Stain-resistant and salt-resistant monomer DLCM for oil extraction and synthesis method thereof

Abstract

The invention discloses an anti-fouling and salt-tolerant monomer DLCM for oil extraction and a synthesis method thereof, and relates to the technical field of oil fields. The invention provides an anti-fouling and salt-tolerant monomer DLCM for oil extraction. A copolymerized polymer molecular chain contains a benzene ring, an alkyl group, two long-chain methylene groups and sulfonic acid groups. The sulfonic acid group provides hydrophilicity and charges, and enhances water solubility and hydrolysis resistance. The long-chain methylene increases the rotation radius of a molecular chain, improves intermolecular friction and physical entanglement, and enhances the tackifying, anti-fouling and salt-tolerant properties. The double-long-chain methylene enables the polymer to be more flexible, and viscoelasticity is improved, so that oil displacement performance is improved. The benzene ring increases the rigidity of the molecular chain, the steric hindrance prevents the molecular chain from curling under hypersalinity or sewage, the anti-fouling and salt-tolerant performance is remarkably improved, and high viscosity is kept. The monomer and the polymer thereof have the characteristics of stain resistance, salt resistance and stain resistance, and can be prepared from oilfield produced sewage, so that the oil recovery rate is increased to a relatively high extent.

Description

Technical Field

[0001] The present invention relates to the technical field of oil fields, and specifically to an anti-fouling and salt-tolerant monomer DLCM for oil production and its synthesis method. Background Art

[0002] Chemical flooding is one of the most effective methods for improving the oil recovery rate among many tertiary oil recovery technologies at present. Polymer flooding can increase the oil recovery rate by more than 10% on the basis of water flooding. It is the most mature and widely used technology in current chemical flooding, and it is of great significance for increasing oil production and ensuring national energy security. During the tertiary oil recovery process, due to the high salinity of a large amount of reservoir groundwater, the viscosity of ordinary polymers in high-salinity water is low, and problems such as "fingering" and "channeling" occur during the oil displacement process, resulting in low displacement efficiency. Therefore, the oil field's demand for anti-fouling and salt-tolerant polymers for oil production is becoming increasingly urgent.

[0003] When ordinary polyacrylamide is dissolved in a high-salinity brine solution, due to the repulsive effect of salt ions on the ionic groups in the polymer molecular chain, as the salt ion concentration increases, the polymer molecular chain is further compressed and curled, and the hydrodynamic volume is greatly reduced. Macroscopically, the viscosity of the polymer solution decreases significantly, and the oil displacement efficiency decreases.

[0004] Currently, the research on anti-fouling and salt-tolerant polymers mainly focuses on copolymerizing anti-fouling and salt-tolerant monomers with acrylamide monomers to introduce anti-fouling and salt-tolerant functional groups into the polymer molecular chain to enhance the anti-fouling and salt-tolerant properties of the polymer. The difficulty of the above research lies in synthesizing a suitable anti-fouling and salt-tolerant monomer. Introducing a rigid anti-fouling and salt-tolerant monomer into the polymer can enhance the anti-compression ability of the polymer molecular chain in salt water, thereby enhancing the anti-fouling and salt-tolerant properties of the polymer. However, the difficulty is that in order to pursue the improvement of anti-fouling and salt-tolerant properties, over-introducing rigid groups in the polymer molecular branches often causes a decrease in the water solubility of the polymer. Therefore, designing and synthesizing a suitable anti-fouling and salt-tolerant monomer to copolymerize with acrylamide monomer to obtain a polymer with excellent water solubility and anti-fouling and salt-tolerant properties has always been a difficult problem in the field of anti-fouling and salt-tolerant polymers. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-fouling and salt-tolerant monomer DLCM for oil production and its synthesis method to solve the problems existing in the prior art.

