Shale oil well wax precipitation inhibitor based on fracturing fluid flowback and preparation method and use method thereof

Abstract

The invention provides a shale oil well wax precipitation inhibitor based on fracturing fluid flowback as well as a preparation method and a use method thereof, and belongs to the technical field of wax precipitation prevention and control. The wax crystal inhibitor is used for inhibiting the precipitation of waxy substances in crude oil and reducing the formation of wax crystals; the dispersing agent is used for dispersing the wax crystals in the fluid so as to prevent the wax crystals from agglomerating into blocks and depositing; the rheological modifier is used for optimizing the rheological property of the fracturing fluid and enhancing the dispersity of the wax precipitation inhibitor in the fracturing fluid; the temperature regulator is used for regulating the activity of the paraffin precipitation inhibitor according to the change of the oil well temperature; and the solvent is used for ensuring the uniform dispersion of the raw material components. The paraffin inhibitor can effectively solve the problem of paraffin precipitation in the shale oil well fracturing fluid flowback process in the prior art, and has wide adaptability and excellent paraffin inhibition effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wax deposition prevention and treatment, in particular to a shale oil well wax deposition inhibitor based on fracturing fluid flowback, a preparation method and a use method thereof. BACKGROUND

[0002] With the continuous growth of global energy demand, shale oil as an important unconventional oil and gas resource, its efficient development has a key significance to alleviate the energy crisis. Shale oil exploitation relies on horizontal drilling and fracturing technology, through the injection of fracturing fluid into the formation to form cracks and flowback to release crude oil in the reservoir. However, during the fracturing fluid flowback process, the wax components (such as paraffin, hard wax) in the crude oil are easy to precipitate due to the sharp fluctuations of temperature, pressure and flow rate, and deposit on the surface of the wellbore, pipeline and equipment to form a wax layer, which leads to the decrease of oil flowability, equipment blockage and increased maintenance cost, and seriously affects the long-term stable production of oil wells.

[0003] The occurrence of wax deposition is closely related to the dynamic changes of crude oil components and environmental parameters. During the fracturing fluid flowback stage, the downhole environment rapidly changes from high pressure and low temperature to low pressure and high temperature, or the shear effect is caused by flow rate changes, which will exacerbate the precipitation and deposition of wax crystals. Traditional wax prevention methods mainly include temperature adjustment, pressure adjustment and the use of various wax inhibitors and other chemical methods. These methods can slow down the occurrence of wax deposition to some extent, but still face the following main problems:

[0004] 1. The temperature and pressure conditions of shale oil wells are complex and unstable, especially during the fracturing fluid flowback process, the sharp fluctuations of temperature and pressure make it difficult for traditional temperature and pressure control measures to effectively prevent the occurrence of wax deposition.

[0005] 2. Traditional wax inhibitors can effectively slow down the precipitation of wax crystals to some extent, but their effect usually depends on fixed environmental conditions, and it is difficult to adapt to the complex conditions of instantaneous changes during the fracturing fluid flowback process. Moreover, existing wax inhibitors may have adverse effects on the viscosity and flowability of fracturing fluid, and even in some cases, it will exacerbate the deposition of wax.

[0006] In addition, traditional wax inhibitors only target a single link of wax crystal precipitation or deposition, and lack of synergistic inhibition of the whole process of wax crystal nucleation, growth, agglomeration and deposition; at the same time, the crude oil components and formation conditions of different oil wells are significantly different, and the existing inhibitor formula is difficult to adjust flexibly, which needs to rely on manual experience optimization, increasing the complexity of field application.

[0007] Although the thermodynamic and kinetic mechanisms of wax crystal precipitation have been preliminarily revealed, the dynamic behavior of wax deposition under the coupling of multiple parameters during the fracturing fluid flowback process still lacks systematic research, which leads to the fact that existing prevention and treatment technologies cannot meet the needs of efficient development of shale oil wells.

[0008] Based on the above, there is an urgent need to develop a wax-inhibiting agent that can adapt to changes in complex environmental parameters, has both wax crystal inhibition and dispersion functions, and has no negative impact on the performance of fracturing fluid. Summary of the Invention

[0009] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the invention.

[0010] The primary objective of this invention is to overcome the problem of wax deposition during the fracturing fluid flowback process in shale oil wells in the prior art, and to provide a wax deposition inhibitor for shale oil wells based on fracturing fluid flowback, which has broad applicability and excellent wax prevention effect.

[0011] To solve the above technical problems, the shale oil well wax inhibitor based on fracturing fluid flowback of the present invention comprises the following components by mass percentage:

[0012] Wax crystal inhibitors (10%–30%) are used to inhibit the precipitation of waxy substances in crude oil and reduce the formation of wax crystals.

[0013] Dispersant 5%–15% is used to disperse wax crystals in the fluid to prevent them from agglomerating into lumpy deposits;

[0014] Rheology modifiers of 2%–8% are used to optimize the rheological properties of fracturing fluids and enhance the dispersibility of wax-deposition inhibitors in fracturing fluids.

[0015] Temperature regulator 2%–6% is used to adjust the activity of wax-deposition inhibitor according to changes in oil well temperature;

[0016] The remainder is solvent, used to ensure uniform dispersion of the raw material components.

[0017] Preferably, the wax crystal inhibitor is one or more of the following materials:

[0018] High molecular weight polymers, including one or more of polyvinyl alcohol, polyacrylate, polyurethane or polyacrylamide;

[0019] Surfactants include nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt.

[0020] Polymer materials, including one or more of polyethylene, polypropylene, polyamide polymers, and natural plant gums;

[0021] Multifunctional molecules, including one or more of maleic anhydride polymers and modified polyurethane compounds;

[0022] Inorganic materials, including one or more of bentonite, montmorillonite, and silica particles.

[0023] Preferably, the dispersant is one or more of the following materials:

[0024] Low molecular weight compound dispersants, including one or more of dodecyl alcohol, myristyl alcohol, and stearyl alcohol;

[0025] Surfactants include nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt.

