Under-scale microbial corrosion inhibitor for oil field water injection and production system and preparation method and application of under-scale microbial corrosion inhibitor

Abstract

The invention discloses an under-scale microbial corrosion inhibitor for an oil field water injection and production system, and a preparation method and application of the under-scale microbial corrosion inhibitor. The under-scale microbial corrosion inhibitor for the oil field water injection and production system comprises the following components in parts by weight: 40-50 parts of a quaternary ammonium salt surfactant containing a thiadiazole heterocyclic ring, 5-10 parts of an organic phosphonic acid or organic phosphonate compound, 25-35 parts of a sterilization auxiliary agent, 4.5-30 parts of water and 0-5 parts of a defoaming agent, the sterilization auxiliary agent is selected from at least one of a biquaternary ammonium salt bactericide and an aldehyde bactericide. The under-scale microbial corrosion inhibitor has four functions of under-scale sterilization, carbon steel corrosion inhibition, solution sterilization and system scale inhibition, and can realize integrated treatment of scale inhibition, corrosion inhibition and sterilization of an oil field water injection and production system.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemistry, and particularly relates to a sub-scale microbial corrosion inhibitor for an oilfield water injection and production system, and a preparation method and application thereof. Background Art

[0002] All production links such as oil and natural gas extraction, transportation and storage are facing increasingly severe corrosion problems. The occurrence of corrosion may cause huge economic losses and even cause serious safety accidents.

[0003] Corrosion inhibitors are substances that exist in a corrosive environment in an appropriate form and concentration and can effectively prevent or slow down the corrosion of materials. They are characterized by low cost, simple operation, quick results, and suitability for long-term use. They have become an important method for major oil fields to deal with corrosion problems. However, the interaction between the corrosion inhibitors currently in service in many oil and gas fields and the scale layer inhibits the corrosion inhibitors from reaching the metal surface below the scale layer, so the corrosion inhibition efficiency is low and it is impossible to effectively control under-scale corrosion. At the same time, the functionality of the corrosion inhibitors currently in service is single, and it is difficult to simultaneously have multiple functions of under-scale sterilization, corrosion inhibition, and scale inhibition. At present, no protective agent has been found for under-scale corrosion that has the functions of corrosion inhibition, scale inhibition, and sterilization. Therefore, it is urgent to develop a multifunctional under-scale microbial corrosion inhibitor that has the functions of corrosion inhibition, sterilization, and scale inhibition. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a sub-scale microbial corrosion inhibitor for oilfield water injection and production systems, a preparation method thereof and an application thereof. The sub-scale microbial corrosion inhibitor has the quadruple functions of sub-scale sterilization, carbon steel corrosion inhibition, solution sterilization and system scale inhibition, and can realize the integrated treatment of scale inhibition, corrosion inhibition and sterilization of oilfield water injection and production systems.

[0005] One aspect of the present invention provides an under-scale microbial corrosion inhibitor for an oilfield injection and production water system, which comprises the following components, by weight: 40 to 50 parts of a quaternary ammonium salt surfactant containing a thiadiazole heterocycle, 5 to 10 parts of an organic phosphonic acid or organic phosphonate compound, 25 to 35 parts of a bactericidal aid, 4.5 to 30 parts of water, and 0 to 5 parts of a defoaming agent; the bactericidal aid is selected from at least one of a diquaternary ammonium salt bactericide and an aldehyde bactericide.

[0006] According to a specific embodiment of the present invention, the quaternary ammonium salt surfactant containing a thiadiazole heterocycle is 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine.

[0007] According to a specific embodiment of the present invention, a method for preparing 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine comprises: contacting 2,5-dimercaptothiadiazole, (3-chloro-2-hydroxypropyl)trimethylammonium chloride and a solvent to react; preferably, the molar ratio of (3-chloro-2-hydroxypropyl)trimethylammonium chloride to 2,5-dimercaptothiadiazole is 1:1.1 to 1.3; preferably, the solvent comprises ethanol; preferably, the reaction temperature is 70 to 80°C, and the reaction time is 4 to 8 hours.

[0008] According to a specific embodiment of the present invention, the organic phosphonic acid compound is selected from at least one of hydroxyethylene diphosphonic acid and diethylene triamine penta (methylene phosphonic acid); and / or the organic phosphonate compound includes ethylene diamine tetra (methylene phosphonate).

