Auxiliary agent for enhancing compatibility of bactericidal corrosion inhibitor, bactericidal corrosion inhibitor and application of bactericidal corrosion inhibitor

Abstract

The invention provides an auxiliary agent for enhancing compatibility of a bactericidal corrosion inhibitor, the bactericidal corrosion inhibitor and application of the bactericidal corrosion inhibitor. The auxiliary agent comprises an ionic liquid and an alcohol compound in a mass ratio of (1-10): (1-5), the ionic liquid comprises one or a combination of several of imidazole ionic liquid, pyridine ionic liquid, quinoline ionic liquid, quaternary ammonium salt ionic liquid and quaternary phosphonium salt ionic liquid. The bactericidal corrosion inhibitor comprises the following components in percentage by mass: 2-15% of an auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor, 10-30% of benzyl-containing quaternary ammonium salt, 5-30% of a guanidine compound and / or glutaraldehyde and the balance of water, wherein the total mass of the bactericidal corrosion inhibitor is 100%. The invention also provides application of the sterilization corrosion inhibitor in corrosion protection in an unconventional gas production system. The assistant provided by the invention can enhance the compatibility of the bactericidal corrosion inhibitor and the flowback fluid. The bactericidal corrosion inhibitor disclosed by the invention has the advantages of good high-temperature stability, no blistering, high bactericidal and corrosion inhibition efficiency and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to an auxiliary agent for enhancing the compatibility of a bactericidal corrosion inhibitor, a bactericidal corrosion inhibitor and an application thereof. Background Art

[0002] With the continuous development of unconventional gases such as shale gas and tight gas, the corrosion and failure of components in the production system of mining has become more and more frequent. There is basically no H2S in unconventional gas, and the molar content of CO2 is between 0 and 2%. Since volume fracturing technology is generally used in unconventional gas mining, the liquid production volume is large. The fracturing fluid contains a large amount of organic matter, which can provide nutrients for the growth of microorganisms, leading to the proliferation of microorganisms. At present, the most harmful bacteria in unconventional gas production systems are sulfate-reducing bacteria (SRB), iron bacteria (IB) and saprophytic bacteria (TGB), especially the coexistence and synergistic metabolism of multiple bacteria, which will cause more serious corrosion. In addition, the return fluid is highly mineralized, Cl - The concentration can exceed 10,000 mg / L. Based on the above corrosion factors, there are corrosion perforation problems in the wellbore and ground of the unconventional gas production system. This not only causes huge economic losses, but also poses serious safety hazards.

[0003] According to various failure analysis reports, the main forms of corrosion in non-gas production systems include microbial corrosion and CO2 corrosion. At present, bactericides and corrosion inhibitors are widely used for corrosion control, and the main method is to combine bactericides and corrosion inhibitors. However, due to the complex components of the return fluid in the production system, the corrosion environment of the wellbore and the ground is quite different. The maximum temperature downhole can reach 150°C, and the surface pipeline temperature is about 40°C. These environmental characteristics make it easy for insoluble substances such as flocculation and precipitation to be produced when the reagent is added to the gas field water. In particular, the downhole temperature is high, and the reagent is more likely to aggregate with suspended matter or sediment in the gas field water at high temperature, resulting in incompatibility. The incompatibility between the reagent and the gas field water increases the risk of well plugging. At the same time, after the reagent is added to the wellbore and returned to the ground, its performance will be greatly reduced. In addition, if the produced water is easy to bubble under the action of airflow during the gathering and transportation process, it will cause gas blockage and reduce the efficiency of triethylene glycol in the dehydration device. These characteristics bring great challenges to the development of reagents. Therefore, in order to ensure the safe and efficient development of gas fields, higher requirements are placed on the high-temperature and normal-temperature compatibility, high-temperature stability and low foaming properties of bactericidal corrosion inhibitors and flowback fluids.

[0004] At present, there are few reports on additives that enhance the compatibility of bactericidal corrosion inhibitors with unconventional gas field return fluids. CN115613035A discloses a corrosion inhibitor compatibility method and application, and a corrosion inhibitor composition. The corrosion inhibitor compatibility method prepares an oil-soluble corrosion inhibitor into an O / W microemulsion system by adding a surfactant, an additive and a hydrocarbon substance to enhance its compatibility in gas field water. However, the method has many steps, and the addition of a surfactant generally has strong foaming properties, which is not conducive to the use of unconventional gas production systems. CN114456148A discloses an oilfield corrosion inhibitor with good compatibility and a preparation method thereof. The preparation method of the oilfield corrosion inhibitor mainly obtains 6-(imidazolinyl)-2-carboxylic acid pyridine by reacting 2,6-pyridinedicarboxylic acid and polyethylene polyamine, and then quaternizes with chlorinated hydrocarbons to obtain N-alkyl-6-(imidazolinyl)-2-carboxylic acid pyridine quaternary ammonium salt corrosion inhibitor. The corrosion inhibitor can be compounded with water purifiers, scale inhibitors, demulsifiers, bactericides, etc. commonly used in oil fields, and has good compatibility. CN112544624A discloses an environmentally friendly integrated bactericidal corrosion inhibitor for shale gas pipelines and a preparation method thereof, using enrofloxacin and norfloxacin as bactericides, thiourea as a corrosion inhibitor, and ethanol or water as a solvent to prepare the bactericidal corrosion inhibitor. However, the document does not mention the compatibility of the bactericidal corrosion inhibitor at room temperature and high temperature.

