Drag reducing agent for oil and gas gathering and transportation and its application

Abstract

The present application relates to the technical field of oil and gas field exploitation, and specifically to a drag reducer for oil and gas gathering and transportation and its application, comprising a first polymer molecule and a second polymer molecule, wherein the first polymer molecule and the second polymer molecule are bonded by intermolecular association; the first polymer molecule comprises the following preparation raw materials: hexadecyl methacrylate, ethylene glycol mono-9-octadecene-1-ether, allyl triethylammonium chloride, azobisisoheptonitrile, polyethylene glycol monooctylphenyl ether, hydroxyethyl cellulose, modified nano-alumina, and an interfacial compatibilizer; the second polymer molecule comprises the following preparation raw materials: hexadecyl methacrylate, styrene p-propanesulfonate, 3,7-dimethyl-6-octenoic acid, azobisisoheptonitrile, polyethylene glycol monooctylphenyl ether, hydroxyethyl cellulose, organically modified nano-diatomaceous earth, and an interfacial compatibilizer; the drag reducer prepared by the association of the two specific polymer molecules has strong shear resistance and high drag reduction rate.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field exploitation, and in particular to a drag reducing agent for oil and gas gathering and transportation and its application. Background Art

[0002] In recent years, my country's oil pipeline construction has made rapid progress, gradually forming a pipeline transportation network. Due to the long length of oil pipelines, any consumption during transportation will result in a significant loss of energy through accumulation. Therefore, ensuring the safe and efficient operation of oil pipelines is extremely important.

[0003] To maximize the transport volume of crude oil and various refined oil products over long distances and reduce transportation time and costs, the oil industry is using drag reduction technology to lower the energy consumption of oil pipeline transportation. Drag reducers are lubricants that reduce pipeline resistance and friction. Their primary function is to improve oil fluidity, reduce pressure loss, lower energy consumption, and increase oil transportation efficiency. Due to their low dosage, significant effectiveness, and minimal impact on oil properties, drag reducers have rapidly gained widespread application. Adding drag reducers effectively reduces frictional resistance in transportation pipelines, rapidly and economically increasing pipeline capacity and throughput. Therefore, they are crucial for accelerating the development and utilization of petroleum products.

[0004] However, the drag reduction effect of existing drag reducers is only effective for straight pipes. For elbows, valves, booster pumps and other parts in the pipeline, the polymer molecular chains are easily sheared and broken and degraded when passing through, thereby reducing the drag reduction effect. In order to ensure the stability of oil transportation in the oil pipeline and reduce transportation costs, long-distance pipeline transportation requires continuous replenishment of drag reducers, resulting in a large consumption of drag reducers. Summary of the Invention

[0005] The present application aims to overcome at least one of the defects of the prior art and provide a drag reducer for oil and gas gathering and transportation and its application. The drag reducer for oil and gas gathering and transportation prepared by the association action of two specific polymer molecules has strong shear resistance and high drag reduction rate.

[0006] In a first aspect, the embodiments of the present application provide a drag reducer for oil and gas gathering and transportation, which is achieved through the following technical solutions:

[0007] A drag reducer for oil and gas gathering and transportation, comprising a first polymer molecule and a second polymer molecule, wherein the first polymer molecule and the second polymer molecule are bonded by intermolecular association;

[0008] The first polymer molecule comprises the following raw materials in parts by weight: 25-30 parts of hexadecyl methacrylate, 12-18 parts of ethylene glycol mono-9-octadecene-1-ether, 6-10 parts of allyltriethylammonium chloride, 0.1-0.3 parts of azobisisoheptonitrile, 0.5-1 parts of polyethylene glycol monooctylphenyl ether, 1-2 parts of hydroxyethyl cellulose, 2-3 parts of modified nano-alumina, and 10-12 parts of an interfacial compatibilizer;

[0009] The second polymer molecule comprises the following raw materials in parts by weight: 25-30 parts of hexadecyl methacrylate, 12-18 parts of p-propanesulfonic acid styrene, 5-8 parts of 3,7-dimethyl-6-octenoic acid, 0.1-0.3 parts of azobisisoheptonitrile, 0.5-1 parts of polyethylene glycol monooctylphenyl ether, 1-2 parts of hydroxyethyl cellulose, 2-3 parts of organically modified nano-diatomaceous earth, and 10-12 parts of an interfacial compatibilizer.

[0010] A drag reducer for oil and gas gathering and transportation according to an embodiment of the present application has at least the following beneficial effects:

[0011] The drag reducer of the present application includes a first polymer molecule and a second polymer molecule, which are bonded by intermolecular association, including not only hydrogen bonding between hydroxyl groups and carboxyl groups and sulfonic acid groups, but also ionic bonding and electrostatic adsorption bonding between quaternary ammonium salts and carboxyl groups and sulfonic acid groups. The association increases the size of the molecular cluster. When passing through a high shear region, the shear force borne is shared compared with a single chain of polymer molecules. Since hydrogen bonds and ionic bonds break before covalent bonds, the number of covalent bond breaks is reduced. When passing through a low shear region, the hydrogen bonds and ionic bonds will automatically associate and reduce, thereby achieving the purpose of shear resistance.

