High-temperature slow-release adsorption type corrosion and scale inhibitor as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature slow-release adsorption type corrosion and scale inhibitor as well as a preparation method and application thereof, and belongs to the technical field of pipeline corrosion prevention and scale inhibition. The preparation method comprises the following steps: adding maleic anhydride into dichloromethane, and then adding an oxidizing agent to carry out oxidation reaction; after the reaction is completed, raising the temperature, adding a catalyst, and carrying out ring-opening polymerization reaction to generate a high-molecular compound; and cooling the high-molecular compound to room temperature, and then adding thiourea for amidation reaction to obtain the high-temperature slow-release adsorption type corrosion and scale inhibitor. The high-temperature slow-release adsorption type corrosion and scale inhibitor is used for solving the technical problems that an existing corrosion and scale inhibitor is high in cost, high in toxicity, not prone to degradation, short in corrosion inhibition time and low in scale inhibition efficiency at the high temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion and scale inhibition of pipelines in oilfield water systems, and particularly relates to a high-temperature slow-release adsorption-type corrosion and scale inhibitor, a preparation method and an application thereof. Background Art

[0002] Scaling and corrosion are common problems in oilfield development, especially when secondary water flooding, tertiary CO2 flooding and other oil recovery technologies are widely used, which makes the properties and composition of the produced fluid more complex and difficult to handle, making the scaling and corrosion problems in the oilfield development process more serious. On the one hand, the scaling problem may lead to a decrease in the heat transfer efficiency of the oilfield heat exchanger, and on the other hand, it may lead to huge production capacity losses caused by regular and irregular shutdowns due to scale removal; in addition, scaling will also reduce the flow area of the pipeline and increase the pumping cost in the oil and gas gathering and transportation process. Corrosion problems can cause fatigue damage to oil and gas field production equipment and pipelines, and in severe cases may lead to oil and gas leakage accidents, which have a significant impact and serious damage to human health, production safety and environmental safety. There are various existing corrosion inhibition methods, such as using corrosion-resistant materials, electrochemical corrosion prevention, and improving the properties of injected water. Oilfield scaling inhibition primarily involves physical inhibition, improving injection water compatibility, and adjusting production parameters. Considering the specific conditions of an oilfield and factors such as cost-effectiveness, practicality, and ease of operation, adding chemical agents with scale and corrosion inhibition properties to the oilfield water system is a wise choice.

[0003] Currently used scale and corrosion inhibitors include both inorganic and organic compounds. Different scale and corrosion inhibitors are commonly used for different pipe materials and cooling water qualities. While effective, these inhibitors also have drawbacks, such as high production costs, high toxicity, difficulty in degradation, and environmental pollution caused by wastewater. For example, scale inhibitors such as hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylene phosphonic acid (ATMP), and polyaminopolyether methylene phosphonic acid (PAPEMP) contain phosphorus. Corrosion inhibitors such as mercury salts, nitrites, dichromates, and chromates are also highly toxic. Discharge of these water treatment agents can cause secondary water pollution, posing serious environmental risks. Furthermore, when used in oilfield water systems, they suffer from short corrosion inhibition times and low scale inhibition efficiency at high temperatures. Therefore, the research and development of new, green, environmentally friendly, and effective slow-release scale and corrosion inhibitors is imperative. Summary of the Invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a high-temperature slow-release adsorption-type corrosion and scale inhibitor and its preparation method and application, so as to solve the technical problems of the existing corrosion and scale inhibitors such as high cost, high toxicity, difficulty in degradation, short corrosion inhibition time, and low scale inhibition efficiency at high temperature.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor, comprising the following steps: Maleic anhydride is added to dichloromethane, and then an oxidant is added to carry out an oxidation reaction; after the reaction is complete, the temperature is increased and a catalyst is added to carry out a ring-opening polymerization reaction to generate a polymer compound; the polymer compound is cooled to room temperature, and then thiourea is added to carry out an amidation reaction to obtain a high-temperature slow-release adsorption-type corrosion and scale inhibitor.