[0009] According to a specific embodiment of the present invention, the diquaternary ammonium salt fungicide is selected from at least one of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt, N,N'-1-alkyl-6-quinolyl-1,3-acetone diamide diquaternary ammonium salt, and 1-(3-(dodecyldimethylamino)-2-hydroxypropyl)-1-(2-hydroxyethyl)-2,5-dimethyl-1H-imidazole-1-ium.

[0010] According to a specific embodiment of the present invention, the aldehyde fungicide includes glutaraldehyde.

[0011] According to a specific embodiment of the present invention, the defoaming agent includes dimethyl silicone oil.

[0012] The second aspect of the present invention provides a method for preparing the above-mentioned sub-scale microbial corrosion inhibitor for the oil field injection and production system, comprising: mixing and stirring a quaternary ammonium salt surfactant containing a thiadiazole heterocycle, an organic phosphonic acid or an organic phosphonate compound, a bactericidal adjuvant, water and, optionally, a defoaming agent.

[0013] The third aspect of the present invention provides the use of the above-mentioned sub-scale microbial corrosion inhibitor in the integrated treatment of scale inhibition, corrosion inhibition and sterilization in the injection and production water system of an oil field.

[0014] A fourth aspect of the present invention provides an integrated treatment method for scale inhibition, corrosion inhibition and sterilization of an oilfield injection and production water system, comprising filling the above-mentioned sub-scale microbial corrosion inhibitor into the oilfield injection and production water system.

[0015] Beneficial effects of the present invention:

[0016] The present invention provides an inhibitor of microbial corrosion under scale, wherein 1) a quaternary ammonium surfactant containing a thiadiazole heterocycle has an integrated effect of corrosion inhibition and sterilization under scale, specifically, the thiadiazole heterocycle contains nitrogen, sulfur atoms and polar groups, and can form an adsorption film on the metal surface to slow down the metal corrosion rate; the quaternary ammonium surfactant cation adsorbs negatively charged bacteria through electrostatic force, hydrogen bond force and hydrophobic binding between surfactant molecules and protein molecules, and gathers on the cell wall to produce a chamber resistance effect, resulting in the inhibition of bacterial growth and having a good sterilization effect, and at the same time, due to its good surface activity, it can be directed to form an adsorption film at the metal interface, and then play an intramolecular synergistic effect with the thiadiazole heterocycle in metal corrosion inhibition. Compared with the prior art, the quaternary ammonium surfactant containing a thiadiazole heterocycle of the present invention contains a thiol group, the electronegativity of the sulfur atom in the thiol group is weak, and the interaction with the scale layer is very weak, so it can diffuse through the scale layer to the metal surface to directly kill the corrosive microorganisms enriched under the scale, inhibit corrosion, and then show excellent corrosion inhibition and sterilization performance under scale. 2) Organic phosphonic acid or organic phosphonate compounds can dissociate into acid radical ions in water, and then react with Ca 2+ Mg 2+ etc. to form a stable six-membered ring complex, reducing the Ca 2+ Mg 2+ The concentration of plasma can reduce the precipitation of calcium carbonate scale in water and play a role in scale inhibition. 3) Sterilization aids include diquaternary ammonium salt bactericides and aldehyde bactericides, which have broad-spectrum bactericidal effects and can be combined with quaternary ammonium salt surfactants containing thiadiazole heterocycles to further improve the bactericidal effect. The present invention obtains a sub-scale microbial corrosion inhibitor with the four functions of sub-scale sterilization, carbon steel corrosion inhibition, solution sterilization and system scale inhibition by compounding the above raw materials and making appropriate weight ratios so that the components cooperate with each other and work synergistically. It can realize the integrated treatment of scale inhibition, corrosion inhibition and sterilization of oilfield injection and production water systems, and greatly reduce the cost of sub-scale protection for oilfield injection and production water systems. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the description in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1

[0019] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.1, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 70°C for 4 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 40 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 25 parts by weight of clean water, 25 parts by weight of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt, and 10 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP) are taken, and the mixture is fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0020] Example 2

[0021] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.2, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 80°C for 8 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 40 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 24.5 parts by weight of clean water, 25 parts by weight of glutaraldehyde, 10 parts by weight of diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), and 0.5 parts by weight of dimethyl silicone oil are taken, and the mixture is fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0022] Example 3

[0023] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.3, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 80°C for 6 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 50 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 17 parts by weight of clean water, 25 parts by weight of glutaraldehyde, and 8 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP) are taken, and the mixture is fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0024] Example 4

