A corrosion inhibitor for oil fields and its preparation method and application

Abstract

The present invention belongs to the field of oil production technology, and in particular to a kind of oilfield corrosion inhibitor and its preparation method and application. The preparation method is as follows: 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and an organic solvent are added to a four-necked flask equipped with a condenser tube, and the reaction is heated and insulated. During the reaction, a sodium hydroxide solution is used to adjust and maintain pH 7-8; a viscous solid is obtained by distillation under reduced pressure, and recrystallized with ethyl acetate to obtain a light yellow solid, which is dried at 105 ° C overnight to obtain a corrosion inhibitor product. The corrosion inhibitor of the present invention has the advantages of high temperature resistance and good corrosion inhibition effect.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction, and particularly relates to a corrosion inhibitor for oil fields and a preparation method and application thereof. Background Art

[0002] Fracturing and acidizing is a widely used production-enhancing measure for the transformation of low-permeability oil and gas reservoirs. By injecting acidic fluids into the formation, they dissolve minerals in the rock, thereby increasing the formation's permeability and boosting oil and gas production. This process, primarily using strong acids such as hydrochloric acid and hydrofluoric acid, chemically corrodes metal surfaces, gradually dissolving them and reducing the strength and wall thickness of the equipment. This can ultimately lead to equipment perforations and ruptures. Furthermore, this corrosion process can be exacerbated by the high temperatures and high pressures found underground.

[0003] Corrosion inhibitors can form a protective film on metal surfaces, preventing direct contact between acidic media and the metal, thereby significantly reducing the metal's corrosion rate. For example, in the high-temperature and high-pressure underground environment, without the protection of corrosion inhibitors, metal equipment may suffer severe damage such as wall thinning and perforation in a short period of time.

[0004] CN106757071A discloses a hydrophilic metal pickling corrosion inhibitor and its application, belonging to the field of metal pickling corrosion and protection. The corrosion inhibitor has multiple hydrophilic groups and has the advantage of good hydrophilicity. The invention can be used for metal pickling corrosion, has a wide range of applications, and has good corrosion inhibition performance. At the same time, the corrosion inhibitor of the invention can better withstand changes in cleaning conditions and has the advantage of a long duration of action. However, the corrosion inhibitor molecules of the invention contain thioglycolate, which has a strong odor when used and has certain environmental hazards.

[0005] CN104109529A discloses an acidifying corrosion inhibitor and its preparation method. The acidifying corrosion inhibitor is mainly made of the following raw materials in parts by weight: 39-41 parts of acetophenone, 24-26 parts of formaldehyde, 9-11 parts of ethylenediamine, 24-25 parts of anhydrous ethanol, 1-2 parts of concentrated hydrochloric acid, and 1-3 parts of propargyl alcohol. The acidifying corrosion inhibitor of the invention uses acetophenone, formaldehyde, anhydrous ethanol, concentrated hydrochloric acid, ethylenediamine and propargyl alcohol as raw materials. Through reasonable compounding, the obtained acidifying corrosion inhibitor has good dispersibility in acid solution. However, the components of the corrosion inhibitor are complex, and the product is a Mannich base with poor water solubility. Therefore, a large amount of ethanol is added as a solvent, which increases the cost. Ethanol is flammable and volatile, and its vapor can form an explosive mixture with air. In addition, propargyl alcohol is highly toxic and volatile. Summary of the Invention

[0006] The present invention aims to overcome the above-mentioned deficiencies in the prior art and provides an oilfield corrosion inhibitor and its preparation method and application. The corrosion inhibitor of the present invention has the advantages of high temperature resistance and good corrosion inhibition effect.

[0007] To achieve the above objectives:

[0008] The first aspect of the present invention discloses a corrosion inhibitor for oil fields, wherein the molecular structure of the corrosion inhibitor is as follows:

[0009]

[0010] In another aspect, the present invention discloses a method for preparing the above-mentioned corrosion inhibitor, and the specific steps of the preparation method are as follows:

[0011] (1) Add 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and an organic solvent to a four-necked flask equipped with a condenser, heat and insulate to react, and adjust and maintain the pH at 7-8 with sodium hydroxide solution;

[0012] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0013] In the present invention, preferably, based on 1 mol part of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, the amount of (3-chloro-2-hydroxypropyl)dodecyldimethylammonium chloride is 1.4-2.6 mol parts.