[0006] To solve the above technical problems, on the one hand, the present invention provides an anti-fouling and salt-tolerant monomer DLCM for oil production, and the anti-fouling and salt-tolerant monomer DLCM for oil production is synthesized by the reaction of the following components:

[0007]

[0008] Among them, component A is a compound with the structure shown in formula (a), component B is a compound with the structure shown in formula (b), and component C is a compound with the structure shown in formula (c);

[0009]

[0010] R1 and R2 are each independently selected from H or C1-C2 alkyl; R3 is selected from H or C1-C4 alkyl; R4 is selected from C1-C2 alkyl; m is an integer from 3 to 15; n is an integer from 5 to 19.

[0011] Furthermore, it is synthesized by the following method:

[0012] (1) Add a certain amount of organic solvent into a three-necked flask equipped with a stirrer, a dropping funnel and a thermometer. Start the stirrer, add a certain amount of component B and a certain amount of component C, and stir to dissolve;

[0013] (2) Slowly add a certain amount of component A dropwise into the above reaction system through the dropping funnel for reaction;

[0014] (3) Add alkali to the above reaction system to neutralize to a pH value of 6-8;

[0015] (4) Filter the above reaction system. After the filtered solid is dried, the anti-fouling and salt-tolerant monomer DLCM for oil production is obtained.

[0016] Furthermore, the temperature of the reaction is 20°C - 80°C, and the reaction time is 1 - 24 h.

[0017] Furthermore, the organic solvent in step (1) can be selected from at least one of dichloromethane, chloroform, hexane, heptane and petroleum ether.

[0018] Furthermore, the mass ratio of the organic solvent to component A is (1.5 - 7.5):1.

[0019] Furthermore, the alkali can be at least one of sodium hydroxide, potassium hydroxide, ammonia water and lithium hydroxide.

[0020] Furthermore, the mass ratio of the alkali to component A is (0.1 - 0.5):1.

[0021] In the second aspect, the present invention provides an anti-fouling and salt-tolerant oil displacement agent for oil production, which is prepared from the above-mentioned anti-fouling and salt-tolerant monomer DLCM for oil production, acrylamide, modified boron nitride and a solvent.

[0022] Furthermore, the preparation method of the modified boron nitride is as follows:

[0023] S1: React porous boron nitride (prepared according to the reference patent CN201910264490.9) in 4 - 6 mol / L sodium hydroxide at 115 - 125 °C for 2 - 4 h. After the reaction is completed, cool the temperature to 0 - 5 °C, add a mixed solution of ethanol and water (volume ratio 1:1) until the concentration of sodium hydroxide is 0.05 - 0.5 mol / L, add palladium chloride, and the molar ratio of hydroxylated porous boron nitride to palladium chloride is 1:0.005 - 0.1. Stir until the palladium source dissolves, then let it stand for 6 - 24 h. Centrifuge the obtained mixed solution at 8000 - 11000 rpm, wash it with acetone 3 times, freeze-dry it at -30 - -18 °C for 12 h, then place it in a tube furnace and reduce it in a hydrogen atmosphere at 160 - 240 °C for 2 - 6 h to obtain nano-palladium-doped boron nitride;

[0024] S2: Dissolve vinyltrimethoxysilane in an ethanol aqueous solution with a volume fraction of 40 - 60% and stir for 4 - 8 h to obtain a hydrolysis solution. Then add nano-palladium-doped boron nitride. The mass ratio of nano-palladium-doped boron nitride to the ethanol aqueous solution is 1 - 5:50, and vinyltrimethoxysilane is 10 - 20% of the mass of nano-palladium-doped boron nitride. Perform surface treatment at 0 - 50 °C for 4 - 8 h. After the reaction ends, filter by suction, wash it with ethanol 2 - 3 times and deionized water 2 - 3 times, and dry it at 80 °C for 12 h to obtain coupling agent-modified palladium-doped boron nitride;

[0025] S3: Mix xylene, methyl (E)-3-(3-formyl-4-hydroxyphenyl)acrylate, pretreated nano-palladium-doped boron nitride, and initiator BPO in a mass ratio of 60:30 - 40:9 - 20:0.5, stir and introduce nitrogen, heat to 110 °C, react for 1 - 3 h, raise the temperature to 120 °C, continue to react for 30 - 50 min, then cool to room temperature, add methanol with a volume 3 times that of xylene, stir at 500 rpm for 1 - 2 h, filter by suction, and dry at 65 °C for 8 h to obtain pretreated palladium-doped boron nitride;

[0026] S4: Mix pretreated palladium-doped boron nitride, diethylenetriamine, and methanol in a ratio of 0.04 g - 0.1 g:0.03 - 0.08 g:10 mL, react at 60 °C for 1.5 - 3 h, filter after cooling to room temperature, wash it with deionized water 3 times and methanol 2 times, and dry at 65 °C for 8 h to obtain modified boron nitride.