[0025] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride were used as raw materials in a molar ratio of 1:1.2, ethanol was used as solvent, and the reaction was carried out at a reflux temperature of 70°C for 6 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 45 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine was taken. 2-(2-oxazolidinone-2-thio)-N,N,N-trimethylpropane-1-amine, 24.5 parts by weight of clean water, 25 parts by weight of N,N'-1-alkyl-6-quinolyl-1,3-acetone diamide diquaternary ammonium salt, 10 parts by weight of hydroxyethylidene diphosphonic acid (HEDP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0026] Example 5

[0027] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride were used as raw materials in a molar ratio of 1:1.1, ethanol was used as solvent, and the reaction was carried out at a reflux temperature of 80°C for 5 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine. 40 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N -trimethylpropane-1-amine, 19.5 parts by weight of clean water, 30 parts by weight of 1-(3-(dodecyldimethylamino)-2-hydroxypropyl)-1-(2-hydroxyethyl)-2,5-dimethyl-1H-imidazole-1-ium, 10 parts by weight of diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0028] Example 6

[0029] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride were used as raw materials in a molar ratio of 1:1.1, ethanol was used as solvent, and the reaction was carried out at a reflux temperature of 80°C for 7 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 45 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine was taken. -2-thio)-N,N,N-trimethylpropane-1-amine, 15.5 parts by weight of clean water, 30 parts by weight of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt, 9 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0030] Example 7

[0031] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.3, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 70°C for 8 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine. 45 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 18.7 parts by weight of clean water, 28 parts by weight of glutaraldehyde, 8 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP), and 0.3 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0032] Example 8

[0033] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.2, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 80°C for 6 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine. 45 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 10.5 parts by weight of clean water, 35 parts by weight of N,N'-1-alkyl-6-quinolyl-1,3-acetone diamide diquaternary ammonium salt, 9 parts by weight of hydroxyethylidene diphosphonic acid (HEDP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0034] Example 9

[0035] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.2, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 80°C for 6 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 50 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 10.5 parts by weight of clean water, 30 parts by weight of glutaraldehyde, 9 parts by weight of hydroxyethylidene diphosphonic acid (HEDP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0036] Example 10

[0037] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.2, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 60°C for 6 hours to synthesize 1,3,4-mercaptothiadiazole quaternary ammonium salt. 50 parts by weight of 1,3,4-mercaptothiadiazole quaternary ammonium salt, 6.5 parts by weight of clean water, 35 parts by weight of 1-(3-(dodecyldimethylamino)-2-hydroxypropyl)-1-(2-hydroxyethyl)-2,5-dimethyl-1H-imidazole-1-ium, 8 parts by weight of hydroxyethylidene diphosphonic acid (HEDP), and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0038] Embodiment 11

[0039] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.2, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 80°C for 8 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 50 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 4.5 parts by weight of clean water, 35 parts by weight of glutaraldehyde, 10 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP) and 0.5 parts by weight of dimethyl silicone oil are fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0040] Comparative Example 1

[0041] Take 25 parts by weight of clean water, 45 parts by weight of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt, and 30 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP), stir and dissolve them uniformly in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0042] Comparative Example 2

[0043] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.1, ethanol is used as a solvent, and the reaction is carried out at a reflux temperature of 70°C for 4 hours to synthesize 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine; 40 parts by weight of 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine, 25 parts by weight of clean water, and 35 parts by weight of ethylenediaminetetramethylenephosphonate (EDTMP) are taken, and the mixture is fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0044] Comparative Example 3

[0045] 2,5-dimercaptothiadiazole and (3-chloro-2-hydroxypropyl)trimethylammonium chloride are used as raw materials in a molar ratio of 1:1.1, ethanol is used as solvent, and the reaction is carried out at a reflux temperature of 70°C for 4 hours to synthesize 1,3,4-mercaptothiadiazole quaternary ammonium salt; 40 parts by weight of 1,3,4-mercaptothiadiazole quaternary ammonium salt, 25 parts by weight of clean water, and 35 parts by weight of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt are taken, and fully stirred and dissolved in a dissolving kettle at room temperature to obtain an under-scale microbial corrosion inhibitor for oilfield injection and production water systems.

[0046] Test example

[0047] 1. Corrosion inhibition performance test method

[0048] The corrosion inhibition effect is evaluated by the coupon method. The coupon method is a classic method for determining the corrosion rate of metals. It is simple, economical and practical. This method is the most basic and commonly used method in the field of corrosion science. Under certain conditions, the corrosion rate of the metal is calculated based on the mass loss before and after the monitoring test piece test, thereby judging the degree of corrosion control of the system metal.