[0026] Preferably, the rheology modifier is one or more of the following materials:

[0027] Water-soluble polymers, including one or more of polyacrylamide, polyvinyl alcohol, sodium carboxymethyl cellulose, and polyvinyl alcohols;

[0028] Cyclic molecules, including one or more of cyclodextrins and polycyclic olefin cyclic polymers.

[0029] Preferably, the temperature regulator is an organic compound, including one or more combinations of imino acid salts, cyclic olefin compounds, or alkylamides.

[0030] Preferably, the solvent is water or a salt solution.

[0031] Preferably, the components and their mass percentages are as follows:

[0032] Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and alkylphenol resin, with a mass percentage of 20%;

[0033] Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ethers, at a mass percentage of 10%;

[0034] Rheology modifier: Imidazole ionic liquid, 10% by mass;

[0035] Temperature regulator: Paraffin-based phase change material, 5% by mass;

[0036] Solvent: Brine, 55% by mass.

[0037] Preferably, the components and their mass percentages are as follows:

[0038] Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and nonpolar alkylphenol resin, with a mass percentage of 20%;

[0039] Dispersant: A combination of polyoxyethylene ethers and polyisobutylene succinimide, with a mass percentage of 10%;

[0040] Rheology modifier: 10% by mass of montmorillonite modified material;

[0041] Temperature regulator: silicate aerogel, 5% by mass;

[0042] Solvent: Brine, 55% by mass.

[0043] Preferably, the components and their mass percentages are as follows:

[0044] Wax crystal inhibitor: a combination of polymethacrylate and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%;

[0045] Dispersant: A combination of polyacrylamide and sodium dodecylbenzenesulfonate, at a mass percentage of 10%;

[0046] Rheology modifier: Imidazole ionic liquid, 10% by mass;

[0047] Temperature regulator: urea peroxide, 5% by mass;

[0048] Solvent: Brine, 55% by mass.

[0049] Preferably, the components and their mass percentages are as follows:

[0050] Wax crystal inhibitor: silica particles, 10% by mass;

[0051] Dispersant: Polyisobutylene succinimide, 10% by mass;

[0052] Rheology modifier: a combination of pour point depressant PPD and polyacrylamide, at a mass percentage of 20%;

[0053] Temperature regulator: Paraffin-based phase change material, 5% by mass;

[0054] Solvent: Brine, 55% by mass.

[0055] Preferably, the components and their mass percentages are as follows:

[0056] Wax crystal inhibitor: a combination of nonpolar alkylphenol resin and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%;

[0057] Dispersant: A combination of polyoxyethylene ethers and polyisobutylene succinimide, with a mass percentage of 10%;

[0058] Rheology modifier: polyacrylamide, 10% by mass;

[0059] Temperature regulator: imino acid salt, 5% by mass;

[0060] Solvent: Brine, 55% by mass.

[0061] Preferably, the components and their mass percentages are as follows:

[0062] Wax crystal inhibitor: a combination of polymethyl methacrylate (PMMA) and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%;

[0063] Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ether, with a mass percentage of 10%;

[0064] Rheology modifier: Imidazole ionic liquid, 10% by mass;

[0065] Temperature regulator: Paraffin-based phase change material, 5% by mass;

[0066] Solvent: Brine, 55% by mass.

[0067] Preferably, the components and their mass percentages are as follows:

[0068] Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and alkylphenol resin, with a mass percentage of 20%;

[0069] Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ethers, at a mass percentage of 10%, wherein the polyoxyethylene ethers are from the Tween and / or Span series;

[0070] Rheology modifier: Imidazole ionic liquid, 10% by mass;

[0071] Temperature regulator: Paraffin-based phase change material, 5% by mass;

[0072] Solvent: Brine, 55% by mass.

[0073] Another objective of this invention is to overcome the problem of wax deposition during the flowback of fracturing fluid in shale oil wells in the prior art, and to provide a method for preparing a wax deposition inhibitor for shale oil wells based on fracturing fluid flowback. The prepared wax deposition inhibitor for shale oil wells has wide applicability and excellent anti-wax effect.

[0074] To address the above technical problems, the present invention provides a method for preparing a wax-caking inhibitor for shale oil wells based on fracturing fluid flowback. The specific process is as follows: Based on the environmental conditions of the shale oil well, the mass percentages of the wax crystal inhibitor, dispersant, rheology modifier, and temperature regulator are determined, and then mixed uniformly to obtain a mixture. The mixture is then added to a solvent, and the particle size is controlled by adjusting the stirring speed, reaction temperature, and stirring time to prepare the wax-caking inhibitor, adapting to different fluid flows and oil well requirements.

[0075] Preferably, the mixture is added to a solvent, the stirring speed is adjusted to 200-500 rpm / min, the reaction temperature is 30-80℃, and the stirring time is 1-3 h.

[0076] Another objective of this invention is to overcome the problem of wax deposition during the fracturing fluid flowback process in shale oil wells in the prior art, and to provide a method for using a wax deposition inhibitor for shale oil wells based on fracturing fluid flowback, which has wide applicability and excellent wax prevention effect.

[0077] To solve the above technical problems, the present invention provides a method for using a wax-deposition inhibitor in shale oil wells based on fracturing fluid flowback, comprising the following steps:

[0078] S1. When fracturing fluid is flowed back into shale oil wells, the wax-deposition inhibitor is fed into the flowback fluid at a ratio of 2% to 12% through a pumping system or mixing device to ensure that the wax-deposition inhibitor is evenly distributed in the flowback fluid.

[0079] S2. By monitoring the temperature, pressure and flow rate of shale oil wells, the amount of wax inhibitor added is adjusted in real time using an automatic control system or manual adjustment method to ensure that it continuously inhibits the precipitation and deposition of wax crystals throughout the entire flowback process.