[0006] In one embodiment, when the maleic anhydride is added, the temperature of the dichloromethane is 40° C.-70° C.; and the oxidation reaction time is 3-6 hours.

[0007] In one embodiment, the oxidant is any one of hydrogen peroxide, potassium hypochlorite, and sodium hypochlorite.

[0008] In one embodiment, the mass ratio of maleic anhydride to dichloromethane is 1:5-1:6; and the molar ratio of maleic anhydride to oxidant is 1:1-1:2.

[0009] In one embodiment, the temperature of the heating is 70° C.-130° C.; the reaction time of the ring-opening polymerization reaction is 6-12 h; and the reaction time of the amidation reaction is 10-24 h.

[0010] In one embodiment, the catalyst is sodium hydroxide or hydroxylamine.

[0011] In one embodiment, the mass of the catalyst is 1%-3% of the sum of the mass of maleic anhydride and the oxidant.

[0012] In one embodiment, the molar ratio of maleic anhydride to thiourea is 1:1-1:3.

[0013] The present invention also provides a high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor prepared by the preparation method of the high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor.

[0014] The present invention also provides the use of the high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor prepared by the preparation method of the high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor in pipelines of an oilfield water system.

[0015] The high-temperature slow-release adsorption-type corrosion and scale inhibitor begins to work at a temperature of 40-100°C, undergoing a hydrolysis reaction to break the amide bond, forming thiourea, polycarboxylic acid and a macromolecular compound with an amino group. Among them, the carboxyl group in the polycarboxylic acid forms a chelate with calcium, magnesium ions and the like in water through a chelating effect, thereby playing a role in scale inhibition. On the other hand, the macromolecular compound with an amino group and thiourea formed can play a role in corrosion inhibition.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In one aspect, the present invention provides a method for preparing a high-temperature, slow-release adsorbable corrosion and scale inhibitor. This method uses relatively inexpensive maleic anhydride as a raw material, reacts it with an oxidant to oxidize double bonds to epoxy groups, then undergoes ring-opening polymerization under alkaline conditions, and finally undergoes an amidation reaction with thiourea to obtain the high-temperature, slow-release adsorbable corrosion and scale inhibitor. Maleic anhydride is a relatively inexpensive and widely available raw material, and the preparation process is simple and easy to operate, enabling full utilization of the raw material and significantly reducing costs.

[0017] On the other hand, the present invention provides a high-temperature slow-release adsorption-type corrosion and scale inhibitor prepared by the above-mentioned preparation method. The amide bond of the agent breaks under the action of underground temperature to generate small-molecule thiourea, polycarboxylic acid, and macromolecular substances with amino groups, which can integrate corrosion inhibition and scale inhibition. The generated macromolecular substances can also be hydrolyzed by the action of high underground temperature, which is beneficial to environmental protection.

[0018] The present invention also provides, on the one hand, the use of the above-mentioned corrosion and scale inhibitor in oilfield water system pipelines for corrosion and scale prevention. During use, the above-prepared corrosion and scale inhibitor is injected into the pipeline. At a temperature of 40-100°C, the amide bond in the corrosion and scale inhibitor breaks, generating a polymer compound with a carboxyl group, a polymer compound with an amino group, and thiourea. The carboxyl group forms a chelate with calcium and magnesium ions in the water through chelation, thereby playing a scale inhibition role. On the other hand, the formed polymer compound with an amino group and thiourea can also play a corrosion inhibition role. Moreover, because the breaking of the amide bond is affected by temperature, it is not released all at once during use, but can be released over a sustained period. This can greatly improve the corrosion and scale inhibition efficiency of the corrosion and scale inhibitor, extend the action time of the corrosion and scale inhibitor, and play a certain cost-saving role. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the preparation process of high-temperature slow-release adsorption-type corrosion and scale inhibitor; Figure 2 The polarization curves of high temperature slow-release adsorption corrosion and scale inhibitors with different concentrations are shown in Figure 1. Figure 3 The scale inhibition rate results of high temperature slow-release adsorption type corrosion and scale inhibitors at different concentrations at 80°C are shown in the figure. Figure 4 The scale inhibition rate results of high-temperature slow-release adsorption-type corrosion and scale inhibitor at different temperatures are 160 mg / L. DETAILED DESCRIPTION

[0020] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values within the range (including integers and fractions).