[0049] 1.1 Reagents and Materials

[0050] (1) n-hexane or petroleum ether

[0051] (2) Anhydrous ethanol

[0052] (3) Hydrochloric acid solution: 1+3 solution

[0053] (4) Sodium hydroxide solution: 60g / L

[0054] (5) Pickling solution: Add 1% to 2% of carbon steel pickling corrosion inhibitor to 1000ml (1+3) hydrochloric acid solution, stir evenly and set aside.

[0055] (6) All chemical reagents (analytical grade or chemical grade) required for the preparation of artificial seawater.

[0056] 1.2 Instruments and equipment

[0057] (1) Experimental apparatus: constant temperature water bath (10-100°C) with stirring function;

[0058] (2) Analytical balance: 0.1 mg;

[0059] (3) Analytical balance: 0.01 g.

[0060] 1.3 Test conditions

[0061] (1) Test water: simulated water;

[0062] (2) Test solution volume: 1150 ml (surface-liquid ratio greater than 20 ml / cm 2 );

[0063] (3) Test temperature: 50°C;

[0064] (4) Test flow rate: 0.5 m / s;

[0065] (5) Test piece material: N-80 steel (also applicable to other grades of carbon steel);

[0066] (6) Test equipment: constant temperature water bath with stirring function, etc.

[0067] (7) Test duration: 7 days;

[0068] (8) According to the experimental requirements, prepare 500 grams of microbial corrosion inhibitor for water injection and prepare a 1% aqueous solution;

[0069] (9) Add a certain amount of microbial corrosion inhibitor for injection water (concentration 200 mg / L) to the test bottle, accurate to 0.01 ml, then add a certain volume of experimental water and mix well to obtain the test solution;

[0070] (10) Place the pre-weighed monitoring test piece in the bottle, cover the bottle with a lid, seal the bottle, shake the test solution, place the bottle in a constant temperature water bath, and start timing;

[0071] (11) When the test time reaches the specified value, turn off the rotating device, open the test bottle cap, take out the test piece and observe its appearance;

[0072] (12) Clean the test piece with a brush, then soak it in the corrosion-inhibiting pickling solution for 3 to 5 minutes, take it out and quickly rinse it with tap water, immediately put it into the sodium hydroxide solution for about 30 seconds, take it out, rinse it with tap water again, wipe it with filter paper and dry the surface moisture of the test piece, soak it in anhydrous ethanol for about 3 minutes, dry it with filter paper and blow it dry with a hair dryer, place it in a desiccator for 4 hours, and weigh it to an accuracy of 0.0001g;

[0073] (13) Observe the appearance of the test piece after pickling. If there is pitting corrosion, the maximum depth of pitting corrosion and the number of pitting corrosion per unit area should be measured.

[0074] 1.4 Representation and calculation of results

[0075] (1) Corrosion rate: V = [87600 × (mm o )] / (A×D×T)

[0076] Where: V-corrosion rate of the specimen, mm / a; m-mass of the specimen before the test, g;

[0077] m o -mass of the test piece after the test, g; A-surface area of ​​the test piece, cm 2 ;

[0078] D-density of the test piece material, g / cm 3 ; T-test time, h; 87600-coefficient.

[0079] (2) Precision: The arithmetic mean of the results of parallel measurements of three test pieces shall be taken as the measurement result. The deviation of the parallel measurement results shall not exceed -10% to +10% of the arithmetic mean.

[0080] 2. Scale inhibition performance test method

[0081] Static scale inhibition test evaluation method: The scale inhibition efficiency of the under-scale corrosion inhibitor is calculated by changing the hardness ion concentration in the test water before and after the test to reflect its scale inhibition effect.

[0082] The static scale inhibition test is carried out in accordance with the standards of "SY / T 5673-1993 Performance Evaluation Method of Scale Inhibitors for Oil Fields" and "GB 7476 Determination of Calcium Ion Concentration in Water".

[0083] 2.1 Test apparatus

[0084] (1) Static scale inhibition test device; (2) Constant temperature box (20~200℃)

[0085] 2.2 Test conditions

[0086] (1) Test water quality: simulated water; (2) Test temperature: 90°C; (3) Test time: 24 hours; (4) Test agent: under-scale corrosion inhibitor; (5) Agent concentration: 200 mg / L

[0087] 3. Bactericidal performance test method

[0088] The bactericidal performance was evaluated by the extinction dilution method.