[0080] S3. Based on the production cycle of shale oil wells, the flow characteristics of flowback fluid, and the wax deposition situation, the amount of wax deposition inhibitor is periodically replenished to the shale oil wells to ensure its effective concentration in the flowback fluid.

[0081] Preferably, the wax-inhibiting inhibitor is suitable for all types of shale oil wells, especially in environments where temperature, pressure, and flow rate vary greatly during fracturing fluid flowback, and has a stable anti-wax effect under conditions of temperature range of -10℃ to 150℃ and pressure of not less than 10MPa.

[0082] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The present invention forms a synergistic anti-wax mechanism of "inhibiting precipitation - dispersing particles - optimizing flowability - temperature adaptation" by combining wax crystal inhibitors, dispersants, rheology modifiers and temperature regulators, which significantly reduces wax crystal precipitation and deposition, improves crude oil fluidity, solves the problem of insufficient effect of traditional single-component inhibitors, and achieves efficient control of the entire waxing process.

[0083] 2. This invention addresses the changes in temperature, pressure, and flow rate during fracturing fluid flowback by adjusting the composition and dosage to ensure that the inhibitor maintains stable activity under conditions such as -10℃ to 150℃ and high pressure above 10MPa. This avoids the failure of anti-wax due to changes in environmental parameters and significantly improves the adaptability to complex working conditions of shale oil wells.

[0084] 3. The preparation process of this invention is simple and controllable. When applied, it can achieve efficient wax prevention by adding in proportion, adjusting in real time and replenishing regularly, without the need for complex equipment or frequent manual intervention. This effectively reduces pipeline blockage and equipment wear caused by wax deposition, reduces the frequency of downtime maintenance, and extends the service life of oil wells and equipment, combining technical reliability and economic rationality. Attached Figure Description

[0085] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit the present invention.

[0086] in:

[0087] Figure 1 This is a flowchart illustrating the preparation method of the wax-caking inhibitor for shale oil wells based on fracturing fluid flowback according to the present invention.

[0088] Figure 2 This is a flowchart illustrating the application method of the wax inhibitor for shale oil wells based on fracturing fluid flowback, as described in this invention. Detailed Implementation

[0089] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0090] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0091] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0092] like Figure 1 As shown, this invention provides a method for preparing a wax-caking inhibitor for shale oil wells based on fracturing fluid flowback. The specific process is as follows:

[0093] Step 100: Determine the mass percentages of wax crystal inhibitor, dispersant, rheology modifier, and temperature regulator based on the environmental conditions of the shale oil well, and then mix them evenly to obtain a mixture;

[0094] Step 200: Add the mixture to the solvent, and control the particle size of the wax inhibitor by adjusting the stirring speed, reaction temperature and stirring time to prepare the wax inhibitor to adapt to different fluid flow and oil well requirements.

[0095] In step 200, the mixture is added to a solvent, the stirring speed is adjusted to 200-500 rpm / min, the reaction temperature is 30-80℃, and the stirring time is 1-3 h.

[0096] In addition, in step 100, the raw material components include the following components by mass percentage:

[0097] With a total volume of 100 parts, 10-30 parts are wax crystal inhibitors to inhibit the precipitation of waxy substances in crude oil and reduce the formation of wax crystals; 5-15 parts are dispersants to disperse wax crystals in the fluid to prevent them from agglomerating into blocky deposits; 2-8 parts are rheology modifiers to optimize the rheological properties of fracturing fluid and enhance the dispersibility of wax crystal inhibitors in fracturing fluid; 2-6 parts are temperature regulators to adjust the activity of wax crystal inhibitors according to changes in well temperature; and the balance is solvent to ensure uniform dispersion of feedstock components.

[0098] The wax crystal inhibitor is one or more of the following materials: high molecular polymers, including one or more of polyvinyl alcohol, polyacrylate, polyurethane, or polyacrylamide; surfactants, including nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt; polymeric materials, including one or more of polyethylene, polypropylene, polyamide polymers, and natural plant gums; multifunctional molecules, including one or more of maleic anhydride polymers and modified polyurethane compounds; and inorganic materials, including one or more of bentonite, montmorillonite, and silica particles.

[0099] The dispersant is one or more of the following materials: low molecular weight compound dispersants, including one or more of dodecyl alcohol, myristol, and stearyl alcohol; surfactants, including nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt.

[0100] The rheology modifier is one or more of the following materials: water-soluble polymers, including one or more of polyacrylamide, polyvinyl alcohol, sodium carboxymethyl cellulose, and polyvinyl alcohols; cyclic molecules, including one or more of cyclodextrins and polycyclic olefin cyclic polymers.

[0101] The temperature regulator is an organic compound, including one or more combinations of imino acid salts, cyclic olefin compounds, or alkylamides. The solvent is water or an aqueous salt solution.

[0102] Reference Figure 2 The present invention also provides a method for using the above-mentioned shale oil well wax inhibitor based on fracturing fluid flowback, comprising the following steps:

[0103] S1. When fracturing fluid is flowed back into shale oil wells, the wax-deposition inhibitor is fed into the flowback fluid at a ratio of 2% to 12% through a pumping system or mixing device to ensure that the wax-deposition inhibitor is evenly distributed in the flowback fluid.

[0104] S2. By monitoring the temperature, pressure and flow rate of shale oil wells, the amount of wax inhibitor added is adjusted in real time using an automatic control system or manual adjustment method to ensure that it continuously inhibits the precipitation and deposition of wax crystals throughout the entire flowback process.

[0105] S3. Based on the production cycle of shale oil wells, the flow characteristics of flowback fluid, and the wax deposition situation, the amount of wax deposition inhibitor is periodically replenished to the shale oil wells to ensure its effective concentration in the flowback fluid.

