An oilfield bacteria-control desulfurizer and its preparation method

Abstract

The present invention discloses an oilfield bacteria-control desulfurizer and a preparation method thereof. The oilfield bacteria-control desulfurizer comprises the following components in percentage by weight: 20-45% of 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride; 5%-10% of 1,3-dithiocyano-5-hydroxyethyltriazine; 2%-4% of SRB inhibitor; 1-4% of stabilizer; 1-3% of chelating agent; 0.1%-0.5% of surfactant oil remover; 0.1-0.5% of defoaming agent; and the balance is water. The oilfield bacteria-control desulfurizer of the present invention has good dual functions of controlling SRB and removing hydrogen sulfide, and can be applied to the treatment of SRB and hydrogen sulfide in single oil wells and oily sewage in oilfields.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry, and in particular to an oilfield bacteria-controlling desulfurizing agent and a preparation method thereof. Background Art

[0002] During the oil production process, offshore oil fields will produce hydrogen sulfide gas for various reasons. Sulfate-reducing bacteria (SRB) release hydrogen sulfide in the process of participating in corrosion, which is one of the important sources of hydrogen sulfide in oil fields. The suitable living conditions in the oil and water treatment section will cause a large number of SRB, iron bacteria, and sticky saprophytes to breed. Groups of colonies produce a large amount of biological slime and inorganic matter, residual oil wrapped, forming sediments attached to the pipe wall, providing bacteria with a closed biofilm. The hydrogen sulfide continuously produced by SRB in it corrodes the pipeline together with the organisms. At present, the addition of fungicides is the main method to inhibit SRB in oil fields, but the large-scale use of fungicides will make bacteria resistant and cause SRB to reproduce rapidly, so that the dosage of fungicides is continuously increased, increasing the cost of medication. In addition, fungicides cannot eliminate hydrogen sulfide that has already been produced. For the treatment of hydrogen sulfide, desulfurizers are the most widely used at sea, but desulfurizers cannot remove SRB that produces secondary hydrogen sulfide during use. Therefore, a single desulfurization and sterilization treatment process only treats the symptoms and not the root cause, and it is difficult to meet the requirements of the oil field. The inability to take into account the treatment of both hydrogen sulfide and SRB is the main difficulty and bottleneck.

[0003] Based on the unique oil production method of offshore oil and the characteristics of H2S distribution in the oil-water gas path, the offshore oil and gas fields use more triazine-based products for hydrogen sulfide removal. Triazine avoids the use restrictions and influence of alcohol amine desulfurizers on temperature, and is widely used due to its high absorption efficiency, fast speed, and completely irreversible reaction. However, triazine is a water-soluble product with no surface activity, and cannot penetrate into the mud and residual oil to react with hydrogen sulfide. At the same time, the triazine desulfurizer itself has no bactericidal effect. For the hydrogen sulfide problem generated by SRB breeding, triazine desulfurizer and bactericide compound products are currently commonly used, but the compound products have poor compatibility, are easy to foam, and have lower bactericidal and desulfurization effects than single products. Therefore, the inventor believes that it is of great significance to provide a product with efficient antibacterial desulfurization function. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an oilfield bacteria-controlling desulfurizer and a preparation method thereof, which are used for eliminating hydrogen sulfide and SRB in the process of offshore crude oil production.

[0005] In a first aspect, the present application provides an oilfield bacteria-controlling desulfurization agent, which is achieved by adopting the following technical solution.

[0006] An oilfield bacteria-controlling desulfurizer, comprising the following components in percentage by weight:

[0007] 20 - 45% of diammonium salt of 1,3 - bis(benzylaminoalkyl)5-(aminoalkyl)triazine dichloride;

[0008] 5% - 10% of 1,3 - dithiocyano - 5 - hydroxyethyltriazine;

[0009] 2% - 4% of SRB inhibitor;

[0010] 1 - 4% of stabilizer;

[0011] 1 - 3% of chelating agent;

[0012] 0.1% - 0.5% of surfactant degreaser;

[0013] 0.1 - 0.5% of defoamer;

[0014] The balance is water.

