Surfactant as well as preparation method and application thereof

Abstract

The invention discloses a surfactant, and relates to the technical field of reservoir fracturing extraction and production integrated transformation in the petroleum industry, in particular to a surfactant as well as a preparation method and application thereof, and preparation raw materials of the surfactant comprise acrylamide or a derivative thereof, acrylic acid, an active monomer, sulfonate I and an initiator; the active monomer is prepared from the following raw materials: alkyl bromide, sulfonate II and a polymerization inhibitor; the surfactant disclosed by the invention is suitable for fracturing fluids used during fracturing transformation of low-permeability reservoirs such as shale and compact sandstone, and the imbibition extraction rate of the fracturing fluids can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of integrated transformation of reservoir fracturing and extraction in the petroleum industry, and in particular to a surfactant and a preparation method and application thereof. Background Art

[0002] During oilfield development, the interfaces of the reservoir include three interfaces: displacement fluid-crude oil, displacement fluid-rock, and crude oil-rock. The properties of the reservoir interface have a great influence on the recovery rate of the reservoir. At present, it is generally believed that changing the wettability of the reservoir can also significantly improve the recovery rate of the reservoir. Wettability is a basic parameter of reservoir physical properties and has a great influence on crude oil recovery. Therefore, how to effectively change the wettability of the reservoir to improve the recovery rate becomes crucial. The change in wettability induced by surfactants has a great influence on the relative permeability of the oil-water phase, the distribution of residual oil, the law of oil-water seepage, and the water drive recovery rate.

[0003] Chinese patent CN113480988B discloses a degradable fracturing fluid oil displacement agent suitable for low permeability and tight oil reservoirs, and its preparation method and application. This prior art has developed a green, environmentally friendly, and easily degradable amphiphilic polymer fracturing fluid oil displacement agent, the preparation method of which has a reliable principle and is easy to operate. The prepared degradable amphiphilic polymer fracturing fluid oil displacement agent has excellent sand carrying capacity, strong shear resistance, temperature resistance and salt resistance, and has both biocompatibility and degradability. It has a wide range of applicability and can be used as an excellent low permeability and tight oil reservoir fracturing and oil displacement integrated system to improve the exploitation efficiency of low permeability and tight oil reservoirs, and has good practical application value. However, the temperature resistance of the degradable fracturing fluid oil displacement agent prepared in this patent is only 80°C, and it is not suitable for all fracturing fluids.

[0004] Chinese patent CN115895635A discloses a fracturing fluid oil-displacing agent and a fracturing fluid, wherein the fracturing fluid oil-displacing agent is prepared by compounding fatty alcohol polyoxyethylene ether, anionic surfactant, and pH regulator as main raw materials, supplemented with deionized water as solvent, and nonionic surfactant fatty alcohol polyoxyethylene ether and anionic surfactant. The salt resistance and high temperature resistance of the fracturing fluid can be effectively improved, but the temperature resistance of the fracturing fluid oil-displacing agent prepared in the patent is only 80°C. When the temperature exceeds 80°C, the fracturing and recovery effect is significantly reduced, and it is not suitable for all fracturing fluids.

[0005] Chinese patent CN113755148B discloses a viscosity-reducing oil displacement composition and a composite oil displacement agent, which is mainly composed of a viscosity-reducing agent and a mobility control agent; the mass ratio of the viscosity-reducing agent to the mobility control agent is 0.2-1.7:0.05-0.4. The mobility control agent and the viscosity-reducing agent in the viscosity-reducing oil displacement composition of the invention can greatly improve the recovery rate of high-mineralization heavy oil reservoirs through synergistic action. The composite oil displacement system formed by the viscosity-reducing oil displacement composition as a viscosity-reducing agent and a mobility control agent has a good ability to reduce crude oil viscosity and improve recovery when applied to heavy oil reservoirs. However, the temperature resistance of the fracturing fluid oil displacement agent prepared in the patent is only 80°C. When it exceeds 80°C, the fracturing and recovery effect is significantly reduced, and it is not suitable for all fracturing fluids.