[0106] It should be noted that the aforementioned wax-inhibiting inhibitor is suitable for all types of shale oil wells, especially in environments where temperature, pressure, and flow rate fluctuate significantly during fracturing fluid flowback. It also exhibits stable wax-inhibiting effects under conditions of -10℃ to 150℃ and pressure not less than 10MPa. The aforementioned types of shale oil wells mainly include:

[0107] 1. Shale oil extraction sector

[0108] The wax deposition inhibitor of this invention is widely applicable to the exploitation process of shale oil wells, especially during the fracturing fluid flowback stage. Shale oil wells typically face complex geological conditions and production environments, where fluctuations in parameters such as temperature, pressure, and flow rate can easily lead to wax deposition. By using the wax deposition inhibitor of this invention, the precipitation and deposition of wax crystals can be effectively suppressed, ensuring long-term stable production of the oil well.

[0109] 2. Development of conventional oilfields and complex reservoirs

[0110] Besides shale oil wells, the wax deposition inhibitor of this invention is also applicable to the development of conventional oil fields and other complex reservoirs. In oil fields, especially under high temperature and high pressure or low temperature and low pressure environments, wax deposition often becomes a problem in production. Using the inhibitor of this invention can effectively prevent the precipitation and deposition of wax in the reservoir, maintain the high productivity of oil wells, and extend the service life of oil wells.

[0111] 3. Application in fracturing fluid flowback process

[0112] This invention is specifically designed to address the wax deposition problem during fracturing fluid flowback and is applicable to the fracturing fluid flowback stage of various oil wells. By mixing the wax deposition inhibitor with the flowback fluid, wax crystal precipitation and deposition caused by changes in factors such as temperature and pressure can be reduced or avoided, ensuring smooth fracturing fluid flowback and improving fracturing efficiency.

[0113] 4. Deepwater oilfields and oilfields in extreme environments

[0114] The inhibitor of this invention has strong adaptability, and is particularly suitable for oilfield development in deepwater or extreme environments. In deepwater oilfields or other extreme environments, wax deposition is easily exacerbated due to drastic fluctuations in temperature and pressure. This wax deposition inhibitor can work effectively in these special environments, preventing wax deposition from affecting the normal production of oil wells.

[0115] 5. Development of unconventional oil and gas resources

[0116] The wax deposition inhibitor of this invention is also applicable to the exploitation of unconventional oil and gas resources, such as oil sands and heavy oil. These unconventional oil and gas resources contain high levels of waxy substances, which easily lead to wax deposition during the oil extraction process. Using the inhibitor of this invention can effectively slow down or inhibit the formation of wax deposition, ensuring the smooth progress of the oil extraction process.

[0117] The technical solution of the present invention will be described in detail below through specific embodiments.

[0118] Example 1

[0119] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is α-olefin-maleic anhydride copolymer + alkylphenol resin, with a mass percentage of 20%; the dispersant is polyisobutylene succinimide + polyoxyethylene ether, with a mass percentage of 10%; the rheology modifier is imidazole ionic liquid, with a mass percentage of 10%; the temperature regulator is paraffin-based phase change material, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 1.

[0120] Table 1. Raw material composition and dosage of wax-inhibiting agent in Example 1

[0121]

[0122]

[0123] According to Table 1, the preparation process of the wax-deposition inhibitor in this embodiment is as follows: Salt water and aqueous solution are placed in a reaction vessel and preheated to 30°C; then, α-olefin-maleic anhydride copolymer, alkylphenol resin, and polyisobutylene succinimide + polyoxyethylene ether are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, paraffin phase change material is added, and stirring is carried out at 50°C; then, imidazole ionic liquid is added, and stirring is continued at 60°C for 2 hours; finally, after thorough stirring, the obtained wax-deposition inhibitor is cooled and subjected to quality testing to ensure uniform particle distribution and good inhibition effect.

[0124] The prepared wax-inhibiting inhibitor is used as follows: during the flowback of fracturing fluid in oil wells, the wax-inhibiting inhibitor is mixed with the fracturing fluid at a ratio of 5%-10%; the amount of wax-inhibiting inhibitor added is adjusted according to real-time monitoring data of the oil well (such as temperature, pressure, flow rate, etc.). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect.

[0125] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 2.

[0126] Table 2 Experimental Results

[0127]

[0128]

[0129] As shown in Table 2, after adding the wax deposition inhibitor, the wax deposition rate decreased from 220 mg / cm³. 2 Reduced to 35 mg / cm 2The reduction rate reached 84.1%; DSC test showed that the wax precipitation enthalpy decreased from 100J / g to 12J / g, a decrease of 88%, which proved that the wax precipitation inhibitor can significantly inhibit wax crystal precipitation.

[0130] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 3:

[0131] Table 3 Test Results

[0132]

[0133] As shown in Table 3, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 420 mPa·s to 180 mPa·s, and the increase was significantly reduced from 425% to 125%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0134] Example 2

[0135] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is α-olefin-maleic anhydride copolymer + nonpolar alkylphenol resin, with a mass percentage of 20%; the dispersant is polyoxyethylene ether + polyisobutylene succinimide, with a mass percentage of 10%; the rheology modifier is montmorillonite modified material, with a mass percentage of 10%; the temperature regulator is silicate aerogel, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 4.

[0136] Table 4. Raw material composition and dosage of wax inhibitor in Example 2

[0137]

[0138]

[0139] According to Table 4, the preparation process of the wax-caking inhibitor in this embodiment is as follows: Salt water and aqueous solution are placed in a reaction vessel and preheated to 40°C; then, α-olefin-maleic anhydride copolymer + non-polar alkylphenol resin, polyoxyethylene ether + polyisobutylene succinimide are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, silicate aerogel is added, and stirring is carried out at 60°C; then, montmorillonite modifier is added, and stirring is continued at 80°C for 2 hours; finally, after thorough stirring, the obtained wax-caking inhibitor is cooled and subjected to quality testing to ensure uniform particle distribution and good inhibition effect.