[0027] The present invention utilizes the double-bond cross-linking reaction of methyl (E)-3-(3-formyl-4-hydroxyphenyl)acrylate with vinyltrimethoxysilane on the surface of palladium-doped boron nitride, and then introduces an o-hydroxybenzaldehyde structure, which can further react with diethylenetriamine to form a Schiff base structure. Since there is a Schiff base on the surface of the modified boron nitride, it can coordinate with metal cations in oilfield sewage, thereby reducing the impact of oilfield sewage on the copolymer, eliminating the polymer curling caused by metal ions, reducing the viscosity loss of the polymer solution prepared with oilfield sewage, and improving its stability, so as to achieve the purpose of improving oil displacement efficiency. Moreover, after coordinating with metal ions, it can act as a co-catalyst, forming a catalyst system with nano-palladium, catalyzing the reaction of the reducing agent in the oil displacement agent with dissolved oxygen, preventing the degradation of the polymer in the polymer system by oxygen, and stabilizing the viscosity of the polymer system. In addition, the modified boron nitride can form strong hydrogen bond interactions with the side groups in the polymer molecules, thereby forming an "organic-inorganic" composite structure, improving the rigidity and anti-fouling and salt-tolerant stability of the polymer molecules.

[0028] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0029] In the molecular structure of the anti-fouling and salt-tolerant monomer DLCM in the present invention, there is a benzene ring structure, and the benzene ring structure contains an alkyl group, a long-chain methylene group, and a sulfonic acid group. After the anti-fouling and salt-tolerant monomer DLCM copolymerizes with acrylamide monomer, the polymer molecular chain contains a benzene ring group, an alkyl group, two long-chain methylene groups, and a sulfonic acid group. The hydrophilicity and strong charge of the sulfonic acid group endow the polymer with good water solubility and hydrolysis resistance; due to the long flexible molecular chain structure of the long-chain methylene group, on the one hand, it greatly increases the rotation radius of the polymer molecular chain, enhances the intermolecular friction and physical entanglement, and effectively improves the thickening performance and anti-fouling and salt-tolerant performance of the polymer. At the same time, the polymer formed by the monomer contains two long-chain methylene groups, enhancing the flexibility of the polymer molecular chain. Since the greater the flexibility of the molecular chain, the more significant the viscoelasticity, therefore, the oil displacement performance of the polymer is also improved. The presence of the benzene ring enhances the rigidity of the polymer molecular chain. Due to the steric hindrance effect, it can effectively prevent the curling of its molecular chain under high salinity conditions, significantly enhancing the anti-fouling and salt-tolerant performance of the polymer and enabling its aqueous solution to maintain a high viscosity under high salinity conditions. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Example 1

[0032] (1) React porous boron nitride in 4 mol / L sodium hydroxide at 115 °C for 2 h. After the reaction is completed, cool down to 0 °C, add a mixed solution of ethanol and water (volume ratio 1:1) until the concentration of sodium hydroxide is 0.05 mol / L, add palladium chloride, and the molar ratio of hydroxylated porous boron nitride to palladium chloride is 1:0.005. Stir until the palladium source is dissolved, then let it stand for 6 h. Centrifuge the obtained mixed solution at 8000 rpm, wash it with acetone three times, freeze-dry it at -30 °C for 12 h, and then place it in a tubular furnace. Reduce it at 160 °C in a hydrogen atmosphere for 6 h to obtain nano-palladium-doped boron nitride;

