Discharge aiding agent for oilfield fracturing and preparation method of discharge aiding agent

Abstract

The invention discloses a discharge aiding agent for oilfield fracturing, and relates to the technical field of oilfield exploitation, the discharge aiding agent comprises 10-500 parts of mahogany petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silica nanoparticles, 2-79 parts of alkyl halide, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water; the invention also discloses a preparation method of the oil field fracturing cleanup additive. According to the formula provided by the invention, the composite fracturing cleanup additive is formed, the surface activity, the rheological property and the high temperature and high pressure resistance are remarkably improved, the flowability and the liquid drainage effect of the oil field fracturing fluid are effectively promoted, the accurately-controlled preparation method is adopted, the steps of stirring, reacting, cooling and pH adjusting are optimized, it is ensured that all the components are uniformly mixed and fully react, and the oil field fracturing fluid is prepared. The discharge aiding agent is suitable for various oil field fracturing operations, and the stability and the anti-pollution capability are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield exploitation, and specifically relates to an oilfield fracturing flowback aid and a preparation method thereof. Background Art

[0002] With the continuous deepening of oilfield exploitation, some problems have gradually emerged in traditional oilfield fracturing flowback aids, such as unstable performance, greater impact on the environment, shorter service life, etc. These problems have seriously affected the oilfield exploitation efficiency and economic benefits. Therefore, developing a new type of oilfield fracturing flowback aid that can improve fluid transportation during oilfield exploitation, reduce fluid residue during oilfield fracturing, improve oilfield exploitation efficiency, and reduce environmental impact has become an urgent need in the industry.

[0003] Existing fracturing flowback aids are mostly composed of a single chemical component or a mixture of a few chemical components, and it is difficult to balance performance and stability. By adopting advanced compounding techniques to develop a new type of fracturing flowback aid that integrates high efficiency, environmental friendliness, and stability, it can effectively improve the fracturing effect of oilfields and solve some technical bottlenecks in existing fracturing flowback aids. Summary of the Invention

[0004] To solve the above technical problems, an oilfield fracturing flowback aid and a preparation method thereof are provided, and this technical solution solves the above problems.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An oilfield fracturing flowback aid is prepared from the following amounts of materials: 10 - 500 parts of petroleum sulfonate, 20 - 450 parts of alkylbenzene sulfonate, 10 - 590 parts of fatty alcohol, 1 - 50 parts of ethylene oxide, 1 - 90 parts of silicon dioxide nanoparticles, 2 - 79 parts of haloalkane, 20 - 90 parts of sodium hydroxide, 1 - 80 parts of sodium carbonate, 5 - 50 parts of xanthan gum, 1 - 78 parts of carbon nanotubes, and 100 - 1000 parts of water.

[0007] Preferably, it is specifically prepared from the following amounts of materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silicon dioxide nanoparticles, 65 parts of haloalkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes, and 800 parts of water.

[0008] Preferably, the petroleum sulfonate is one of the mono-sulfonic acid salt and the bis-sulfonic acid salt. The petroleum sulfonic acid salt is prepared by a sulfonation reaction. It is obtained by sulfonating petroleum fractions with fuming sulfuric acid and sulfur trioxide to produce petroleum sulfonate, followed by separation and purification. The alkylbenzene sulfonate is one of the linear alkylbenzene sulfonate and the branched-chain alkylbenzene sulfonate. The sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate, and sodium carbonate decahydrate.

[0009] Preferably, the fatty alcohol is one of the saturated fatty alcohol and the unsaturated fatty alcohol. The fatty alcohol is prepared based on the hydrogenation method of natural oils. Using natural oils as raw materials, under the action of a catalyst, it reacts with hydrogen to convert the fatty acid glyceride in the oil into fatty alcohol. The ethylene oxide is one of industrial-grade ethylene oxide and high-purity ethylene oxide. The silicon dioxide nanoparticles include spherical silicon dioxide nanoparticles and non-spherical silicon dioxide nanoparticles, which are prepared based on gas-phase reactions; the haloalkane is one or more of fluoroalkane, chloroalkane, bromoalkane, and iodoalkane;

[0010] Preferably, the xanthan gum is one of low-viscosity xanthan gum, medium-viscosity xanthan gum, and high-viscosity xanthan gum. The carbon nanotubes are one of single-walled carbon nanotubes and multi-walled carbon nanotubes. The sodium hydroxide is one of flake sodium hydroxide, granular sodium hydroxide, and liquid sodium hydroxide. The water is deionized water.