[0005] Therefore, it is of great significance to the control of unconventional gas corrosion to develop methods to enhance the compatibility of bactericidal and corrosion inhibitors and to provide new bactericidal and corrosion inhibitors that meet the needs of production systems. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide an auxiliary agent for enhancing the compatibility of a bactericidal corrosion inhibitor, a bactericidal corrosion inhibitor and its application. The auxiliary agent provided by the present invention can enhance the compatibility of the bactericidal corrosion inhibitor with the return fluid. The bactericidal corrosion inhibitor provided by the present invention has the advantages of good high temperature stability, good bactericidal and corrosion inhibition performance, etc.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides an additive for enhancing the compatibility of a bactericidal corrosion inhibitor, which comprises an ionic liquid and an alcohol compound in a mass ratio of 1 to 10:1 to 5; wherein the ionic liquid comprises one or a combination of imidazole ionic liquids, pyridine ionic liquids, quinoline ionic liquids, quaternary ammonium salt ionic liquids and quaternary phosphonium salt ionic liquids;

[0008] The structural formula of the imidazole ionic liquid is shown in Formula I:

[0009]

[0010] The structural formula of the pyridine ionic liquid is shown in Formula II:

[0011]

[0012] The structural formula of the quinoline ionic liquid is shown in Formula III:

[0013]

[0014] The structural formula of the quaternary ammonium salt ionic liquid is shown in Formula IV:

[0015]

[0016] The structural formula of the quaternary phosphonium salt ionic liquid is shown in Formula V:

[0017]

[0018] In Formula I, Formula II, Formula III, Formula IV and Formula V, R1, R2, R3, R4 and R5 are each independently selected from one of a C1-C4 straight-chain alkyl group, a C3-C4 branched-chain alkyl group, a C1-C4 alkoxy group, a C1-C4 alkanol group and a C2-C4 alkenyl group, and Z1 - Selected from HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them, Z2 - Selected from Cl - 、HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them.

[0019] In the above-mentioned additives for enhancing the compatibility of the bactericidal corrosion inhibitor, preferably, the alcohol compound includes a C1-C4 small molecule alcohol compound. Specifically, the alcohol compound includes one or a combination of methanol, ethanol, n-propanol, isopropanol, n-butanol and tert-butanol.

[0020] The second aspect of the present invention provides a bactericidal corrosion inhibitor, which, based on its total mass as 100%, includes the following components: 2 to 15% of the above-mentioned additive for enhancing the compatibility of the bactericidal corrosion inhibitor, 10 to 30% of a benzyl quaternary ammonium salt, 5 to 30% of a guanidine compound and / or glutaraldehyde, and the remainder of water.

[0021] According to a specific embodiment of the present invention, preferably, based on the total mass of the bactericidal corrosion inhibitor being 100%, the content of the ionic liquid therein is 1-10%, and the content of the alcohol compound is 1-5%.

[0022] In the above-mentioned bactericidal corrosion inhibitor, preferably, the benzyl-containing quaternary ammonium salt includes a benzyl-containing aromatic heterocyclic quaternary ammonium salt compound. More preferably, the benzyl-containing quaternary ammonium salt includes one or a combination of benzylquinoline quaternary ammonium salt, benzylpyridinium quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt and benzylimidazole quaternary ammonium salt.

[0023] In the above-mentioned bactericidal corrosion inhibitor, preferably, the anion in the benzyl quaternary ammonium salt includes Cl - Br - ,I - 、HSO4 - 、NO3 - 、ClO4 - 、BF4 - PF6 - 、CH3COO - 、N(CN)2 - and SCN - One or a combination of the above.

[0024] In the above-mentioned bactericidal corrosion inhibitor, preferably, the guanidine compound includes one or a combination of polyhexamethylene monoguanidine salt, polyhexamethylene biguanidine salt, chlorhexidine and its salts.

[0025] The third aspect of the present invention provides the use of the above-mentioned bactericidal corrosion inhibitor for corrosion protection in an unconventional gas production system.

[0026] In summary, the present invention provides an auxiliary agent for enhancing the compatibility of a bactericidal corrosion inhibitor, a bactericidal corrosion inhibitor and its application. The auxiliary agent provided by the present invention can enhance the compatibility of the bactericidal corrosion inhibitor with the return fluid, and enhance the adaptability of the bactericidal corrosion inhibitor in the unconventional gas production system. The bactericidal corrosion inhibitor provided by the present invention has good high-temperature stability, does not foam, has a good bactericidal effect on SRB, IB and TGB, and has a good corrosion inhibition effect on CO2 corrosion. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0028] The present invention provides an additive for enhancing the compatibility of a bactericidal corrosion inhibitor, comprising an ionic liquid and an alcohol compound in a mass ratio of 1 to 10:1 to 5; wherein the ionic liquid comprises one or a combination of imidazole ionic liquids, pyridine ionic liquids, quinoline ionic liquids, quaternary ammonium salt ionic liquids and quaternary phosphonium salt ionic liquids;

[0029] The structural formula of the imidazole ionic liquid is shown in Formula I:

[0030]

[0031] The structural formula of the pyridine ionic liquid is shown in Formula II:

[0032]

[0033] The structural formula of the quinoline ionic liquid is shown in Formula III:

[0034]

[0035] The structural formula of the quaternary ammonium salt ionic liquid is shown in Formula IV:

[0036]

[0037] The structural formula of the quaternary phosphonium salt ionic liquid is shown in Formula V:

[0038]

[0039] In Formula I, Formula II, Formula III, Formula IV and Formula V, R1, R2, R3, R4 and R5 are each independently selected from one of a C1-C4 straight-chain alkyl group, a C3-C4 branched-chain alkyl group, a C1-C4 alkoxy group, a C1-C4 alkanol group and a C2-C4 alkenyl group, and Z1 - Selected from HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them, Z2 - Selected from Cl - 、HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them.