[0012] The side chains of the drag reducer molecules of the present application contain longer side chains and benzene rings. The longer side chains will increase their flexibility and enable them to fully stretch in the pipeline, thereby enhancing their shear resistance and drag reduction performance. The benzene ring is a rigid monomer with very strong shear resistance. The combination of long side chains and benzene rings can significantly improve the drag reduction effect while increasing the molecular weight. In addition to long side chains and benzene rings, the introduction of quaternary ammonium salts, hydroxyl groups, ether bonds, carboxyl groups, sulfonic acid groups and other groups can also facilitate the adjustment of the solubility of the drag reducer molecules. The polymer drag reducer can only exhibit a good drag reduction effect if it is uniformly dissolved in the fluid. If the solubility is too strong, the drag reduction effect will be obvious in the initial stage of addition, but the drag reduction effect will not be sustained after a period of degradation. If the solubility is poor, polymer crystallization will occur, affecting the opening of the molecular chain and affecting the drag reduction effect.

[0013] The polyethylene glycol monooctylphenyl ether in this application is a nonionic emulsifier, and hydroxyethyl cellulose is an emulsifying dispersant. The addition of both can improve the polymerization quality of the product, increase the molecular weight and uniformity, thereby increasing the viscosity of the product, and at the same time can further enhance the drag reduction effect.

[0014] The present application introduces inorganic nanoparticle-modified nano-alumina and organically modified nano-diatomaceous earth into the drag reducer to form a nanocomposite polymer. These nanoparticles can increase the rigidity and strength of the polymer, thereby further improving the shear resistance of the drag reducer.

[0015] According to some embodiments of the present application, the weight ratio of the first polymer molecules to the second polymer molecules is (1.1-1.2):1.

[0016] According to some embodiments of the present application, the preparation of the first polymer molecule comprises the following steps:

[0017] A1. According to parts by weight, hexadecyl methacrylate, ethylene glycol mono-9-octadecene-1-ether, allyl triethylammonium chloride, polyethylene glycol monooctylphenyl ether, and hydroxyethyl cellulose were mixed and added to toluene, stirred at a speed of 300-500 r / min, nitrogen was introduced, and azobisisoheptanenitrile was added at a temperature of 70-90 ° C. After the reaction for 10-12 h, heating was stopped, and after cooling, an appropriate amount of anhydrous ethanol was added. After precipitation and separation, the mixture was washed several times with anhydrous ethanol and dried under vacuum at 60 ° C to constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyl triethylammonium chloride;

[0018] A2. The interfacial compatibilizer was added to a n-heptane solution of the polymer hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride in parts by weight, and then the modified nano-alumina was added. After mixing evenly, the mixture was stirred at a low speed at 60-80°C for 1-2 hours to obtain a first polymer molecule.

[0019] According to some embodiments of the present application, the preparation of the second polymer molecule comprises the following steps:

[0020] B1. Hexadecyl methacrylate, p-propanesulfonic acid styrene, 3,7-dimethyl-6-octenoic acid, polyethylene glycol monooctylphenyl ether, and hydroxyethyl cellulose were mixed and added to toluene, stirred at a speed of 300-500 r / min, nitrogen was introduced, and azobisisoheptanenitrile was added at a temperature of 70-90 ° C. After the reaction for 10-12h, heating was stopped, and after cooling, an appropriate amount of anhydrous ethanol was added. After precipitation and separation, the mixture was washed with anhydrous ethanol several times and dried under vacuum at 60 ° C to constant weight to obtain a polymer of hexadecyl methacrylate - p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid;

[0021] B2. Add the interfacial compatibilizer according to parts by weight to the n-heptane solution of the polymer hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, then add the organically modified nano-diatomaceous earth, mix well, and react with low-speed stirring at 60-80°C for 1-2 hours to obtain a second polymer molecule.

[0022] According to some embodiments of the present application, the preparation of the modified nano-alumina comprises the following steps:

[0023] S1. Ultrasonic dispersion of nano-alumina in a mixed solution of anhydrous ethanol and deionized water (8-9:1 mass ratio) was performed, and glycidyloxypropyltrimethoxysilane coupling agent was added under stirring. The temperature was raised to 70-80°C and magnetic stirring was maintained at a constant temperature for 5-8 hours. After centrifugation, washing, and drying, the organosilicon-modified nano-alumina was obtained.

[0024] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0025] S3. Add the graphene pretreated in step S2 to ethanol for ultrasonic dispersion, add the organosilicon-modified nano-alumina prepared in step S1, stir rapidly at 25-35°C to fully react, centrifuge, wash several times with anhydrous ethanol, vacuum dry, and grind to obtain modified nano-alumina.

[0026] Modified nano-alumina is used as a filler in nano-composite polymers. Due to its large specific surface area and high adsorption performance, nanomaterials can enhance the mechanical properties of polymers; alumina can effectively improve rigidity, antioxidant and corrosion resistance; silicone can increase the dispersion of nano-alumina in monomers, improving the rigidity and corrosion resistance of poly-nano-composite polymers; after graphene is acidified, its surface will be oxidized into carboxyl groups, which will combine with silicone-modified nano-alumina, reducing the problem of graphene's easy agglomeration. The layered structure of graphene makes the mixing between filler and resin more complete, thereby improving the shear strength of nano-composite polymers.