[0140] The prepared wax-caking inhibitor is then put into use as follows: In deepwater oilfields or other high-temperature, high-pressure oilfields, the wax-caking inhibitor is mixed with fracturing fluid at a concentration of 5%-12%. The amount of wax-caking inhibitor added is adjusted according to real-time monitoring data of the oil well (such as temperature, pressure, flow rate, etc.). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect. Supplementation is also carried out quarterly to ensure that wax crystals in the oil well remain effectively suppressed.

[0141] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 5.

[0142] Table 5 Experimental Results

[0143]

[0144]

[0145] As shown in Table 5, after adding the wax deposition inhibitor, the wax deposition rate decreased from 200 mg / cm³. 2 Reduced to 50 mg / cm 2 The reduction rate reached 77.1%; DSC test showed that the wax precipitation enthalpy decreased from 180J / g to 25J / g, a decrease of 86%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0146] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 6:

[0147] Table 6 Test Results

[0148]

[0149] As shown in Table 6, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 600 mPa·s to 100 mPa·s, and the increase was significantly reduced from 1100% to 200%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0150] In addition, under high temperature and high pressure conditions, wax inhibitors prevent the precipitation and deposition of wax crystals, thereby improving the production efficiency of oil wells and significantly reducing the number of equipment maintenance operations. At the same time, the stability of wax inhibitors under high temperature conditions has effectively controlled the waxing problem in deepwater oilfields.

[0151] Example 3

[0152] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is polymethacrylate + α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; the dispersant is polyacrylamide + sodium dodecylbenzenesulfonate, with a mass percentage of 10%; the rheology modifier is imidazole ionic liquid, with a mass percentage of 10%; the temperature regulator is urea peroxide, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 7.

[0153] Table 7. Raw material composition and dosage of wax inhibitor in Example 3

[0154]

[0155] According to Table 7, the preparation process of the wax-deposition inhibitor in this embodiment is as follows: at room temperature, saline and aqueous solutions are placed in a reaction vessel; then, polymethacrylate + α-olefin-maleic anhydride copolymer and polyacrylamide + sodium dodecylbenzenesulfonate are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, urea peroxide is added and stirred at room temperature; then, imidazole ionic liquid is added and stirred at 60°C for 30 min; finally, after thorough stirring, the obtained wax-deposition inhibitor is cooled and quality tested to ensure that its particle distribution is uniform and its inhibition effect is good.

[0156] The prepared wax-deposition inhibitor is then put into use as follows: In heavy oil wells with high wax content, the wax-deposition inhibitor is mixed with fracturing fluid at a ratio of 5%-10%. The amount of wax-deposition inhibitor added is adjusted based on real-time monitoring data of the oil well (such as temperature, pressure, and flow rate). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect. Simultaneously, the wax deposition in the oil well is checked regularly, and the frequency of inhibitor replenishment is adjusted according to the well's operational status.

[0157] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 8.

[0158] Table 8 Experimental Results

[0159]

[0160] As shown in Table 8, after adding the wax deposition inhibitor, the wax deposition rate decreased from 900 mg / cm³. 2 Reduced to 250 mg / cm 2 The reduction rate reached 72.2%; DSC test showed that the wax precipitation enthalpy decreased from 280J / g to 100J / g, a decrease of 64.3%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0161] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 9:

[0162] Table 9 Test Results

[0163]

[0164] As shown in Table 9, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 1000 mPa·s to 350 mPa·s, and the increase was significantly reduced from 400% to 75%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0165] In addition, by using the wax inhibitor provided in this embodiment, the amount of wax precipitation in heavy oil wells is significantly reduced, crude oil fluidity is restored, the production stability of oil wells is significantly improved, and the occurrence of pipeline blockage and equipment wear is reduced, thus lowering maintenance costs.

[0166] Example 4

[0167] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is silica particles, with a mass percentage of 10%; the dispersant is polyisobutylene succinimide, with a mass percentage of 10%; the rheology modifier is pour point depressant (PPD) + polyacrylamide, with a mass percentage of 20%; the temperature regulator is paraffin-based phase change material, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 10.

[0168] Table 10. Raw material composition and dosage of wax inhibitor in Example 4

[0169] Ingredient Chemical Name Mass Percent (%) Wax Crystal Inhibitor Silica Particles 10 Dispersant Polyisobutylene Succinimide 10 Rheology Modifier Pour Point Depressant (PPD) + Polyacrylamide 20 Temperature Modifier Paraffin Wax Phase Change Material 5 Solvent Brine 55 Total 100

[0170] According to Table 10, the preparation process of the wax-deposition inhibitor in this embodiment is as follows: at room temperature, brine and aqueous solution are placed in a reaction vessel; then silica particles and polyisobutylene succinimide are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then paraffin phase change material is added, and stirring is carried out at room temperature; then pour point depressant (PPD) + polyacrylamide is added, and stirring is continued; finally, after thorough stirring, the obtained wax-deposition inhibitor is cooled and quality is tested to ensure that its particle distribution is uniform and the inhibition effect is good.

[0171] The prepared wax-deposition inhibitor is then put into use as follows: During the fracturing fluid flowback process in conventional oilfields, the wax-deposition inhibitor is mixed with the fracturing fluid at a ratio of 2%-5%. The dosage of the wax-deposition inhibitor is adjusted based on real-time well monitoring data (such as temperature, pressure, and flow rate). Finally, it is injected into the well via a pumping system to ensure uniform fluid distribution and maintain a high-efficiency wax-prevention effect. Simultaneously, the wax deposition in the well is checked regularly, and the frequency of inhibitor replenishment is adjusted according to the well's operational status.

[0172] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 11.