[0011] A preparation method of a fracturing fluid flowback aid for oil fields, and the preparation steps are as follows:

[0012] S1. Prepare materials, including: 10 - 500 parts of petroleum sulfonate, 20 - 450 parts of alkylbenzene sulfonate, 10 - 590 parts of fatty alcohol, 1 - 50 parts of ethylene oxide, 1 - 90 parts of silicon dioxide nanoparticles, 2 - 79 parts of haloalkane, 20 - 90 parts of sodium hydroxide, 1 - 80 parts of sodium carbonate, 5 - 50 parts of xanthan gum, 1 - 78 parts of carbon nanotubes, and 100 - 1000 parts of water;

[0013] S2. Prepare the sodium hydroxide and sodium carbonate solutions. Add sodium hydroxide and water to the reaction kettle and stir to dissolve, making a sodium hydroxide solution, and take it out for standby; add sodium carbonate and water to the reaction kettle and stir to obtain a sodium carbonate solution, and take it out for standby;

[0014] S3. React the fatty alcohol with ethylene oxide. Add the fatty alcohol to the reaction kettle, stir and heat up to 120 - 150 °C, and slowly add ethylene oxide to the reaction kettle through a constant-pressure dropping funnel. The dropping time is 2 h; wait for the dropping to complete, and continue to stir and react for 3 - 4 h to make the fatty alcohol react with ethylene oxide to obtain fatty alcohol polyoxyethylene ether;

[0015] S4. Mixed surfactant material: Cool the prepared fatty alcohol polyoxyethylene ether to 60 - 80 °C, add petroleum sulfonate and alkylbenzene sulfonate, stir for 1 - 2 h until evenly mixed; then add silicon dioxide nanoparticles, and increase the stirring speed to 500 - 600 r / min, stir for 2 - 3 h to disperse the silicon dioxide nanoparticles in the system; continue to add alkyl halide, xanthan gum and carbon nanotubes and keep stirring for 3 - 4 h until evenly dispersed.

[0016] S5. Neutralization and pH adjustment: While stirring, add sodium hydroxide solution and sodium carbonate solution dropwise to the reaction kettle to adjust the pH value of the system to 7 - 9.

[0017] S6. Filtration and finished product: Take out the mixture and filter it through a filter to remove impurities and agglomerates, transfer the filtered product to a storage container to obtain the fracturing flowback aid.

[0018] Preferably, the S2 specifically includes:

[0019] Add sodium hydroxide and water to the reaction kettle in a predetermined ratio, start the stirring system in the reaction kettle, set the stirring speed to 200 - 300 r / min, and keep stirring for 20 minutes until the sodium hydroxide is completely dissolved to ensure the formation of a uniform sodium hydroxide solution. After this solution is completed, transfer it to a storage container and label it with the preparation date and concentration of the solution for standby.

[0020] Add sodium carbonate powder and water to the reaction kettle, start stirring, keep the stirring rate at 200 - 300 r / min, and keep stirring until the sodium carbonate is completely dissolved to form a sodium carbonate solution. After the stirring is completed, take out this solution and transfer it to a storage container for standby, ensuring that the solution is uniform and has no precipitation.

[0021] Preferably, the S3 specifically includes:

[0022] Add fatty alcohol to the reaction kettle in proportion for preliminary mixing with other components in the reaction kettle. Subsequently, heat the reaction kettle through an external heating device to reach the target temperature of 120 - 150 °C to ensure the reaction between fatty alcohol and ethylene oxide. During this process, monitor the temperature and pressure in the reaction kettle in real time, and continuously track the progress of the reaction through temperature sensors and pressure sensors.