[0027] Furthermore, the weight ratio of the nano-alumina, the anhydrous ethanol and the glycidyloxypropyltrimethoxysilane coupling agent is 1:(8-10):(0.1-0.2).

[0028] Furthermore, the average particle size of the nano-alumina is 50-200 nm.

[0029] According to some embodiments of the present application, the preparation of the organically modified nano-diatomite includes the following steps: dissolving the nano-diatomite in deionized water, adding a Na2CO3 solution dropwise while stirring until the pH value stabilizes at 10, and simultaneously adding propylene glycol alginate and allowing to stand to obtain a stable suspension, heating to 120-150°C, adding a hexadecyltrimethylammonium bromide solution and isopropanol, reacting for 5-8 hours to obtain a modified diatomite suspension slurry, centrifuging to obtain a diatomite precipitate, washing away excess Br ions with an ethanol solution, using AgNO3 to test whether no yellow precipitate is produced, drying and grinding to obtain the organically modified nano-diatomite.

[0030] Furthermore, the weight ratio of the nano-diatomaceous earth, the hexadecyltrimethylammonium bromide solution and the isopropyl alcohol is 1:(1-2):(0.5-0.8).

[0031] Furthermore, the amount of propylene glycol alginate is 1% by weight of the nano-diatomaceous earth.

[0032] Furthermore, the mass percentage concentration of the Na2CO3 solution is 20-30%.

[0033] Furthermore, the stirring speed is 2000-3000 r / min.

[0034] According to some embodiments of the present application, the preparation of the interfacial compatibilizer includes the following steps: taking polyα-olefin, adding anhydrous ethanol to completely disperse it, using an ultrasonic cell crusher to ultrasonically crush it for 5-10 minutes, adding maleic anhydride that has been dried for 6-12 hours, and continuing ultrasonication for 10-30 minutes to obtain polyα-olefin grafted with anhydride as an interfacial compatibilizer.

[0035] Furthermore, the weight ratio of the poly-α-olefin to the maleic anhydride is 100:(2-4).

[0036] In a second aspect, the embodiments of the present application provide the application of the above-mentioned drag reducer for oil and gas gathering and transportation in oil product gathering and transportation.

[0037] The drag reducer of the present application is used in oil gathering and transportation, and can effectively reduce the friction resistance of the transportation pipeline, quickly and economically improve the pipeline transportation capacity, and increase the pipeline transportation volume. Since the drag reducer is not easily broken by shearing, it can better ensure the oil transportation stability of the oil pipeline and reduce transportation costs.

[0038] According to some embodiments of the present application, the specific application method is as follows: a first polymer molecule and a second polymer molecule are mixed according to a weight ratio, a certain amount of oil is added to dissolve the oil, and the amount of the oil is sufficient to dissolve the drag reducer, and then the drag reducer oil solution is injected into the oil gathering pipeline;

[0039] The amount of the drag reducer added to the oil gathering and transportation pipeline is 10-1000ppm.

[0040] Furthermore, the oil product includes crude oil, gasoline, kerosene or diesel. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions and advantages of this application more clear, the following will be further described in detail with reference to specific embodiments. The embodiments described here are only part of the embodiments of this application and should not be understood as limiting the scope of protection of this application.

[0042] Example 1

[0043] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0044] (1) Preparation of the first polymer molecule: 28 parts of hexadecyl methacrylate, 15 parts of ethylene glycol mono-9-octadecene-1-ether, 8 parts of allyl triethylammonium chloride, 0.8 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed with anhydrous ethanol several times and dried under vacuum at 60° C. to a constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 2.5 parts of modified nano-alumina were added. The mixture was mixed evenly and reacted at 70° C. with low-speed stirring for 1.5 hours to obtain a first polymer molecule;

[0045] (2) Preparation of the second polymer molecule: 27 parts of hexadecyl methacrylate, 15 parts of p-propanesulfonic acid styrene, 7 parts of 3,7-dimethyl-6-octenoic acid, 0.7 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed several times with anhydrous ethanol and dried under vacuum at 60°C to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 2.5 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed evenly and reacted at 70°C with low-speed stirring for 1.5 hours to obtain a second polymer molecule;

[0046] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.15:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0047] Among them, the preparation of modified nano-alumina:

[0048] S1. The nano-alumina was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 8.5:1. Glycidyl ether oxypropyl trimethoxysilane coupling agent was added under stirring. The temperature was raised to 75°C and magnetic stirring was maintained at a constant temperature for 6.5 hours. After centrifugation, washing, and drying, the organosilicon-modified nano-alumina was obtained.

[0049] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0050] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and rapidly stirred at 30°C to fully react, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0051] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:9:0.15;

[0052] Preparation of organically modified nano-diatomite: Nano-diatomite was dissolved in deionized water, and a 25% by mass concentration of Na2CO3 solution was added dropwise while stirring at a speed of 2500 r / min until the pH value stabilized at 10. At the same time, propylene glycol alginate was added dropwise in an amount of 1% by weight of the nano-diatomite and the mixture was allowed to stand to obtain a stable suspension. The temperature was raised to 35°C, and a hexadecyltrimethylammonium bromide solution and isopropanol were added. The mixture was reacted for 6.5 hours to obtain a modified diatomite suspension slurry. The mixture was centrifuged to obtain a diatomite precipitate. Excess Br ions were washed off with an ethanol solution. No yellow precipitate was produced by AgNO3 testing. The mixture was dried and ground to obtain the organically modified nano-diatomite.