[0015] By adopting the above - mentioned technical solution, the quaternary ammonium salt can selectively adsorb on the cell wall of SRB, penetrate the cell membrane, change the electron transfer and selective material transfer of cell molecules, destroy the genetic system of the cell, resulting in the inhibition or even death of bacterial activity. The commonly used quaternary ammonium salt is 1227, which is prone to produce a large number of bubbles during use. At the same time, long - term use will make bacteria develop drug resistance, and the dosage gradually increases, causing cost increases. In practical applications, a concentration greater than 100 ml / L needs to be added to achieve a 99.0% killing target, and the drug concentration needs to be further increased after the emergence of drug resistance later. The triazine quaternary ammonium salt in the present invention has a double - quaternary ammonium salt structure, and the hydrophobic group contains water - soluble groups. It has low foaming property, stronger surface activity and dispersion degree in oil - water. Its sludge stripping and bactericidal performance are stronger than those of single - quaternary ammonium salts. When used alone, adding 40 ml / L can achieve a 99.0% killing target. 1,3 - dithiocyano - 5 - hydroxyethyltriazine in the present invention introduces an organic thiocyanide bactericidal group on the triazine ring, and the linking group contains an S - S bond, which easily changes the physicochemical properties of sulfur - containing proteins and thus has more excellent bactericidal performance. After being compounded with the triazine quaternary ammonium salt, it has good killing effects on sulfate - reducing bacteria, iron bacteria, saprophytic bacteria and various algae.

[0016] In addition, after the N on the triazine ring grafts a long - chain group, the electrophilicity of N on the triazine ring will be enhanced, promoting the enhancement of the nucleophilic reaction activity of triazine to hydrogen sulfide and improving the speed of the desulfurization reaction. Compared with the conventional triazine desulfurizer hydroxyethyl hexahydro - s - triazine, the desulfurization performance has been further improved. In addition, after desulfurization, the triazine molecule is transformed into an S - containing heterocyclic compound, which synergistically acts with the quaternary ammonium salt group to further improve the bactericidal effect.

[0017] In summary, after compounding 1,3 - bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride and 1,3 - dithiocyanato - 5 - hydroxyethyltriazine with components such as SRB inhibitors, the product has the characteristics of high - efficiency sterilization and antibacterial, desulfurization effect, low foaming, and safe use. It is suitable for the oil - water treatment process in oilfields and has excellent treatment effects on microorganisms, bacteria, and hydrogen sulfide in the process.

[0018] Further, the 1,3 - bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride is selected from one or more of 1,3 - bis(benzyldimethylaminoethyl)-5-(dimethylaminoethyl)triazine diammonium dichloride, 1,3 - bis(benzyldiethylaminoethyl)-5-(diethylaminoethyl)triazine diammonium dichloride, 1,3 - bis(benzyldimethylaminopropyl)-5-(dimethylaminopropyl)triazine diammonium dichloride, and 1,3 - bis(benzyldiethylaminopropyl)-5-(diethylaminopropyl)triazine diammonium dichloride.

[0019] Further, the preparation method of the 1,3 - bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride is as follows:

[0020] a. After mixing alkylamines with a solvent and a catalyst, an aqueous formaldehyde solution is added. The molar ratio of alkylamines to formaldehyde is 1:(1 - 2.5). The mixture is refluxed for 3 - 6 hours, and the water generated in the system is continuously removed during the reaction. After the reaction ends, the organic phase is separated, the solvent is distilled off, the residue is washed with chloroform / water (mass ratio 3 / 1), the organic layer is separated, dried, and chloroform is distilled off to obtain an intermediate product.

[0021] b. The intermediate product is mixed evenly with DMF and sodium hydroxide, and benzyl chloride is added dropwise while maintaining the temperature below 10°C. The molar ratio of the intermediate product to benzyl chloride is 1:2 - 1:3. After the dropwise addition, the reaction is carried out at 50 - 150°C for 2 - 10 hours, and the solvent is distilled off under reduced pressure to obtain 1,3 - bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride.