[0006] Chinese patent CN115851251A discloses a fracturing oil-displacing agent and its preparation method and application. A fracturing oil-displacing agent is prepared with fatty alcohol polyoxyethylene ether nonionic surfactant and heavy alkylbenzene sulfonate as main raw materials. When displacing crude oil in low permeability reservoirs and / or tight oil reservoirs, the fracturing oil-displacing agent has low interfacial tension, high imbibition and oil washing efficiency, moderate emulsification, and can effectively change rock wettability and improve recovery. In addition, the fracturing oil-displacing agent has low adsorption in the target reservoir and good long-term stability. The fracturing oil-displacing agent has little effect on the gelling property, viscosity, rheology and other properties of the fracturing fluid, and the actual production and promotion cycle is short, which has good application and promotion prospects.

[0007] At present, under the condition of certain reservoir properties and fracturing technology, in order to further improve the recovery rate of ultra-low and ultra-low permeability reservoirs and shale reservoirs, it is necessary to use fracturing fluid to supplement energy, improve seepage, prevent scaling, and improve water injection efficiency. Furthermore, it is necessary to work on fluid dynamics to improve oil seepage efficiency, improve oil and water migration capacity, and allow crude oil to fully enter the main fracture channel to improve single well productivity and achieve the purpose of increasing production. In other words, an important factor that determines the development efficiency of ultra-low and ultra-low permeability reservoirs such as shale oil is the oil and water permeability, which plays a decisive role in oil well productivity.

[0008] Therefore, it is urgent to carry out research on key materials for improving oil recovery by using high-efficiency surfactants, and to cooperate with fracturing fluids to improve oil and gas replacement and recovery efficiency, and to make full use of the effect of fracturing fluids in the formation, so as to achieve economical and efficient development of shale oil reservoirs. At the same time, it can be promoted and used in fracturing and recovery of tight oil and gas and coalbed methane, and has good application prospects. Summary of the invention

[0009] The present invention aims to solve the problems in the prior art that the recovery rate of ultra-low and ultra-low permeability oil reservoirs and shale oil reservoirs is low, and the oil-water absorption capacity of the existing fracturing fluid used for the recovery of ultra-low and ultra-low permeability oil reservoirs and shale oil reservoirs is poor. The present invention provides a high-efficiency surfactant, which has a synergistic effect with the fracturing fluid and can improve the performance of oil and gas replacement and recovery efficiency.

[0010] In order to solve the above technical problems, the first aspect of the present invention provides a surfactant, which is a polymerization product of four monomers: acrylamide or its derivatives, acrylic acid, active monomer, and sulfonate I; the raw materials for preparing the active monomer include brominated alkanes, sulfonate II and an inhibitor.

[0011] According to some embodiments of the present invention, based on the total mass of acrylamide or its derivatives, acrylic acid, active monomers and sulfonate I as 100%, wherein:

[0012] The content of acrylamide or its derivatives is 30% to 55%, preferably 40%;

[0013] The content of acrylic acid is 10% to 25%, preferably 15%;

[0014] The content of active monomer is 20% to 30%, preferably 25%;

[0015] The content of sulfonate I is 15% to 35%, preferably 20%.

[0016] According to some embodiments of the present invention, in the raw material for preparing the active monomer, the mass ratio of the brominated alkane to the sulfonate II is 1:(0.8-1.3), preferably 1:1.

[0017] According to some embodiments of the present invention, the mass of the polymerization inhibitor is 0.05% to 0.1% of the total mass of the brominated alkane and the sulfonate II.

[0018] According to some embodiments of the present invention, the acrylamide derivative is selected from alkyl acrylamide; preferably, the alkyl acrylamide is selected from at least one of octadecyl acrylamide, N-dodecyl acrylamide and N,N-tetradecyl acrylamide.

