Enhanced bactericidal corrosion inhibitor compatibility aids and bactericidal corrosion inhibitors and their use

Abstract

The application provides an auxiliary agent for enhancing the compatibility of bactericidal corrosion inhibitor, a bactericidal corrosion inhibitor and application thereof. The auxiliary agent comprises ionic liquid and alcohol compound in a mass ratio of 1-10:1-5; the ionic liquid comprises one or a combination 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 2-15% of the auxiliary agent for enhancing the compatibility of bactericidal corrosion inhibitor, 10-30% of benzyl quaternary ammonium salt, 5-30% of guanidine compound and / or glutaraldehyde, and the balance of water, based on 100% of the total mass of the bactericidal corrosion inhibitor. The application also provides application of the bactericidal corrosion inhibitor to corrosion protection in an unconventional gas production system. The auxiliary agent provided by the application can enhance the compatibility of the bactericidal corrosion inhibitor with flowback fluid. The bactericidal corrosion inhibitor has the advantages of good high-temperature stability, no foaming, high bactericidal and corrosion inhibition efficiency, etc.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to additives that enhance the compatibility of bactericides and corrosion inhibitors, bactericides and corrosion inhibitors, and their applications. Background Technology

[0002] With the continuous development of unconventional gases such as shale gas and tight gas, corrosion failure of components in the production systems is becoming increasingly frequent. Unconventional gases contain virtually no H2S, while the molar content of CO2 is between 0% and 2%. Because unconventional gas extraction commonly employs volumetric fracturing technology, the fluid production is large. The fracturing fluid contains a large amount of organic matter, which provides nutrients for microbial growth, leading to its proliferation. Currently, 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 causes even more severe corrosion. Furthermore, the flowback fluid has high mineralization and contains Cl... - Concentrations can exceed 10,000 mg / L. These corrosive factors have led to corrosion and perforation problems in both the wellbore and the surface of unconventional gas production systems. This not only causes significant economic losses but also poses serious safety hazards.

[0003] Based on various failure analysis reports, the main forms of corrosion in non-gas production systems include microbial corrosion and CO2 corrosion. Currently, bactericides and corrosion inhibitors are commonly used for corrosion control, primarily in combination. However, due to the complex composition of the flowback fluid in the production system and the significant differences in corrosion environments between the wellbore and the surface (with downhole temperatures reaching up to 150°C and surface pipeline temperatures around 40°C), these environmental characteristics make it easy for reagents added to the gas field water to produce flocculation, precipitation, and other insoluble substances. Especially at high downhole temperatures, reagents are more likely to aggregate with suspended solids or precipitates in the gas field water, resulting in incompatibility. This incompatibility increases the risk of well blockage. Furthermore, the performance of reagents added to the wellbore and flowed back to the surface is significantly reduced. In addition, if the produced water is prone to foaming under the influence of airflow during gathering and transportation, it can cause gas blockage and reduce the efficiency of triethylene glycol in the dehydration unit. These characteristics pose significant challenges to reagent development. Therefore, in order to ensure the safe and efficient development of gas fields, higher requirements are placed on the compatibility of bactericides and corrosion inhibitors with flowback fluids at high and low temperatures, their high-temperature stability, and their low foaming properties.

[0004] Currently, there are few reports on additives that enhance the compatibility of bactericidal corrosion inhibitors with unconventional gas flowback fluids. CN115613035A discloses a corrosion inhibitor formulation method and application, as well as a corrosion inhibitor composition. This corrosion inhibitor formulation method enhances the compatibility of oil-soluble corrosion inhibitors in gas field water by adding surfactants, additives, and hydrocarbons to form an O / W microemulsion system. However, this method involves many steps, and the added surfactants generally have strong foaming properties, which is not conducive to use in unconventional gas production systems. CN114456148A discloses an oilfield corrosion inhibitor with good compatibility and its preparation method. The preparation method of this oilfield corrosion inhibitor mainly involves reacting 2,6-pyridinedicarboxylic acid and polyethylenepolyamine to obtain pyridine 6-(imidazolinyl)-2-carboxylic acid, and then subjecting it to a quaternization reaction with chlorinated hydrocarbons to obtain N-alkyl-6-(imidazolinyl)-2-carboxylic acid quaternary ammonium salt corrosion inhibitor. This corrosion inhibitor can be compounded with commonly used oilfield cleaning agents, scale inhibitors, demulsifiers, and bactericides, exhibiting good compatibility. CN112544624A discloses an environmentally friendly integrated bactericide and corrosion inhibitor specifically for shale gas pipelines and its preparation method. It utilizes enrofloxacin and norfloxacin as bactericides and thiourea as corrosion inhibitors, with ethanol or water as the solvent. However, this document does not address the compatibility of the bactericide and corrosion inhibitor at room temperature and high temperature.

