Method for improving performance of resistance reducing agent based on cyclodextrin solubilization modification and application

Abstract

The invention discloses a method for improving the performance of a resistance reducing agent based on cyclodextrin solubilization modification and application, and belongs to the technical field of fracturing fluids. The method comprises the following steps: S1, preparing a mixed liquid from hydrophobic associated polymer dry powder and cyclodextrin; s2, stirring the mixed liquid, testing the particle size of the mixed liquid at the same time interval, and ending stirring after the particle size is reduced to a stable size, so as to obtain the hydrophobic associated polymer solution. The cyclodextrin polymer not only has a high-molecular effect, but also retains the inclusion ability of a cyclodextrin cavity, and has better inclusion performance under the condition of larger guest molecules. The hydrophobic association polymer is modified through a host-guest inclusion technology, the solubility of the hydrophobic association polymer is improved on the basis of guaranteeing the resistance reducing effect of the hydrophobic association polymer, and the prepared hydrophobic association polymer resistance reducing agent has the advantages of being fast in dissolution and good in shear resistance and resistance reducing effect.

Description

Technical Field

[0001] The invention relates to the technical field of fracturing fluids, and in particular to a method and application of improving the drag reducing performance of a drag reducing agent based on cyclodextrin solubilization modification. Background Art

[0002] Unconventional resources such as shale gas and tight gas are gradually becoming a very important part of the current and future oil and gas supply. With the development of unconventional gas reservoirs, the level of fracturing technology has gradually increased, and volume fracturing has become the main way to develop unconventional gas reservoirs. Using fracturing fluids such as slick water to conduct large-scale volume fracturing of shale gas and tight gas reservoirs is currently the key technology for the effective development of shale gas and tight gas in China's oil. Slick water is prepared from drag reducers, surfactants, bactericides, etc. according to formation conditions and construction requirements, among which the most critical additive is drag reducer.

[0003] After years of development, the performance of slippery water drag reducers has made great progress, and excellent products represented by hydrophobic associating polymers have emerged, which further improve the drag reduction performance of slippery water through intermolecular and intramolecular associations. At present, the hydrophobic associating polymer drag reducers that are widely used on site are mainly inverse emulsions and suspended emulsions. The amount added on site is large, and a large amount of oil phase, stabilizers, emulsifiers, etc. are introduced, which not only increases the cost of use, but also poses a potential risk of damage to the reservoir, and further increases the difficulty of fracturing flowback fluid disposal.

[0004] Dry powder hydrophobically associating polymer drag reducer is a preferred method to solve the above problems. Not only does it have a high effective concentration, which greatly reduces the cost of use, but it also does not introduce unfavorable components such as oil phase, stabilizer, emulsifier, etc. However, the dry powder hydrophobically associating polymer drag reducer has poor solubility (slow dissolution rate) and is difficult to completely dissolve within a limited dissolution time, resulting in the site being forced to increase the amount of drag reducer to meet the drag reduction performance requirements, which actually increases the cost of use, and there are problems such as the formation of "fish eyes" that affect the quality of slippery water.

[0005] Therefore, the following application is made. Summary of the invention

[0006] The technical problem to be solved by the present invention is to improve the problems that the existing dry powder drag reducing agent has good drag reducing effect but is slow to dissolve, difficult to operate and has low construction efficiency.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present application proposes a method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification, comprising the following steps:

[0009] S1: preparing a mixed liquid of a hydrophobic associating polymer dry powder and cyclodextrin;

[0010] S2: stirring the mixed liquid, and testing the particle size in the mixed liquid at the same time interval, and stopping the stirring after the particle size is reduced to a stable size to obtain a hydrophobic associating polymer solution.

[0011] Preferably, the hydrophobically associating polymer dry powder is one substance or a combination of multiple substances selected from the group consisting of quaternary ammonium salt type hydrophobically associating polymer, nonionic hydrophobically associating polymer and rigid structure type hydrophobically associating polymer.

[0012] Preferably, the quaternary ammonium salt type hydrophobically associating polymer is PAAD, and the PAAD has the following molecular structural formula:

[0013]

[0014] Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5.