[0033] (2) Dissolve vinyltrimethoxysilane in an ethanol aqueous solution with a volume fraction of 40% and stir for 4 h to obtain a hydrolysis solution. Then add nano-palladium-doped boron nitride. The mass ratio of nano-palladium-doped boron nitride to the ethanol aqueous solution is 1:50, and vinyltrimethoxysilane is 10% of the mass of nano-palladium-doped boron nitride. Conduct surface treatment at 40 °C for 4 h. After the reaction is completed, filter it, wash it with ethanol twice and deionized water twice, and dry it at 80 °C for 12 h to obtain coupling agent-modified palladium-doped boron nitride;

[0034] (3) Mix xylene, methyl (E)-3-(3-formyl-4-hydroxyphenyl)acrylate, pretreated nano-palladium-doped boron nitride, and initiator BPO according to a mass ratio of 60:30:9:0.5, stir and introduce nitrogen, heat to 110 °C, react for 1 h, raise the temperature to 120 °C, continue to react for 30 min, then cool to room temperature, add methanol three times the volume of xylene, stir at 500 rpm for 1 - 2 h, filter it, and dry it at 65 °C for 8 h to obtain pretreated palladium-doped boron nitride;

[0035] (4) Mix pretreated palladium-doped boron nitride, diethylenetriamine, and methanol in a ratio of 0.04 g:0.03:10 mL, react at 60 °C for 1.5 h, filter it after cooling to room temperature, wash it with deionized water three times and methanol twice, and dry it at 65 °C for 8 h to obtain modified boron nitride;

[0036] (5) Add 120 g of dichloromethane to a three-necked flask equipped with a stirrer, a dropping funnel, and a thermometer. Start the stirrer, add 20 g of dodecylsulfonyl chloride and 22 g of pentadecylsulfonyl chloride. After fully dissolving, add 30 g of 4-methylisopropyltoluene dropwise to the above reaction system through the dropping funnel, keep the reaction temperature at 35 °C, and react for 5.5 h; add 10 g of sodium hydroxide to neutralize to a pH value of 6.6; filter the above reaction system, and dry the filtered solid matter to obtain the monomer;

[0037] (6) Weigh 1000 kg of deionized water and add it to the reaction kettle. Start the stirrer, add 350 kg of acrylamide, add 52 kg of monomer, and stir until completely dissolved. Add 0.7 kg of initiator azobisisobutyronitrile. Pass nitrogen into the material system for 35 minutes to remove the dissolved oxygen in the water. Add 20 g of sodium bisulfate, keep the temperature at 80 °C for 8 hours to obtain a polymer colloid. Feed the above polymer colloid into the hydrolysis reaction kettle, add 112 kg of solid sodium hydroxide to the hydrolysis reaction kettle, stir well to mix, heat up to 90 °C, keep the temperature for 3 hours, and then dry, grind, and screen to obtain the oil-displacing polymer.

[0038] (7) Mix the oil-displacing polymer, modified boron nitride, and hydrazine hydrate in a mass ratio of 100:10:5, and use it immediately after preparation to obtain the oil-displacing agent.

[0039] Example 2

[0040] (1) React porous boron nitride in 5 mol / L sodium hydroxide at 120 °C for 3 hours. After the reaction is completed, cool down to 2 °C, add a mixed solution of ethanol and water (volume ratio 1:1) until the sodium hydroxide concentration is 0.2 mol / L. Add palladium chloride, and the molar ratio of hydroxylated porous boron nitride to palladium chloride is 1:0.01. Stir until the palladium source is dissolved, then let it stand for 14 hours. Centrifuge the obtained mixed solution at 1000 rpm, wash it with acetone 3 times, freeze-dry it at -25 °C for 12 hours, and then place it in a tube furnace and reduce it in a hydrogen atmosphere at 200 °C for 4 hours to obtain nano-palladium-doped boron nitride.