[0005] Therefore, developing methods to enhance the compatibility of bactericides and corrosion inhibitors and providing novel bactericides and corrosion inhibitors that meet the needs of production systems are of great significance for the control of unconventional gas corrosion. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide an adjuvant that enhances the compatibility of bactericides and corrosion inhibitors, as well as the bactericides and corrosion inhibitors themselves, and their applications. The adjuvant provided by the present invention can enhance the compatibility of bactericides and corrosion inhibitors with flowback solutions. The bactericides and corrosion inhibitors provided by the present invention have advantages such as good high-temperature stability and good bactericidal and corrosion-inhibiting properties.

[0007] To achieve the above objectives, the first aspect of the present invention provides an adjuvant that enhances the compatibility of bactericides and corrosion inhibitors, 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 several 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-based ionic liquid is shown in Formula II:

[0011]

[0012] The structural formula of the quinoline-based 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 formulas I, II, III, IV, and V, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a straight-chain alkyl group (C1-C4), a branched-chain alkyl group (C3-C4), an alkoxy group (C1-C4), an alkanol group (C1-C4), and an alkenyl group (C2-C4). - 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 adjuvants that enhance the compatibility of bactericides and corrosion inhibitors, preferably, the alcohol compounds include small molecule alcohol compounds of C1 to C4. Specifically, the alcohol compounds include one or a combination of several 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 of 100%, comprises the following components: 2-15% of the above-mentioned adjuvants that enhance the compatibility of the bactericidal corrosion inhibitor, 10-30% of a benzyl quaternary ammonium salt, 5-30% of a guanidine compound and / or glutaraldehyde, and the balance being water.

[0021] According to a specific embodiment of the present invention, preferably, based on 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%.

[0022] In the aforementioned bactericidal and corrosion-inhibiting agents, preferably, the benzyl quaternary ammonium salt includes benzyl-containing aromatic heterocyclic quaternary ammonium salt compounds. More preferably, the benzyl quaternary ammonium salt includes one or a combination of several of benzylquinoline quaternary ammonium salt, benzylpyridine quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt, and benzylimidazolium quaternary ammonium salt.

[0023] In the aforementioned bactericidal and corrosion-inhibiting agents, 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 more of these.

[0024] In the above-mentioned bactericidal and corrosion-inhibiting agents, preferably, the guanidine compounds include one or a combination of several of polyhexamethylene monoguanidine salts, polyhexamethylene biguanidine salts, and dichlorophenylbiguanidine hexane and its salts.

[0025] The third aspect of this invention provides the application of the above-mentioned bactericide and corrosion inhibitor in corrosion protection in unconventional gas production systems.