[0023] Slowly and evenly drip ethylene oxide into the reaction kettle through a constant pressure dropping funnel, control the dropping time to 2 hours. After the dropping is completed, continue to stir and react for 3 - 4 hours to ensure the full reaction between fatty alcohol and ethylene oxide to form fatty alcohol polyoxyethylene ether.

[0024] Preferably, the S4 specifically includes:

[0025] After the synthesis of fatty alcohol polyoxyethylene ether is completed, the temperature is rapidly decreased. The temperature decrease time is set to 2 hours. During the temperature decrease process, cooling water is used to help the reaction kettle dissipate heat;

[0026] Petroleum sulfonic acid hydrochloride is added into the reaction kettle in advance and stirred for 30 minutes to ensure its full dissolution and uniform dispersion. Then alkylbenzene sulfonate is added into the reaction kettle and stirring is continued until the materials in the reaction kettle are fully mixed evenly;

[0027] After stirring evenly, silica nanoparticles are slowly added, the stirring speed is increased to 500 - 600 r / min, and stirring is continued for 2 - 3 hours to ensure that the silica nanoparticles are fully dispersed in the whole system.

[0028] Preferably, the S6 specifically includes:

[0029] After the reaction is completed, the mixture in the reaction kettle is taken out and filtered through a filter. The aperture of the upper filter screen of the selected filter is 10 - 50 μm to remove any residual impurities and agglomerates;

[0030] The filtered product is sent to the inspection department for quality inspection to ensure that it meets the standard requirements, including the concentration and viscosity of the surfactant. The qualified product is sealed and labeled before packaging, indicating the batch number, production date and usage instructions of the product.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The present invention proposes to form a composite fracturing fluid flowback aid by combining various components such as petroleum sulfonate, alkylbenzene sulfonate, fatty alcohol, ethylene oxide, silica nanoparticles, and haloalkane, which significantly improves the surface activity, rheology and high temperature and high pressure resistance, effectively promotes the fluidity and drainage effect of the oilfield fracturing fluid. An accurately controlled preparation method is adopted to optimize the steps of stirring, reaction, temperature decrease and pH adjustment to ensure the uniform mixing and full reaction of each component, guarantee the high-efficiency and stable product quality. In addition, natural source raw materials such as fatty alcohol and silica nanoparticles are selected to reduce the environmental impact, and at the same time, the cost is controlled through an accurate formula, with good economy. This flowback aid is applicable to various oilfield fracturing operations, enhances the stability and anti-pollution ability, ensures the long-term maintenance of the effect, and reduces the performance loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the step flow framework diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations.

[0035] Referring to Figure 1 as shown, a kind of oilfield fracturing flowback aid and its preparation method include:

[0036] A kind of oilfield fracturing flowback aid is prepared from the following parts by weight of materials: 10 - 500 parts of petroleum sulfonate, 20 - 450 parts of alkylbenzene sulfonate, 10 - 590 parts of fatty alcohol, 1 - 50 parts of ethylene oxide, 1 - 90 parts of silicon dioxide nanoparticles, 2 - 79 parts of haloalkane, 20 - 90 parts of sodium hydroxide, 1 - 80 parts of sodium carbonate, 5 - 50 parts of xanthan gum, 1 - 78 parts of carbon nanotubes and 100 - 1000 parts of water.

[0037] Preferably, it is specifically prepared from the following parts by weight of materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silicon dioxide nanoparticles, 65 parts of haloalkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes and 800 parts of water.

[0038] Preferably, the petroleum sulfonate is one of mono - sulfonic acid salt and bis - sulfonic acid salt, and the petroleum sulfonate is prepared by sulfonation reaction. Sulfonation is carried out by fuming sulfuric acid, sulfur trioxide and petroleum fraction to generate petroleum sulfonate, and then it is obtained through separation and purification. The alkylbenzene sulfonate is one of linear alkylbenzene sulfonate and branched - chain alkylbenzene sulfonate. The sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate and sodium carbonate decahydrate.