[0022] Furthermore, in step a, the alkylamines are selected from one or more of dimethylethylenediamine, dimethylpropylenediamine, dimethylbutylenediamine, diethylethylenediamine, and diethylpropylenediamine.

[0023] Furthermore, in step a, the solvent is selected from one or more of toluene, xylene, acetonitrile, and DMF; the addition amount of the solvent is in an equal - mass ratio to the alkylamines.

[0024] Furthermore, in step a, the catalyst is a basic resin catalyst, and the addition amount is 0.5 - 1% of the mass of the alkylamines.

[0025] Further, in step b, the intermediate product is uniformly mixed with DMF in an equal mass ratio and 10% sodium hydroxide.

[0026] The structural formula of 1,3 - bis(benzylaminoalkyl)-5-(aminoalkyl)triazine dichloride diammonium is as follows:

[0027] R is C x H 2x-1

[0028] Further, the preparation method of 1,3 - dithiocyano - 5 - hydroxyethyltriazine is as follows:

[0029] Sodium thiocyanate, oxalic acid, and acetonitrile are mixed to form a (COOH)2 / NaSCN reagent system. Hydroxyethyl hexahydro - s - triazine is added dropwise to (COOH)2 / NaSCN at a molar ratio of hydroxyethyl hexahydro - s - triazine to sodium thiocyanate of 1:(2 - 3), and the mixture is refluxed at 50 - 100 °C for 3 - 8 hours. The resulting mixed solution is adjusted to pH 11 - 14 with solid base, and the solvent is removed by vacuum distillation to obtain 1,3 - dithiocyano - 5 - hydroxyethyltriazine.

[0030] Further, a (COOH)2 / NaSCN reagent system is prepared by mixing 30 - 45% sodium thiocyanate, 2 - 4% oxalic acid, and 55 - 65% acetonitrile.

[0031] The structural formula of 1,3 - dithiocyano - 5 - hydroxyethyltriazine is as follows:

[0032]

[0033] Further, the stabilizer is a mixture of sodium hydroxide and sodium nitrite.

[0034] Further, the mass ratio of sodium hydroxide to sodium nitrite is 1:(3 - 4.5).

[0035] Further, the chelating agent is selected from one or more of sodium EDTA, sodium dioctyl sulfosuccinate, and sodium diamino disuccinate.

[0036] Further, the SRB inhibitor is selected from one or more of borates, selenates, molybdates, and guanidines.

[0037] Further, the surfactant degreasing agent is selected from one or more of OP - 10, span80, and AEO - 7.

[0038] Further, the defoaming agent is selected from one or more of polyether defoaming agents, silicone defoaming agents, and silicone - polyether defoaming agents.

[0039] In a second aspect, the present application provides a method for preparing a bacteriostatic desulfurizer for oil fields, which is achieved by adopting the following technical solutions.

[0040] A method for preparing the above-mentioned bacteriostatic desulfurizer for oil fields includes the following steps:

[0041] Under room temperature conditions, weigh a specified amount of 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride, SRB inhibitor, stabilizer, chelating agent and mix and dissolve them with water, then add a specified amount of 1,3-dithiocyano-5-hydroxyethyltriazine, surfactant oil remover and defoamer, and obtain a bacteriostatic desulfurizer for oil fields after stirring.

[0042] The present application has the following beneficial effects.

[0043] In the bacteriostatic desulfurizer for oil fields of the present invention, the main agents 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride and 1,3-dithiocyano-5-hydroxyethyltriazine both graft molecular groups with bactericidal functions on the nitrogen heterocycle of triazine, making triazine have an alkane chain, benzene ring, quaternary ammonium salt, and organic thiocyanate structure, enabling a single agent to simultaneously have bactericidal, desulfurizing, and slime stripping effects, and simplifying the steps of oil field water treatment work. Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of the desulfurization performance evaluation equipment of the desulfurizer of the present invention.