[0026] In summary, this invention provides an adjuvant that enhances the compatibility of bactericides and corrosion inhibitors, as well as the bactericides and corrosion inhibitors themselves and their applications. The adjuvant provided by this invention enhances the compatibility of the bactericides and corrosion inhibitors with backflow solutions and improves their adaptability in unconventional gas production systems. The bactericides and corrosion inhibitors provided by this invention exhibit good high-temperature stability, do not foam, and demonstrate good bactericidal effects against SRB, IB, and TGB, while also exhibiting excellent corrosion inhibition against CO2. Detailed Implementation

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

[0028] This invention provides an adjuvant that enhances the compatibility of bactericides and corrosion inhibitors, comprising an ionic liquid and an alcohol compound in a mass ratio of 1-10:1-5; wherein the ionic liquid comprises one or a combination of several 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-based ionic liquid is shown in Formula II:

[0032]

[0033] The structural formula of the quinoline-based 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 formulas I, II, III, IV, and V, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a straight-chain alkyl group (C1-C4), a branched-chain alkyl group (C3-C4), an alkoxy group (C1-C4), an alkanol group (C1-C4), and an alkenyl group (C2-C4). - 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 compounds include small molecule alcohol compounds of C1 to C4. Specifically, the alcohol compounds include one or a combination of several of methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol.

[0041] The additives for enhancing the compatibility of bactericides and corrosion inhibitors provided by this invention include ionic liquids and alcohol compounds. These additives primarily utilize the dispersing and solubilizing effects of the cations and anions in ionic liquids. On the one hand, they promote the dissolution of precipitates in the flowback solution; on the other hand, they enhance the dispersibility of the bactericides and corrosion inhibitors in the flowback solution, inhibiting flocculation and precipitation after aggregation, thus improving compatibility. However, the inventors have found that when the alkyl chain in the ionic liquid is too long, its solubility in the flowback solution is low, and it does not enhance compatibility. Furthermore, the inventors have also found that the type of anion has a significant impact on the compatibility-enhancing effect of the ionic liquid. However, when the anion is SO4... 2- H2PO4 - CF3SO3 - C6H6-SO3 - When acid radicals are present, they readily react with Ba in the effluent. 2+ or Ca 2+ On the one hand, it can form precipitates, and on the other hand, it can promote the aggregation and precipitation of insoluble substances. The chemical structure of the ionic liquid has a significant impact on the effect of the additive in enhancing the compatibility of the bactericide and corrosion inhibitor with the flowback solution. In addition, the additive of the present invention contains alcohol compounds, which can further enhance the solubility of the bactericide and corrosion inhibitor in the flowback solution. However, excessively long carbon chain lengths of alcohol compounds can also lead to low solubility in the flowback solution. After extensive research, the inventors of this invention have developed the additive for enhancing the compatibility of the bactericide and corrosion inhibitor, which includes an ionic liquid with a specific chemical structure and a small-molecule alcohol compound, and can significantly enhance the compatibility of the bactericide and corrosion inhibitor with the flowback solution.

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

[0043] In some specific embodiments of the present invention, the bactericide and corrosion inhibitor, based on a total mass of 100%, comprises 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 balance being water.

[0044] In some specific embodiments of the present invention, the benzyl-containing quaternary ammonium salt includes benzyl-containing aromatic heterocyclic quaternary ammonium salt compounds. More preferably, the benzyl-containing quaternary ammonium salt includes one or a combination of several of benzylquinoline quaternary ammonium salt, benzylpyridine quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt, and benzylimidazolium 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 more of these.

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

[0047]

[0048] The structural formula of the benzylpyridine 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 benzylimidazolium quaternary ammonium salt is shown in Formula IX:

[0053]

[0054] In equations VⅠ, VⅡ, VⅢ, and IX, X - Selected from Cl - ,Br - I - HSO4 - NO3 - ClO4 - BF4 - PF6 - CH3COO - N(CN)2 - and SCN - One of the following; in formula IX, R is selected from one of the following: a straight-chain alkyl group of C1 to C4, a branched alkyl group of C3 to C4, an alkoxy group of C1 to C4, and an alkenyl group of C2 to C4.

[0055] In some specific embodiments of the present invention, the guanidine compounds include one or a combination of several of polyhexamethylene monoguanidine salts, polyhexamethylene biguanidine salts, and dichlorophenylbiguanidine hexane and its salts.