[0019] According to some embodiments of the present invention, the sulfonate I and sulfonate II are the same or different, and are independently selected from sodium p-styrene sulfonate or sodium C14-C18 olefin sulfonate; preferably, the sodium C14-C18 olefin sulfonate is selected from at least one of sodium tetradecene sulfonate, sodium hexadecene sulfonate, and sodium octadecene sulfonate.

[0020] According to some embodiments of the present invention, the brominated alkane is selected from at least one of dodecane bromide, tetradecane bromide, hexadecane bromide and octadecane bromide.

[0021] According to some embodiments of the present invention, the polymerization inhibitor is selected from at least one of hydroquinone, p-benzoquinone, and p-hydroxyanisole.

[0022] According to some embodiments of the present invention, the preparation of the active monomer comprises: mixing a brominated alkane and a sulfonate II in a solvent I, and reacting in the presence of a polymerization inhibitor to obtain the active monomer.

[0023] According to some embodiments of the present invention, based on the total mass of the brominated alkane, the sulfonate II and the solvent I being 100%, the mass fraction of the brominated alkane and the sulfonate II is 15% to 45%, preferably 30%.

[0024] According to some embodiments of the present invention, the reaction conditions include: the reaction temperature is 30° C. to 50° C., preferably 45° C.; the reaction time is 8 h to 24 h, preferably 16 h.

[0025] According to some embodiments of the present invention, the solvent I is selected from at least one of acetone, ethanol and ether.

[0026] In the present invention, when the active monomer is prepared, after the reaction is completed, the process further includes naturally cooling to room temperature, then washing the unreacted monomer with ether to precipitate white crystals, and vacuum drying at room temperature to obtain the active monomer; wherein the reaction path of the active monomer is as follows:

[0027]

[0028] The second aspect of the present invention provides a method for preparing the above-mentioned surfactant, comprising the following steps:

[0029] 1) performing a first mixing of acrylamide or a derivative thereof, acrylic acid and at least 1 / 2 weight of a solvent II to obtain a first mixture;

[0030] 2) after a second mixing of the active monomer, the sulfonate salt I and the remaining weight solvent II, an initiator is added to obtain a second mixture;

[0031] 3) Under stirring conditions, adding the second mixture obtained in step 2) to the first mixture obtained in step 1) to react to obtain the surfactant.

[0032] According to some embodiments of the present invention, the total mass of acrylamide or its derivatives, acrylic acid, active monomers and sulfonate I accounts for 45% to 60%, preferably 50%, of the total mass of solvent II.

[0033] In the present invention, the mass ratio of the solvent II in step 1) to the remaining weight of the solvent II in step 2) is 3:2.

[0034] According to some embodiments of the present invention, the solvent II is selected from at least one of anhydrous ethanol, acetone, acetonitrile, ether and petroleum ether.

[0035] According to some embodiments of the present invention, in step 1), the conditions of the first mixing include: temperature of 20°C to 25°C, preferably 25°C, time of 10 min to 20 min, preferably 15 min, stirring rate of 200 r / min to 400 r / min, preferably 300 r / min.

[0036] According to some embodiments of the present invention, in step 2), the mass of the initiator is 0.2% to 0.5%, preferably 0.4%, of the total mass of the acrylamide or its derivative, acrylic acid, active monomer and sulfonate I.

[0037] According to some embodiments of the present invention, in step 2), the initiator is selected from at least two of disodium ethylenediaminetetraacetate, azobisisobutyramidine hydrochloride, azobisisobutyronitrile, and azobisisoheptylonitrile; preferably, the initiator is disodium ethylenediaminetetraacetate and azobisisobutyramidine hydrochloride, wherein the mass ratio of disodium ethylenediaminetetraacetate to azobisisobutyramidine hydrochloride is 5:(2-4), preferably 5:3.

[0038] According to some embodiments of the present invention, in step 2), the conditions for the second mixing include: temperature of 20°C to 25°C, preferably 25°C, time of 10 min to 20 min, preferably 15 min, and stirring rate of 200 r / min to 400 r / min, preferably 300 r / min.