[0173] Table 11 Experimental Results

[0174]

[0175] As shown in Table 11, after adding the wax deposition inhibitor, the wax deposition rate decreased from 250 mg / cm³. 2 Reduced to 40 mg / cm 2 The reduction rate reached 84%; DSC test showed that the wax precipitation enthalpy decreased from 90J / g to 18J / g, a decrease of 80%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0176] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 12:

[0177] Table 12 Test Results

[0178]

[0179] As shown in Table 12, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 350 mPa·s to 120 mPa·s, and the increase was significantly reduced from 337.5% to 50.0%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0180] In addition, the application of this wax deposit inhibitor effectively controls wax deposition in conventional oilfields, preventing blockages in pipelines and production equipment, and increasing well production efficiency by 15%-20%. The wax deposit inhibitor exhibits good stability and is easy to operate, reducing the need for equipment downtime maintenance and significantly lowering production costs.

[0181] Example 5

[0182] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is a non-polar alkylphenol resin + α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; the dispersant is a polyoxyethylene ether (Tween, Span series) + polyisobutylene succinimide, with a mass percentage of 10%; the rheology modifier is polyacrylamide, with a mass percentage of 10%; the temperature regulator is an imino acid salt, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 13.

[0183] Table 13. Raw material composition and dosage of wax inhibitor in Example 5

[0184]

[0185] According to Table 13, the preparation process of the wax-deposition inhibitor in this embodiment is as follows: Salt water and aqueous solution are placed in a reaction vessel and preheated to 30°C; then, non-polar alkylphenol resin + α-olefin-maleic anhydride copolymer, polyoxyethylene ethers (Tween, Span series) + polyisobutylene succinimide are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, imino acid salt is added and stirred; then, polyacrylamide is added and stirring continues; finally, after thorough stirring, the prepared wax-deposition inhibitor is cooled and subjected to quality testing to ensure uniform particle distribution and good inhibition effect.

[0186] The prepared wax-deposition inhibitor is then put into use as follows: In oil wells of low-temperature oilfields, the wax-deposition inhibitor is mixed with fracturing fluid at a ratio of 3%-8%; the amount of wax-deposition inhibitor added is adjusted according to real-time monitoring data of the oil well (such as temperature, pressure, flow rate, etc.). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect; at the same time, the wax deposition in the oil well is checked regularly, and the frequency of inhibitor replenishment is adjusted according to the operating status of the oil well.

[0187] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 14.

[0188] Table 14 Experimental Results

[0189]

[0190] As shown in Table 14, after adding the wax deposition inhibitor, the wax deposition rate decreased from 1200 mg / cm³. 2 Reduced to 300 mg / cm 2 The reduction rate reached 75%; DSC test showed that the wax precipitation enthalpy decreased from 600J / g to 80J / g, a decrease of 87%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0191] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 15:

[0192] Table 15 Test Results

[0193]

[0194] As shown in Table 15, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 800 mPa·s to 150 mPa·s, and the increase was significantly reduced from 700% to 50.0%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0195] Furthermore, the application of this wax deposition inhibitor effectively curbed wax precipitation in low-temperature oilfields, significantly improving well production performance under lower temperature conditions. The inhibitor exhibits good stability at low temperatures, and wax deposition in wells is significantly reduced. Oilfield production efficiency increased by approximately 18%, and the frequency of equipment blockage and downtime for maintenance decreased.

[0196] Example 6

[0197] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is polymethyl methacrylate (PMMA) + α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; the dispersant is polyisobutylene succinimide + polyoxyethylene ether, with a mass percentage of 10%; the rheology modifier is imidazole ionic liquid, with a mass percentage of 10%; the temperature regulator is paraffin-based phase change material, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 16.

[0198] Table 16. Raw material composition and dosage of wax inhibitor in Example 6

[0199]

[0200] According to Table 16, the preparation process of the wax-caking inhibitor in this embodiment is as follows: Salt water and aqueous solution are placed in a reaction vessel and preheated to 30°C; then, polymethyl methacrylate (PMMA) + α-olefin-maleic anhydride copolymer and polyisobutylene succinimide + polyoxyethylene ether are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, paraffin-based phase change material is added and stirred at 50°C; then, imidazole-based ionic liquid is added, and stirring is continued at 60°C for 1 hour; finally, after thorough stirring, the obtained wax-caking inhibitor is cooled and subjected to quality testing to ensure uniform particle distribution and good inhibition effect.

[0201] The prepared wax-deposition inhibitor is then put into use as follows: In oil sands extraction, the wax-deposition inhibitor is mixed with fracturing fluid at a concentration of 5%. The amount of wax-deposition inhibitor added is adjusted based on real-time monitoring data of the oil well (such as temperature, pressure, and flow rate). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect. At the same time, the wax deposition in the oil well is checked regularly, and the frequency of inhibitor replenishment is adjusted according to the operating status of the oil well.

[0202] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 17.

[0203] Table 17 Experimental Results

[0204]

[0205] As shown in Table 17, after adding the wax deposition inhibitor, the wax deposition rate decreased from 20 mg / cm³. 2 Reduced to 4 mg / cm 2The reduction rate reached 80%; DSC test showed that the wax precipitation enthalpy decreased from 45.2 J / g to 22.7 J / g, a decrease of 49.8%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0206] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 18:

[0207] Table 18 Test Results

[0208]

[0209] As shown in Table 18, after adding the wax inhibitor, the apparent viscosity of crude oil at 60℃ decreased from 2500 mPa·s to 1300 mPa·s, and the increase was significantly reduced from 3025% to 1525%, indicating that the wax inhibitor effectively improved low-temperature fluidity. This further verifies the optimizing effect of the wax inhibitor on the rheological properties of crude oil, especially its significant effect under low-temperature conditions.

[0210] In addition, the application of this wax inhibitor effectively curbed the wax precipitation problem in oil sands mining, restored the fluidity of crude oil, reduced equipment wear, and extended the service life of the equipment.