[0045] Among them, 1. Nitrogen gas tank; 2. Hydrogen sulfide tank; 3. Mixing tank; 4. Absorption tank; 5. Tail gas absorption alkali liquid tank. Detailed Embodiments

[0046] The following further describes this patent application in combination with examples.

[0047] Example 1

[0048] A method for preparing a bacteriostatic desulfurizer for oil fields includes the following steps:

[0049] 1. Mix 88.1 g of N,N-dimethylethylenediamine with 120 g of toluene and 0.445 g of basic resin catalyst, heat up to 50 °C, and dropwise add 94.4 g of formaldehyde aqueous solution. After the addition is completed, control the reflux reaction for 4 hours. During the reaction process, continuously remove the water generated in the system using a water separator. After the reaction ends, separate the organic phase, distill off the solvent under reduced pressure, wash the residue with 120 g of chloroform / water (mass ratio 3 / 1), separate the organic layer, add anhydrous sodium sulfate and dry overnight, filter out the liquid, and distill off chloroform to obtain 73.5 g of a clear oily intermediate product A with a yield of 75%.

[0050] 2. Weigh 28.8 g of intermediate product A, 64.68 g of benzyl chloride, 65 g of DMF, and 5 g of sodium hydroxide. Add them to a four-necked flask reaction kettle with stirring, and keep the temperature below 10 °C while dropping 64.68 g of benzyl chloride. After the dropping is completed, raise the temperature to 90 °C and react for 2.5 hours. Cool to room temperature, and distill off the solvent under reduced pressure to obtain 77.9 g of 1,3-bis(benzyldimethylamino)-5-(dimethylamino)triazine dichloride diammonium (product B), with a yield of 68%.

[0051] 3. Mix 17.8 g of sodium thiocyanate, 1.5 g of oxalic acid, and 30 g of acetonitrile and stir evenly to prepare a (COOH)2 / NaSCN reagent system. Slowly drop triazine into the prepared (COOH)2 / NaSCN reagent according to the molar ratio of hydroxyethyl hexahydro-s-triazine to sodium thiocyanate of 1:2.5. Reflux and react at 80 °C for 6 hours to obtain a mixed solution. After distilling off most of the solvent, adjust the pH to 12 with a small amount of solid sodium hydroxide, and then distill off the remaining solvent under reduced pressure to obtain 27.64 g of 1,3-dithiocyano-5-hydroxyethyl triazine, with a yield of 75%.

[0052] 4. Preparation of oilfield bacteria control and desulfurization agent

[0053] Add 1,3-bis(benzyldimethylamino)-5-(dimethylamino)triazine dichloride diammonium, sodium molybdate / or sodium borate / or PHMB, sodium hydroxide and sodium nitrite (the mass ratio of sodium hydroxide to sodium nitrite is 1:3.5), EDTA-4Na and water to the reaction flask in sequence. After dissolving in the reaction kettle, add 1,3-dithiocyano-5-hydroxyethyl triazine, op-10, and polyether defoamer, and stir until completely dissolved to prepare. The addition amounts of each component are shown in Table 1.

[0054] Table 1 Product composition of oilfield bacteria control and desulfurization agent

[0055]

[0056]

[0057] Note: KS-1: 1,3-bis(benzyldimethylamino)-5-(dimethylamino)triazine dichloride diammonium; KS-2: 1,3-dithiocyano-5-hydroxyethyl triazine; PHMB: polyhexamethylene biguanide, 20% industrial product.

[0058] Performance detection

[0059] I. SRB control performance: The evaluation method for the control performance of SRB bacteria adopts the test bottle method of the extinction dilution method, and the reference standard is "Evaluation Method for Bactericidal Performance" (SY / T 5890-1993). The sulfate-reducing bacteria (SRB) strain is from the produced fluid of the Pengbo WHPE platform, and the bacterial suspension is prepared with the produced water from the Pengbo Oilfield. The contact time between the bacteria and the medicine is 2 h, and T = 50 °C;

[0060] The oilfield bacteria control and desulfurization agents S1-S3 in Example 1 of the present invention were compared with other SRB bactericides in terms of bactericidal performance (the dosing concentration was selected according to the principle of consistent cost of each agent). The test results of the bactericidal performance are shown in Table 2.