[0040] In some specific embodiments of the present invention, the alcohol compound includes a C1-C4 small molecule alcohol compound. Specifically, the alcohol compound includes one or a combination of methanol, ethanol, n-propanol, isopropanol, n-butanol and tert-butanol.

[0041] The auxiliary agent provided by the present invention for enhancing the compatibility of the bactericidal corrosion inhibitor includes an ionic liquid and an alcohol compound. The auxiliary agent mainly utilizes the dispersibility and solubilization effect of the anions and cations of the ionic liquid. On the one hand, it can promote the dissolution of the precipitate in the return fluid, and on the other hand, it can enhance the dispersibility of the bactericidal corrosion inhibitor in the return fluid, inhibit the flocculation and precipitation after its aggregation, and improve its compatibility. However, the inventors of this case have found through research that when the alkyl chain in the ionic liquid is too long, its solubility in the return fluid is low and it does not have the effect of enhancing compatibility. In addition, the inventors of this case have also found that the type of anion has a greater influence on the effect of the ionic liquid in enhancing the compatibility. However, when the anion is SO4 2- 、H2PO4 - CF3SO3 - , C6H6-SO3 - When the acid radical ions are present, they are easy to react with Ba in the return liquid. 2+ or Ca 2+ On the one hand, it can form a precipitate, and on the other hand, it can promote the aggregation and precipitation of insoluble matter. The chemical structure of the ionic liquid has a great influence on the role of the auxiliary agent in enhancing the compatibility of the bactericidal corrosion inhibitor with the return fluid. In addition, the auxiliary agent of the present invention contains alcohol compounds, which can further enhance the solubility of the bactericidal corrosion inhibitor in the return fluid. However, the excessively long carbon chain length of the alcohol compound will also cause the problem of low solubility in the return fluid. After a lot of research, the inventor of this case has developed the auxiliary agent of the present invention that enhances the compatibility of the bactericidal corrosion inhibitor, which includes an ionic liquid with a specific chemical structure and a small molecule alcohol compound, which can significantly enhance the compatibility of the bactericidal corrosion inhibitor with the return fluid.

[0042] The present invention also provides a bactericidal corrosion inhibitor, which comprises the following components based on its total mass as 100%: 2-15% of the above-mentioned auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor, 10-30% of benzyl quaternary ammonium salt, 5-30% of guanidine compounds and / or glutaraldehyde, and the remainder of water.

[0043] In some specific embodiments of the present invention, based on the total mass of the bactericidal corrosion inhibitor as 100%, it includes the following components: 1-10% ionic liquid, 1-5% alcohol compound, 10-30% benzyl quaternary ammonium salt, 5-30% guanidine compound and / or glutaraldehyde, and the remainder water.

[0044] In some specific embodiments of the present invention, the benzyl-containing quaternary ammonium salt includes a benzyl-containing aromatic heterocyclic quaternary ammonium salt compound. More preferably, the benzyl-containing quaternary ammonium salt includes one or a combination of benzylquinoline quaternary ammonium salt, benzylpyridinium quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt and benzylimidazole quaternary ammonium salt.

[0045] In some specific embodiments of the present invention, the anion in the benzyl quaternary ammonium salt includes Cl - Br -,I - 、HSO4 - 、NO3 - 、ClO4 - 、BF4 - PF6 - 、CH3COO - 、N(CN)2 - and SCN - One or a combination of the above.

[0046] Specifically, the structural formula of the benzylquinoline quaternary ammonium salt is shown in Formula VI:

[0047]

[0048] The structural formula of the benzylpyridinium quaternary ammonium salt is shown in Formula VII:

[0049]

[0050] The structural formula of the benzylbenzothiazole quaternary ammonium salt is shown in Formula VIII:

[0051]

[0052] The structural formula of the benzyl imidazole quaternary ammonium salt is shown in Formula IX:

[0053]

[0054] In Formula VI, Formula VII, Formula VIII and Formula IX, X - Selected from Cl - Br - ,I - 、HSO4 - 、NO3 - 、ClO4 - 、BF4 - PF6 - 、CH3COO - 、N(CN)2 - and SCN - In formula IX, R is selected from one of C1-C4 straight-chain alkyl, C3-C4 branched-chain alkyl, C1-C4 alkoxy and C2-C4 alkenyl.

[0055] In some specific embodiments of the present invention, the guanidine compound includes one or a combination of polyhexamethylene monoguanidine salt, polyhexamethylene biguanidine salt, chlorhexidine and its salts.