[0211] Example 7

[0212] In this embodiment, the raw material components of the wax crystal inhibitor are as follows: the wax crystal inhibitor is α-olefin-maleic anhydride copolymer + alkylphenol resin, with a mass percentage of 20%; the dispersant is polyisobutylene succinimide + polyoxyethylene ether (Tween, Span series), with a mass percentage of 10%; the rheology modifier is imidazole ionic liquid, with a mass percentage of 10%; the temperature regulator is paraffin phase change material, with a mass percentage of 5%; and the solvent is brine, with a mass percentage of 55%, as shown in Table 16.

[0213] Table 19. Raw material composition and dosage of wax inhibitor in Example 7

[0214]

[0215] According to Table 19, the preparation process of the wax-deposition inhibitor in this embodiment is as follows: Salt water and aqueous solution are placed in a reaction vessel and preheated to 30°C; then, α-olefin-maleic anhydride copolymer + alkylphenol resin, polyisobutylene succinimide + polyoxyethylene ethers (Tween, Span series) are added to the solution in proportion, and stirring is started, maintaining a stirring speed of 300 rpm / min; then, paraffin phase change material is added and stirred at 60°C for 30 min; then, imidazole ionic liquid is added and stirring continues; finally, after thorough stirring, the obtained wax-deposition inhibitor is cooled and subjected to quality testing to ensure uniform particle distribution and good inhibition effect.

[0216] The prepared wax-deposition inhibitor is then put into use as follows: In heavy oil wells, the wax-deposition inhibitor is mixed with fracturing fluid at a ratio of 5% to 10%. The amount of wax-deposition inhibitor added is adjusted according to real-time monitoring data of the oil well (such as temperature, pressure, flow rate, etc.). Finally, it is injected into the oil well through a pumping system to ensure uniform liquid distribution and maintain a high-efficiency wax-prevention effect. At the same time, the wax deposition in the oil well is checked regularly, and the frequency of inhibitor replenishment is adjusted according to the operating status of the oil well.

[0217] In this embodiment, a high-pressure cold finger test apparatus and a differential scanning calorimeter (DSC) were used to conduct cold finger experiments and DSC tests to analyze the effects of inhibitors on wax crystal precipitation temperature and crystallization behavior. The experimental results are shown in Table 20.

[0218] Table 20 Experimental Results

[0219]

[0220] As shown in Table 20, after adding the wax deposition inhibitor, the wax deposition rate decreased from 250 mg / cm³. 2 Reduced to 42 mg / cm 2 The reduction rate reached 83.20%; DSC test showed that the wax precipitation enthalpy decreased from 112 J / g to 26 J / g, a decrease of 86.78%, which proved that the wax deposition inhibitor significantly reduced the amount of wax deposition and could effectively prevent the adhesion and accumulation of wax crystals on the pipe wall; at the same time, the wax deposition inhibitor greatly reduced the energy required for wax crystal precipitation, indicating that it inhibited the formation of wax crystals by interfering with the nucleation or growth process of wax crystals.

[0221] In addition, this embodiment also utilizes a rotational rheometer (Haake RS6000) to conduct apparent viscosity tests on crude oil, aiming to evaluate the impact of wax-reducing inhibitors on the rheological properties of crude oil. The test results are shown in Table 21:

[0222] Table 21 Test Results

[0223]

[0224] Table 21 shows that the wax-deposition inhibitor has a relatively small impact on crude oil viscosity at high temperatures (a decrease of 3.5%), indicating that its effect is mainly targeted at the low-temperature wax crystal precipitation stage. The inhibitor significantly reduces low-temperature viscosity (a decrease of 50.6%), effectively inhibiting wax crystal formation or disrupting its network structure, thus improving fluidity. The addition of the wax-deposition inhibitor reduces the temperature sensitivity of crude oil by 54.2%, significantly alleviating low-temperature flow obstacles. This verifies the optimizing effect of the wax-deposition inhibitor on the rheological properties of crude oil, especially under low-temperature conditions. The production stability of oil wells is improved, and equipment maintenance costs are reduced.

[0225] Therefore, the above-mentioned wax inhibitor for shale oil wells based on fracturing fluid flowback, its preparation method and application method can effectively solve the shortcomings of existing technologies in the waxing problem during the fracturing fluid flowback process of shale oil wells, and has wide applicability and excellent wax prevention effect.

[0226] The above description is merely a preferred embodiment of the present invention, showing and describing the basic principles, main features, and advantages of the present invention. It is not intended to limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. In addition to the above embodiments, the present invention may have other implementations without departing from the spirit and scope of the invention. Various changes and modifications to the present invention are possible, and all technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents. Technical features not described in the present invention can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A wax-deposition inhibitor for shale oil wells based on fracturing fluid flowback, characterized in that, The following components are included by mass percentage: Wax crystal inhibitors (10%~30%) are used to inhibit the precipitation of waxy substances in crude oil and reduce the formation of wax crystals. Dispersant 5%~15% is used to disperse wax crystals in the fluid to prevent wax crystals from agglomerating into lumpy deposits; Rheology modifiers of 2% to 8% are used to optimize the rheological properties of fracturing fluids and enhance the dispersibility of wax-forming inhibitors in fracturing fluids. Temperature regulator 2%~6% is used to adjust the activity of wax inhibitor according to changes in oil well temperature; The remainder is solvent, used to ensure uniform dispersion of the raw material components.

2. The wax-caking inhibitor for shale oil wells based on fracturing fluid flowback according to claim 1, characterized in that, The wax crystal inhibitor is one or more of the following materials: High molecular weight polymers, including one or more of polyvinyl alcohol, polyacrylate, polyurethane or polyacrylamide; Surfactants include nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt. Polymer materials, including one or more of polyethylene, polypropylene, polyamide polymers, and natural plant gums; Multifunctional molecules, including one or more of maleic anhydride polymers and modified polyurethane compounds; Inorganic materials, including one or more of bentonite, montmorillonite, and silica particles.

