High-temperature-resistant drag reducer for well cementation cement and preparation method of high-temperature-resistant drag reducer

Abstract

The invention relates to an oil well exploitation auxiliary agent, in particular to a high-temperature-resistant drag reducer for well cementation cement and a preparation method of the high-temperature-resistant drag reducer, and the high-temperature-resistant drag reducer comprises the following components in parts by weight: 1-15 parts of 2-acryloyloxybutyl sulfonic acid, 5-20 parts of acrylic acid and 10-30 parts of isopentenol polyoxyethylene ether. The method has the beneficial effects that the drag reduction effect is good, and the economical efficiency is good; the effects of fast solidification at low temperature and still good dispersion effect at high temperature are achieved; the method can be used in different stratums.

Description

Technical Field

[0001] This invention relates to the field of oil well additives technology, and in particular to a high-temperature drag-reducing agent for cementing and its preparation method. Background Technology

[0002] Oil well cement drag reducers are widely used admixtures in oilfield cementing operations. They primarily reduce the viscosity of cement slurry, improve its flow properties, thereby reducing pumping resistance and ensuring that the cement slurry can efficiently and safely replace drilling fluid to form a uniform and complete cement sheath. Commonly used drag reducers include natural derivatives, naphthalene-based drag reducers, aldehyde-ketone drag reducers, polycarboxylate-based drag reducers, and olefin copolymers. Their mechanism of action involves increasing delta potential and enhancing steric hindrance to improve dispersibility.

[0003] Currently, most drag-reducing agents used in oil well cement are aldehyde-ketone type drag-reducing agents. These are polymers formed by the condensation of ketones, aldehydes, and sulfonating agents through a series of chemical reactions, with methyl ethyl ketone-formaldehyde condensate as a representative high-performance synthetic polymer dispersant. Through their unique branched structure and sulfonic acid groups, they provide a dual stabilization mechanism of electrostatics and steric hindrance, thus providing efficient, stable, and reliable drag reduction and dispersion for oil well cement slurries under harsh conditions such as high temperature, high salinity, and high calcium. They are one of the indispensable key chemicals in modern complex well cementing technology.

[0004] Under the current global trend of oil and gas exploration and development, resource demand is driving drilling operations to continuously advance into deeper and ultra-deep formations. Increased well depth directly leads to a sharp rise in downhole circulating temperature (BHCT) and bottom static temperature (BHST). Extreme high temperatures can cause the molecular chains of drag-reducing agents to degrade. Generally, the chemical bonds of drag-reducing agents become unstable, and functional groups undergo hydrolysis, leading to polymer molecular chain breakage, a decrease in molecular weight, and thus a permanent loss of their dispersing effect. Simultaneously, high temperatures disrupt the hydrogen bonds between polymer molecules and water molecules, and intensify molecular thermal motion, causing the molecular chains to change from an effectively extended state to a useless coiled spherical shape. The complete collapse of their "comb-like" or "linear" dispersion structure prevents the drag-reducing agent from adsorbing cement particles through the extension of its molecular chains in water, and prevents it from functioning through electrostatic repulsion and steric hindrance.

[0005] The invention, with publication number CN1050211A, is entitled "A Preparation Method of an Oil Well Cement Drag Reducing Agent," which is an aldehyde-ketone type drag reducing agent. The method involves using a molar ratio of sodium metabisulfite:sodium hydroxide:acetone:formaldehyde of 0.4~0.6:0.8~1.2:0.8~1.2:2.8~3.2. After the solution reacts, it is allowed to stand for 12 hours, cooled to room temperature, and then heated to 95°C and refluxed for 1 hour to obtain a liquid product. This is followed by spray drying to obtain a solid product. The product exhibits good drag reduction performance at both room and high temperatures. However, due to its retarding effect, the 24-hour strength value of the sample slurry is significantly lower than that of the base slurry, failing to meet industry standards. Furthermore, this drag reducing agent is primarily composed of formaldehyde, which has a certain environmental impact.