[0056] Specifically, the structural formula of the polyhexamethylene guanidine salt is shown in Formula X:

[0057]

[0058] The structural formula of the polyhexamethylene biguanide salt is shown in Formula XI:

[0059]

[0060] The structure of the chlorhexidine is shown in Formula XII:

[0061]

[0062] The structure of the salt of chlorhexidine is shown in Formula XIII:

[0063]

[0064] In Formula X, Formula XI and Formula XIII, Y is selected from Cl - Br - ,I - 、HSO4 - 、NO3 - 、C6H6-SO3 - 、ClO4 - 、CH3COO - 、N(CN)2 - 、SCN - 、CH3CH2COO - and CH2OH-(CHOH)4-COO - In Formula X and Formula XI, n is an integer of 5 to 100; in Formula XIII, m is an integer of 1 to 4.

[0065] In some specific embodiments of the present invention, the bactericidal corrosion inhibitor can be prepared by the following steps: at 25-40° C., according to the mass percentage of each component, benzyl quaternary ammonium salt, guanidine compound and / or glutaraldehyde, ionic liquid, alcohol compound and water are mixed, and stirred until the system is clear to obtain the bactericidal corrosion inhibitor.

[0066] The bactericidal corrosion inhibitor of the present invention adopts a benzyl quaternary ammonium salt as a corrosion inhibition component, a guanidine compound and / or glutaraldehyde as a bactericidal component, and simultaneously adopts the auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor of the present invention, and the bactericidal corrosion inhibitor is compounded to obtain the bactericidal corrosion inhibitor. The auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor of the present invention, that is, the combination of ionic liquid and alcohol compound, can enhance the adaptability of the bactericidal corrosion inhibitor of the present invention in the unconventional gas production system. In addition, the addition of ionic liquid can enhance the bactericidal and corrosion inhibition performance of the bactericidal corrosion inhibitor to a certain extent, and the alcohol compound can enhance the bactericidal performance of the bactericidal corrosion inhibitor. The bactericidal corrosion inhibitor of the present invention has the advantages of good high temperature stability, no foaming, high bactericidal and corrosion inhibition efficiency, etc.

[0067] The present invention will be specifically described below by way of examples and comparative examples, but the present invention is not limited to these examples and can of course be implemented with various modifications within the scope of the gist of the present invention.

[0068] The raw materials used in the following examples and comparative examples include:

[0069] Benzylquinoline quaternary ammonium chloride: CAS: 15619-48-4, Aladdin Reagent Co., Ltd.

[0070] Benzylpyridinium quaternary ammonium chloride: CAS: 2876-13-3, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0071] Benzylpyridinium quaternary ammonium acetate: CAS: 58990-04-8, prepared by referring to The phytotoxicity of several S-benzyl-, S-phenacylisothiouronium, N-benzyl and N-phenacyltrimethylammonium N-benzyl-, and N-phenacylpyridinium alkanoates (Mededelingen van de Faculteit Landbouwwetenschappen, Universiteit Gent (1975), 40 (2), 859-69);

[0072] Benzyl imidazole quaternary ammonium bromide: CAS: 65039-11-4, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0073] Benzyl imidazole quaternary ammonium hydrogen sulfate: CAS: 956597-95-8, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0074] Benzylbenzothiazole quaternary ammonium chloride (N-benzylbenzothiazole chloride): prepared in-house with reference to the description in Cyanine dyes, New potentantitumor agents (Chemical & Pharmaceutical Bulletin (1982), 30 (9), 3106-20);

[0075] Polyhexamethyleneguanidine salt: CAS: 57028-96-3, Aladdin Reagent Co., Ltd.

[0076] Glutaraldehyde: 50% glutaraldehyde aqueous solution, Aladdin Reagent Co., Ltd.;

[0077] Chlorhexidine: Sigma-Aldrich Reagent Company;

[0078] Chlorhexidine gluconate: Sigma-Aldrich Reagent Company;

[0079] 1-Ethyl-3-methylimidazolium hydrogen sulfate: CAS: 412009-61-1, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0080] Tetrakis(hydroxymethyl)phosphonium chloride: CAS: 124-64-1, Aladdin Reagent Co., Ltd.

[0081] 1-Ethylquinoline nitrate: prepared by referring to the description in Corrosion inhibitors for steels inacids.II.Electrochemical kinetics of corrosion in the presence of inhibitors (Trudy Gosudarst.Inst.Priklad.Khim.(1960),No.44,39-64);

[0082] 1-Ethyl-3-methylimidazole perchlorate: CAS: 665039-04-5, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0083] Tributyl methyl ammonium acetate: Sigma-Aldrich Reagent Company;

[0084] Isopropyl alcohol: Aladdin Reagent Co., Ltd.;

[0085] Methanol: Aladdin Reagent Co., Ltd.;

[0086] Ethanol: Aladdin Reagent Co., Ltd.;

[0087] n-Propanol: Aladdin Reagent Co., Ltd.;

[0088] n-Butanol: Aladdin Reagent Co., Ltd.;

[0089] Triethylhexyl ammonium bis(trifluoromethanesulfonyl)imide salt: CAS: 210230-46-9, ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0090] Oleic acid imidazoline: MacLean Reagent Company.

[0091] Example 1

[0092] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0093] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylquinoline quaternary ammonium chloride, 30% of polyhexamethylene monoguanidine salt, 5% of 1-ethyl-3-methylimidazole hydrogen sulfate, 5% of isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 1.