[0056] Specifically, the structural formula of the polyhexamethylene monoguanidine 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 dichlorobenzylguanidine hexane is shown in Formula XII:

[0061]

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

[0063]

[0064] In equations X, XI, and XIII, Y is selected from Cl. - ,Br - I - HSO4 - NO3 - C6H6-SO3 - ClO4 - CH3COO - N(CN)2 - SCN - CH3CH2COO - and CH2OH-(CHOH)4-COO - One of the following; in equations X and XI, n is an integer from 5 to 100; in equation XIII, m is an integer from 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, a mixture of benzyl quaternary ammonium salt, guanidine compound and / or glutaraldehyde, ionic liquid, alcohol compound and water is mixed according to the mass percentage of each component, and stirred until the system is clear to obtain the bactericidal corrosion inhibitor.

[0066] The bactericidal and corrosion inhibitor of this invention uses a benzyl quaternary ammonium salt as the corrosion inhibitor component, guanidine compounds and / or glutaraldehyde as the bactericidal component, and incorporates the compatibility-enhancing adjuvants of this invention to obtain the bactericidal and corrosion inhibitor. The compatibility-enhancing adjuvants of this invention, namely the combination of ionic liquids and alcohol compounds, can enhance the adaptability of the bactericidal and corrosion inhibitor in unconventional gas production systems. Furthermore, the addition of ionic liquids can enhance the bactericidal and corrosion-inhibiting properties of the bactericidal and corrosion-inhibiting agent to a certain extent, while alcohol compounds can improve the bactericidal performance. The bactericidal and corrosion inhibitor of this invention has advantages such as good high-temperature stability, no foaming, and high bactericidal and corrosion-inhibiting efficiency.

[0067] The present invention is illustrated below by way of examples and comparative examples, but the present invention is not limited to these examples. Of course, various modifications can be made within the scope 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] Benzylpyridine 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 according to the record in The phytotoxicity of several S-benzyl-, S-phenacylisothiouronium, N-benzyl and N-phenacyltrimethylammonium N-benzyl-, and N-phenacylpyridinium alkanoates (Mededelingen van de FaculteitLandbouwwetenschappen,Universiteit Gent (1975), 40(2), 859-69);

[0072] Benzylimidazolium quaternary ammonium bromide: CAS: 65039-11-4, Ionic liquids, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

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

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

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

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

[0077] Dichlorobenzylguanidine hexane: Sigma-Aldrich Reagents;

[0078] Dichlorobenzylguanidine hexane gluconate: Sigma-Aldrich Reagents;

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

[0080] Tetramethylphosphorus chloride: CAS: 124-64-1, Aladdin Reagent Co., Ltd.;

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

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

[0083] Tributylmethylammonium acetate: Sigma-Aldrich Reagents Company;

[0084] Isopropanol: 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] Triethylhexylammonium bis(trifluoromethanesulfonyl)imide salt: CAS: 210230-46-9, Ionic liquids from Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;

[0090] Imidazoline oleate: Maclean's Reagents.

[0091] Example 1

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

[0093] Under conditions of 25–40°C, with the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylquinoline quaternary ammonium chloride, 30% polyhexamethylene monoguanidine salt, 5% 1-ethyl-3-methylimidazolium hydrogen sulfate, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 1.

[0094] Example 2

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

[0096] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylquinoline quaternary ammonium chloride, 30% polyhexamethylene monoguanidine salt, 7% 1-ethyl-3-methylimidazolium hydrogen sulfate, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 2.

[0097] Example 3

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

[0099] Under conditions of 25–40°C, with the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylquinoline quaternary ammonium chloride, 30% polyhexamethylene monoguanidine salt, 9% 1-ethyl-3-methylimidazolium hydrogen sulfate, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 3.

[0100] Example 4

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

[0102] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylpyridine quaternary ammonium chloride, 10% polyhexamethylene monoguanidine salt, 2% tetrahydroxymethyl phosphorus chloride, 5% methanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 4.

[0103] Example 5

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

[0105] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylpyridine quaternary ammonium chloride, 10% polyhexamethylene monoguanidine salt, 4% tetrahydroxymethyl phosphorus chloride, 5% methanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 5.