[0061] Table 2 Comparison of the evaluation of bacteria control performance

[0062] Agent Name Dosing Concentration / mg / L SRB Inhibition Rate / % S1 20 99.15 S2 20 99.32 S3 20 99.52 THPS 20 99.10 CIT / MIT 15 98.10 1227 15 99.05

[0063] Note: (1) Specifications of the agents used in Table 2: CIT / MIT - isothiazolinone, 14% industrial product; THPS - tetrakis(hydroxymethyl)phosphonium sulfate, 75% industrial product; 1227 - dodecyldimethylbenzylammonium chloride, 44% industrial product. (2) The number of blank SRB bacteria is 5×10 5 .

[0064] It can be seen from the data in Table 2 that under the condition of the same cost, the bacteria control and desulfurization agents of the present invention have better bacteria control and bactericidal performance than single agents such as isothiazolinone.

[0065] II. Desulfurization performance test

[0066] The oilfield bacteria control and desulfurization agents S1-S3 prepared in Example 1 of the present invention were tested for desulfurization performance. The specific process is as follows: 4 g of the oilfield bacteria control and desulfurization agents S1-S3 and commercially available triazine desulfurization agents were respectively added to the desulfurization performance evaluation equipment, and an H2S / N2 mixed gas with a hydrogen sulfide concentration of 400 mg / L was introduced. After 400 min, the hydrogen sulfide concentration at the outlet was measured with a hydrogen sulfide detection tube, and then the sulfur capacity was calculated according to the formula. The experimental results are shown in Table 3.

[0067] The structure of the desulfurization performance evaluation equipment is as Figure 1 shown, including a nitrogen gas tank 1, a hydrogen sulfide tank 2, a mixing tank 3, an absorption tank 4 and a plurality of tail gas absorption alkali liquid tanks 5 connected by pipelines. Nitrogen and hydrogen sulfide are mixed in the mixing tank 3 and then introduced into the absorption tank 4 to react with the desulfurization agent in the absorption tank 4, and the tail gas generated by the reaction is absorbed by the tail gas absorption alkali liquid tank 5.

[0068] Sulfur capacity calculation formula:

[0069] P: Sulfur capacity of the desulfurization agent, g / g;

[0070] c1: Hydrogen sulfide concentration at the inlet before the desulfurization experiment, ppm;

[0071] c2: Hydrogen sulfide concentration at the inlet after the desulfurization experiment, ppm;

[0072] l1: Nitrogen flow rate, L / min;

[0073] l2: Flow rate of hydrogen sulfide mixed gas, L / min;

[0074] t: Breakthrough time, min;

[0075] m: Dosage of desulfurizer, g.

[0076] Table 3 Comparison of desulfurization performance evaluation

[0077]

[0078] As can be seen from Table 3, the inhibition rate of commercially available triazine compounds on hydrogen sulfide is lower than that of S1 - S3. Among the sulfur capacity tests, the triazine agent has the least weight gain, indicating its low sulfur capacity. Therefore, it can be seen that the antibacterial desulfurizers S1 - S3 prepared in the embodiments of the present application have better inhibition performance on hydrogen sulfide than commercially available desulfurizers.

[0079] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An oilfield bacteria control and desulfurization agent, characterized in that: It consists of the following components by weight percentage: Diammonium 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine dichloride 20 - 45%; 1,3-Dithiocyano-5-hydroxyethyltriazine 5% - 10%; SRB inhibitor 2% - 4%; Stabilizer 1 - 4%; Chelating agent 1 - 3%; Surfactant degreaser 0.1% - 0.5%; Defoamer 0.1 - 0.5%; The balance is water.