[0039] Preferably, the fatty alcohol is one of saturated fatty alcohol and unsaturated fatty alcohol, and the fatty alcohol is prepared based on the hydrogenation method of natural oils and fats. Using natural oils and fats as raw materials, under the action of a catalyst, it reacts with hydrogen to convert fatty acid glycerides in the oils and fats into fatty alcohols. The ethylene oxide is one of industrial - grade ethylene oxide and high - purity ethylene oxide. The silicon dioxide nanoparticles include spherical silicon dioxide nanoparticles and non - spherical silicon dioxide nanoparticles, and are prepared based on gas - phase reaction; the haloalkane is one or more of fluoroalkane, chloroalkane, bromoalkane and iodoalkane;

[0040] Preferably, the xanthan gum is one of low - viscosity xanthan gum, medium - viscosity xanthan gum and high - viscosity xanthan gum, the carbon nanotubes are one of single - wall carbon nanotubes and multi - wall carbon nanotubes, the sodium hydroxide is one of flake caustic soda, granular sodium hydroxide and liquid sodium hydroxide, and the water is deionized water.

[0041] A preparation method of an oilfield fracturing flowback aid, the preparation steps are as follows:

[0042] S1. Prepare materials, including: 10 - 500 parts of petroleum sulfonate, 20 - 450 parts of alkylbenzene sulfonate, 10 - 590 parts of fatty alcohol, 1 - 50 parts of ethylene oxide, 1 - 90 parts of silicon dioxide nanoparticles, 2 - 79 parts of haloalkane, 20 - 90 parts of sodium hydroxide, 1 - 80 parts of sodium carbonate, 5 - 50 parts of xanthan gum, 1 - 78 parts of carbon nanotubes, and 100 - 1000 parts of water;

[0043] S2. Prepare sodium hydroxide and sodium carbonate solutions. Add sodium hydroxide and water to a reaction kettle, stir and dissolve to make a sodium hydroxide solution, and take it out for standby; add sodium carbonate and water to the reaction kettle and stir to obtain a sodium carbonate solution, and take it out for standby;

[0044] Dissolving sodium hydroxide and sodium carbonate separately can ensure their stable existence in the solution, avoid unnecessary chemical reactions due to mixing, thus ensuring the purity and concentration of their respective solutions. Separately preparing the solutions helps to more precisely control the concentrations of sodium hydroxide and sodium carbonate, which is beneficial for precise operations in subsequent experiments or reactions, ensuring the controllability and efficiency of the reactions. In subsequent steps, sodium hydroxide and sodium carbonate solutions with corresponding concentrations can be precisely added as needed, thereby improving the efficiency of chemical reactions and the quality of reaction products. Through stirring and appropriate conditions, sodium hydroxide and sodium carbonate can better exert their solubility when dissolved in water separately, reducing the possible crystallization or incomplete dissolution phenomena during the dissolution process. During the separate preparation process, the sharp reactions or heat release that may occur when sodium hydroxide and sodium carbonate are dissolved simultaneously can be avoided, enhancing the safety of the operation process;

[0045] S3. React fatty alcohol with ethylene oxide. Add fatty alcohol to a reaction kettle, stir and heat up to 120 - 150 °C, and slowly add ethylene oxide to the reaction kettle through a constant pressure dropping funnel over a period of 2 h; wait for the addition to be completed, and continue stirring and reacting for 3 - 4 h to react fatty alcohol with ethylene oxide to obtain fatty alcohol polyoxyethylene ether;

[0046] Ethylene oxide is slowly added dropwise through a constant-pressure dropping funnel, which can precisely control the reaction rate, avoid the formation of by-products or incomplete reactions caused by the too-fast reaction of ethylene oxide. Heating to 120 - 150 °C helps to accelerate the reaction, improve the reaction efficiency between fatty alcohol and ethylene oxide, and ensure the full reaction of reactants during the reaction process. Slowly adding dropwise ethylene oxide can effectively avoid the excess or too-high concentration of ethylene oxide, reduce the occurrence of over-reaction or by-products, thereby improving the purity of the target product. The dropping time and subsequent stirring reaction ensure the full reaction between fatty alcohol and ethylene oxide, contribute to obtaining a fatty alcohol polyoxyethylene ether with a longer and more stable molecular chain, and improve the uniformity and quality of the product. Through stepwise addition, the temperature change in the reaction kettle is effectively controlled, avoiding local overheating or overcooling, and ensuring the controllability and stability of the reaction. Through long-term stirring and reaction, it can promote the complete reaction between fatty alcohol and ethylene oxide, ensure the stability and performance of fatty alcohol polyoxyethylene ether, and avoid the residue of unreacted raw materials. The process of slowly adding dropwise ethylene oxide helps to improve the reaction yield and the output of the product, reducing waste;