[0014] More preferably, based on 1 mol part of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, the amount of (3-chloro-2-hydroxypropyl)dodecyldimethylammonium chloride used is 1.85-2.15 mol parts.

[0015] In the present invention, preferably, the organic solvent in step (1) is one of methanol, ethanol, propanol, butanol, and isobutanol, and the weight ratio of the organic solvent to 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride is 10-20:1.

[0016] More preferably, the organic solvent is one of ethanol or isobutanol.

[0017] In the present invention, preferably, the heating and heat preservation time in step (1) is 1-8h and the temperature is 60-80°C.

[0018] The synthetic reaction equation of the oilfield corrosion inhibitor of the present invention is as follows:

[0019]

[0020] The third object of the present invention is to disclose the application of the above corrosion inhibitor in oil field acid fracturing.

[0021] The oilfield acidizing corrosion inhibitor of the present invention belongs to Gemi surfactants and contains two pairs of symmetrical quaternary ammonium salts and pyridines. Its corrosion inhibition effect is far greater than that of ordinary surfactants. The quaternary ammonium salts have a positive charge and high electrical properties, which can be adsorbed on metal surfaces, preventing hydrogen ions in the acid solution from approaching the metal surface and hindering electrons in the metal from being captured by hydrogen ions, thereby protecting the metal from acid corrosion. The pyridine salt itself is an acidizing corrosion inhibitor for various high-temperature oil wells. The dodecyl group has a hydrophobic structure, which can slow the approach of the acidic aqueous phase to the metal surface, thereby further enhancing the corrosion inhibition effect.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) The oilfield corrosion inhibitor of the present invention is adaptable to different temperatures and has a good corrosion inhibition effect from 60-180°C;

[0024] (2) The oilfield corrosion inhibitor of the present invention has a good corrosion inhibition effect. When 1 wt% of the corrosion inhibitor is added to a 20 wt% hydrochloric acid solution at 90°C, the corrosion rate does not exceed 2.2 g / (m 2 ·h); add 1wt% corrosion inhibitor to 12wt% hydrochloric acid + 3wt% hydrofluoric acid solution at 90℃, the corrosion rate does not exceed 3g / (m 2 ·h). DETAILED DESCRIPTION

[0025] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0026] The present invention will be further described below with reference to specific embodiments:

[0027] Example 1

[0028] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 14 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 41.1 g of methanol were added. The mixture was heated to 60°C and kept warm for 4 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0029] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0030] Example 2

[0031] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 26 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 82.2 g of propanol were added, heated to 60°C, and kept warm for 8 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0032] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0033] Example 3

[0034] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 16 mmol of (3-chloro-2-hydroxypropyl)dodecyldimethylammonium chloride, and 52.3 g of butanol were added, heated to 80°C, and kept warm for 1 hour. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0035] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0036] Example 4

[0037] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 24 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 76.6 g of methanol were added. The mixture was heated to 60°C and kept warm for 4 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0038] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0039] Example 5

[0040] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 18 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 71 g of ethanol were added, heated to 60°C, and kept warm for 6 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0041] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0042] Example 6

[0043] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 22 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 80 g of ethanol were added, heated to 60°C, and kept warm for 6 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0044] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0045] Example 7

[0046] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 19 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 72.1 g of ethanol were added, heated to 60°C, and kept warm for 2 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0047] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0048] Example 8

[0049] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 21 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 79 g of isobutyl alcohol were added, heated to 70°C, and kept warm for 4 h. During this time, sodium hydroxide solution was used to adjust and maintain the pH at 7-8.