[0023] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0024] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0025] The present invention provides a high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor, and its preparation method and application. The preparation principle of the preparation method is: using an oxidant to oxidize the double bond in maleic anhydride to generate an epoxy bond, then adding a catalyst to cause ring-opening polymerization, and finally reacting with thiourea to obtain a high-temperature slow-release corrosion inhibitor and scale inhibitor. The preparation process of the corrosion inhibitor and scale inhibitor is as follows: Figure 1 The reaction process is shown.

[0026] An embodiment of the present invention provides a method for preparing a high-temperature slow-release adsorption-type corrosion inhibitor and scale inhibitor, and the specific steps are as follows: adding maleic anhydride to dichloromethane, and then adding an oxidant to carry out an oxidation reaction; after the reaction is complete, heating and then adding a catalyst to carry out a ring-opening polymerization reaction to generate a polymer compound; the polymer compound is cooled to room temperature, and then adding thiourea to carry out an amidation reaction to obtain a high-temperature slow-release adsorption-type slow-release corrosion inhibitor and scale inhibitor.

[0027] In one embodiment, a method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor comprises the following steps: S1: Add a certain amount of dichloromethane to a three-necked flask. At a temperature of 40°C-70°C, add an appropriate amount of maleic anhydride while stirring. Stir until the maleic anhydride is completely dissolved. Then, add an oxidizing agent and react for 3-6 hours. The oxidizing agent can be an oxidizing substance such as hydrogen peroxide or hypochlorite. The mass ratio of maleic anhydride to dichloromethane is 1:5-1:6; the molar ratio of maleic anhydride to oxidizing agent is 1:1-1:2. The hypochlorite can be either sodium hypochlorite or potassium hypochlorite.

[0028] S2: After S1 is complete, heat to 70-130°C, add a catalyst, and continue the reaction for 6-12 hours. The catalyst can be sodium hydroxide or hydroxylamine, and the mass of the catalyst is 1%-3% of the combined mass of maleic anhydride and oxidant.

[0029] S3: After S2 is completely reacted, the mixture is cooled to room temperature, and then a certain amount of thiourea is added and stirred for 10-24 hours. The molar ratio of maleic anhydride to thiourea is 1:1-1:3.

[0030] Another embodiment of the present invention also provides a high-temperature slow-release adsorption-type corrosion inhibitor and scale inhibitor prepared by the above-mentioned preparation method, wherein maleic anhydride is used as a raw material, the double bonds in the maleic anhydride are oxidized into epoxy groups by an oxidant, and then ring-opening polymerization occurs under the action of a catalyst to generate a polymer compound, and finally an amidation reaction occurs with thiourea to obtain the high-temperature slow-release adsorption-type corrosion inhibitor and scale inhibitor.

[0031] The high-temperature slow-release adsorption-type corrosion and scale inhibitor prepared as described above is used in oilfield water system pipelines to play an anti-corrosion and scale inhibition role. First, the polymer substance formed by polymerization has a functional amino group, which can be adsorbed on the metal surface to form a dense protective film, playing a corrosion inhibition role. When the substance is affected by the formation temperature, the amide bond in the polymer breaks, and thiourea, polycarboxylic acid and macromolecules with amino groups are generated. Due to the presence of carboxyl groups in polycarboxylic acids, they can form soluble complexes with calcium and magnesium ions in water, reducing the concentration of free ions, thereby preventing the crystallization of insoluble salts such as calcium carbonate and magnesium carbonate, playing a scale inhibition role; the generated thiourea and macromolecules with amino groups will continue to adsorb on the surface of the metal, forming a dense protective film, continuing to protect the metal, thereby extending the corrosion inhibition time and action cycle.