[0039] According to some embodiments of the present invention, in step 3), the stirring rate is 200 r / min to 400 r / min, preferably 300 r / min.

[0040] According to some embodiments of the present invention, in step 3), the reaction conditions include: temperature of 40°C to 50°C, preferably 44°C, and time of 3.5h to 6h, preferably 4.5h.

[0041] According to some embodiments of the present invention, in step 3), the reaction is then kept warm for 4 to 8 hours, preferably 6 hours.

[0042] According to some embodiments of the present invention, in step 3), the heat preservation further includes purification.

[0043] In the present invention, the surfactant obtained in step 3) is a crude product, and the purification comprises transferring the crude product to a round-bottom flask, removing the solvent by rotary evaporation at a temperature of 50°C to obtain a white solid; then adding anhydrous acetic acid to the round-bottom flask, shaking, so that the unreacted raw materials are dissolved in the anhydrous acetic acid, and then filtering with a Buchner funnel to obtain a precipitate; washing the precipitate with anhydrous ether for multiple times, filtering with suction, to obtain a product with higher purity; finally transferring the product to a watch glass, placing it in a vacuum drying oven for drying, and obtaining a surfactant product after drying.

[0044] The synthetic route of the surfactant described in the present invention is as follows:

[0045]

[0046] A third aspect of the present invention provides a fracturing fluid, comprising the above-mentioned surfactant; preferably, in the fracturing fluid, based on 100% water, the added amount of the surfactant is 0.1 wt% to 0.7 wt%.

[0047] A fourth aspect of the present invention provides a use of the above surfactant in a fracturing fluid.

[0048] The surfactant of the present invention is suitable for use in fracturing fluid used in fracturing and reforming low-permeability reservoirs such as shale and dense sandstone.

[0049] Beneficial effects:

[0050] The surfactant is prepared by copolymerizing acrylamide or its derivatives, acrylic acid, active monomers and sulfonates, wherein acrylamide is cheap and serves as the main body, acrylic acid serves as a hydrophobic monomer to maintain hydrophobicity, the active monomer provides a hydrophilic group to improve water solubility, and the sulfonates mainly improve temperature resistance. The surfactant is used in fracturing fluid used in fracturing and transformation of low-permeability reservoirs such as shale and dense sandstone, and the surfactant can be adsorbed on the rock surface, improve the wettability of the rock surface, and promote the desorption and stripping of crude oil from the rock surface. In addition, the surfactant has amphiphilic properties and can form an adsorption film on the surface of oil droplets, promote oil-water emulsification, and enable the oil to be discharged with the flowback fluid, thereby improving the absorption and recovery rate of the fracturing fluid. DETAILED DESCRIPTION

[0051] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.

[0052] The three-necked flask, the constant pressure dropping funnel, the Buchner funnel, the vacuum drying oven and the heat-collecting magnetic heating stirring water bath pot in the present invention are all common commercially available products.

[0053] The sodium p-styrene sulfonate in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0054] The hydroquinone in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0055] Acrylamide in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0056] Acrylic acid in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0057] The azobisisobutylamidine hydrochloride in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0058] The disodium ethylenediaminetetraacetic acid in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0059] The brominated alkane in the present invention was purchased from Aladdin Biochemical Technology Co., Ltd. and was analytically pure.

[0060] The steps for preparing the active monomer used in the embodiments of the present invention are as follows:

[0061] Acetone is added as a solvent in a three-necked flask, and then brominated alkane and sodium p-styrene sulfonate are added (the mass ratio of brominated alkane to sodium p-styrene sulfonate is 1:1) to obtain a reaction solution; based on the total mass of the reaction solution being 100%, the mass fraction of brominated alkane and sodium p-styrene sulfonate in the reaction solution is 30%; then a polymerization inhibitor (hydroquinone) is added to the reaction solution; based on the total mass of brominated alkane and sodium p-styrene sulfonate being 100%, the added amount of the polymerization inhibitor is 0.05% of the total mass, and finally the three-necked flask was installed in a heat-collecting magnetic heating stirring water bath, stirred and heated to a reaction temperature of 45°C at a rate of 100r / min, and reacted at a temperature of 45°C for 16h to obtain a viscous liquid; after the reaction, the viscous liquid was naturally cooled to 25°C, and then the unreacted brominated alkane and sodium p-styrene sulfonate were washed away with ether, white crystals were precipitated, and vacuum dried at a temperature of 25°C to obtain the active monomer.