[0053] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:1.5:0.65;

[0054] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 7 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 9 hours was added and ultrasonicated for 20 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0055] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:3.

[0056] Example 2

[0057] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0058] (1) Preparation of the first polymer molecule: 30 parts of hexadecyl methacrylate, 12 parts of ethylene glycol mono-9-octadecene-1-ether, 10 parts of allyl triethylammonium chloride, 0.5 parts of polyethylene glycol monooctylphenyl ether, and 2 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 300 r / min. Nitrogen protective gas was introduced, and 0.1 parts of azobisisoheptonitrile was added at a temperature of 90°C. After the reaction was stopped for 12 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the fraction was precipitated. After separation, the mixture was washed with anhydrous ethanol several times and dried under vacuum at 60° C. to constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 10 parts of an interfacial compatibilizer were added to a n-heptane solution of the polymer hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 3 parts of modified nano-alumina were added. The mixture was mixed evenly and then stirred at a low speed at 60° C. for 2 hours to obtain a first polymer molecule;

[0059] (2) Preparation of the second polymer molecule: 25 parts of hexadecyl methacrylate, 18 parts of p-propanesulfonic acid styrene, 5 parts of 3,7-dimethyl-6-octenoic acid, 1 part of polyethylene glycol monooctylphenyl ether, and 1 part of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 500 r / min. Nitrogen protective gas was introduced, and 0.3 parts of azobisisoheptonitrile was added at a temperature of 70°C. After the reaction was stopped for 10 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed several times with anhydrous ethanol and dried under vacuum at 60°C to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 12 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 2 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed well and stirred at a low speed at 80°C for 1 hour to obtain a second polymer molecule;

[0060] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.2:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0061] Among them, the preparation of modified nano-alumina:

[0062] S1. Ultrasonic dispersion of nano-alumina in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 8:1 was performed, and glycidyloxypropyltrimethoxysilane coupling agent was added under stirring. The temperature was raised to 80°C and magnetic stirring was maintained at this temperature for 5 hours. After centrifugation, washing, and drying, organosilicon-modified nano-alumina was obtained.

[0063] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0064] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and the mixture was rapidly stirred at 35°C to fully react, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0065] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:8:0.2;

[0066] Preparation of organically modified nano-diatomite: Nano-diatomite is dissolved in deionized water, and a 30% by mass concentration of Na2CO3 solution is added dropwise while stirring at a speed of 2000 r / min until the pH value stabilizes at 10. At the same time, propylene glycol alginate is added dropwise in an amount of 1% by weight of the nano-diatomite and the mixture is allowed to stand to obtain a stable suspension. The temperature is raised to 120°C, and a cetyltrimethylammonium bromide solution and isopropanol are added. The mixture is reacted for 8 hours to obtain a modified diatomite suspension slurry. The mixture is centrifuged to obtain a diatomite precipitate. Excess Br ions are washed off with an ethanol solution. No yellow precipitate is produced by AgNO3 testing. The mixture is dried and ground to obtain the organically modified nano-diatomite.

[0067] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:1:0.8;

[0068] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 5 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 12 hours was added and ultrasonicated for 10 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0069] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:4.

[0070] Example 3

[0071] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0072] (1) Preparation of the first polymer molecule: 25 parts of hexadecyl methacrylate, 18 parts of ethylene glycol mono-9-octadecene-1-ether, 6 parts of allyl triethylammonium chloride, 1 part of polyethylene glycol monooctylphenyl ether, and 1 part of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 500 r / min. Nitrogen protective gas was introduced, and 0.3 parts of azobisisoheptonitrile was added at a temperature of 70°C. After the reaction was stopped for 10 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed with anhydrous ethanol several times and dried under vacuum at 60° C. to a constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 12 parts of an interfacial compatibilizer were added to a n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 2 parts of modified nano-alumina were added. The mixture was mixed well and then stirred at a low speed at 80° C. for 1 hour to obtain a first polymer molecule;

[0073] (2) Preparation of the second polymer molecule: 30 parts of hexadecyl methacrylate, 12 parts of p-propanesulfonic acid styrene, 8 parts of 3,7-dimethyl-6-octenoic acid, 0.5 parts of polyethylene glycol monooctylphenyl ether, and 2 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 300 r / min. Nitrogen protective gas was introduced, and 0.1 parts of azobisisoheptonitrile was added at a temperature of 90°C. After the reaction was stopped for 12 hours, an appropriate amount of anhydrous ethanol was added after cooling, and precipitation and separation were performed. The mixture was then washed several times with anhydrous ethanol and dried at 60°C under vacuum conditions to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 10 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 3 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed evenly and stirred at a low speed at 60°C for 2 hours to obtain a second polymer molecule;

[0074] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.1:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0075] Among them, the preparation of modified nano-alumina:

[0076] S1. Ultrasonic dispersion of nano-alumina in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 9:1 was performed, and glycidyloxypropyltrimethoxysilane coupling agent was added under stirring. The temperature was raised to 70°C and magnetic stirring was maintained at this temperature for 8 hours. After centrifugation, washing, and drying, organosilicon-modified nano-alumina was obtained.