[0006] The invention, with publication number CN1052886A, entitled "Drag Reducing Agent for Oil Well Cement Slurry and its Preparation Method," describes a naphthalene-based drag reducing agent. The process involves taking 1 part by weight of naphthalene, adding 1 to 1.1 parts by weight of sulfuric acid, and subjecting the mixture to a sulfonation reaction at a temperature above 125°C for 3 hours. Hydrolysis is then performed with water, maintaining an acidity above 25%. Next, 0.8 parts by weight of formaldehyde are added for condensation, with the temperature controlled below 100°C. After the addition of formaldehyde, the temperature is maintained at 105°C to 108°C for 1 to 2 hours. A first-type modifier is then added, and the mixture is stirred until homogeneous. Finally, a second-type modifier is added, controlling the pH to ≤5 to obtain the final product. This powder product requires a relatively large dosage, failing to meet the current cost-reduction and efficiency-enhancing requirements. Furthermore, the product has a limited applicable temperature range; there is no valid data to support its application at temperatures above 100°C.

[0007] The invention, with publication number CN102382270A, is titled "Drag Reducing Agent for Oil Well Cement Slurry and its Preparation Method," and describes a polycarboxylate-based drag reducing agent. This oil well cement slurry drag reducing agent is mainly composed of 10-80 parts of allyl alcohol polyoxyethylene ether, 15-80 parts of acrylic acid, and 15-35 parts of hydroxyethyl acrylate copolymerized together. However, the product composition lacks suitable high-temperature resistant monomers and cannot meet the requirements for use under current high-temperature conditions.

[0008] In the performance evaluation system of oil well cement admixtures, a common phenomenon is that most drag-reducing agents, while effectively improving the rheological properties of cement slurry, will, to varying degrees, slow down the cement hydration process, exhibiting certain retarding side effects. This directly leads to the cement stone formed from test slurry samples containing drag-reducing agents having significantly lower early (e.g., 24 or 48 hours) compressive strength than base slurry without any admixtures, failing to meet current industry testing standards. From practical field applications, the retarding side effects of drag-reducing agents in shallow wells at low temperatures delay the cement slurry solidification time, causing the cement slurry to remain in a semi-liquid state for an extended period. This gradually diminishes the effective liquid column pressure of the cement slurry column, making it impossible to balance formation pressure. The casing may become unstable due to the lack of solid cement sheath support for an extended period. Cementing operations in formations prone to leakage and cross-contamination are akin to achieving a highly difficult balance on a fragile foundation. Any imbalance in any aspect can lead to catastrophic consequences. Among these, a series of chain reactions triggered by excessively long cement slurry solidification time is one of the core failure pathways ultimately leading to cement slurry leakage, interlayer cross-contamination, and even annular pressure. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature drag-reducing agent for cementing and its preparation method. This drag-reducing agent focuses on solving the problems of insufficient dispersion performance of drag-reducing agents under high temperature conditions and the deterioration of cement stone strength caused by drag-reducing agents under medium and low temperature conditions.

[0010] It should be noted that this solution mainly addresses the following situations: existing drag-reducing agents exhibit decreased drag-reducing performance after high-temperature curing, and have a retarding effect at medium and low temperatures, leading to a decrease in the strength of cement stone, thus failing to meet the requirements of testing standards.

[0011] The objective of this invention is achieved through the following technical solution: a high-temperature drag-reducing agent for cementing, comprising, by weight: 1 to 15 parts of 2-acryloyloxybutylsulfonic acid (AOBS), 5 to 20 parts of acrylic acid (AA), and 10 to 30 parts of isopentenyl alcohol polyoxyethylene ether (TPEG-2400).

[0012] Further, by weight, it includes: 3 to 12 parts of 2-acryloyloxybutylsulfonic acid, 8 to 15 parts of acrylic acid and 15 to 25 parts of isopentenyl alcohol polyoxyethylene ether.