[0062] Example 1

[0063] This embodiment provides a surfactant.

[0064] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 15%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 20%;

[0065] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0066] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0067] The preparation method is as follows:

[0068] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0069] 2) 25 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the second mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0070] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0071] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0072] Example 2

[0073] This embodiment provides a surfactant.

[0074] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 15%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 20%;

[0075] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (acetone);

[0076] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0077] The preparation method is as follows:

[0078] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 120 g of acetone as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0079] 2) After dissolving 25 g of active monomer and 20 g of sodium p-styrene sulfonate in 80 g of acetone for a second mixing, 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of disodium ethylenediaminetetraacetate were added to obtain a second mixture after complete dissolution, and the second mixture was transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the second mixing temperature was 25° C., the time was 15 min, and the stirring rate was 300 r / min;

[0080] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0081] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent acetone is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0082] Example 3

[0083] This embodiment provides a surfactant.

[0084] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 15%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 20%;

[0085] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (ether);

[0086] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0087] The preparation method is as follows:

[0088] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 120 g of ether as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and turning on magnetic stirring for a first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0089] 2) 25 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 80 g of ether for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0090] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0091] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent ether is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0092] Example 4

[0093] This embodiment provides a surfactant.

[0094] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 15%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 20%;

[0095] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 40% of the total mass of solvent II (anhydrous ethanol);

[0096] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0097] The preparation method is as follows:

[0098] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 150 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0099] 2) 25 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 100 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0100] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0101] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0102] Example 5

[0103] This embodiment provides a surfactant.

[0104] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 15%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 20%;

[0105] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 60% of the total mass of solvent II (anhydrous ethanol);

[0106] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0107] The preparation method is as follows:

[0108] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g acrylamide and 15 g acrylic acid into the three-necked flask, using 100 g anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0109] 2) 25 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 67 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0110] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to about 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0111] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0112] Example 6

[0113] This embodiment provides a surfactant.

[0114] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 30%, the content of acrylic acid is 15%, the content of active monomer is 35%, and the content of sodium p-styrene sulfonate is 20%;

[0115] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0116] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0117] The preparation method is as follows:

[0118] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 30 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0119] 2) 35 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0120] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to about 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0121] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0122] Example 7

[0123] This embodiment provides a surfactant.

[0124] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 50%, the content of acrylic acid is 15%, the content of active monomer is 15%, and the content of sodium p-styrene sulfonate is 20%;

[0125] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0126] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0127] The preparation method is as follows:

[0128] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 50 g of acrylamide and 15 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0129] 2) 15 g of active monomer and 20 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0130] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to about 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0131] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0132] Example 8

[0133] This embodiment provides a surfactant.

[0134] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 50%, the content of acrylic acid is 20%, the content of active monomer is 5%, and the content of sodium p-styrene sulfonate is 25%;

[0135] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0136] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0137] The preparation method is as follows:

[0138] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 50 g of acrylamide and 20 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0139] 2) 5 g of active monomer and 25 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0140] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0141] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0142] Example 9

[0143] This embodiment provides a surfactant.

[0144] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 25%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 10%;

[0145] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0146] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0147] The preparation method is as follows:

[0148] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 25 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0149] 2) 25 g of active monomer and 10 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0150] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0151] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0152] Example 10

[0153] This embodiment provides a surfactant.