[0106] Example 6

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

[0108] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 30% benzylpyridine quaternary ammonium chloride, 10% polyhexamethylene monoguanidine salt, 6% tetrahydroxymethyl phosphorus chloride, 5% methanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 6.

[0109] Example 7

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

[0111] Under conditions of 25–40°C, with the total mass of the bactericide and corrosion inhibitor as 100%, 10% benzylpyridine quaternary ammonium acetate, 30% glutaraldehyde aqueous solution, 2% tetrahydroxymethyl phosphorus chloride, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 7.

[0112] Example 8

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

[0114] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 10% benzylpyridine quaternary ammonium acetate, 30% glutaraldehyde aqueous solution, 4% tetrahydroxymethyl phosphorus chloride, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 8.

[0115] Example 9

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

[0117] Under conditions of 25–40°C, based on the total mass of the bactericidal and corrosion-inhibiting agent as 100%, 10% benzylpyridine quaternary ammonium acetate, 30% glutaraldehyde aqueous solution, 6% tetrahydroxymethyl phosphorus chloride, 5% isopropanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericidal and corrosion-inhibiting agent, which is designated as No. 9.

[0118] Example 10

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

[0120] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 10% benzylimidazolium quaternary ammonium bromide, 10% dichlorobenzylguanidine hexane, 5% 1-ethylquinoline nitrate, 5% ethanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 10.

[0121] Example 11

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

[0123] Under conditions of 25–40°C, based on the total mass of the bactericide and corrosion inhibitor as 100%, 10% benzylimidazolium quaternary ammonium hydrogen sulfate, 20% dichlorobenzylbisguanidine hexane gluconate, 5% 1-ethyl-3-methylimidazolium perchlorate, 5% n-propanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 11.

[0124] Example 12

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

[0126] Under conditions of 25–40°C, with the total mass of the bactericide and corrosion inhibitor as 100%, 10% benzylbenzothiazole quaternary ammonium chloride, 20% glutaraldehyde aqueous solution, 5% tributylmethylammonium acetate, 5% n-butanol, and the balance water are mixed and stirred until the system is clear to obtain the bactericide and corrosion inhibitor, which is designated as No. 12.

[0127] Comparative Example 1

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

[0129] The bactericide and corrosion inhibitor in this comparative example is designated as A, and is used for comparison with Examples 1 to 3.

[0130] Comparative Example 2

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

[0132] The bactericide and corrosion inhibitor in this comparative example is designated as B, and is used for comparison with Examples 4-6.

[0133] Comparative Example 3

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

[0135] The bactericide and corrosion inhibitor in this comparative example is designated as C, and is used for comparison with Examples 7-9.

[0136] Comparative Example 4

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

[0138] Comparative Example 5

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

[0140] Comparative Example 6

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

[0142] Comparative Example 7

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

[0144] Test Example 1

[0145] This test case evaluated the compatibility of the bactericidal corrosion inhibitors provided in Examples 1-12 and Comparative Examples 1-7 with the backflow solution.

[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", bactericidal corrosion inhibitors are added to the flowback fluid of unconventional gas wells. Taking the total mass of the flowback fluid after adding the bactericidal corrosion inhibitors as 100%, the amount of bactericidal corrosion inhibitors added is 10%. Then, the fluids are placed at 40℃ and 120℃ for 24 hours respectively, and the compatibility between the bactericidal corrosion inhibitors and the flowback fluids in the field is observed.

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

[0148] Table 1

[0149]

[0150]

[0151] In Table 1, the solubility (mg / L) of each ion in the flowback fluid of a well in this tight gas field is as follows: Na + 89700, K + 162, Mg 2+ 35.0, Ca 2+ 348, SO4 2- 5.56, HCO3 - 595, Cl - 11700, with a total mineralization of 22.7 g / L.

[0152] Table 2

[0153]

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

[0155] Table 3

[0156]

[0157]

[0158] In Table 3, the solubility (mg / L) of each ion in water sample 1 is as follows: Na + 89700, K + 162, Mg 2+ 35.0, Ca2+ 348, SO4 2- 5.56, HCO3 - 595, Cl - 11700, with a total mineralization of 22.7 g / L.