[0094] Example 2

[0095] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0096] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylquinoline quaternary ammonium chloride, 30% of polyhexamethylene guanidine salt, 7% of 1-ethyl-3-methylimidazole hydrogen sulfate, 5% of isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 2.

[0097] Example 3

[0098] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0099] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylquinoline quaternary ammonium chloride, 30% of polyhexamethylene guanidine salt, 9% of 1-ethyl-3-methylimidazole hydrogen sulfate, 5% of isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 3.

[0100] Example 4

[0101] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0102] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylpyridinium ammonium chloride, 10% of polyhexamethylene monoguanidine salt, 2% of tetrakishydroxymethylphosphonium chloride, 5% of methanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 4.

[0103] Example 5

[0104] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0105] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylpyridinium ammonium chloride, 10% of polyhexamethylene monoguanidine salt, 4% of tetrakishydroxymethylphosphonium chloride, 5% of methanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 5.

[0106] Example 6

[0107] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0108] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 30% of benzylpyridinium ammonium chloride, 10% of polyhexamethylene monoguanidine salt, 6% of tetrakishydroxymethylphosphonium chloride, 5% of methanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 6.

[0109] Example 7

[0110] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0111] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% benzylpyridinium ammonium acetate, 30% glutaraldehyde aqueous solution, 2% tetrakishydroxymethylphosphonium chloride, 5% isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 7.

[0112] Example 8

[0113] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0114] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% benzylpyridinium ammonium acetate, 30% glutaraldehyde aqueous solution, 4% tetrakishydroxymethylphosphonium chloride, 5% isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 8.

[0115] Example 9

[0116] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0117] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% of benzylpyridinium ammonium acetate, 30% of glutaraldehyde aqueous solution, 6% of tetrakishydroxymethylphosphonium chloride, 5% of isopropanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 9.

[0118] Example 10

[0119] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0120] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% of benzyl imidazole quaternary ammonium bromide, 10% of chlorhexidine, 5% of 1-ethylquinoline nitrate, 5% of ethanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 10.

[0121] Embodiment 11

[0122] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0123] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% of benzyl imidazole quaternary ammonium hydrogen sulfate, 20% of chlorhexidine gluconate, 5% of 1-ethyl-3-methylimidazole perchlorate, 5% of n-propanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 11.

[0124] Example 12

[0125] This embodiment provides a bactericidal corrosion inhibitor, which is prepared by the following steps:

[0126] At 25-40° C., based on the total mass of the bactericidal corrosion inhibitor being 100%, 10% of benzylbenzothiazole quaternary ammonium chloride, 20% of glutaraldehyde aqueous solution, 5% of tributyl methylammonium acetate, 5% of n-butanol and the remainder of water were mixed and stirred until the system became clear to obtain a bactericidal corrosion inhibitor, which was recorded as No. 12.

[0127] Comparative Example 1

[0128] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components based on the total mass of the bactericidal corrosion inhibitor as 100%: 30% benzylquinoline quaternary ammonium chloride, 30% polyhexamethylene monoguanidine salt and the balance water. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0129] The bactericidal corrosion inhibitor of this comparative example is recorded as A, as a comparison with Examples 1 to 3.

[0130] Comparative Example 2

[0131] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components based on the total mass of the bactericidal corrosion inhibitor as 100%: 30% benzylpyridinium quaternary ammonium chloride, 10% polyhexamethylene monoguanidine salt and the balance water. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0132] The bactericidal corrosion inhibitor of this comparative example is recorded as B, as a comparison with Examples 4 to 6.

[0133] Comparative Example 3

[0134] This comparative example provides a bactericidal corrosion inhibitor, which comprises the following components, based on the total mass of the bactericidal corrosion inhibitor being 100%, benzylpyridinium quaternary ammonium acetate 10%, glutaraldehyde aqueous solution 30% and water as the balance. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0135] The bactericidal corrosion inhibitor of this comparative example is recorded as C, as a comparison with Examples 7 to 9.

[0136] Comparative Example 4

[0137] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components, based on the total mass of the bactericidal corrosion inhibitor as 100%, benzylpyridinium quaternary ammonium acetate 10%, glutaraldehyde aqueous solution 30%, triethylhexylammonium bis(trifluoromethanesulfonyl)imide salt 5%, isopropanol 5% and the balance of water, denoted as D, as a comparison with Examples 7 to 9. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0138] Comparative Example 5

[0139] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components, based on the total mass of the bactericidal corrosion inhibitor as 100%, benzylquinoline quaternary ammonium chloride 30%, polyhexamethylene monoguanidine salt 30%, 1-ethyl-3-methylimidazole hydrogen sulfate 5% and the balance of water, denoted as E, as a comparison with Example 1. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0140] Comparative Example 6

[0141] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components, based on the total mass of the bactericidal corrosion inhibitor as 100%, 30% of oleic acid imidazoline, 30% of polyhexamethylene monoguanidine salt, 5% of 1-ethyl-3-methylimidazole hydrogen sulfate, 5% of isopropanol and the balance of water, denoted as F, as a comparison with Example 1. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0142] Comparative Example 7

[0143] This comparative example provides a bactericidal corrosion inhibitor, which includes the following components, based on the total mass of the bactericidal corrosion inhibitor as 100%, benzylpyridinium quaternary ammonium chloride 5%, polyhexamethylene monoguanidine salt 40%, tetrakishydroxymethylphosphonium chloride 0.5%, methanol 10% and water balance, denoted as G, as a comparison with Examples 4 to 6. The preparation method of the bactericidal corrosion inhibitor is the same as that of the above example.