[0154] The raw materials for preparation are calculated based on the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate as 100%, wherein the content of acrylamide is 40%, the content of acrylic acid is 5%, the content of active monomer is 25%, and the content of sodium p-styrene sulfonate is 30%;

[0155] The total mass of the acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate accounts for 50% of the total mass of solvent II (anhydrous ethanol);

[0156] The brominated alkane used in the reactive monomer is tetradecane bromide.

[0157] The preparation method is as follows:

[0158] 1) installing a three-necked flask in a heat-collecting magnetic heating stirring water bath, adding 40 g of acrylamide and 5 g of acrylic acid into the three-necked flask, using 120 g of anhydrous ethanol as a solvent, placing a magnetic rotor, installing a thermometer and a condenser on the three-necked flask, and starting magnetic stirring for first mixing to obtain a first mixture; wherein the first mixing temperature is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0159] 2) 25 g of active monomer and 30 g of sodium p-styrene sulfonate are dissolved in 80 g of anhydrous ethanol for a second mixing, and then 0.15% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of azobisisobutylamidine hydrochloride and 0.25% of the total mass of acrylamide, acrylic acid, active monomer and sodium p-styrene sulfonate of disodium ethylenediaminetetraacetate are added to obtain a second mixture after complete dissolution, and the second mixture is transferred to a constant pressure dropping funnel and placed on the three-necked flask in step 1); wherein the temperature of the first mixing is 25° C., the time is 15 min, and the stirring rate is 300 r / min;

[0160] 3) Turn on the heating switch of the heat-collecting magnetic heating stirring water bath and maintain a stirring rate of 300 r / min. When heated to 44°C, open the constant pressure dropping funnel to allow the second mixture to drip into the three-necked flask to react with the first mixture. The entire dropping time is controlled within 4.5 h. After the dropping is completed, keep warm for 6 h, stop heating, and obtain a crude product.

[0161] 4) Purification of crude product: The crude product in the three-necked flask is transferred to a round-bottom flask, and the solvent anhydrous ethanol is removed by rotary evaporation at a temperature of 50° C. to obtain a white solid; then anhydrous acetic acid is added to the round-bottom flask, and the mixture is shaken to dissolve the unreacted raw material in the anhydrous acetic acid, and then filtered with a Buchner funnel to obtain a precipitate; the precipitate is washed with anhydrous ether for multiple times and filtered to obtain a product with higher purity; finally, the product is transferred to a watch glass, and placed in a vacuum drying oven for drying, and the surfactant is obtained after drying.

[0162] Comparative Example 1

[0163] This comparative example provides a surfactant.

[0164] The method described in Example 1 was followed, except that no active monomer was added during the preparation of the surfactant.

[0165] Comparative Example 2

[0166] This comparative example provides a surfactant.

[0167] The method described in Example 1 was followed, except that sodium p-styrene sulfonate was not added during the preparation of the surfactant.

[0168] Comparative Example 3

[0169] This comparative example provides a surfactant.

[0170] The method described in Example 1 was followed, except that acrylamide was not added during the preparation of the surfactant.

[0171] Comparative Example 4

[0172] This comparative example provides a surfactant.

[0173] The method described in Example 1 was followed, except that no acrylic acid was added during the preparation of the surfactant.

[0174] In order to further illustrate the progress of the present invention, the contents of acrylamide, acrylic acid, active monomers and sodium p-styrene sulfonate (sulfonate I), the amount of initiator added, and the proportion of the total mass of acrylamide, acrylic acid, active monomers and sodium p-styrene sulfonate (sulfonate I) to the total mass of solvent II in Examples 1-10 and Comparative Examples 1-4 of the present invention are statistically shown in Table 1 below;

[0175] Table 1

[0176]

[0177] In Table 1 above, the total amount of monomers is the ratio of the total mass of acrylamide, acrylic acid, active monomers and sodium p-styrene sulfonate to the total mass of solvent II.