[0047] S4. Mixed surfactant material: Cool the prepared fatty alcohol polyoxyethylene ether to 60 - 80 °C, add petroleum sulfonate and alkylbenzene sulfonate, stir for 1 - 2 h to mix evenly; then add silicon dioxide nanoparticles, and increase the stirring speed to 500 - 600 r / min, stir for 2 - 3 h to disperse the silicon dioxide nanoparticles in the system; continue to add haloalkane, xanthan gum and carbon nanotubes and keep stirring for 3 - 4 h to stir and disperse evenly;

[0048] Adding petroleum sulfonate and alkylbenzene sulfonate at 60 - 80 °C and stirring for 1 - 2 hours can ensure the full mixing of these surfactants, form a uniform solution or emulsion, improve the compatibility of each component, and provide a basis for subsequent reactions and dispersions. Adding silicon dioxide nanoparticles and increasing the stirring speed to 500 - 600 r / min can promote the uniform dispersion of silicon dioxide nanoparticles in the system. A higher stirring speed helps to break the particle agglomeration phenomenon, make the nanoparticles more evenly distributed in the solution, thereby improving the stability and performance of the material. The addition of haloalkane, xanthan gum and carbon nanotubes further enhances the performance of the system. For example, haloalkane can improve the solubility of the surfactant, xanthan gum helps to increase the viscosity and stability of the system, and carbon nanotubes can enhance the mechanical properties and electrical conductivity of the material. This process ensures the full reaction and uniform distribution of various components through continuous stirring and dispersion, thereby improving various physical and chemical properties such as the stability, mechanical properties, and electrical conductivity of the final product, making it have better application performance. Nanoparticles can be better dispersed in the solution during this process, which not only improves their surface activity but also enhances their functionality in various applications, such as providing enhanced performance in coatings, plastics or chemicals;

[0049] S5, Neutralization and pH adjustment: While stirring, add sodium hydroxide solution and sodium carbonate solution to the reaction kettle to adjust the pH value of the system to 7 - 9.

[0050] S6, Filtration and finished product: Take out the mixture and filter it through a filter to remove impurities and agglomerates. Transfer the filtered product to a storage container to obtain the fracturing fluid drainage aid.

[0051] Preferably, the S2 specifically includes:

[0052] Add sodium hydroxide and water to the reaction kettle in a predetermined ratio. Start the stirring system in the reaction kettle, set the stirring speed to 200 - 300 r / min, and continuously stir for 20 minutes until the sodium hydroxide is completely dissolved to ensure the formation of a uniform sodium hydroxide solution. After this solution is completed, transfer it to a storage container and label it with the preparation date and concentration of the solution for standby.

[0053] Add sodium carbonate powder and water to the reaction kettle and start stirring. Keep the stirring rate at 200 - 300 r / min and continuously stir until the sodium carbonate is completely dissolved to form a sodium carbonate solution. After the stirring is completed, take out this solution and transfer it to a storage container for standby, ensuring that the solution is uniform and has no precipitation.

[0054] Preferably, the S3 specifically includes:

[0055] Add fatty alcohol to the reaction kettle in proportion for preliminary mixing with other components in the reaction kettle. Subsequently, heat the reaction kettle through an external heating device to reach the target temperature of 120 - 150 °C to ensure the reaction between fatty alcohol and ethylene oxide. During this process, continuously monitor the temperature and pressure in the reaction kettle, and continuously track the progress of the reaction through temperature sensors and pressure sensors.