[0050] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0051] Example 9

[0052] (1) In a four-necked flask equipped with a condenser, 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, 20 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 78 g of isobutyl alcohol were added, heated to 70°C, and kept warm for 4 h. During this time, the pH was adjusted and maintained at 7-8 with sodium hydroxide solution.

[0053] (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105° C. overnight to obtain a corrosion inhibitor product.

[0054] Example 10 Corrosion Rate Test

[0055] The static corrosion rate at normal pressure and the dynamic corrosion rate at high temperature and high pressure were determined with reference to the method in SY / T 5405-2019 “Test method and evaluation method for performance of corrosion inhibitors for acidification”. The different test parameters are shown in Tables 1 and 2, and the test results are shown in Table 3.

[0056] Comparative experiments were conducted using 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride (Comparative Example 1) and Shaanxi Rixin Petrochemical Co., Ltd.'s RX-203 acidizing corrosion inhibitor (Comparative Example 2).

[0057] Table 1 Conditions for determining static corrosion rate at normal pressure

[0058]

[0059] Table 2 High temperature and high pressure dynamic corrosion rate measurement conditions

[0060]

[0061]

[0062] Table 3 Corrosion rate test results

[0063]

[0064] From Table 3 we can see that:

[0065] (1) When 1 wt% corrosion inhibitor is added to a 20 wt% hydrochloric acid solution at 90°C, the static corrosion rate does not exceed 2.2 g / (m 2 ·h); while the corrosion rate of Comparative Example 1 is 7g / (m 2 ·h), the corrosion rate of comparative example 2 is 4.6g / (m 2 h), are significantly higher than those of the present invention.

[0066] (2) When 1 wt% of corrosion inhibitor is added to 12 wt% hydrochloric acid + 3 wt% hydrofluoric acid solution at 90 °C, the static corrosion rate does not exceed 3 g / (m 2 ·h); while the corrosion rate of Comparative Example 1 is 8.8g / (m 2 ·h), the corrosion rate of comparative example 2 is 6.8g / (m 2 h), are significantly higher than those of the present invention.

[0067] (3) When 5 wt% corrosion inhibitor is added to 20 wt% hydrochloric acid solution at 16 MPa and 180 °C, the dynamic corrosion rate is lower than 21 g / (m 2 ·h); while the dynamic corrosion rate of Comparative Example 1 is 89.3g / (m 2 ·h), the dynamic corrosion rate of comparative example 2 is 36.5g / (m 2 h), are significantly higher than those of the present invention.

[0068] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0069] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0070] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A corrosion inhibitor for oil fields, characterized in that: The molecular structural formula of the corrosion inhibitor is as follows: 。 2. The method for preparing the corrosion inhibitor according to claim 1, wherein The specific steps of the preparation method are as follows: (1) Add 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and an organic solvent to a four-necked flask equipped with a condenser, and heat to allow the reaction to proceed. During this time, adjust and maintain the pH at 7-8 with sodium hydroxide solution. (2) Vacuum distillation was performed to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried at 105°C overnight to obtain a corrosion inhibitor product; Based on 1 mol part of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, the amount of the (3-chloro-2-hydroxypropyl)dodecyldimethylammonium chloride used is 1.4-2.6 mol parts.

3. The preparation method according to claim 2, characterized in that Based on 1 mol part of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride, the amount of the (3-chloro-2-hydroxypropyl)dodecyldimethylammonium chloride used is 1.85-2.15 mol parts.

4. The preparation method according to claim 2, characterized in that The organic solvent in step (1) is one of methanol, ethanol, propanol, butanol and isobutanol.

5. The preparation method according to claim 4, characterized in that The weight ratio of the organic solvent to 1,1'-bis(4-aminophenyl)-[4,4'-bipyridyl]-1,1'-diammonium chloride is 10-20:

1.

6. The preparation method according to claim 4, characterized in that The organic solvent is ethanol or isobutanol.

7. The preparation method according to claim 2, characterized in that The heating and heat preservation time in step (1) is 1-8h and the temperature is 60-80℃.

8. Use of the corrosion inhibitor according to claim 1 in oil field acid fracturing.

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