[0077] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0078] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and the mixture was rapidly stirred at 25°C to fully react, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0079] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:10:0.1;

[0080] Preparation of organically modified nano-diatomite: Nano-diatomite is dissolved in deionized water, and a 20% by mass concentration of Na2CO3 solution is added dropwise while stirring at a speed of 3000 r / min until the pH value stabilizes at 10. At the same time, propylene glycol alginate is added dropwise in an amount of 1% by weight of the nano-diatomite and the mixture is allowed to stand to obtain a stable suspension. The temperature is raised to 150°C, and a hexadecyltrimethylammonium bromide solution and isopropanol are added. The mixture is reacted for 5 hours to obtain a modified diatomite suspension slurry. The mixture is centrifuged to obtain a diatomite precipitate. Excess Br ions are washed off with an ethanol solution. No yellow precipitate is produced by AgNO3 testing. The mixture is dried and ground to obtain the organically modified nano-diatomite.

[0081] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:2:0.5;

[0082] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 10 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 6 hours was added and ultrasonicated for 30 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0083] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:2.

[0084] Example 4

[0085] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0086] (1) Preparation of the first polymer molecule: 27 parts of hexadecyl methacrylate, 14 parts of ethylene glycol mono-9-octadecene-1-ether, 8 parts of allyl triethylammonium chloride, 0.7 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and precipitation and separation were performed. The mixture was then washed with anhydrous ethanol several times and dried under vacuum at 60° C. to a constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 3 parts of modified nano-alumina were added. The mixture was mixed well and then stirred at a low speed at 70° C. for 1.5 hours to obtain a first polymer molecule;

[0087] (2) Preparation of the second polymer molecule: 28 parts of hexadecyl methacrylate, 15 parts of p-propanesulfonic acid styrene, 7 parts of 3,7-dimethyl-6-octenoic acid, 0.8 parts of polyethylene glycol monooctylphenyl ether, and 1.6 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 85°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed several times with anhydrous ethanol and dried under vacuum at 60°C to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 2.5 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed evenly and reacted at 70°C with low-speed stirring for 1.5 hours to obtain a second polymer molecule;

[0088] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.18:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0089] Among them, the preparation of modified nano-alumina:

[0090] S1. Ultrasonic dispersion of nano-alumina in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 8.5:1 was performed, and glycidyloxypropyltrimethoxysilane coupling agent was added under stirring. The temperature was raised to 75°C and magnetic stirring was maintained at this temperature for 6 hours. After centrifugation, washing, and drying, organosilicon-modified nano-alumina was obtained.

[0091] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0092] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and rapidly stirred at 32°C for full reaction, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0093] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:9:0.2;

[0094] Preparation of organically modified nano-diatomite: Nano-diatomite is dissolved in deionized water, and a 24% by mass concentration of Na2CO3 solution is added dropwise while stirring at a speed of 2500 r / min until the pH value stabilizes at 10. At the same time, propylene glycol alginate is added dropwise in an amount of 1% by weight of the nano-diatomite and the mixture is allowed to stand to obtain a stable suspension. The temperature is raised to 130°C, and a cetyltrimethylammonium bromide solution and isopropanol are added. The mixture is reacted for 6 hours to obtain a modified diatomite suspension slurry. The mixture is centrifuged to obtain a diatomite precipitate. Excess Br ions are washed off with an ethanol solution. No yellow precipitate is produced by AgNO3 testing. The mixture is dried and ground to obtain the organically modified nano-diatomite.

[0095] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:1.4:0.6;

[0096] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 8 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 10 hours was added and ultrasonicated for 25 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0097] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:3.

[0098] Comparative Example 1

[0099] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0100] (1) Preparation of the first polymer molecule: 36 parts of hexadecyl methacrylate, 15 parts of ethylene glycol mono-9-octadecene-1-ether, 0.8 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min, and nitrogen protective gas was introduced. 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C, and the heating was stopped after the reaction for 11 hours. After cooling, an appropriate amount of anhydrous ethanol was added, and after precipitation and separation, the mixture was washed with anhydrous ethanol for multiple times, and dried under vacuum conditions at 60°C to constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether; 11 parts of an interfacial compatibilizer were added to the n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether, and 2.5 parts of modified nano-alumina were added. After mixing evenly, the mixture was stirred at a low speed at 70°C for 1.5 hours to obtain the first polymer molecule;

[0101] (2) Preparation of the second polymer molecule: 27 parts of hexadecyl methacrylate, 15 parts of p-propanesulfonic acid styrene, 7 parts of 3,7-dimethyl-6-octenoic acid, 0.7 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed several times with anhydrous ethanol and dried under vacuum at 60°C to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 2.5 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed evenly and reacted at 70°C with low-speed stirring for 1.5 hours to obtain a second polymer molecule;

[0102] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.15:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0103] Among them, the preparation of modified nano-alumina:

[0104] S1. The nano-alumina was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 8.5:1. Glycidyl ether oxypropyl trimethoxysilane coupling agent was added under stirring. The temperature was raised to 75°C and magnetic stirring was maintained at a constant temperature for 6.5 hours. After centrifugation, washing, and drying, the organosilicon-modified nano-alumina was obtained.