[0013] Further, by weight, it includes: 3 parts 2-acryloyloxybutylsulfonic acid, 8 parts acrylic acid and 20 parts isopentenyl alcohol polyoxyethylene ether.

[0014] Further, by weight, it includes: 7 parts 2-acryloyloxybutylsulfonic acid, 12 parts acrylic acid and 20 parts isopentenyl alcohol polyoxyethylene ether.

[0015] Further, by weight, it includes: 12 parts 2-acryloyloxybutylsulfonic acid, 15 parts acrylic acid and 25 parts isopentenyl alcohol polyoxyethylene ether.

[0016] Further, by weight, it includes: 15 parts 2-acryloyloxybutylsulfonic acid, 20 parts acrylic acid and 30 parts isopentenyl alcohol polyoxyethylene ether.

[0017] Secondly, a method for preparing a high-temperature drag-reducing agent for well cementing is also provided, the steps of which are as follows: Weigh out 2-acryloyloxybutylsulfonic acid and isopentenyl alcohol polyoxyethylene ether by weight, dissolve them together in water, mix and stir to obtain a mixed solution; at the same time, weigh out acrylic acid by weight and dissolve it in water to prepare an acrylic acid solution with a concentration of 40% to 60%. After heating the prepared mixed solution to 60℃~80℃, the acrylic acid solution is added dropwise to the heated mixed solution, and an initiator aqueous solution is also added at the same time; after stirring the reaction for a period of time, a high-temperature drag-reducing agent for cementing is obtained.

[0018] Furthermore, the initiator used is a peroxide initiator, the concentration of the initiator aqueous solution is 3-6%, and the amount of initiator added is 0.05-0.8% of the weight of the high-temperature drag-reducing agent for cementing.

[0019] To facilitate understanding, the core principles of this solution will be explained as follows: I. In the drag-reducing agent of this scheme, the macromonomer isopentenyl polyoxyethylene ether (TPEG-2400) was selected. The double bond at the end of TPEG-2400 is an allyl ether structure. The double bond in this structure has a high electron cloud density and is very active, making it easier to undergo copolymerization reaction with other monomers (acrylate AA). In addition, TPEG-2400 has polyoxyethylene side chains. These side chains are long and flexible and can fully extend in water. This effect and the macromonomer structure enable the drag-reducing agent to form a strong steric hindrance effect, which can effectively prevent cement particles from approaching each other and flocculating. In short, the above principle allows the expanded structure of the drag-reducing agent in this solution to effectively separate cement particles, thus achieving better drag reduction effect with less drag-reducing agent (and better economy). II. In this scheme, AOBS with sulfonic acid groups is used as the high-temperature resistant monomer. The double bonds in the molecule are acrylate structures, which have higher polymerization reactivity than acrylamide monomers. This means that it is easier to copolymerize with other monomers, easier to obtain polymers with higher molecular weight and more uniform molecular weight distribution, and less unpolymerized monomers remain after the reaction, which is beneficial to environmental protection and product performance. The linking groups of AOBS are flexible. Straight-chain alkyl groups, while commonly used AMPS linking groups are rigid. The flexible side chains contribute to better rheological properties, allowing the polymer molecular chains to extend more easily in solution and function more quickly. Most importantly, in the AOBS molecule, the sulfonic acid group is connected via an ester group. and a stable ether bond The flexible alkyl chains are connected to the main skeleton, and the hydrolytic stability of aliphatic ester bonds is significantly higher than that of amide bonds. Under the same harsh high-temperature environment, the molecular bonds of AOBS are more difficult to break, and the sulfonic acid groups will not easily fall off. The polymer can maintain its hydration ability and dispersion effect for a longer period of time.