[0144] Test Example 1

[0145] This test example evaluated the compatibility of the bactericidal corrosion inhibitors provided in the above-mentioned Examples 1 to 12 and Comparative Examples 1 to 7 with the flowback fluid.

[0146] The specific evaluation process is as follows: referring to the compatibility evaluation method in the standard SY / T 7437-2019 "Technical Requirements and Evaluation Methods for Corrosion Inhibitors for Natural Gas Gathering and Transportation", the bactericidal corrosion inhibitor is added to the return fluid of unconventional gas wells. The total mass of the return fluid after adding the bactericidal corrosion inhibitor is 100%, and the amount of bactericidal corrosion inhibitor added is 10%. Then, it is placed at 40°C and 120°C for 24 hours respectively to observe the compatibility of the bactericidal corrosion inhibitor with the on-site return fluid.

[0147] The evaluation results are shown in Table 1, Table 2 and Table 3.

[0148] Table 1

[0149]

[0150]

[0151] In Table 1, the concentrations of various ions (mg / L) in the flowback fluid of a well in the tight gas field are: Na + 89700, K + 162.Mg 2+ 35.0, Ca 2+ 348、SO4 2- 5.56, HCO3 - 595、Cl - 11700, total mineralization is 22.7 g / L.

[0152] Table 2

[0153]

[0154] In Table 2, the solubility (mg / L) of each ion in the return fluid of a well in the shale gas field is: Na + 1330, K + 45.Mg 2+ 82. Ca 2+ 139. HCO3 - 128. Cl - 3000、Sr 2+ 4.6, and the total mineralization is 6.58 g / L.

[0155] Table 3

[0156]

[0157]

[0158] In Table 3, the solubility (mg / L) of each ion in the water sample is: Na + 89700, K + 162.Mg 2+ 35.0, Ca2+ 348、SO4 2- 5.56, HCO3 - 595、Cl - 11700, total mineralization is 22.7 g / L.

[0159] The solubility (mg / L) of each ion in the water sample 2 is: Na + 12300, Fe 2+ 11.4 K + 136.Mg 2+ 143. Ca 2+ 596. HCO3 - 138、Cl - 23400、Sr 2+ 8.9, and the total mineralization is 37.7 g / L.

[0160] The solubility (mg / L) of each ion in the water sample 3 is: Na + 16200, Fe 2+ 10.5, K + 158.Mg 2+ 193.Ca 2+ 941, HCO3 - 144、Cl - 31100、Sr 2+ 8.7 SO4 2- 11.6, and the total mineralization is 51.2 g / L.

[0161] The solubility (mg / L) of each ion in the water sample 4 is: Na + 13800, Fe 2+ 9.84, K + 132.Mg 2+ 220、Ca 2+ 958, HCO3 - 142、Cl - 27500、Sr 2+ 6.9 SO4 2- 10.5, and the total mineralization is 44.6 g / L.

[0162] The solubility (mg / L) of each ion in the water sample 5 is: Na + 874000、Fe 2+ 12.4 K + 158.Mg 2+ 106. Ca 2+ 442. HCO3 - 289、Cl - 14600、Sr 2+ 7.8 SO4 2-22.1, and the total mineralization is 25.1 g / L.

[0163] It can be seen from Table 1, Table 2 and Table 3 that under the conditions of 40°C and 120°C, the compatibility of the bactericidal corrosion inhibitor No. 1-12 containing ionic liquids and alcohol compounds provided in Examples 1 to 12 with the return flow fluids of different unconventional gas wells has been greatly improved compared to the A, B and C type bactericidal corrosion inhibitors provided in Comparative Examples 1 to 3 that do not contain ionic liquids and alcohol compounds. This shows that the adjuvant of the present invention can effectively improve the compatibility of the bactericidal corrosion inhibitor with the return flow fluid. From the compatibility results of the D-G type bactericidal corrosion inhibitor and the return flow fluid provided in Comparative Examples 4 to 7, it can be seen that changing the carbon chain length or anion of the ionic liquid in the adjuvant of Comparative Examples 4 to 7, or not adding alcohol compounds, or changing the ratio of ionic liquids and alcohol compounds, all make the compatibility of the bactericidal corrosion inhibitor unable to achieve the excellent effects of the embodiments of the present invention.

[0164] Test Example 2

[0165] This test example evaluated the bactericidal performance of the bactericidal corrosion inhibitors provided in the above-mentioned Examples 1 to 12 and Comparative Examples 1 to 7.