[0015] Preferably, the nonionic hydrophobically associating polymer is PAAO, and the PAAO has the following molecular structure formula:

[0016]

[0017] Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5, n represents the number of ethylene oxide, 9≤n≤30.

[0018] Preferably, the rigid structured hydrophobic associating polymer is PSEM, and the PSEM has the following molecular structure formula:

[0019]

[0020] Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5, n represents the number of ethylene oxide, 9≤n≤30.

[0021] Preferably, the cyclodextrin is one cyclodextrin selected from α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, or a combination of multiple cyclodextrins.

[0022] Preferably, in the hydrophobically associating polymer solution, the molar ratio of the cyclodextrin to the hydrophobically associating polymer powder in the mixed liquid of S1 is 1:1 to 2:2;

[0023] The concentration of the hydrophobically associating polymer in the hydrophobically associating polymer solution of S2 is 400 mg / L to 600 mg / L.

[0024] Preferably, the stirring environment temperature in S2 is 20°C to 40°C;

[0025] The stirring speed is 150 rpm to 400 rpm;

[0026] In the particle size test, a laser particle size analyzer is used for measurement, and the measurement interval time is 4 minutes to 6 minutes.

[0027] Preferably, the molecular weight of the hydrophobically associating polymer is 1 to 20 million g / mol.

[0028] In order to achieve the above object, the present invention also provides the use of the hydrophobic associating polymer solution prepared by the above method based on cyclodextrin solubilization modification to improve the performance of the drag reducing agent in oil and gas field development.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) This application utilizes the characteristics of cyclodextrin, which is hydrophilic on the outside and hydrophobic on the inside, and applies it to the solubilization of insoluble substances. The cyclodextrin polymer not only has a high molecular effect, but also retains the inclusion capacity of the cyclodextrin cavity, and has better inclusion performance when the guest molecule is large. The hydrophobic associating polymer is modified by the host-guest inclusion technology, and its solubility is improved on the basis of ensuring its drag reduction effect. The prepared hydrophobic associating polymer drag reducing agent has the advantages of fast dissolution, shear resistance and good drag reduction effect.

[0031] (2) The present invention establishes the Langmuir isotherm adsorption equation through rheological testing, analyzes and calculates the inclusion constant, entropy change and enthalpy change of the process from the perspective of molecular dynamics, and determines its accurate inclusion constant and ratio, that is, through the combination of molecular dynamics simulation, theoretical equations and experiments, the inclusion interaction between the hydrophobic segment of the hydrophobic associating compound and the cyclodextrin cavity is systematically studied, and the interaction energy, radial distribution function and gyration radius of the inclusion process are obtained, and the matching relationship between the hydrophobic associating structure and the cyclodextrin cavity is obtained. The cyclodextrin cavity with a high degree of matching can promote the dissolution of dry powder hydrophobic associating polymers, improve the drag reduction effect of the polymer aqueous solution to a certain extent, and make it have a wide range of application prospects in the field.

[0032] (3) The present invention is based on the difference in hydrophilicity and hydrophobicity inside and outside the cyclodextrin cavity, and conducts solubilization modification research through host-guest inclusion. The effects of cyclodextrin type, concentration, dissolution temperature and stirring time on the solubility of dry powder hydrophobic associating polymers were systematically studied, and it was confirmed that with β-CD (β-cyclodextrin) as the main substance, the ratio of β-CD to hydrophobic chain segment was 2:1, and stirring at 25°C for 45 minutes can completely dissolve the dry powder hydrophobic associating polymer; the Langmuir isotherm adsorption equation was established through rheological tests to calculate the inclusion constants at 25°C, 35°C, and 45°C, which were 0.8065, 1.1114, and 1.4911, respectively. The entropy change of the process was -78.12 J / mol·K, and the enthalpy change was -23.41 kJ / mol; molecular simulation from molecular dynamics The interaction energy, radial distribution function and gyration radius of the inclusion process were calculated from a mechanical perspective. The introduction of β-CD increased the interaction energy between the dry powder hydrophobic associating polymer and water, increased the hydrogen bond content of the system, and increased the hydrodynamic radius of the dry powder hydrophobic associating polymer, proving that β-CD can promote the dissolution of dry powder hydrophobic associating polymers. β-CD recognizes the hydrophobic structure in the system through host-guest interaction and quickly includes it, changing its hydrophilicity and hydrophobicity, thereby accelerating dissolution. The generation of hydrophobic segment association is adjusted by controlling the amount of β-CD added, thereby taking into account both the solubility and drag reduction properties of the dry powder hydrophobic associating polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 is a dissolution time curve of the hydrophobically associating polymer in Example 1;