[0105] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0106] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and rapidly stirred at 30°C to fully react, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0107] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:9:0.15;

[0108] Preparation of organically modified nano-diatomite: Nano-diatomite was dissolved in deionized water, and a 25% by mass concentration of Na2CO3 solution was added dropwise while stirring at a speed of 2500 r / min until the pH value stabilized at 10. At the same time, propylene glycol alginate was added dropwise in an amount of 1% by weight of the nano-diatomite and the mixture was allowed to stand to obtain a stable suspension. The temperature was raised to 35°C, and a hexadecyltrimethylammonium bromide solution and isopropanol were added. The mixture was reacted for 6.5 hours to obtain a modified diatomite suspension slurry. The mixture was centrifuged to obtain a diatomite precipitate. Excess Br ions were washed off with an ethanol solution. No yellow precipitate was produced by AgNO3 testing. The mixture was dried and ground to obtain the organically modified nano-diatomite.

[0109] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:1.5:0.65;

[0110] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 7 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 9 hours was added and ultrasonicated for 20 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0111] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:3.

[0112] Comparative Example 2

[0113] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0114] (1) Preparation of the first polymer molecule: 28 parts of hexadecyl methacrylate, 15 parts of ethylene glycol mono-9-octadecene-1-ether, 8 parts of allyl triethylammonium chloride, 0.8 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed with anhydrous ethanol several times and dried under vacuum at 60° C. to a constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 2.5 parts of modified nano-alumina were added. The mixture was mixed evenly and reacted at 70° C. with low-speed stirring for 1.5 hours to obtain a first polymer molecule;

[0115] (2) Preparation of the second polymer molecule: 27 parts of hexadecyl methacrylate, 15 parts of styrene p-propanesulfonate, 7 parts of 3,7-dimethyl-6-octenoic acid, 0.7 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction for 11 hours, heating was stopped, and after cooling, an appropriate amount of anhydrous ethanol was added. After precipitation and separation, the mixture was washed with anhydrous ethanol several times, and dried under vacuum conditions at 60°C to constant weight to obtain a polymer of hexadecyl methacrylate-styrene p-propanesulfonate-3,7-dimethyl-6-octenoic acid; 11 parts of an interfacial compatibilizer were added to the n-heptane solution of the polymer hexadecyl methacrylate-styrene p-propanesulfonate-3,7-dimethyl-6-octenoic acid, mixed evenly, and reacted at 70°C with low-speed stirring for 1.5 hours to obtain the second polymer molecule;

[0116] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.15:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0117] Among them, the preparation of modified nano-alumina:

[0118] S1. The nano-alumina was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water in a mass ratio of 8.5:1. Glycidyl ether oxypropyl trimethoxysilane coupling agent was added under stirring. The temperature was raised to 75°C and magnetic stirring was maintained at a constant temperature for 6.5 hours. After centrifugation, washing, and drying, the organosilicon-modified nano-alumina was obtained.

[0119] S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground.

[0120] S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and rapidly stirred at 30°C to fully react, centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried, and ground to obtain modified nano-alumina with an average particle size of 50-200 nm;

[0121] The weight ratio of nano-alumina, anhydrous ethanol and glycidyloxypropyltrimethoxysilane coupling agent is 1:9:0.15;

[0122] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 7 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 9 hours was added and ultrasonicated for 20 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0123] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:3.

[0124] Comparative Example 3

[0125] Preparation of drag reducing agent for oil and gas gathering and transportation:

[0126] (1) Preparation of the first polymer molecule: 28 parts of hexadecyl methacrylate, 15 parts of ethylene glycol mono-9-octadecene-1-ether, 8 parts of allyl triethylammonium chloride, 0.8 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation and then washed with anhydrous ethanol. The mixture was washed with alcohol several times and dried under vacuum at 60° C. to a constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride, and 2.5 parts of nano-alumina with an average particle size of 50-200 nm were added, the mixture was mixed evenly, and the mixture was stirred at a low speed at 70° C. for 1.5 hours to obtain a first polymer molecule;

[0127] (2) Preparation of the second polymer molecule: 27 parts of hexadecyl methacrylate, 15 parts of p-propanesulfonic acid styrene, 7 parts of 3,7-dimethyl-6-octenoic acid, 0.7 parts of polyethylene glycol monooctylphenyl ether, and 1.5 parts of hydroxyethyl cellulose were mixed and added to toluene according to weight parts, and stirred continuously at a speed of 400 r / min. Nitrogen protective gas was introduced, and 0.2 parts of azobisisoheptonitrile was added at a temperature of 80°C. After the reaction was stopped for 11 hours, an appropriate amount of anhydrous ethanol was added after cooling, and the mixture was separated by precipitation. The mixture was then washed several times with anhydrous ethanol and dried under vacuum at 60°C to a constant weight to obtain a polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid; 11 parts of an interfacial compatibilizer were added to an n-heptane solution of the polymer of hexadecyl methacrylate-p-propanesulfonic acid styrene-3,7-dimethyl-6-octenoic acid, and 2.5 parts of organically modified nano-diatomaceous earth were added. The mixture was mixed evenly and reacted at 70°C with low-speed stirring for 1.5 hours to obtain a second polymer molecule;