[0041] (2) Dissolve vinyltrimethoxysilane in an ethanol aqueous solution with a volume fraction of 50% and stir for 6 hours to obtain a hydrolysis solution. Then add nano-palladium-doped boron nitride. The mass ratio of nano-palladium-doped boron nitride to the ethanol aqueous solution is 3:50, and vinyltrimethoxysilane is 15% of the mass of nano-palladium-doped boron nitride. Perform surface treatment at 40 °C for 6 hours. After the reaction is completed, filter by suction, wash it with ethanol 2 times and deionized water 2 times, and dry it at 80 °C for 12 hours to obtain coupling agent-modified palladium-doped boron nitride.

[0042] (3) Mix xylene, (E)-3-(3-formyl-4-hydroxyphenyl) methyl acrylate, pretreated nano-palladium-doped boron nitride, and initiator BPO in a mass ratio of 60:35:15:0.5, stir and pass nitrogen, heat up to 110 °C, react for 1 - 3 hours, raise the temperature to 120 °C, continue to react for 40 minutes, then cool to room temperature, add methanol 3 times the volume of xylene, stir at 500 rpm for 1.5 hours, filter by suction, and dry at 65 °C for 8 hours to obtain pretreated palladium-doped boron nitride.

[0043] (4) Mix the pretreated palladium-doped boron nitride, diethylenetriamine, and methanol in a ratio of 0.07 g: 0.05 g: 10 mL, react at 60 °C for 2 h, filter after cooling to room temperature, wash 3 times with deionized water and 2 times with methanol, and dry at 65 °C for 8 h to obtain modified boron nitride;

[0044] (5)(1) Add 150 g of chloroform to a three-necked flask equipped with a stirrer, dropping funnel, and thermometer. Start the stirrer, add 25 g of dodecylsulfonyl chloride and 29 g of octadecylsulfonyl chloride. After complete dissolution, slowly and uniformly add 36 g of 4-methylisopropenyltoluene to the above reaction system through the dropping funnel, maintain the reaction temperature at 40 °C, and react for 8 h; add 13 g of sodium hydroxide to neutralize to a pH value of 7.2; filter the above reaction system, and after drying the filtered solid, obtain the monomer;

[0045] (6) Measure 1000 kg of deionized water and add it to the reaction kettle. Start the stirrer, add 350 kg of acrylamide, add 46 kg of the monomer, and stir until completely dissolved; add 0.7 kg of the initiator azobisisobutyronitrile; pass nitrogen through the material system for 35 min to remove dissolved oxygen in the water; add 20 g of sodium bisulfate, keep warm for 8 h to obtain a polymer colloid; send the above polymer colloid to the hydrolysis reaction kettle, add 112 kg of solid sodium hydroxide to the hydrolysis reaction kettle, stir and mix well, heat up to 90 °C, keep warm for 2 h, and then dry, grind, and screen to obtain the oil-displacing polymer;

[0046] (7) Mix the oil-displacing polymer, modified boron nitride, and hydrazine hydrate in a mass ratio of 100: 10 - 20: 5, and use it immediately after preparation to obtain the oil-displacing agent.

[0047] Example 3

[0048] (1) React porous boron nitride in 6 mol / L sodium hydroxide at 125 °C for 4 h. After the reaction is completed, cool to 5 °C, add a mixed solution of ethanol and water (volume ratio 1:1) until the sodium hydroxide concentration is 0.5 mol / L, add palladium chloride, and the molar ratio of hydroxylated porous boron nitride to palladium chloride is 1:0.1. Stir until the palladium source is dissolved, then let it stand for 24 h. Centrifuge the obtained mixed solution at 11000 rpm, wash 3 times with acetone, freeze-dry at -18 °C for 12 h, and then place it in a tube furnace and reduce it in a hydrogen atmosphere at 240 °C for 6 h to obtain nano-palladium-doped boron nitride;

[0049] (2) Dissolve vinyltrimethoxysilane in an ethanol aqueous solution with a volume fraction of 60% and stir for 8 h to obtain a hydrolysis solution. Then add nano-palladium-doped boron nitride. The mass ratio of nano-palladium-doped boron nitride to the ethanol aqueous solution is 5:50, and vinyltrimethoxysilane is 20% of the mass of nano-palladium-doped boron nitride. Perform surface treatment at 40 °C for 8 h. After the reaction, perform suction filtration, wash with ethanol 3 times and wash with deionized water 3 times, and dry at 80 °C for 12 h to obtain coupling agent-modified palladium-doped boron nitride;