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

[0160] The solubility (mg / L) of each ion in water sample 3 is as follows: 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, with a total mineralization of 51.2 g / L.

[0161] The solubility (mg / L) of each ion in water sample four is as follows: 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, with a total mineralization of 44.6 g / L.

[0162] The solubility (mg / L) of each ion in water sample five is as follows: 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, with a total mineralization of 25.1 g / L.

[0163] As shown in Tables 1, 2, and 3, under conditions of 40℃ and 120℃, the compatibility of the bactericidal and corrosion inhibitors No. 1-12 (containing ionic liquids and alcohol compounds) provided in Examples 1-12 with flowback fluids from different unconventional gas wells is significantly improved compared to the A, B, and C type bactericidal and corrosion inhibitors (not containing ionic liquids and alcohol compounds) provided in Comparative Examples 1-3. This indicates that the additives of the present invention can effectively improve the compatibility of bactericidal and corrosion inhibitors with flowback fluids. However, the compatibility results of the D-G type bactericidal and corrosion inhibitors provided in Comparative Examples 4-7 with flowback fluids show that changing the carbon chain length or anion of the ionic liquid, omitting the addition of alcohol compounds, or changing the ratio of ionic liquids and alcohol compounds in the additives of Comparative Examples 4-7 all prevent the bactericidal and corrosion inhibitors from achieving the excellent compatibility of the embodiments of the present invention.

[0164] Test Example 2

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

[0166] The specific evaluation process is as follows: Bactericidal and corrosion-inhibiting agents 1-12 and A-G types were added at a dosage of 10% (based on the total mass of the fracturing flowback fluid after adding the bactericidal and corrosion-inhibiting agents being 100%) to the fracturing flowback fluid of a well in a shale gas field. After being placed at 40℃ and 120℃ for 24 hours respectively, the flowback fluid containing the bactericidal and corrosion-inhibiting agents was taken. The bactericidal and corrosion-inhibiting agents were then added to water samples containing SRB, IB, and TGB bacteria at a dosage of 100 mg / L for bactericidal and corrosion-inhibiting agent addition, and a bactericidal test was conducted. The bactericidal test method was as follows: After adding the flowback fluid containing the bactericidal and corrosion-inhibiting agents to the bacterial-containing water sample, it was incubated in an anaerobic environment at 25℃ for 24 hours. The bacterial content in the water sample was determined according to standard SY / T 0532-2012 "Analysis Method for Bacteria in Oilfield Injection Water (Extinction Dilution Method)," and the bactericidal rate was calculated. The formula for calculating the bactericidal rate is as follows:

[0167]

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

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

[0170] Table 4

[0171]

[0172] As shown in Table 4, after the mixture of bactericides and corrosion inhibitors No. 1-12 provided in Examples 1-12 with the flowback fluid of shale gas wells was placed at 40°C for 24 hours, under the condition that the bactericide and corrosion inhibitor content was 100 ppm, the bactericidal rate against SRB was as low as 93.6% and as high as 100.0%, the bactericidal rate against IB was as low as 90.0% and as high as 100.0%, and the bactericidal rate against TGB was as low as 97.3% and as high as 100.0%. The mixtures of bactericides and corrosion inhibitors No. 1-12 provided in Examples 1-12 with the flowback fluid from shale gas wells, after being placed at 120°C for 24 hours, exhibited the following bactericidal rates: a minimum of 91.3% and a maximum of 100.0% for SRB, a minimum of 91.3% and a maximum of 100.0% for IB, and a minimum of 97.7% and a maximum of 100.0% for TGB, all at a concentration of 100 ppm. Therefore, the bactericides and corrosion inhibitors prepared in Examples 1-12 possess excellent bactericidal properties and good high-temperature stability; after being placed at 120°C, the bactericidal rates of the bactericides and corrosion inhibitors against SRB, IB, and TGB remained essentially unchanged compared to those placed at 40°C. The bactericidal and corrosion inhibitors A, B, C, and F provided in the comparative studies showed that their bactericidal efficacy against the three types of bacteria was below 85% after being placed at 40℃ and 120℃ for 24 hours. Furthermore, their bactericidal efficacy decreased to some extent after high temperatures because some of the agent precipitated out when mixed with the water on site, resulting in a reduced dosage in the solution and thus a poorer bactericidal effect. While bactericidal and corrosion inhibitors D, E, and G showed bactericidal efficacy above 90% against the three types of bacteria at room temperature, their bactericidal efficacy also significantly weakened after high temperatures. This is related to their poor compatibility and reduced dosage in the solution after high temperatures.