[0128] (3) mixing the first polymer molecules and the second polymer molecules in a weight ratio of 1.15:1, and adding a certain amount of diesel to dissolve the drag reducer;

[0129] The organically modified nano-diatomite was prepared by dissolving the nano-diatomite in deionized water, adding a 25% Na2CO3 solution by mass while stirring at 2500 r / min until the pH value stabilized at 10, and simultaneously adding propylene glycol alginate in an amount of 1% by weight of the nano-diatomite and allowing the mixture to stand to obtain a stable suspension. The mixture was heated to 35°C, and a hexadecyltrimethylammonium bromide solution and isopropanol were added. The mixture was reacted for 6.5 hours to obtain a modified diatomite suspension slurry. The mixture was centrifuged to obtain a diatomite precipitate. Excess Br ions were washed off with an ethanol solution. No yellow precipitate was produced by AgNO3 testing. The mixture was dried and ground to obtain the organically modified nano-diatomite.

[0130] The weight ratio of nano-diatomaceous earth, hexadecyltrimethylammonium bromide solution and isopropyl alcohol is 1:1.5:0.65;

[0131] Preparation of interfacial compatibilizer: Poly-α-olefin was completely dispersed in anhydrous ethanol, and ultrasonicated for 7 minutes using an ultrasonic cell crusher. Maleic anhydride dried for 9 hours was added and ultrasonicated for 20 minutes to obtain poly-α-olefin grafted with anhydride as an interfacial compatibilizer;

[0132] The weight ratio of the poly-α-olefin to the maleic anhydride is 100:3.

[0133] Experimental example

[0134] The drag reducers for oil and gas gathering and transportation prepared in Examples 1-4 and Comparative Examples 1-3 were tested for initial drag reduction rate and drag reduction rate after shearing for 10 minutes and 20 minutes, respectively.

[0135] The test data is shown in Table 1 below:

[0136] Table 1

[0137]

[0138] As can be seen from Table 1, the drag reducers for oil and gas gathering and transportation prepared in Examples 1-4 of the present application have good drag reduction rates and shear resistance.

[0139] In Comparative Example 1, allyl triethylammonium chloride in the raw material of the first polymer molecule was replaced with an equal weight of hexadecyl methacrylate, and the rest were the same as in Example 1. The drag reduction rate and shear resistance of the drag reducer for oil and gas gathering and transportation prepared in Comparative Example 1 were significantly reduced, indicating that the addition of the quaternary ammonium salt group of the present application can not only enhance the intermolecular association effect, but also regulate the solubility of the drag reducer molecules, thereby improving the drag reduction effect of the drag reducer.

[0140] The raw materials of the second polymer molecule in Comparative Example 2 do not contain organically modified nano-diatomite, and the rest are the same as in Example 1. The shear resistance of the drag reducer for oil and gas gathering and transportation prepared in Comparative Example 2 is significantly reduced, indicating that the present application introduces organically modified nano-diatomite into the drag reducer to form a nano-composite polymer, which can increase the rigidity and strength of the polymer, thereby further improving the shear resistance of the drag reducer.

[0141] In Comparative Example 3, ordinary nano-alumina is used instead of modified nano-alumina in the raw materials of the first polymer molecule, and the rest are the same as in Example 1. The drag reduction rate and shear resistance of the drag reducer for oil and gas gathering and transportation prepared in Comparative Example 3 are significantly reduced, indicating that modified alumina can increase the rigidity of the nano-composite polymer, thereby enhancing the shear strength of the nano-composite polymer. At the same time, the carboxylation treatment of the modified silicone and graphene surfaces can affect the solubility of the first polymer molecules, thereby improving the drag reduction rate.

[0142] Although the embodiments of the present application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions or variations may be made to these embodiments without departing from the principles and purpose of the present application, and that the technical solutions after these changes, modifications, substitutions or variations will fall within the scope of protection of the present application.

