7.5 and component a) containing a product that is a mixture of compounds of formulae (5), (6), and optionally (5') as well as a product that is a mixture of compounds of formulae (7), (8), and optionally (7'), is obtained; RsCOO

wherein R^ C12-C22 ( 7)

R₅: C₁₂-C₂2 and/or C₁₈-C₅₄

wherein R2: C2-C!2 ( 8)

R₅: C₁₂-C₂2 and/or C]₈-C₅₄

wherein R₃: Ci2-C2₄ ( 7^')

R₅: C12-C22 and/or Cj₈-C₅₄ II) introduction to component a), in an amount from 0.155 to 85 % by weight, preferably from 1.55 to 51 % by weight, and to the mentioned component d), of further inhibitor components:

component b), that is oxyethylenated fatty amines containing from 14 to 22 carbon atoms per molecule and from 2 to 22, preferably from 5 to 15, ethoxyl groups per molecule, in an amount from 0.01 to 20 % by weight,

and optionally component c), that is aliphatic polyols in an amount from 0.1 to 50 % by weight,

and finally, optionally component e), that is an anti-foaming agent in an amount from 0.01 to 2 % by weight.

8. The method according to claim 7, characterized in that neutralization with acetic acid and/or benzoic acid of the following imidazoline derivativesis carried out in the process A):

i) the new mixture of modified imidazoline derivatives, which is condensation product of diethylenetriamine with fatty acids containing 12-22 carbon atoms per molecule and aliphatic dicarboxylic acids containing 6-10 carbon atoms per molecule, where the molar ratio of diethylenetriamine to fatty acids and to aliphatic dicarboxylic acids is 1 : 0,5-0,99: 0.01-0.5, at a temperature of at least 140°C, preferably 150°C, with the formation of an aminoamide mixture of general formulas (3) and (4),

wherein R₂: C₆-C₁₀ (4) with acid number < 10 mg KOH/g, after which the temperature of the reaction is raised to above 180 °C, preferably to 220 °C, and as a result of the reaction, a mixture of compounds of general formulae (1) and (2) is obtained

wherein R₂: C₆-C₁₀ (2) with acid number < 1 mg KOH/g ii) optionally added the known product of condensation of diethylenetriamine with fatty acids produced by a known method, and then neutralization is carried out in a process B), of the resultant intermediate product, with fatty acids with acid number from 180 to 210 mg KOH/g, saponification number from 180 to 210 mg KOH/g and iodine number from 80 to 130 g J2 /100 g, in which the main component is oleic acid C₁₈H₃₄0₂ and/or fatty acid polymers containing dimers as their main component with acid number from 190 to 197 mg KOH/g.

9. The method according to claim 8, characterized in that neutralization of the new mixture of modified imidazoline derivatives with the optional addition of the known product of condensation of diethylenetriamine with fatty acids is performed by using glacial acetic acid, and after that, the produced intermediate product is neutralized with fatty acids containing oleic acid C₁₈H₃₄0₂ as their main component and/or fatty acid polymers containing dimers as their main component.