[0166] The specific evaluation process is: add bactericidal corrosion inhibitors No. 1-12 and A-G types at 10% addition (the total mass of fracturing flowback fluid after adding bactericidal corrosion inhibitor is 100%) to the fracturing flowback fluid of a well in a shale gas field, and then place it at 40℃ and 120℃ for 24 hours, take the flowback fluid containing bactericidal corrosion inhibitor, add the flowback fluid containing bactericidal corrosion inhibitor to the water sample containing SRB, IB and TGB bacteria at a bactericidal corrosion inhibitor addition amount of 100mg / L, and conduct a bactericidal test. Method of bactericidal test: After adding the flowback fluid containing bactericidal corrosion inhibitor to the water sample containing bacteria, culture it in an anaerobic environment at 25℃ for 24 hours, and refer to the standard SY / T 0532-2012 "Oilfield Injection Water Bacterial Analysis Method (Extinction Dilution Method)" to determine the bacterial content in the water sample, and calculate the bactericidal rate. The bactericidal rate calculation formula is as follows:

[0167]

[0168] Where: X is the sterilization rate (%); a2 is the number of bacteria after sterilization (pieces / mL); a1 is the number of blank bacteria (pieces / mL).

[0169] The sterilization rate results are shown in Table 4.

[0170] Table 4

[0171]

[0172] It can be seen from Table 4 that after the mixed solution of the bactericidal corrosion inhibitor No. 1-12 provided in Examples 1 to 12 and the backflow fluid of the shale gas well is placed at 40°C for 24 hours, under the condition that the content of the bactericidal corrosion inhibitor is 100 ppm, the bactericidal rate for SRB is as low as 93.6% and as high as 100.0%, the bactericidal rate for IB is as low as 90.0% and as high as 100.0%, and the bactericidal rate for TGB is as low as 97.3% and as high as 100.0%. After the mixed solution of the bactericidal corrosion inhibitor No. 1-12 provided in Examples 1 to 12 and the flowback liquid of the shale gas well was placed at 120°C for 24 hours, under the condition that the content of the bactericidal corrosion inhibitor was 100ppm, the bactericidal rate of SRB was as low as 91.3% and as high as 100.0%, the bactericidal rate of IB was as low as 91.3% and as high as 100.0%, and the bactericidal rate of TGB was as low as 97.7% and as high as 100.0%. Therefore, the bactericidal corrosion inhibitor prepared in Examples 1 to 12 has good bactericidal performance and good high temperature stability. After being placed at 120°C, the bactericidal rate of the bactericidal corrosion inhibitor to SRB, IB, and TGB is basically unchanged from the bactericidal rate after being placed at 40°C. After the bactericidal corrosion inhibitors A, B, C, and F provided in the comparative example were placed at 40°C and 120°C for 24 hours, their bactericidal effects on the three bacteria were all below 85%, and their bactericidal effects were reduced to a certain extent after high temperature, because after mixing with the on-site water, some of the agents would be precipitated, resulting in a reduction in the dosage of the medicine in the solution, thereby making the bactericidal effect worse. Although the bactericidal effects of bactericidal corrosion inhibitors D, E, and G on the three bacteria were above 90% at room temperature, their bactericidal effects were also greatly weakened after high temperature, which was related to their poor compatibility after high temperature and the reduction in the dosage of the medicine in the solution.

[0173] Test Example 3

[0174] This test example evaluated the corrosion inhibition performance of the bactericidal corrosion inhibitors provided in the above-mentioned Examples 1 to 12 and Comparative Examples 1 to 7.

[0175] The specific evaluation process is as follows: bactericidal corrosion inhibitors No. 1-12 and A-G are added to the fracturing flowback fluid of a well in a shale gas field at an addition amount of 10% (the total mass of the fracturing flowback fluid after adding the bactericidal corrosion inhibitor is 100%), and then placed at 120°C for 24 hours, and then the flowback fluid containing the bactericidal corrosion inhibitor is taken, and the corrosion test is carried out on a 5% NaCl water sample containing 800ppm CO2 at an addition amount of 1000mg / L of bactericidal corrosion inhibitor. The corrosive material is L245N. After being placed in an anaerobic environment at 60°C for 72 hours, the corrosion rate is calculated with reference to the standard SY / T 7437-2019 "Technical Requirements and Evaluation Methods for Corrosion Inhibitors for Natural Gas Gathering and Transportation". The corrosion rate calculation formula is as follows:

[0176]

[0177] Where: V is the uniform corrosion rate, millimeters per year (mm / a); m is the weight loss of the specimen, grams (g); s is the exposed area of ​​the specimen, square centimeters (cm 2 );t—experimental time, hours (h);ρ—relative density of the test piece, grams per cubic centimeter (g / cm 3 ).

[0178] The corrosion rate results are shown in Table 5.

[0179] Table 5

[0180]

[0181]

[0182] It can be seen from Table 5 that the corrosion rates of the bactericidal corrosion inhibitors No. 1-12 provided in Examples 1 to 12 after being placed at 120°C for 24 hours are all below 0.076 mm / a. It can be seen that the bactericidal corrosion inhibitors provided in Examples 1 to 12 have good corrosion inhibition performance. From the results of the comparative examples, the corrosion rates of the comparative examples are all above 0.076 mm / a. The poor compatibility of the bactericidal corrosion inhibitor will affect its effective use concentration in the solution, so that the corrosion rate does not meet the current application requirements. The auxiliary agent of the present invention improves the compatibility of the bactericidal corrosion inhibitor in on-site water and enhances its on-site applicability in unconventional gas fields.

[0183] Test Example 4

[0184] This test example evaluated the foaming performance of the bactericidal corrosion inhibitors provided in the above Examples 1 to 12 and Comparative Examples 1 to 7.