Claims

1. A drag reducer for oil and gas gathering and transportation, characterized in that: comprising a first polymer molecule and a second polymer molecule, wherein the first polymer molecule and the second polymer molecule are bound to each other through intermolecular association; The first polymer molecule comprises the following raw materials in parts by weight: 25-30 parts of hexadecyl methacrylate, 12-18 parts of ethylene glycol mono-9-octadecene-1-ether, 6-10 parts of allyltriethylammonium chloride, 0.1-0.3 parts of azobisisoheptonitrile, 0.5-1 parts of polyethylene glycol monooctylphenyl ether, 1-2 parts of hydroxyethyl cellulose, 2-3 parts of modified nano-alumina, and 10-12 parts of an interfacial compatibilizer; The second polymer molecule comprises the following raw materials in parts by weight: 25-30 parts of hexadecyl methacrylate, 12-18 parts of p-styrenepropanesulfonic acid, 5-8 parts of 3,7-dimethyl-6-octenoic acid, 0.1-0.3 parts of azobisisoheptonitrile, 0.5-1 parts of polyethylene glycol monooctylphenyl ether, 1-2 parts of hydroxyethyl cellulose, 2-3 parts of organically modified nano-diatomaceous earth, and 10-12 parts of an interfacial compatibilizer; The preparation of the modified nano-alumina comprises the following steps: S1. Ultrasonic dispersion of nano-alumina in a mixed solution of anhydrous ethanol and deionized water (8-9:1 mass ratio) was performed, and glycidyloxypropyltrimethoxysilane coupling agent was added under stirring. The temperature was raised to 70-80°C and magnetic stirring was maintained at a constant temperature for 5-8 hours. After centrifugation, washing, and drying, the organosilicon-modified nano-alumina was obtained. S2. Graphene pretreatment: Graphene was ultrasonically dispersed in a mixture of sulfuric acid and nitric acid, then refluxed at 80°C for 4 h. After the reaction, the graphene was dried and ground. S3. The graphene pretreated in step S2 was added to ethanol and ultrasonically dispersed, and the organosilicon-modified nano-alumina prepared in step S1 was added, and the reaction was rapidly stirred at 25-35 ° C., centrifuged, washed several times with anhydrous ethanol, and then vacuum-dried and ground to obtain modified nano-alumina; The preparation of the organically modified nano-diatomite comprises the following steps: dissolving the nano-diatomite in deionized water, adding a Na2CO3 solution dropwise while stirring until the pH value stabilizes at 10, simultaneously adding propylene glycol alginate dropwise and allowing the mixture to stand to obtain a stable suspension, heating the mixture to 120-150° C., adding a cetyltrimethylammonium bromide solution and isopropyl alcohol, reacting the mixture for 5-8 hours to obtain a modified diatomite suspension slurry, centrifuging the mixture to obtain a diatomite precipitate, washing the mixture with an ethanol solution to remove excess Br ions, verifying that no yellow precipitate is produced by AgNO3 testing, drying and grinding the mixture to obtain the organically modified nano-diatomite; The preparation of the interfacial compatibilizer comprises the following steps: taking polyalphaolefin, adding anhydrous ethanol to completely disperse it, using an ultrasonic cell crusher to ultrasonically crush it for 5-10 minutes, adding maleic anhydride dried for 6-12 hours, and continuing ultrasonication for 10-30 minutes to obtain polyalphaolefin grafted with anhydride as the interfacial compatibilizer.

2. The drag reducer for oil and gas gathering and transportation according to claim 1, characterized in that: The weight ratio of the first polymer molecules to the second polymer molecules is (1.1-1.2):

1.

3. The drag reducer for oil and gas gathering and transportation according to claim 1, characterized in that: The preparation of the first polymer molecule comprises the following steps: A1. According to parts by weight, hexadecyl methacrylate, ethylene glycol mono-9-octadecene-1-ether, allyl triethylammonium chloride, polyethylene glycol monooctylphenyl ether, and hydroxyethyl cellulose were mixed and added to toluene, stirred at a speed of 300-500 r / min, nitrogen was introduced, and azobisisoheptanenitrile was added at a temperature of 70-90 ° C. After the reaction for 10-12 h, heating was stopped, and after cooling, an appropriate amount of anhydrous ethanol was added. After precipitation and separation, the mixture was washed several times with anhydrous ethanol and dried under vacuum at 60 ° C to constant weight to obtain a polymer of hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyl triethylammonium chloride; A2. The interfacial compatibilizer was added to a n-heptane solution of the polymer hexadecyl methacrylate-ethylene glycol mono-9-octadecene-1-ether-allyltriethylammonium chloride in parts by weight, and then the modified nano-alumina was added. After mixing evenly, the mixture was stirred at a low speed at 60-80°C for 1-2 hours to obtain a first polymer molecule.

4. The drag reducer for oil and gas gathering and transportation according to claim 1, characterized in that: The preparation of the second polymer molecule comprises the following steps: B1. Hexadecyl methacrylate, p-styrenepropanesulfonic acid, 3,7-dimethyl-6-octenoic acid, polyethylene glycol monooctylphenyl ether, and hydroxyethyl cellulose were mixed and added to toluene, stirred at a speed of 300-500 r / min, nitrogen was introduced, and azobisisoheptanenitrile was added at a temperature of 70-90 ° C. After the reaction for 10-12h, heating was stopped, and after cooling, an appropriate amount of anhydrous ethanol was added. After precipitation and separation, it was washed several times with anhydrous ethanol and dried under vacuum at 60 ° C to constant weight to obtain a polymer of hexadecyl methacrylate - p-styrenepropanesulfonic acid -3,7-dimethyl-6-octenoic acid; B2. Add the interfacial compatibilizer according to parts by weight to the n-heptane solution of the polymer hexadecyl methacrylate-p-styrenepropanesulfonic acid-3,7-dimethyl-6-octenoic acid, then add the organically modified nano-diatomaceous earth, mix well, and react with low-speed stirring at 60-80°C for 1-2 hours to obtain a second polymer molecule.

5. The drag reducer for oil and gas gathering and transportation according to claim 1, characterized in that: The weight ratio of the nano-alumina, the anhydrous ethanol and the glycidyloxypropyltrimethoxysilane coupling agent is 1:(8-10):(0.1-0.2).

6. Use of the drag reducer for oil and gas gathering and transportation according to any one of claims 1 to 5 in oil gathering and transportation.

7. The use of a drag reducer for oil and gas gathering and transportation according to claim 6, characterized in that: The oil products include crude oil, gasoline, kerosene or diesel.

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