[0035] Figure 2 is a dissolution time curve of the hydrophobically associating polymer in Example 2;

[0036] Figure 3 is a dissolution time curve of the hydrophobically associating polymer in Example 3;

[0037] Figure 4 is a dissolution time curve of the hydrophobically associating polymer in Example 4;

[0038] Figure 5 is a dissolution time curve of the hydrophobically associating polymer in Example 5;

[0039] Figure 6is a dissolution time curve of the hydrophobically associating polymer in Example 6;

[0040] Figure 7 This is a host-guest inclusion conformation diagram of the embodiment system of the present invention;

[0041] Figure 8 This is a diagram of the host-guest inclusion solubilization mechanism of an embodiment of the present invention;

[0042] Fig. 9 It is a schematic diagram of the solubility performance of hydrophobic associating polymers in the prior art;

[0043] Fig.10 Schematic diagram of the solubility performance of the hydrophobic associating polymer in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0047] Compared with the prior art CN114605982A, the embodiment of the present invention has the following differences:

[0048] (1) Dissolution promotion and inclusion optimization: Patent CN114605982A uses a compound of cyclodextrin and surfactant. First, Tween-80, sodium dodecyl sulfate and cyclodextrin β-CD are mixed in a certain proportion, and then a certain concentration of hydrophobic associating polymer is added. The viscosity of the solution is tested with a viscometer at the same interval. Based on the collaborative research of multivariate methods, the embodiment of the present invention obtains an implementation scheme for achieving the purpose of dissolution promotion by including hydrophobic associating polymer in cyclodextrin without using surfactants, and the improvement of solubility does not harm the drag reduction performance, but improves the drag reduction performance to a certain extent. Patent CN114605982A only focuses on the improvement of solubility performance.

[0049] (2) Technical optimization: Patent CN114605982A shields the hydrophobic association of polymers and uses cyclodextrin and surfactants to change the polarity of polymer aqueous solution, thereby increasing the solubility of hydrophobic associating polymers. Figure 7-8 As shown, the embodiment of the present invention systematically studies the inclusion effect of the hydrophobic segment of the hydrophobic associating polymer and the cyclodextrin cavity for the first time by combining molecular dynamics simulation, theoretical equations and experiments, obtains the interaction energy, radial distribution function and gyration radius of the inclusion process, and obtains the matching relationship between the hydrophobic associating structure and the cyclodextrin cavity. The cyclodextrin cavity with a high degree of matching can promote the dissolution of dry powder hydrophobic associating polymers.

[0050] (3) Key solution: Patent CN114605982A determined the better preparation conditions through experimental comparison. The results were affected by experimental errors and system changes, and the influence of surfactants was unclear. The embodiment of the present invention studied the changes in state functions from a macroscopic perspective through thermodynamic analysis, calculated the inclusion constant and the thermodynamic parameters of the inclusion process. Based on this, the inclusion constant of the system under different conditions and environments can be accurately determined by measuring the rheological properties of the system, and the optimal inclusion ratio can be obtained. The inclusion constant of β-CD and dry powder hydrophobic associating polymer is shown in Table 1 below:

[0051]

[0052] (4) Performance improvement: Figure 9-10 As shown, under the same polymer concentration and the same cyclodextrin addition amount, the dissolution time of the embodiment of the present invention is shortened by more than 40 minutes compared with the dissolution time of patent CN114605982A, which is significantly improved, and the drag reduction performance is improved by 5.76% compared with the performance without adding cyclodextrin.