[0173] Test Example 3

[0174] This test case evaluates the corrosion inhibition performance of the bactericidal corrosion inhibitors provided in Examples 1-12 and Comparative Examples 1-7.

[0175] The specific evaluation process is as follows: Bactericidal and corrosion inhibitors No. 1-12 and Types A-G were added to the fracturing flowback fluid of a well in a shale gas field at a dosage of 10% (based on the total mass of the fracturing flowback fluid after adding the bactericidal and corrosion inhibitors being 100%). After being placed at 120℃ for 24 hours, flowback fluids containing the bactericidal and corrosion inhibitors were taken. Corrosion tests were then conducted on 5% NaCl water samples containing 800ppm CO2, using 1000 mg / L of bactericidal and corrosion inhibitors. The corrosion material was L245N. After being placed in an oxygen-free environment at 60℃ for 72 hours, the corrosion rate was calculated according to 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—uniform corrosion rate, millimeters per year (mm / a); m—weight loss of the specimen, grams (g); s—exposed area of ​​the specimen, square centimeters (cm²) 2 ); t—experimental time, hours (h); ρ—relative density of the sample, grams per cubic centimeter (g / cm³) 3 ).

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

[0179] Table 5

[0180]

[0181]

[0182] As shown in Table 5, the corrosion rates of the bactericides and corrosion inhibitors 1-12 provided in Examples 1-12 after being placed at 120℃ for 24 hours were all below 0.076 mm / a. This demonstrates that the bactericides and corrosion inhibitors provided in Examples 1-12 possess good corrosion inhibition performance. In contrast, the corrosion rates of the comparative examples were all above 0.076 mm / a. The poor compatibility of the bactericides and corrosion inhibitors affected their effective concentration in solution, resulting in corrosion rates that did not meet current application requirements. The additives of this invention improve the compatibility of the bactericides and corrosion inhibitors in field water, enhancing their applicability in unconventional gas fields.

[0183] Test Example 4

[0184] This test case evaluated the foaming properties of the bactericides and corrosion inhibitors provided in Examples 1-12 and Comparative Examples 1-7.

[0185] The specific evaluation process was as follows: Referring to the method in standard Q / SY 16859-2020 "Technical Specification for Foam Drainage Process of Shale Gas Wells", 100 mL of fracturing flowback fluid from a shale gas well was taken, and 0.5 mL of bactericide and corrosion inhibitor No. 1-12 and type A-G were added respectively. After stirring with a high-speed stirrer at a speed of 11000±200 r / min for 1 min, the mixture was immediately poured into a 200 mL graduated cylinder. The initial and upper foam volumes after 3 min were recorded, and the experiment was repeated at least 3 times. The average values ​​of the 3 test results are shown in Table 6.

[0186] Table 6

[0187]

[0188]

[0189] As shown in Table 6, when the bactericidal and corrosion inhibitors 1-12 provided in Examples 1-12 were added to the unconventional gas well flowback fluid samples, the initial foam volume was all below 6 mL, and the foam completely disappeared after 3 minutes. This indicates that the bactericidal and corrosion inhibitors provided in Examples 1-12 basically do not foam when added to the flowback fluid, which meets the requirements for field application. In contrast, bactericidal and corrosion inhibitors A, B, and C without added additives produced foam volumes of 20-45 mL within 1 minute. Furthermore, bactericidal and corrosion inhibitor D, which contains a long-chain ionic liquid, and type F, which uses an oleic acid imidazoline corrosion inhibitor, both produced larger foam volumes, which do not meet the requirements for field application. Bactericidal and corrosion inhibitor type E, which does not contain alcohol additives, produced a slightly larger foam volume within 1 minute.