3. The wax-caking inhibitor for shale oil wells based on fracturing fluid flowback according to claim 1, characterized in that, The dispersant is one or more of the following materials: Low molecular weight compound dispersants, including one or more of dodecyl alcohol, myristyl alcohol, and stearyl alcohol; Surfactants include nonionic surfactants, anionic surfactants, or cationic surfactants, wherein the nonionic surfactant is one or more of Tween and Span, the anionic surfactant is sodium dodecylbenzenesulfonate, and the cationic surfactant is a quaternary ammonium salt.

4. The wax-deposition inhibitor for shale oil wells based on fracturing fluid flowback according to claim 1, characterized in that, The rheology modifier is one or more of the following materials in combination: Water-soluble polymers, including one or more of polyacrylamide, polyvinyl alcohol, sodium carboxymethyl cellulose, and polyvinyl alcohols; Cyclic molecules, including one or more of cyclodextrins and polycyclic olefin cyclic polymers.

5. The wax-caking inhibitor for shale oil wells based on fracturing fluid flowback according to claim 1, characterized in that, The temperature regulator is an organic compound, including one or more combinations of imino acid salts, cyclic olefin compounds, or alkylamides.

6. The wax-deposition inhibitor for shale oil wells based on fracturing fluid flowback according to claim 1, characterized in that, The solvent is water or a salt solution.

7. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and alkylphenol resin, with a mass percentage of 20%; Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ethers, at a mass percentage of 10%; Rheology modifier: Imidazole ionic liquid, 10% by mass; Temperature regulator: Paraffin-based phase change material, 5% by mass; Solvent: Brine, 55% by mass.

8. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and nonpolar alkylphenol resin, with a mass percentage of 20%; Dispersant: A combination of polyoxyethylene ethers and polyisobutylene succinimide, at a mass percentage of 10%; Rheology modifier: 10% by mass of montmorillonite modified material; Temperature regulator: silicate aerogel, 5% by mass; Solvent: Brine, 55% by mass.

9. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of polymethacrylate and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; Dispersant: A combination of polyacrylamide and sodium dodecylbenzenesulfonate, at a mass percentage of 10%; Rheology modifier: Imidazole ionic liquid, 10% by mass; Temperature regulator: urea peroxide, 5% by mass; Solvent: Brine, 55% by mass.

10. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: silica particles, 10% by mass; Dispersant: Polyisobutylene succinimide, 10% by mass; Rheology modifier: a combination of pour point depressant PPD and polyacrylamide, at a mass percentage of 20%; Temperature regulator: Paraffin-based phase change material, 5% by mass; Solvent: Brine, 55% by mass.

11. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of nonpolar alkylphenol resin and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; Dispersant: A combination of polyoxyethylene ethers and polyisobutylene succinimide, at a mass percentage of 10%; Rheology modifier: polyacrylamide, 10% by mass; Temperature regulator: imino acid salt, 5% by mass; Solvent: Brine, 55% by mass.

12. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of polymethyl methacrylate (PMMA) and α-olefin-maleic anhydride copolymer, with a mass percentage of 20%; Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ether, at a mass percentage of 10%; Rheology modifier: Imidazole ionic liquid, 10% by mass; Temperature regulator: Paraffin-based phase change material, 5% by mass; Solvent: Brine, 55% by mass.

13. The shale oil well wax-deposition inhibitor based on fracturing fluid flowback according to claim 1, characterized in that, The components and their mass percentages are as follows: Wax crystal inhibitor: a combination of α-olefin-maleic anhydride copolymer and alkylphenol resin, with a mass percentage of 20%; Dispersant: A combination of polyisobutylene succinimide and polyoxyethylene ethers, with a mass percentage of 10%, wherein the polyoxyethylene ethers are from the Tween and / or Span series; Rheology modifier: Imidazole ionic liquid, 10% by mass; Temperature regulator: Paraffin-based phase change material, 5% by mass; Solvent: Brine, 55% by mass.

14. A method for preparing a shale oil well wax inhibitor based on fracturing fluid flowback as described in any one of claims 1 to 13, characterized in that, The specific process is as follows: Based on the environmental conditions of shale oil wells, determine the mass percentages of wax crystal inhibitors, dispersants, rheology modifiers, and temperature regulators, and then mix them evenly to obtain a mixture; add the mixture to a solvent, and control the particle size by adjusting the stirring speed, reaction temperature, and stirring time to prepare a wax crystal inhibitor to adapt to different fluid flow rates and oil well requirements.

15. The method for preparing a wax-caking inhibitor for shale oil wells based on fracturing fluid flowback according to claim 14, characterized in that, The mixture is added to a solvent, the stirring speed is adjusted to 200-500 rpm / min, the reaction temperature is 30-80℃, and the stirring time is 1-3 h.

16. A method for using a wax-deposition inhibitor in shale oil wells based on fracturing fluid flowback as described in any one of claims 1 to 13, characterized in that, Includes the following steps: S1. When fracturing fluid is flowed back into shale oil wells, the wax-deposition inhibitor is fed into the flowback fluid at a ratio of 2% to 12% through a pumping system or mixing device to ensure that the wax-deposition inhibitor is evenly distributed in the flowback fluid. S2. By monitoring the temperature, pressure and flow rate of shale oil wells, the amount of wax inhibitor added is adjusted in real time using an automatic control system or manual adjustment method to ensure that it continuously inhibits the precipitation and deposition of wax crystals throughout the entire flowback process. S3. Based on the production cycle of shale oil wells, the flow characteristics of flowback fluid, and the wax deposition situation, the amount of wax deposition inhibitor is periodically replenished to the shale oil wells to ensure its effective concentration in the flowback fluid.

17. The method for using a wax-deposition inhibitor in shale oil wells based on fracturing fluid flowback as described in claim 16, characterized in that, The wax-inhibiting inhibitor is suitable for all types of shale oil wells, especially in environments where temperature, pressure, and flow rate vary greatly during fracturing fluid flowback. It also has a stable anti-wax effect under conditions of -10℃ to 150℃ and pressure not less than 10MPa.

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