[0020] The present invention has the following advantages: (1) Better drag reduction effect and better economy; The drag-reducing agent in this solution has a sufficiently flexible side chain structure that allows it to fully expand in water; therefore, the drag-reducing agent has a better expansion effect, resulting in a better steric hindrance effect on cement particles—that is, a better drag reduction effect; the same drag reduction effect can be achieved with a smaller dosage, thus resulting in lower cost and better economic efficiency. (2) It combines the effects of slow setting at low temperatures and good dispersion at high temperatures, and can be used in different formations; The high-temperature drag-reducing agent for cementing in this solution still has good dispersion at high temperatures and can meet the standard testing requirements at high temperatures; due to its salt and high-temperature resistance, it can be used in various complex formations. In addition, the drag-reducing agent in this solution has minimal retarding side effects at low temperatures and can meet the standard testing requirements for low temperatures in the industry standard SY / T 5504.3-2018. Attached Figure Description

[0021] Figure 1 This is a thickening curve of cement slurry obtained by the present invention when the drag-reducing agent addition is 0% under the condition of use temperature less than 80°C; Figure 2 This is a thickening curve of cement slurry obtained by the present invention when the drag-reducing agent content is 0.5% under the condition of use temperature below 80℃; Figure 3 This is a thickening curve of cement slurry obtained by the present invention when the drag-reducing agent content is 1.0% under the condition of use temperature less than 80°C; Figure 4 This is a thickening curve of cement slurry obtained by the present invention when the drag-reducing agent content is 1.5% under the condition of use temperature less than 80℃. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0023] (Example 1) A method for preparing a drag-reducing agent: Dissolve 3g of 2-acryloyloxybutylsulfonic acid (AOBS) and 20g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 8g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain a high-temperature drag-reducing agent for well cementing.

[0024] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.05% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is ammonium persulfate.

[0025] (Example 2) A method for preparing a drag-reducing agent: Dissolve 7g of 2-acryloyloxybutylsulfonic acid (AOBS) and 20g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 12g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain a high-temperature drag-reducing agent for well cementing.

[0026] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.2% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is ammonium persulfate.

[0027] (Example 3) A method for preparing a drag-reducing agent: Dissolve 12g of 2-acryloyloxybutylsulfonic acid (AOBS) and 20g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 15g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain a high-temperature drag-reducing agent for well cementing.

[0028] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.3% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is ammonium persulfate.

[0029] (Example 4) A method for preparing a drag-reducing agent: Dissolve 12g of 2-acryloyloxybutylsulfonic acid (AOBS) and 25g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 15g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain a high-temperature drag-reducing agent for well cementing.

[0030] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.4% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is potassium persulfate.

[0031] (Example 5) A method for preparing a drag-reducing agent: Dissolve 15g of 2-acryloyloxybutylsulfonic acid (AOBS) and 30g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 20g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain a high-temperature drag-reducing agent for well cementing.

[0032] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.6% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is ammonium persulfate.

[0033] (Comparative Example 1) A method for preparing a drag-reducing agent: Dissolve 7g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 20g of isopentenyl alcohol polyoxyethylene ether (TPEG) in water, mix and stir evenly, then pour into a three-necked beaker and heat to 60~80℃. Prepare 12g of acrylic acid (AA) into a 40~60% aqueous solution and add it dropwise to the mixed solution. At the same time, add an initiator aqueous solution with a concentration of 3~6% to initiate the reaction. Stir the reaction for 2 hours to obtain the drag-reducing agent for comparison.

[0034] The initiator is an inorganic peroxide initiator, and the amount of the initiator added is 0.2% of the weight of the high-temperature drag-reducing agent for cementing; the inorganic peroxide compound is ammonium persulfate.

[0035] (Experimental Example 1) The performance comparison of the high-temperature drag-reducing agent for cementing prepared in this invention under different addition amounts and different experimental temperatures.

[0036] The high-temperature drag-reducing agent for cementing prepared in Example 2 of this invention was added to cement slurry at different amounts, and its effects on cement rheological properties, cement stone strength, thickening curve and other properties were tested at different experimental temperatures.