2. The oilfield bacteria control and desulfurization agent according to claim 1, wherein: The diammonium 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine dichloride is selected from one or more of diammonium 1,3-bis(benzyldimethylaminoethyl)-5-(dimethylaminoethyl)triazine dichloride, diammonium 1,3-bis(benzyldiethylaminoethyl)-5-(diethylaminoethyl)triazine dichloride, diammonium 1,3-bis(benzyldimethylaminopropyl)-5-(dimethylaminopropyl)triazine dichloride, and diammonium 1,3-bis(benzyldiethylaminopropyl)-5-(diethylaminopropyl)triazine dichloride.

3. The oilfield bacteria control and desulfurization agent according to claim 1, characterized in that: The preparation method of the diammonium 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine dichloride is as follows: a. After mixing alkylamine with a solvent and a catalyst, an aqueous formaldehyde solution is added. The molar ratio of alkylamine to formaldehyde is 1:(1 - 2.5). The mixture is refluxed for 3 - 6 hours, and the water generated in the system is continuously removed during the reaction. After the reaction is completed, the organic phase is separated, the solvent is distilled off, the residue is washed with chloroform / water, the organic layer is separated, dried, and chloroform is distilled off to obtain an intermediate product. b. The intermediate product is mixed evenly with DMF and sodium hydroxide. Benzyl chloride is added dropwise while maintaining the temperature below 10°C. The molar ratio of the intermediate product to benzyl chloride is 1:2 - 1:

3. After the dropwise addition is completed, the reaction is carried out at 50 - 150°C for 2 - 10 hours, and the solvent is removed under reduced pressure to obtain diammonium 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine dichloride.

4. The oilfield bacteria control and desulfurization agent according to claim 3, characterized in that: In step a, the alkylamine is selected from one or more of dimethylethylenediamine, dimethylpropylenediamine, dimethylbutylenediamine, diethylethylenediamine, and diethylpropylenediamine.

5. The oilfield bacteria-control desulfurizer according to claim 1, wherein: The preparation method of the 1,3-dithiocyano-5-hydroxyethyltriazine is as follows: Sodium thiocyanate, oxalic acid, and acetonitrile are mixed to form a (COOH)2 / NaSCN reagent system. Hydroxyethylhexahydro-s-triazine is added dropwise to (COOH)2 / NaSCN according to the molar ratio of hydroxyethylhexahydro-s-triazine to sodium thiocyanate of 1:(2 - 3). The mixture is refluxed at 50 - 100°C for 3 - 8 hours. The obtained mixed solution is adjusted to pH 11 - 14 with a solid base, and the solvent is removed by vacuum distillation to obtain 1,3-dithiocyano-5-hydroxyethyltriazine.

6. The oilfield bacteria control and desulfurization agent according to claim 1, characterized in that: The stabilizer is a mixture of sodium hydroxide and sodium nitrite.

7. The bacteriostatic desulfurizer for oil fields according to claim 6, wherein: The mass ratio of sodium hydroxide to sodium nitrite is 1:(3 - 4.5).

8. The oilfield bacteria-controlling desulfurizer according to claim 1, wherein: The chelating agent is selected from one or more of sodium EDTA, sodium dioctyl sulfosuccinate, and disodium diaminodisuccinate.

9. The bacteriostatic desulfurizer for oil fields according to claim 1, wherein: The SRB inhibitor is selected from one or more of borate, selenate, molybdate, and guanidine salt.

10. A preparation method of the oilfield bacteria-control and desulfurization agent according to any one of claims 1-9, characterized in that: It includes the following steps: At room temperature, weigh a specified amount of 1,3-bis(benzylaminoalkyl)-5-(aminoalkyl)triazine diammonium dichloride, SRB inhibitor, stabilizer, chelating agent and mix and dissolve them with water, then add a specified amount of 1,3-dithiocyano-5-hydroxyethyltriazine, surfactant degreaser and defoamer, and obtain an oilfield bacteria-control and desulfurization agent after stirring.

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