[0178] Test Case

[0179] The surfactants prepared in Examples 1-10 of the present invention and Comparative Examples 1-4 were applied to fracturing fluids for extraction, and the surface tension and interfacial tension of the fracturing fluid containing the surfactant of the present invention were measured according to the "SY / T5370 Surface and Interfacial Tension Determination Method", and the imbibition extraction rate of the fracturing fluid containing the surfactant of the present invention was measured according to the "Q_SLCG0403-2021 Imbibition Extraction Agent for Fracturing Fluid", and the measurement results are statistically shown in Table 2; in addition, the surfactants prepared in Examples 1-10 of the present invention and Comparative Examples 1-4 were placed in an oven at a temperature of 60°C to 130°C for 4 hours, and then taken out to measure their surface and interfacial tensions, and the temperature resistance of the surfactant was judged according to whether the surface and interfacial tensions of the surfactant changed significantly; for example, the surfactant prepared in Example 1 of the present invention was placed in an oven at a temperature of 120°C for 4 hours, and then taken out to measure that its surface and interfacial tensions did not change, thereby judging that its temperature resistance can reach 120°C;

[0180] As mentioned above, the fracturing fluid is prepared: based on 100% water, the added amount of the drag reducing agent is 0.3wt%, the added amount of the clay stabilizer is 0.1wt%, the added amount of the drainage agent is 0.1wt%, the added amount of the drainage agent and the surfactant of the present invention is 0.2wt%; wherein the drag reducing agent is a drag reducing agent for fracturing, liquid, numbered Q / SLCG0089, purchased from Beijing Hongyi Enze Energy Technology Co., Ltd.; the clay stabilizer product number is acid fracturing / clay stabilizer, liquid, numbered Q / SHCG125, purchased from Beijing Hongyi Enze Energy Technology Co., Ltd.; the drainage agent is purchased from the Petroleum Engineering Research Institute of China Petrochemical Corporation, industrial grade (preparation method such as Example 1 of CN108239532B); other components are commonly used components of fracturing fluid and are not limited.

[0181] Table 2

[0182]

[0183]

[0184] In Table 2, the blank group is a fracturing fluid without adding the surfactant of the present invention; the pure water group is a fracturing fluid containing only water;

[0185] It can be seen from the data in Table 2 that, compared with the pure water group, although the blank group added a drag reducer, a clay stabilizer and a drainage agent to reduce the surface tension and interfacial tension of the fracturing fluid, the imbibition recovery rate did not improve at all; while in Comparative Examples 1-4, compared with the blank group, the surfactants prepared in Comparative Examples 1-4 were added respectively, which reduced the surface tension and interfacial tension of the fracturing fluid to a certain extent, and improved the imbibition recovery rate of the fracturing fluid; in Examples 1-10, compared with the blank group and Comparative Examples 1-4, the surfactants prepared in Examples 1-10 were added respectively, which significantly reduced the surface tension and interfacial tension of the fracturing fluid, and improved the imbibition recovery rate of the fracturing fluid, indicating that the surfactants described in the present invention can improve the imbibition recovery rate of the fracturing fluid.

[0186] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A surfactant, characterized in that The surfactant is a polymerization product of four monomers: acrylamide or its derivatives, acrylic acid, active monomer, and sulfonate I; the active monomer is prepared from raw materials including brominated alkane, sulfonate II and inhibitor.

2. The surfactant according to claim 1, characterized in that Taking the total mass of acrylamide or its derivatives, acrylic acid, active monomers and sulfonate I as 100%, wherein: The content of acrylamide or its derivatives is 30% to 55%, preferably 40%; The content of acrylic acid is 10% to 25%, preferably 15%; The content of active monomer is 20% to 30%, preferably 25%; The content of sulfonate I is 15% to 35%, preferably 20%; and / or, in the raw material for preparing the active monomer, the mass ratio of the brominated alkane to the sulfonate II is 1:(0.8-1.3), preferably 1:1; And / or, the mass of the polymerization inhibitor is 0.05% to 0.1% of the total mass of the brominated alkane and the sulfonate II.