[0185] The specific evaluation process is as follows: refer to the method in standard Q / SY 16859-2020 "Technical Specifications for Foam Drainage Process in Shale Gas Wells", take 100mL of shale gas well fracturing flowback fluid sample, add 0.5mL of bactericidal corrosion inhibitor No. 1-12 and A~G respectively, use a high-speed stirrer to stir at a speed of 11000±200r / min for 1min, and then immediately pour into a 200mL measuring cylinder, record the initial and 3min upper foam volume, and repeat more than 3 times. The average value of the 3 test results is shown in Table 6.

[0186] Table 6

[0187]

[0188]

[0189] As can be seen from Table 6, when the bactericidal corrosion inhibitors No. 1-12 provided in Examples 1 to 12 are added to the water samples of the unconventional gas well field return fluid, the initial foam volume is less than 6 mL, and the foam disappears completely after 3 minutes. It can be seen that the bactericidal corrosion inhibitors provided in Examples 1 to 12 are basically not foamed when added to the field return fluid, which can meet the field application. The bactericidal corrosion inhibitors A, B, and C without additives have a foaming volume of 20 to 45 mL in 1 minute. In addition, the bactericidal corrosion inhibitor D adds an ionic liquid with a longer carbon chain and the oleic acid imidazoline corrosion inhibitor is used in type F. Their foam volume is large and does not meet the field application. However, alcohol additives are not added to the bactericidal corrosion inhibitor type E, and its foam volume in 1 minute is slightly larger.

[0190] In summary, the additive provided by the present invention can enhance the compatibility of the bactericidal corrosion inhibitor with the backflow liquid. The type of additives such as the carbon chain length of the ionic liquid, the type of anion, whether an alcohol compound is used, and the proportion of each component in the bactericidal corrosion inhibitor will affect the adaptability and application of the bactericidal corrosion inhibitor in the unconventional gas production system. The bactericidal corrosion inhibitor provided by the present invention has good high-temperature stability, does not foam, has a good bactericidal effect on SRB, IB and TGB, and has a good corrosion inhibition effect on CO2 corrosion.

[0191] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. An additive for enhancing the compatibility of a bactericidal corrosion inhibitor, comprising an ionic liquid and an alcohol compound in a mass ratio of 1 to 10:1 to 5; wherein: The ionic liquid includes one or a combination of imidazole ionic liquids, pyridine ionic liquids, quinoline ionic liquids, quaternary ammonium salt ionic liquids and quaternary phosphonium salt ionic liquids; The structural formula of the imidazole ionic liquid is shown in Formula I: The structural formula of the pyridine ionic liquid is shown in Formula II: The structural formula of the quinoline ionic liquid is shown in Formula III: The structural formula of the quaternary ammonium salt ionic liquid is shown in Formula IV: The structural formula of the quaternary phosphonium salt ionic liquid is shown in Formula V: In Formula I, Formula II, Formula III, Formula IV and Formula V, R1, R2, R3, R4 and R5 are each independently selected from one of a C1-C4 straight-chain alkyl group, a C3-C4 branched-chain alkyl group, a C1-C4 alkoxy group, a C1-C4 alkanol group and a C2-C4 alkenyl group, and Z1 - Selected from HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them, Z2 - Selected from Cl - 、HSO4 - 、NO3 - 、ClO4 - and CH3COO - One of them.

2. The auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor according to claim 1, wherein: The alcohol compounds include small molecule alcohol compounds of C1 to C4.

3. The auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor according to claim 2, wherein: The alcohol compound includes one or a combination of methanol, ethanol, n-propanol, isopropanol, n-butanol and tert-butanol.

4. A bactericidal corrosion inhibitor, which comprises the following components based on its total mass as 100%: 2-15% of the auxiliary agent for enhancing the compatibility of the bactericidal corrosion inhibitor as described in any one of claims 1-3, 10-30% of a benzyl quaternary ammonium salt, 5-30% of a guanidine compound and / or glutaraldehyde, and the remainder of water.

5. The bactericidal corrosion inhibitor according to claim 4, wherein Taking the total mass of the bactericidal corrosion inhibitor as 100%, the content of the ionic liquid is 1-10%, and the content of the alcohol compound is 1-5%.

6. The bactericidal corrosion inhibitor according to claim 4, wherein The benzyl-containing quaternary ammonium salt includes benzyl-containing aromatic heterocyclic quaternary ammonium salt compounds.

7. The bactericidal corrosion inhibitor according to claim 6, wherein The benzyl-containing quaternary ammonium salt includes one or a combination of benzylquinoline quaternary ammonium salt, benzylpyridinium quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt and benzylimidazole quaternary ammonium salt.

8. The bactericidal corrosion inhibitor according to claim 6, wherein The anion in the benzyl quaternary ammonium salt includes Cl - Br - ,I - 、HSO4 - 、NO3 - 、ClO4 - 、BF4 - PF6 - 、CH3COO - 、N(CN)2 - and SCN - One or a combination of the following.

9. The bactericidal corrosion inhibitor according to claim 4, wherein: The guanidine compound includes one or a combination of polyhexamethylene monoguanidine salt, polyhexamethylene biguanidine salt, and chlorhexidine and its salts.

10. Use of the bactericidal corrosion inhibitor according to any one of claims 4 to 9 for corrosion protection in an unconventional gas production system.

Images