[0089] 3.1 Experimental setup

[0090] (1) Bacterial incubator; (2) Constant temperature incubator (20-100°C)

[0091] 3.2 Test conditions

[0092] (1) Test SRB strain: laboratory culture; (2) Test temperature: 37°C; (3) Test time: 14 days; (4) Test agent: under-deposit corrosion inhibitor; (5) Agent concentration: 200 mg / L.

[0093] The corrosion inhibition, scale prevention and sterilization effects of the sub-scale microbial corrosion inhibitor for oilfield water injection and production systems prepared in the above examples are shown in Table 1 below.

[0094] Table 1 Corrosion inhibition, scale inhibition and sterilization effects of under-scale corrosion inhibitors

[0095]

[0096] Combined with the comparative example, it can be seen from Table 1 that the corrosion rate of the under-scale corrosion inhibitor prepared in the embodiments of the present invention is less than 0.076 mm / a, the scale inhibition rate is >96%, and the sterilization rate is almost 100%. It can be seen that the under-scale corrosion inhibitor of the present invention has excellent under-scale sterilization, carbon steel corrosion inhibition, solution sterilization and system scale inhibition. The quadruple function meets the actual application needs of the oil field; and removing any one component cannot simultaneously meet the above functions.

[0097] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A sub-scale microbial corrosion inhibitor for oilfield water injection and production systems, characterized in that: By weight, it includes the following components: 40-50 parts of quaternary ammonium salt surfactant containing thiadiazole heterocycle, 5-10 parts of organic phosphonic acid or organic phosphonate compound, 25-35 parts of bactericidal adjuvant, 4.5-30 parts of water, 0-5 parts of defoaming agent; The bactericidal auxiliary agent is selected from at least one of a diquaternary ammonium salt bactericide and an aldehyde bactericide.

2. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 1, characterized in that: The quaternary ammonium salt surfactant containing a thiadiazole heterocycle is 2-hydroxy-3-(5-mercapto-1,3,4-thiadiazole-2-thio)-N,N,N-trimethylpropane-1-amine.

3. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 2, characterized in that: The preparation method of the quaternary ammonium salt containing thiadiazole heterocycle comprises: contacting 2,5-dimercaptothiadiazole, (3-chloro-2-hydroxypropyl)trimethylammonium chloride and a solvent to react; Preferably, the molar ratio of (3-chloro-2-hydroxypropyl)trimethylammonium chloride to 2,5-dimercaptothiadiazole is 1:1.1-1.3; Preferably, the solvent comprises ethanol; Preferably, the reaction temperature is 70-80° C., and the reaction time is 4-8 hours.

4. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 1, characterized in that: The organic phosphonic acid compound is selected from at least one of hydroxyethylene diphosphonic acid and diethylene triamine penta (methylene phosphonic acid); and / or the organic phosphonate compound includes ethylene diamine tetra (methylene phosphonate).

5. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 1, characterized in that: The diquaternary ammonium salt fungicide is selected from at least one of N,N'-1-alkyl-3-pyridyl-1,3-acetone diamide diquaternary ammonium salt, N,N'-1-alkyl-6-quinolyl-1,3-acetone diamide diquaternary ammonium salt, and 1-(3-(dodecyldimethylamino)-2-hydroxypropyl)-1-(2-hydroxyethyl)-2,5-dimethyl-1H-imidazole-1-ium.

6. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 1, characterized in that: The aldehyde fungicide includes glutaraldehyde.

7. The under-scale microbial corrosion inhibitor for oilfield water injection and production system according to claim 1, characterized in that: The defoaming agent includes dimethyl silicone oil.

8. A method for preparing the under-scale microbial corrosion inhibitor for oilfield water injection and production system according to any one of claims 1 to 7, characterized in that: The preparation method comprises: mixing and stirring a quaternary ammonium surfactant containing a thiadiazole heterocycle, an organic phosphonic acid or an organic phosphonate compound, a bactericidal auxiliary, water and, optionally, a defoaming agent.

9. Use of the sub-scale microbial corrosion inhibitor according to any one of claims 1 to 7 in the integrated treatment of scale inhibition, corrosion inhibition and sterilization in oilfield injection and production water systems.

10. An integrated treatment method for scale inhibition, corrosion inhibition and sterilization of oilfield injection and production water system, characterized in that: The method comprises filling the under-scale microbial corrosion inhibitor according to any one of claims 1 to 7 into an oilfield injection and production water system.

Images