Corrosion inhibitor for oil field as well as preparation method and application of corrosion inhibitor

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a corrosion inhibitor for an oil field and a preparation method and application thereof. The preparation method comprises the following steps: adding 1, 1 '-bis (4-aminophenyl)-[4, 4'-bipyridyl]-1, 1 '-ammonium dichloride, (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride and an organic solvent into a four-neck flask provided with a condensing tube, heating and carrying out a heat preservation reaction, and adjusting and maintaining the pH to be 7-8 by using a sodium hydroxide solution during the reaction; and carrying out reduced pressure distillation to obtain a viscous solid, recrystallizing with ethyl acetate to obtain a faint yellow solid, and drying at 105 DEG C overnight to obtain the corrosion inhibitor product. The corrosion inhibitor 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 in particular relates to a corrosion inhibitor for oil fields and a preparation method and application thereof. Background Art

[0002] Fracturing acidification is a production-increasing measure widely used in the transformation of low-permeability oil and gas reservoirs. By injecting acidic liquid into the formation, the minerals in the rock are dissolved, thereby increasing the permeability of the formation and increasing oil and gas production. In this process, the acid used mainly includes strong acids such as hydrochloric acid and hydrofluoric acid. These acids will chemically corrode the metal surface, causing the metal surface to gradually dissolve, resulting in reduced strength and thinning of the wall thickness of the equipment, which may eventually cause equipment perforation, rupture and other accidents. Moreover, this corrosion process may be exacerbated by the high temperature and high pressure environment underground.

[0003] Corrosion inhibitors can form a protective film on the metal surface to prevent acidic media from directly contacting the metal, thereby significantly reducing the corrosion rate of the metal. For example, in a high-temperature and high-pressure underground environment, without the protection of corrosion inhibitors, metal equipment may suffer serious 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 especially has the advantage of a long continuous action time. However, the corrosion inhibitor molecules of the invention contain thioglycolate, which has a strong odor when used and has certain harm to the environment.

[0005] CN104109529A discloses an acidifying corrosion inhibitor and a preparation method thereof, which 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 to increase the cost, and 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 at the above-mentioned deficiencies of the prior art and provides a corrosion inhibitor for oil fields and a preparation method and application thereof. The corrosion inhibitor of the present invention has the advantages of high temperature resistance and good corrosion inhibition effect.

[0007] In order 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'-bipyridine]-1,1'-diammonium chloride, (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and an organic solvent into a four-necked flask equipped with a condenser, heat and keep warm for reaction, and use sodium hydroxide solution to adjust and maintain the pH at 7-8;

[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'-bipyridine]-1,1'-diammonium chloride, the amount of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride used is 1.4-2.6 mol parts.

[0014] More preferably, based on 1 mol part of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-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 corrosion inhibitor for oil fields 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 oil field acidification corrosion inhibitor of the present invention belongs to Gemi surfactant, contains two pairs of symmetrical quaternary ammonium salts and pyridine, and has a corrosion inhibition effect far greater than that of ordinary surfactants. The quaternary ammonium salt has a positive charge and a high electrical property, and can be adsorbed on the metal surface, preventing hydrogen ions in the acid solution from approaching the metal surface, and preventing electrons in the metal from being captured by hydrogen ions, thereby protecting the metal from being corroded by acid; the pyridine salt itself is an acidification corrosion inhibitor for a variety of high-temperature oil wells; the dodecyl group is a hydrophobic structure, which can slow down the approach of the acidic water phase to the metal surface, thereby further strengthening 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 corrosion inhibitor for oil fields 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 and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[0026] The present invention will be further described below in conjunction with 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'-bipyridine]-1,1'-diammonium chloride, 14 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 41.1 g of methanol were added, heated to 60°C, and kept warm for 4 hours. During this time, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 26 mmol of (3-chloro-2-hydroxypropyl) dodecyl dimethyl ammonium chloride, and 82.2 g of propanol to a four-necked flask equipped with a condenser, heat to 60°C, and keep the temperature for 8 hours. During this time, adjust and maintain the pH 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'-bipyridine]-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, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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'-bipyridine]-1,1'-diammonium chloride, 24 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 76.6 g of methanol were added, heated to 60°C, and kept warm for 4 hours. During this time, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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'-bipyridine]-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 hours. During this time, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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'-bipyridine]-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 hours. During this time, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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'-bipyridine]-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 hours. During this time, a sodium hydroxide solution was used to adjust and maintain the pH at 7-8;

[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) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 21 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 79 g of isobutyl alcohol to a four-necked flask equipped with a condenser, heat to 70°C, and keep the temperature for 4 hours. During this time, adjust and maintain the pH at 7-8 with sodium hydroxide solution;

[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) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 20 mmol of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and 78 g of isobutyl alcohol to a four-necked flask equipped with a condenser, heat to 70°C, and keep the temperature for 4 hours. During this time, adjust and maintain the pH 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 “Performance Test Method and Evaluation Method 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. 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% of the 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 the corrosion inhibitor is added to a 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% of corrosion inhibitor is added to 20 wt% hydrochloric acid solution at 16 MPa and 180 °C, the dynamic corrosion rate is less 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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope 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 suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0070] In addition, 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 method for preparing a corrosion inhibitor for oil fields, characterized in that: The specific steps of the preparation method are as follows: (1) Add 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride, and an organic solvent into a four-necked flask equipped with a condenser, heat and keep warm for reaction, and use sodium hydroxide solution to adjust and maintain the pH at 7-8; (2) distilling under reduced pressure to obtain a viscous solid, recrystallizing from ethyl acetate to obtain a light yellow solid, and drying at 105° C. overnight to obtain a corrosion inhibitor product; Based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, the amount of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride used is 1.4-2.6 moles.

2. The method for preparing a corrosion inhibitor for oil fields according to claim 1, characterized in that: Based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, the amount of (3-chloro-2-hydroxypropyl) dodecyldimethylammonium chloride used is 1.85-2.15 mole parts.

3. The method for preparing a corrosion inhibitor for oil fields according to claim 1, characterized in that: The organic solvent in step (1) is one of methanol, ethanol, propanol, butanol and isobutanol.

4. The method for preparing a corrosion inhibitor for oil fields according to claim 3, characterized in that: The weight ratio of the organic solvent to 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride is 10-20:

1.

5. The method for preparing a corrosion inhibitor for oil fields according to claim 3, characterized in that: The organic solvent is ethanol or isobutanol.

6. The method for preparing a corrosion inhibitor for oil fields according to claim 1, characterized in that: The heating and heat preservation time in step (1) is 1-8h and the temperature is 60-80°C.

7. A corrosion inhibitor for oil fields, characterized in that: The molecular structure of the corrosion inhibitor is as follows:

8. Use of the corrosion inhibitor according to claim 7 in oil field acid fracturing.

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