[0050] (3) Mix xylene, methyl (E)-3-(3-formyl-4-hydroxyphenyl)acrylate, pretreated nano-palladium-doped boron nitride, and initiator BPO in a mass ratio of 60:40:20:0.5, stir and introduce nitrogen, heat to 110 °C, react for 3 h, raise the temperature to 120 °C, continue to react for 50 min, then cool to room temperature, add methanol 3 times the volume of xylene, stir at 500 rpm for 2 h, perform suction filtration, and dry at 65 °C for 8 h to obtain pretreated palladium-doped boron nitride;

[0051] (4) Mix pretreated palladium-doped boron nitride, diethylenetriamine, and methanol in a ratio of 0.1 g:0.08 g:10 mL, react at 60 °C for 3 h, filter after cooling to room temperature, wash with deionized water 3 times and wash with methanol 2 times, and dry at 65 °C for 8 h to obtain modified boron nitride;

[0052] (5) Add 160 g of chloroform to a three-necked flask equipped with a stirrer, a dropping funnel, and a thermometer. Start the stirrer, add 23 g of pentadecylsulfonyl chloride and 25 g of octadecylsulfonyl chloride. After complete dissolution, slowly and uniformly add 39 g of 4-methylisopropenyltoluene to the above reaction system through the dropping funnel, keep the reaction temperature at 55 °C, and react for 12 h; add 11.2 g of sodium hydroxide to neutralize to a pH value of 6.9; filter the above reaction system, and the filtered solid matter is dried to obtain a monomer;

[0053] (6) Measure 1000 kg of deionized water and add it to the reaction kettle. Start the stirrer, add 350 kg of acrylamide, add 44 kg of monomer, and stir until completely dissolved; add 0.7 kg of initiator azobisisobutyronitrile; introduce nitrogen into the material system for 35 min to remove dissolved oxygen in the water; add 20 g of sodium bisulfate, keep warm for 8 h to obtain a polymer colloid; send the above polymer colloid to a hydrolysis reaction kettle, add 112 kg of solid sodium hydroxide to the hydrolysis reaction kettle, stir and mix well, raise the temperature to 90 °C, keep warm for 4 h, and then dry, grind, and screen to obtain an oil-displacing polymer;

[0054] (7) Mix the oil-displacing polymer, modified boron nitride, and hydrazine hydrate in a mass ratio of 100:20:5 and use it immediately to obtain an oil-displacing agent.

[0055] Example 4

[0056] (1) React porous boron nitride in 4.5 mol / L sodium hydroxide at 118 °C for 3.5 h. After the reaction is completed, cool the temperature to 2 °C, add a mixed solution of ethanol and water (volume ratio 1:1) until the concentration of sodium hydroxide is 0.17 mol / L, add palladium chloride, and the molar ratio of hydroxylated porous boron nitride to palladium chloride is 1:0.05. Stir until the palladium source is dissolved, then let it stand for 12 h. Centrifuge the obtained mixed solution at 8000 rpm, wash it with acetone three times, freeze-dry it at -18 °C for 12 h, and then place it in a tube furnace. Reduce it in a hydrogen atmosphere at 220 °C for 4 h to obtain nano-palladium-doped boron nitride;

[0057] (2) Dissolve vinyltrimethoxysilane in an ethanol aqueous solution with a volume fraction of 45% and stir for 6 h to obtain a hydrolysis solution. Then add nano-palladium-doped boron nitride. The mass ratio of nano-palladium-doped boron nitride to the ethanol aqueous solution is 4:50, and vinyltrimethoxysilane is 12% of the mass of nano-palladium-doped boron nitride. Perform surface treatment at 50 °C for 7 h. After the reaction is completed, filter it, wash it with ethanol three times and deionized water three times, and dry it at 80 °C for 12 h to obtain coupling agent-modified palladium-doped boron nitride;