[0056] Slowly and evenly add ethylene oxide to the reaction kettle through a constant pressure dropping funnel. Control the dropping time to 2 hours. After the dropping is completed, continue to stir and react for 3 - 4 hours to ensure the full reaction between fatty alcohol and ethylene oxide to form fatty alcohol polyoxyethylene ether.

[0057] Preferably, the S4 specifically includes:

[0058] After the synthesis of fatty alcohol polyoxyethylene ether is completed, quickly cool down. Set the cooling time to 2 hours. During the cooling process, use cooling water to help the reaction kettle dissipate heat.

[0059] Pre - add petroleum sulfonic acid hydrochloride to the reaction kettle and stir for 30 minutes to ensure its full dissolution and uniform dispersion. Then add alkyl benzene sulfonate to the reaction kettle and continue to stir until the materials in the reaction kettle are fully mixed and uniform.

[0060] After stirring evenly, slowly add silicon dioxide nanoparticles, increase the stirring speed to 500 - 600 r / min, and continue stirring for 2 - 3 hours to ensure that the silicon dioxide nanoparticles are fully dispersed throughout the system.

[0061] Preferably, the S6 specifically includes:

[0062] After the reaction is completed, take out the mixture in the reaction kettle and filter it through a filter. The aperture of the upper filter screen of the selected filter is 10 - 50 μm to remove any residual impurities and agglomerates;

[0063] The filtered product is sent to the inspection department for quality inspection to ensure that it meets the standard requirements, including the concentration and viscosity of the surfactant. Seal and label the qualified product before packaging, indicating the batch number, production date and usage instructions of the product.

[0064] In summary, the advantages of the present invention are as follows:

[0065] By combining various components such as petroleum sulfonate, alkylbenzene sulfonate, fatty alcohol, ethylene oxide, silicon dioxide nanoparticles, and haloalkane, the present invention forms a composite fracturing flowback aid. The synergistic effect of each component significantly improves the surface activity, rheology, high temperature and high pressure resistance and other properties of the flowback aid, effectively promoting the fluidity and drainage effect of the oilfield fracturing fluid;

[0066] The present invention adopts a precisely controlled preparation method. By optimizing key steps such as stirring, reaction, cooling, and pH adjustment, it ensures that the components of the flowback aid can be evenly mixed and fully reacted, guaranteeing the high efficiency and stability of the final product. In addition, measures such as real-time temperature and pressure monitoring and filtration ensure the controllability of the entire preparation process and the high quality of the product;

[0067] The various raw materials selected in the present invention, such as fatty alcohol, silicon dioxide nanoparticles, xanthan gum, etc. from natural sources, have low environmental hazards, which is beneficial to reducing the environmental burden during oilfield exploitation. At the same time, the proportion of the components in the formula is precisely calculated, which can not only ensure the performance but also control the cost, having good economy;

[0068] This fracturing flowback aid can be widely used in various types of oilfield fracturing operations, especially in oilfield exploitation under complex geological environments, which can improve the overall efficiency of oilfield exploitation. Due to its unique formula and preparation method, it can also meet the requirements of different reservoirs and well conditions, having strong adaptability;

[0069] The flowback aid in the present invention uses a variety of additives and nanoparticles to enhance its stability and anti-pollution ability, and can maintain its effect for a long time, reducing the performance loss caused by precipitation or decomposition.

[0070] Experimental Procedures for the Performance and Efficiency of Fracturing Flowback Agents

[0071] Prepare experimental materials, including fracturing flowback agent solutions, solvents, and experimental equipment;

[0072] Add a certain amount of fracturing flowback agent to a known volume of deionized water at a concentration of 1% w / v. Stir the solution thoroughly in a stirrer to ensure complete dissolution of the flowback agent.