[0053] In order to better understand the technical solution of the present invention, the experimental methods, samples and instruments of the embodiments are introduced as follows:

[0054] The materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources unless otherwise specified. The types of cyclodextrin in the following implementation are α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, which are provided by Sichuan Kelong Pharmaceutical Co., Ltd. The hydrophobic associating polymer is homemade in the laboratory, and the viscosity-average molecular weight is 1-20 million g / mol. The concentration of the hydrophobic associating polymer in the hydrophobic associating polymer solution is 400 mg / L to 600 mg / L, and the preparation volume is 500 mL.

[0055] Cyclodextrin: α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, wherein the molar concentration ratio of cyclodextrin to hydrophobically associating polymer powder is 1:1 to 2:2. The dissolution method is as follows: the hydrophobically associating polymer powder and cyclodextrin are prepared in a certain proportion and concentration, and the particle size of the solution is tested at the same time interval using a laser particle size analyzer, and the stirring is terminated when the particle size gradually decreases and tends to be stable, so as to obtain a hydrophobically associating polymer solution.

[0056] Example 1

[0057] Prepare 500mL of quaternary ammonium salt hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add α-cyclodextrin according to the molar ratio of quaternary ammonium salt hydrophobically associating polymer dry powder to cyclodextrin of 1:2, adjust the speed of the mechanical stirrer to 150rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 40°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is as follows: Figure 4 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 18 minutes, and the drag reduction rate is increased by 4.74%.

[0058] Example 2

[0059] Prepare 500mL of nonionic hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add β-cyclodextrin according to the ratio of nonionic hydrophobically associating polymer to cyclodextrin of 1.1:1.8, adjust the speed of the mechanical stirrer to 200rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 35°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is as follows: Figure 5 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 15 minutes, and the drag reduction rate is increased by 5.76%.

[0060] Example 3

[0061] Prepare 500mL of rigid structure hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add γ-cyclodextrin according to the ratio of rigid structure hydrophobically associating polymer dry powder to cyclodextrin of 1.5:1.5, adjust the speed of the mechanical stirrer to 250rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 30°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is shown in Figure 6 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 21 minutes, and the drag reduction rate is increased by 4.12%.

[0062] Example 4

[0063] Prepare 500mL of quaternary ammonium salt hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add α-cyclodextrin according to the ratio of quaternary ammonium salt hydrophobically associating polymer to cyclodextrin of 1.6:1.3, adjust the speed of the mechanical stirrer to 300rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 30°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is as follows: Figure 7 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 29 minutes, and the drag reduction rate is increased by 1.36%.

[0064] Example 5

[0065] Prepare 500mL of nonionic hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add β-cyclodextrin according to the ratio of nonionic hydrophobically associating polymer to cyclodextrin of 1.8:1.1, adjust the speed of the mechanical stirrer to 350rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 35°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is as follows: Figure 8 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 23 minutes, and the drag reduction rate is increased by 3.11%.

[0066] Example 6

[0067] Prepare 500mL of rigid structure hydrophobically associating polymer mixed solution, heat it to the preparation temperature, add γ-cyclodextrin according to the ratio of rigid structure hydrophobically associating polymer to cyclodextrin of 2:1, adjust the speed of the mechanical stirrer to 400rmp for stirring, and measure the particle size change of the polymer solution every five minutes at 20°C with a laser particle size analyzer. When the particle size gradually decreases and tends to be stable, stop stirring to obtain a hydrophobically associating polymer solution. The dissolution time curve of 500mg / L hydrophobically associating polymer is as follows: Fig. 9 As shown, based on the particle size of the polymer solution measured every five minutes and the judgment basis for ending the experiment when the particle size gradually decreases and tends to be stable, the dissolution time of 500 mg / L hydrophobic associating polymer is less than 27 minutes, and the drag reduction rate is increased by 1.47%.