[0058] (3) Mix xylene, methyl (E)-3-(3-formyl-4-hydroxyphenyl)acrylate, pretreated nano-palladium-doped boron nitride, and initiator BPO according to a mass ratio of 60:34:18:0.5, stir and introduce nitrogen, heat to 110 °C, react for 2 h, raise the temperature to 120 °C, continue to react for 38 min, then cool to room temperature, add methanol three times the volume of xylene, stir at 500 rpm for 1.5 h, filter it, and dry it at 65 °C for 8 h to obtain pretreated palladium-doped boron nitride;

[0059] (4) Mix pretreated palladium-doped boron nitride, diethylenetriamine, and methanol in a ratio of 0.08 g:0.07 g:10 mL, react at 60 °C for 2.5 h, filter it after cooling to room temperature, wash it with deionized water three times and methanol twice, and dry it at 65 °C for 8 h to obtain modified boron nitride;

[0060] (5) Add 160 g of chloroform to a three-necked flask equipped with a stirrer, a dropping funnel, and a thermometer. Start the stirrer, add 23 g of pentadecylsulfonyl chloride and 25 g of octadecylsulfonyl chloride. After fully dissolving, slowly and uniformly drop 39 g of 4-methylisopropenyltoluene into the above reaction system through the dropping funnel, keep the reaction temperature at 55 °C, and react for 12 h; add 11.2 g of sodium hydroxide to neutralize to a pH value of 6.9; filter the above reaction system, and dry the filtered solid matter to obtain the monomer;

[0061] (6) Weigh 1000 kg of deionized water and add it to the reaction kettle. Start the stirrer, add 350 kg of acrylamide, add 55 kg of monomer, and stir until completely dissolved; add 0.7 kg of initiator azodiisovaleronitrile; pass nitrogen through the material system for 35 minutes to remove dissolved oxygen in the water; add 20 g of sodium bisulfate, keep the temperature at 8 h to obtain a polymer colloid; feed the above polymer colloid into the hydrolysis reaction kettle, add 112 kg of potassium hydroxide in the hydrolysis reaction kettle, stir and mix well, heat up to 90 °C, keep the temperature for 4 h, and then dry, grind and screen to obtain the oil displacement polymer;

[0062] (7) Mix the oil displacement polymer, modified boron nitride, and hydrazine hydrate in a mass ratio of 100:12:5, and use it immediately after preparation to obtain the oil displacement agent.

[0063] Performance effect test

[0064] 1. Evaluation of anti-fouling and salt tolerance performance

[0065] A comparative test of anti-fouling and salt tolerance was carried out between the oil displacement agent, the oil displacement polymer, and the ordinary polymer (conventional polyacrylamide with a molecular weight of 16 million). It was formulated with aqueous solutions under different concentrations of sodium chloride. The polymer concentration was 1000 mg / L, the detection temperature was 45 °C, and the detection instrument was a Brookfield viscometer. The viscosities of the aqueous solutions under different concentrations of sodium chloride are shown in Table 1 below:

[0066] Table 1 Viscosities of aqueous solutions under different concentrations of sodium chloride

[0067]

[0068] The oil displacement agents obtained in each example maintained a relatively high viscosity under different concentrations of sodium chloride, with a small decrease, indicating that the present invention has anti-fouling and salt tolerance.

[0069] 2. Viscosity stability

[0070] Prepare and dilute the oil displacement agent and the oil displacement polymer with the field sewage of a certain oil production plant in Daqing to a solution with a polymer concentration of 1000 mg / L, and use a Brookfield viscometer to detect the viscosities after standing for 0 d, 3 d, 15 d, 30 d, 60 d, and 90 d at 45 °C and under anaerobic conditions. The detection results are shown in Table 2 below:

[0071] Table 2 Viscosities after standing for different times

[0072]

[0073]

[0074] As can be seen from the data in the table, after the oil-displacing polymer and the oil-displacing agent in the present invention are placed for 90 days at 45°C under anaerobic conditions, the average viscosity retention rate exceeds 110%, while that of the ordinary polymer is 0, indicating that the present invention can resist sewage and has excellent stability.