[0037] The experimental methods for rheology, cured cement stone strength, and curing thickening curve were all conducted in accordance with the requirements of the national standard GB / T 19139-2012. Cement slurry preparation was carried out according to Chapter 5 of GB / T 19139-2012, rheology determination was carried out according to Chapter 12 of GB / T 19139-2012, cement stone strength determination was carried out according to Chapter 7 of GB / T 19139-2012, and thickening curve determination was carried out according to Chapter 9 of GB / T 19139-2012.

[0038] The performance data of cement grout are based on industry standard SY / T 5504.3-2018 and enterprise standard Q / SH CG0002—2023.

[0039] For the pure cement paste formula used at a temperature below 80℃: 792g of Grade G cement + 349g of distilled water.

[0040] For cement slurry formulations containing liquid drag-reducing agents used at temperatures below 80℃: 792g of Grade G cement + 349g of distilled water (including the mass of liquid drag-reducing agent) + liquid drag-reducing agent (reference addition 1.5%).

[0041] For cement slurry thickening test conditions at temperatures below 80℃: 52℃ * 35.6MPa * 28min.

[0042] For cement stone curing conditions at temperatures below 80℃: 67℃ * normal pressure * 24h.

[0043] Table 1. Performance of cement slurry with different addition amounts of the high-temperature drag-reducing agent for cementing obtained in Example 2 of the present invention at operating temperatures below 80°C. From Table 1, we can conclude that: 1. With the increase of drag-reducing agent dosage, the rheological value of high-temperature slurry was improved; 2. The amount of drag-reducing agent added has little effect on the thickening time; 3. Changes in the amount of drag-reducing agent added have no effect on the strength of cement stone; 4. Figures 1-4 Temperature and pressure are merely experimental conditions for the product; the product's performance is primarily reflected in its consistency curve. Figure 1The thickening curves show that without drag-reducing agents, the initial consistency of the slurry is too high, the consistency value fluctuates frequently, and problems such as steps occur during the rise. 5. Figures 2-4 It can be seen that as the amount of drag-reducing agent increases, the initial consistency of the slurry gradually decreases, and the curve during cement setting becomes smoother.

[0044] For pure cement paste formulation used at temperatures above 120℃: Grade G oil well cement + 600g + silica fume 210g + distilled water 330g + 6g HX-36L.

[0045] For cement slurry formulations containing liquid drag reducers used at temperatures above 120℃: 600g G-grade oil well cement + 210g silica fume + 330g distilled water (including the mass of the liquid drag reducer) + 6g HX-36L + liquid drag reducer (reference addition 0.7%) For cement slurry curing conditions at temperatures above 120℃: 120℃ * 73.9MPa * 61min.

[0046] Table 2. Performance of cement slurry with different addition amounts of the high-temperature drag-reducing agent for cementing obtained in Example 2 of the present invention when used at temperatures above 120°C. From Table 2, we can conclude that: 1. Under high-temperature experimental conditions, this high-temperature drag-reducing agent can maintain good flowability of cement slurry with a relatively small dosage; 2. With the increase of drag-reducing agent, the high-temperature rheological properties of cement slurry are also significantly improved.

[0047] The above embodiments only illustrate preferred implementation methods, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these all fall within the protection scope of this invention.

[0048] (Experimental Example 2) The performance comparison of the high-temperature drag-reducing agent for cementing prepared in this invention under the condition of changing raw materials by a single factor.

[0049] The high-temperature drag-reducing agents for ancient well cement prepared in Example 2 and Comparative Example 1 of this invention were added to cement slurry at different amounts, and the effect on the rheological properties of cement slurry under high temperature conditions was tested.

[0050] Cement slurry preparation was carried out in accordance with Chapter 5 of GB / T 19139-2012, and rheological determination was carried out in accordance with Chapter 12 of GB / T 19139-2012.