[0073] Measure the turbidity of the solution using a photometer or turbidimeter to determine whether there are undissolved solid particles in the solution;

[0074] Test the viscosity change of the aqueous solution using a viscometer and record the effect of the flowback agent on the solution viscosity;

[0075] At different temperatures, test the stability of the solution and record the time change. Test the solubility of the flowback agent by titration and analyze its dissolution efficiency in water;

[0076] Prepare acid solutions with known concentrations, including hydrochloric acid and sulfuric acid. Add a certain amount of the flowback agent to the acid solution at a concentration of 1% w / v. Heat the mixture in a constant temperature water bath and stir under constant temperature conditions to ensure that the flowback agent reacts fully with the acid solution;

[0077] Measure the pH value change of the acid solution, observe the acid solubility effect of the solution, and evaluate the dissolution efficiency of the flowback agent in the acid solution by measuring the precipitation of solid particles in the solution.

[0078] Table 1 below is the data table obtained during the experiment

[0079]

[0080] Table 1

[0081] The above has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A fracturing aid for oil fields, characterized in that: The invention is prepared from the following materials: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of halogenated alkane, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water.

2. The oilfield fracturing drainage agent according to claim 1, characterized in that: It is specifically prepared from the following materials: 500 parts of petroleum sulfonate, 450 parts of alkylbenzene sulfonate, 500 parts of fatty alcohol, 45 parts of ethylene oxide, 55 parts of silica nanoparticles, 65 parts of halogenated alkane, 20 parts of sodium hydroxide, 78 parts of sodium carbonate, 15 parts of xanthan gum, 22 parts of carbon nanotubes and 800 parts of water.

3. The oilfield fracturing drainage agent according to claim 2, characterized in that: Petroleum sulfonate is one of monosulfonic hydrochloric acid and disulfonic hydrochloric acid. Petroleum sulfonic hydrochloric acid is prepared by sulfonation reaction. Fuming sulfuric acid, sulfur trioxide and petroleum fractions are sulfonated to generate petroleum sulfonate, which is obtained by separation and purification. Alkylbenzene sulfonate is one of linear alkylbenzene sulfonate and branched alkylbenzene sulfonate. Sodium carbonate includes anhydrous sodium carbonate, sodium carbonate monohydrate and sodium carbonate decahydrate.

4. The oilfield fracturing drainage agent according to claim 3, characterized in that: The fatty alcohol is one of a saturated fatty alcohol and an unsaturated fatty alcohol. The preparation of the fatty alcohol is based on a natural oil hydrogenation method. Natural oil is used as a raw material. Under the action of a catalyst, it reacts with hydrogen to convert the fatty acid glyceride in the oil into fatty alcohol. The ethylene oxide is one of industrial grade ethylene oxide and high-purity ethylene oxide. The silica nanoparticles include spherical silica nanoparticles and non-spherical silica nanoparticles, which are prepared based on a gas phase reaction. The alkyl halide is one or more of a fluoroalkane, a chloroalkane, a bromoalkane and an iodoalkane.

5. The oilfield fracturing drainage agent according to claim 4, characterized in that: The xanthan gum is one of low-viscosity xanthan gum, medium-viscosity xanthan gum and high-viscosity xanthan gum, the carbon nanotube is one of single-walled carbon nanotube and multi-walled carbon nanotube, the sodium hydroxide is one of flake sodium hydroxide, granular sodium hydroxide and liquid sodium hydroxide, and the water is deionized water.