[0075] 3. Oil-displacing performance

[0076] Using Berea cores (30×4.5×4.5; water permeability is 100 mD), an oil-displacing experiment was carried out to study the oil-displacing effect of the anti-fouling and salt-resistant polymer for injection slug oil production. The oil-displacing agent and the oil-displacing polymer in Examples 1-3 were used to prepare an aqueous polymer solution with a concentration of 1150 mg / L (viscosity is 40 mPa·s), and an aqueous polymer solution with a concentration of 1150 mg / L was prepared with the comparative sample of the ordinary polymer. Water was injected into the core at a speed of 0.35 mL / min, and the water flooding ended when the water cut exceeded 98%; after injecting 0.5 PV at the same injection speed, subsequent water was injected, and the experiment ended when the produced liquid water cut was greater than 98%. The recovery rates are shown in Table 3 below:

[0077] Table 3 Recovery rate results

[0078]

[0079] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claim.

Claims

1. An anti-fouling and salt-resistant monomer DLCM for oil production, characterized in that, The anti-fouling and salt-tolerant monomer DLCM for oil production is synthesized by the reaction of the following components: Among them, component A is a compound with the structure shown in formula (a), component B is a compound with the structure shown in formula (b), and component C is a compound with the structure shown in formula (c); R1 and R2 are each independently selected from H or C1-C2 alkyl; R3 is selected from H or C1-C4 alkyl; R4 is selected from C1-C2 alkyl; m is an integer of 3-15; n is an integer of 5-19.

2. The anti-fouling and salt-tolerant monomer DLCM for oil production according to claim 1, wherein It is synthesized by the following method: (1) Add a certain amount of organic solvent to a three-necked flask equipped with a stirrer, a dropping funnel and a thermometer. Start the stirrer, add a certain amount of component B and a certain amount of component C, and stir to dissolve; (2) Slowly add a certain amount of component A to the above reaction system through the dropping funnel for reaction; (3) Add alkali to the above reaction system to neutralize to a pH value of 6-8; (4) Filter the above reaction system, and after drying the filtered solid, the anti-fouling and salt-tolerant monomer DLCM for oil production is obtained.

3. The anti-fouling and salt-tolerant monomer DLCM for oil production according to claim 2, wherein The temperature of the reaction is 20°C-80°C, and the reaction time is 1-24 h.

4. The anti-fouling and salt-tolerant monomer DLCM for oil production according to claim 2, characterized in that, The organic solvent described in step (1) can be selected from at least one of dichloromethane, chloroform, hexane, heptane and petroleum ether.

5. The anti-fouling and salt-tolerant monomer DLCM for oil production according to claim 2, wherein The mass ratio of the organic solvent to component A is (1.5-7.5):

1.

6. The anti-fouling and salt-tolerant monomer DLCM for oil production according to claim 2, characterized in that, The alkali can be at least one of sodium hydroxide, potassium hydroxide, ammonia water and lithium hydroxide.

7. The anti-fouling and salt-resistant monomer DLCM for oil production according to claim 2, characterized in that, The mass ratio of the alkali to component A is (0.1-0.5):

1.

8. An anti-fouling and salt-tolerant oil displacement agent for oil production, characterized in that, It is prepared from the anti-fouling and salt-tolerant monomer DLCM for oil production according to any one of claims 1-7, acrylamide, modified microspheres, hydrazine hydrate and a solvent.

9. The anti-fouling and salt-tolerant oil displacement agent for oil production according to claim 8, wherein The preparation method of the modified microspheres is as follows: Immerse hydroxylated porous boron nitride in a palladium source solution. After complete adsorption, freeze-dry and reduce it under a hydrogen atmosphere to obtain a palladium / porous mixture, and then modify it.

10. The anti-fouling and salt-tolerant oil displacement agent for oil production according to claim 9, characterized in that, The modification is to modify the palladium / porous mixture with vinyltrimethoxysilane, (E)-3-(3-formyl-4-hydroxyphenyl) methyl acrylate and diethylenetriamine.

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