[0068] The experimental verification results of the above embodiments 1-6 are summarized as shown in the following Table 2:

[0069]

[0070] The embodiment of the present invention provides a method and application for improving the drag reduction rate of a drag reducing agent based on cyclodextrin solubilization modification, wherein the types of hydrophobically associating polymers include quaternary ammonium salt type hydrophobically associating polymers PAAD, nonionic hydrophobically associating polymers PAAO and rigid structure type hydrophobically associating polymers PSEM, wherein the concentration of the hydrophobically associating polymer is 500 mg / L, and the molar concentration ratio of cyclodextrin to hydrophobic group is 1:1 to 2:2. The dissolution method is: preparing hydrophobically associating polymer dry powder and cyclodextrin according to a certain proportion and concentration, testing the polymer particle size in the solution at the same time interval with a laser particle size analyzer, and stopping the test after the particle size decreases to a stable state to obtain a hydrophobically associating polymer solution.

[0071] The SW slippery water system was developed with the solubilized and modified dry powder drag reducing agent as the main agent, and its various properties were studied. Rheological tests confirmed that the system had good viscoelasticity; under the same stirring conditions, 0.025wt% SW-41 (β-CD) and SW-4 (dry powder hydrophobic associating polymer + β-CD) systems were prepared and stirred in clean water for 10 minutes, and the drag reduction rates were 40.76% and 71.43%, respectively, confirming that the introduction of β-CD can achieve low-concentration and high-efficiency drag reduction, only accelerate the dissolution process, and help improve the stability and drag reduction performance of the system; the NaCl concentration was 1.2×10 5 mg / L, CaCl2 concentration is 1×10 3 When the content of SW-4 in the system was 0.075wt%, the drag reduction rates of the system were 72.28% and 74.23%, respectively, with good salt resistance, excellent temperature resistance and excellent shear resistance.

[0072] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification, characterized in that: The following steps are involved: S1: preparing a mixed liquid of a hydrophobic associating polymer dry powder and cyclodextrin; S2: stirring the mixed liquid, and testing the particle size in the mixed liquid at the same time interval, and stopping the stirring after the particle size is reduced to a stable size to obtain a hydrophobic associating polymer solution.

2. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 1, characterized in that: The hydrophobically associating polymer dry powder is one substance or a combination of multiple substances selected from the group consisting of quaternary ammonium salt type hydrophobically associating polymer, nonionic type hydrophobically associating polymer and rigid structure type hydrophobically associating polymer.

3. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 2, characterized in that: The quaternary ammonium salt type hydrophobic associating polymer is PAAD, and the PAAD has the following molecular structural formula: Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5.

4. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 2, characterized in that: The nonionic hydrophobic associating polymer is PAAO, and the PAAO has the following molecular structure formula: Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5, n represents the number of ethylene oxide, 9≤n≤30.

5. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 2, characterized in that: The rigid structure type hydrophobic associating polymer is PSEM, and the PSEM has the following molecular structure formula: Among them, 70≤x≤90, 5≤y≤30, 0≤z≤5, n represents the number of ethylene oxide, 9≤n≤30.

6. A method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 1, characterized in that: The cyclodextrin is one cyclodextrin selected from α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, or a combination of multiple cyclodextrins.

7. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 1, characterized in that: In the hydrophobically associating polymer solution, the molar ratio of the cyclodextrin to the hydrophobically associating polymer powder in the mixed liquid of S1 is 1:1 to 2:2; The concentration of the hydrophobically associating polymer in the hydrophobically associating polymer solution of S2 is 400 mg / L to 600 mg / L.

8. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 1, characterized in that: The stirring environment temperature in S2 is 20℃~40℃; The stirring speed is 150 rpm to 400 rpm; In the particle size test, a laser particle size analyzer is used for measurement, and the measurement interval time is 4 minutes to 6 minutes.

9. The method for improving the performance of a drag reducing agent based on cyclodextrin solubilization modification according to claim 1, characterized in that: The molecular weight of the hydrophobic associating polymer is 1 million to 20 million g / mol.

10. Use of the hydrophobic associating polymer solution prepared by the method for improving the performance of the drag reducing agent based on cyclodextrin solubilization modification as claimed in any one of claims 1 to 9 in the development of oil and gas fields.

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