3. The surfactant according to claim 2, characterized in that The acrylamide derivative is selected from alkyl acrylamide; preferably, the alkyl acrylamide is selected from at least one of octadecyl acrylamide, N-dodecyl acrylamide, and N,N-tetradecyl acrylamide; And / or, the sulfonate I and sulfonate II are the same or different, and are independently selected from sodium p-styrene sulfonate or sodium C14-C18 olefin sulfonate; preferably, the sodium C14-C18 olefin sulfonate is selected from at least one of sodium tetradecene sulfonate, sodium hexadecene sulfonate, and sodium octadecene sulfonate; And / or, the brominated alkane is at least one selected from dodecane bromide, tetradecane bromide, hexadecane bromide, and octadecane bromide; And / or, the polymerization inhibitor is selected from at least one of hydroquinone, p-benzoquinone and p-hydroxyanisole.

4. The surfactant according to any one of claims 1 to 3, characterized in that The preparation of the active monomer comprises: mixing bromoalkane and sulfonate II in solvent I, and reacting in the presence of a polymerization inhibitor to obtain the active monomer.

5. The surfactant according to claim 4, characterized in that Based on the total mass of the brominated alkane, the sulfonate II and the solvent I as 100%, the mass fraction of the brominated alkane and the sulfonate II is 15% to 45%, preferably 30%; And / or, the reaction conditions include: reaction temperature of 30°C to 50°C, preferably 45°C; reaction time of 8h to 24h, preferably 16h; And / or, the solvent I is selected from at least one of acetone, ethanol and ether.

6. A method for preparing a surfactant as claimed in any one of claims 1 to 5, characterized in that: The steps include: 1) performing a first mixing of acrylamide or a derivative thereof, acrylic acid and solvent II to obtain a first mixture; 2) after a second mixing of the active monomer, the sulfonate salt I and the solvent II, an initiator is added to obtain a second mixture; 3) Under stirring conditions, adding the second mixture obtained in step 2) to the first mixture obtained in step 1) to react to obtain the surfactant.

7. The preparation method according to claim 6, characterized in that: The total mass of the acrylamide or its derivatives, acrylic acid, active monomers and sulfonate I accounts for 45% to 60% of the mass of solvent II, preferably 50%; and / or, the solvent II is selected from at least one of anhydrous ethanol, acetone, acetonitrile, ether and petroleum ether; And / or, in step 1), the first mixing conditions include: temperature of 20°C to 25°C, time of 10min to 20min, stirring rate of 200r / min to 400r / min; And / or, in step 2), the mass of the initiator is 0.2% to 0.5%, preferably 0.4%, of the total mass of the acrylamide or its derivative, acrylic acid, active monomer and sulfonate I; And / or, in step 2), the initiator is selected from at least two of disodium ethylenediaminetetraacetate, azobisisobutyramidine hydrochloride, azobisisobutyronitrile, and azobisisoheptylonitrile; And / or, in step 2), the second mixing conditions include: temperature of 20°C to 25°C, time of 10 min to 20 min, and stirring rate of 200 r / min to 400 r / min.

8. The preparation method according to claim 6 or 7, characterized in that: In step 3), the stirring rate is 200r / min to 400r / min; And / or, the reaction conditions include: temperature of 40°C to 50°C, preferably 44°C, time of 3.5h to 6h, preferably 4.5h; And / or, the reaction is followed by heat preservation for 4 to 8 hours, preferably 6 hours; And / or, the heat preservation further includes purification.

9. A fracturing fluid, characterized in that: The fracturing fluid comprises the surfactant described in any one of claims 1 to 5 or the surfactant prepared by the preparation method described in any one of claims 6 to 9; preferably, in the fracturing fluid, based on 100% water, the added amount of the surfactant is 0.1 wt% to 0.7 wt%.

10. Use of the surfactant according to any one of claims 1 to 5 or the surfactant prepared by the preparation method according to any one of claims 6 to 9 in fracturing fluid.

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