[0051] The performance data of cement grout are based on industry standard SY / T 5504.3-2018 and enterprise standard Q / SH CG0002—2023.

[0052] For cement slurry formulation containing liquid drag reducer at operating temperatures above 120℃: 600g G-grade oil well cement + 210g silica fume + 330g distilled water (including the mass of liquid drag reducer) + 6g HX-36L + liquid drag reducer.

[0053] For cement slurry curing conditions at temperatures above 120℃: 120℃ * 73.9MPa * 61min.

[0054] Table 3 shows the performance of the high-temperature drag-reducing agent for cementing obtained in Comparative Example 1 at different dosages under conditions exceeding 120°C. Combining the data from Tables 2 and 3, we can obtain: 1. The main difference between Example 2 and Comparative Example 1 is 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 2-acryloyloxybutylsulfonic acid (AOBS). The high-temperature resistance was compared by changing the raw material composition using a single factor. 2. It can be seen that under the high temperature test conditions of 120℃, the rheological properties of the high temperature drag reducing agent prepared by AOBS are better than those prepared by AMPS. 3. The rheological properties of cement grout improve with increasing drag-reducing agent dosage.

[0055] The above embodiments only illustrate preferred implementation methods, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A high-temperature drag-reducing agent for cementing, characterized in that: By weight, it includes: 1 to 15 parts of 2-acryloyloxybutylsulfonic acid, 5 to 20 parts of acrylic acid, and 10 to 30 parts of isopentenyl alcohol polyoxyethylene ether.

2. The high-temperature drag-reducing agent for cementing as described in claim 1, characterized in that: By weight, it includes: 3-12 parts 2-acryloyloxybutylsulfonic acid, 8-15 parts acrylic acid and 15-25 parts isopentenyl alcohol polyoxyethylene ether.

3. A high-temperature drag-reducing agent for cementing according to claim 1 or 2, characterized in that: By weight, it includes: 3 parts 2-acryloyloxybutylsulfonic acid, 8 parts acrylic acid and 20 parts isopentenyl alcohol polyoxyethylene ether.

4. A high-temperature drag-reducing agent for cementing according to claim 1 or 2, characterized in that: By weight, it includes: 7 parts 2-acryloyloxybutylsulfonic acid, 12 parts acrylic acid and 20 parts isopentenyl alcohol polyoxyethylene ether.

5. A high-temperature drag-reducing agent for cementing according to claim 1 or 2, characterized in that: By weight, it includes: 12 parts 2-acryloyloxybutylsulfonic acid, 15 parts acrylic acid and 25 parts isopentenyl alcohol polyoxyethylene ether.

6. A high-temperature drag-reducing agent for cementing according to claim 1 or 2, characterized in that: By weight, it includes: 15 parts 2-acryloyloxybutylsulfonic acid, 20 parts acrylic acid and 30 parts isopentenyl alcohol polyoxyethylene ether.

7. A method for preparing a high-temperature drag-reducing agent for cementing as described in any one of claims 1 to 6, characterized in that: The steps are as follows: Weigh out 2-acryloyloxybutylsulfonic acid and isopentenyl alcohol polyoxyethylene ether by weight, dissolve them together in water, mix and stir to obtain a mixed solution; at the same time, weigh out acrylic acid by weight and dissolve it in water to prepare an acrylic acid solution with a concentration of 40% to 60%. The prepared mixed solution is heated to 60℃~80℃, and then acrylic acid solution is added dropwise to the heated mixed solution. At the same time as the dropwise addition, an initiator aqueous solution is also added. After reacting for a period of time, a high-temperature drag-reducing agent for well cementing is obtained.

8. The method for preparing a high-temperature drag-reducing agent for cementing according to claim 7, characterized in that: The initiator used is a peroxide initiator, the concentration of the initiator aqueous solution is 3~6%, and the amount of initiator added is 0.05~0.8% of the weight of the high temperature drag-reducing agent for cementing.

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