6. A method for preparing an oilfield fracturing agent, characterized in that: The preparation steps are: S1. Prepare materials, including: 10-500 parts of petroleum sulfonate, 20-450 parts of alkylbenzene sulfonate, 10-590 parts of fatty alcohol, 1-50 parts of ethylene oxide, 1-90 parts of silicon dioxide nanoparticles, 2-79 parts of alkyl halide, 20-90 parts of sodium hydroxide, 1-80 parts of sodium carbonate, 5-50 parts of xanthan gum, 1-78 parts of carbon nanotubes and 100-1000 parts of water; S2, sodium hydroxide and sodium carbonate solution preparation, add sodium hydroxide and water in a reactor and stir, dissolve, make sodium hydroxide solution, take out for use; add sodium carbonate and water in a reactor and stir, get sodium carbonate solution, take out for use; S3, reacting fatty alcohol with ethylene oxide, adding fatty alcohol to a reactor, stirring and heating to 120-150°C, slowly adding ethylene oxide to the reactor through a constant pressure dropping funnel, the dropping time is 2h; waiting for the addition to be completed, continuing to stir the reaction for 3-4h, so that the fatty alcohol and ethylene oxide react to obtain fatty alcohol polyoxyethylene ether; S4, mixing surfactant materials, cooling the prepared fatty alcohol polyoxyethylene ether to 60-80°C, adding petroleum sulfonate and alkylbenzene sulfonate, stirring for 1-2 hours, and mixing evenly; then adding silica nanoparticles, and increasing the stirring speed to 500-600r / min, stirring for 2-3 hours, and dispersing the silica nanoparticles in the system; continue to add alkyl halides, xanthan gum and carbon nanotubes and continue stirring for 3-4 hours, stirring and dispersing evenly; S5, neutralization pH adjustment, under stirring, sodium hydroxide solution and sodium carbonate solution are added dropwise to the reaction kettle to adjust the pH value of the system to 7-9; S6, filtration and finished product, take out the mixture and filter it through a filter to remove impurities and agglomerates, transfer the filtered product to a storage container to obtain a fracturing drainage agent.

7. The method for preparing an oilfield fracturing drainage agent according to claim 6, characterized in that: The S2 specifically includes: Add sodium hydroxide and water into the reactor in a predetermined ratio, start the stirring system in the reactor, set the stirring speed to 200-300r / min, and continue stirring for 20 minutes until the sodium hydroxide is completely dissolved to ensure the formation of a uniform sodium hydroxide solution. After the solution is completed, transfer it to a storage container and affix a label to indicate the preparation date and concentration of the solution for standby use; Add sodium carbonate powder and water into the reactor, start stirring, maintain the stirring rate at 200-300r / min, and continue stirring until the sodium carbonate is completely dissolved to form a sodium carbonate solution. After stirring, take out the solution and transfer it to a storage container for standby use, ensuring that the solution is uniform and free of precipitation.

8. The method for preparing an oilfield fracturing drainage agent according to claim 6, characterized in that: The S3 specifically includes: Fatty alcohol is added to the reactor in proportion and preliminarily mixed with other ingredients in the reactor. Subsequently, the reactor is heated by an external heating device to a target temperature of 120-150°C to ensure that the fatty alcohol reacts with ethylene oxide. During this process, the temperature and pressure in the reactor are monitored in real time, and the progress of the reaction is continuously tracked by temperature sensors and pressure sensors. Through a constant pressure dropping funnel, slowly and evenly add ethylene oxide into the reactor. The dropping time is controlled to be 2 hours. After the dropping is completed, continue to stir the reaction for 3 to 4 hours to ensure that the fatty alcohol and ethylene oxide react fully to form fatty alcohol polyoxyethylene ether.

9. The method for preparing an oilfield fracturing drainage agent according to claim 6, characterized in that: The S4 specifically includes: After the synthesis of fatty alcohol polyoxyethylene ether is completed, the temperature is quickly lowered. The cooling time is set to 2 hours. During the cooling process, cooling water is used to help the reactor dissipate heat. Add petroleum sulfonic acid into the reactor in advance and stir for 30 minutes to ensure that it is fully dissolved and evenly dispersed. Then add alkylbenzene sulfonate into the reactor and continue stirring until the materials in the reactor are fully mixed. After stirring evenly, slowly add silica nanoparticles, increase the stirring speed to 500-600r / min, and continue stirring for 2-3 hours to ensure that the silica nanoparticles are fully dispersed in the entire system.

10. The method for preparing an oilfield fracturing drainage agent according to claim 6, characterized in that: The S6 specifically includes: After the reaction is completed, the mixture in the reactor is taken out and filtered through a filter with a pore size of 10-50 μm to remove any remaining impurities and agglomerates; The filtered product is sent to the testing department for quality inspection to ensure that it meets the standard requirements, including the concentration and viscosity of the surfactant. The qualified products are sealed and labeled before packaging, indicating the product's batch number, production date and instructions for use.

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