[0190] In summary, the additives provided by this invention can enhance the compatibility between the bactericide and corrosion inhibitor and the backflow solution. The type of additive, such as the carbon chain length of the ionic liquid, the type of anion, whether an alcohol compound is used, and the proportions of each component in the bactericide and corrosion inhibitor, all affect the adaptability and application of the bactericide and corrosion inhibitor in unconventional gas production systems. The bactericide and corrosion inhibitor provided by this invention exhibits good high-temperature stability, does not foam, and has good bactericidal effects against SRB, IB, and TGB, as well as good corrosion inhibition against CO2 corrosion.

[0191] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A bactericidal and corrosion inhibitor, comprising, by weight of 100%, the following components: 2-15% of an adjuvant that enhances the compatibility of the bactericidal and corrosion inhibitor, 10-30% of a benzyl quaternary ammonium salt, 5-30% of a guanidine compound and / or glutaraldehyde, and water as the balance. The additives that enhance the compatibility of the bactericide and corrosion inhibitor include an ionic liquid and an alcohol compound in a mass ratio of 1-10:1-5. Based on the total mass of the bactericide and corrosion inhibitor as 100%, the content of the ionic liquid is 1-10%, and the content of the alcohol compound is 1-5%. in, The ionic liquid includes one or a combination of several of the following: imidazole 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: Formula I, The structural formula of the quinoline-based ionic liquid is shown in Formula III: Formula III, The structural formula of the quaternary ammonium salt ionic liquid is shown in Formula IV: Formula IV, The structural formula of the quaternary phosphonium salt ionic liquid is shown in Formula V: Formula V, In formulas I, III, IV, and V, R1, R2, R3, R4, and R5 are each independently selected from one of the following: a straight-chain alkyl group (C1-C4), a branched-chain alkyl group (C3-C4), an alkoxy group (C1-C4), an alkanoyl group (C1-C4), and an alkenyl group (C2-C4). - Selected from HSO4 - NO3 - ClO4 - and CH3COO - One of them, Z2 - Selected from Cl - HSO4 - NO3 - ClO4 - and CH3COO - One of them; The alcohol compounds include one or a combination of several of methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol; The benzyl quaternary ammonium salt includes one or a combination of several of benzylquinoline quaternary ammonium salt, benzylpyridine quaternary ammonium salt, benzylbenzothiazole quaternary ammonium salt, and benzylimidazol quaternary ammonium salt; The guanidine compounds include one or a combination of several of polyhexamethylene monoguanidine salts, polyhexamethylene biguanidine salts, and dichlorophenylbiguanidine hexane and its salts.

2. The bactericidal and corrosion-inhibiting agent according to claim 1, wherein, The alcohol compound is methanol, ethanol, n-propanol, isopropanol, or n-butanol.

3. The bactericidal and corrosion-inhibiting agent according to claim 1, wherein, The guanidine compound is a polyhexamethylene monoguanidine salt, dichlorobenzylguanidine hexane, or dichlorobenzylguanidine hexane gluconate.

4. The bactericidal and corrosion-inhibiting agent according to claim 1, 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 more of them.

5. The bactericidal and corrosion-inhibiting agent according to claim 1 or 4, wherein, The benzyl quaternary ammonium salt is benzylquinoline quaternary ammonium chloride, benzylpyridine quaternary ammonium chloride, benzylpyridine quaternary ammonium acetate, benzylimidazolium quaternary ammonium bromide, benzylimidazolium quaternary ammonium hydrogen sulfate, or benzylbenzothiazole quaternary ammonium chloride.

6. The application of the bactericide and corrosion inhibitor according to any one of claims 1-5 in corrosion protection in unconventional gas production systems.

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