[0032] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0033] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0034] Example 1: 50 g of dichloromethane was added to a 250 ml three-necked flask and heated to 40°C. Then, 10.0 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 7.58 g of sodium hypochlorite was added and the reaction was continued with stirring for 4 hours. The temperature was then raised to 70°C, 0.18 g of sodium hydroxide was added, and the reaction was continued for 6 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 7.75 g of thiourea was added. After stirring for 10 hours, the product was obtained by distillation.

[0035] Example 2: 50 g of dichloromethane was added to a 250 ml three-necked flask and heated to 70°C. Then, 10.0 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 15.18 g of sodium hypochlorite was added and the reaction was continued with stirring for 4 hours. The temperature was then raised to 130°C, 0.76 g of sodium hydroxide was added, and the reaction was continued for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 23.25 g of thiourea was added. After stirring for 24 hours, the product was obtained by distillation.

[0036] Example 3: To a 250 ml three-necked flask, add 60 g of dichloromethane and heat to 40°C. Then, add 10.0 g of maleic anhydride and stir until the maleic anhydride is dissolved. Add 9.2 g of potassium hypochlorite and continue stirring to react for 4 hours. Then, raise the temperature to 70°C, add 0.192 g of sodium hydroxide and continue to react for 6 hours. After the reaction is complete, cool the mixture to room temperature, then add 7.75 g of thiourea and stir for 10 hours. Then, distill to obtain the product.

[0037] Example 4: To a 250 ml three-necked flask, 60 g of dichloromethane was added and heated to 70°C. Then, 10 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 18.38 g of potassium hypochlorite was added and the reaction was continued with stirring for 4 hours. The temperature was then raised to 130°C, 0.28 g of hydroxylamine was added, and the reaction was continued for 6 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 7.75 g of thiourea was added. After stirring for 10 hours, the product was obtained by distillation.

[0038] Example 5: To a 250ml three-necked flask, 60g of dichloromethane was added and heated to 40°C. Then, 10.00g of maleic anhydride was added and stirred until the maleic anhydride dissolved. 3.46g of hydrogen peroxide was added and the reaction was continued with stirring for 4 hours. The temperature was then raised to 70°C, 0.40g of hydroxylamine was added, and the reaction was continued for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 23.25g of thiourea was added. After stirring for 24 hours, the product was obtained by distillation.

[0039] Example 6: 60 g of dichloromethane was added to a 250 ml three-necked flask and heated to 70°C. Then, 10 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 7.6 g of sodium hypochlorite was added and the reaction was continued with stirring for 4 hours. The temperature was then raised to 130°C, 0.53 g of sodium hydroxide was added, and the reaction was continued for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 23.25 g of thiourea was added. After stirring for 24 hours, the product was obtained by distillation.

[0040] Example 7: 50 g of dichloromethane was added to a 250 ml three-necked flask and heated to 40°C. Then, 10.0 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 7.58 g of sodium hypochlorite was added and the reaction was continued with stirring for 3 hours. The temperature was then raised to 70°C, 0.18 g of sodium hydroxide was added, and the reaction was continued for 6 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 7.75 g of thiourea was added. After stirring for 10 hours, the product was obtained by distillation.

[0041] Example 8: 50 g of dichloromethane was added to a 250 ml three-necked flask and heated to 70°C. Then, 10.0 g of maleic anhydride was added and stirred until the maleic anhydride was dissolved. 15.18 g of sodium hypochlorite was added and the reaction was continued with stirring for 6 hours. The temperature was then raised to 130°C, 0.76 g of sodium hydroxide was added, and the reaction was continued for 6 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 23.25 g of thiourea was added. After stirring for 10 hours, the product was obtained by distillation.

[0042] Example 9: To a 250ml three-necked flask, 60g of dichloromethane was added and heated to 40°C. Then, 10.0g of maleic anhydride was added and stirred until the maleic anhydride dissolved. 6.9g of hydrogen peroxide was added and the reaction was continued with stirring for 3 hours. The temperature was then raised to 70°C, 0.17g of sodium hydroxide was added, and the reaction was continued for 6 hours. After the reaction was complete, the mixture was cooled to room temperature, and then 7.75g of thiourea was added. After stirring for 10 hours, the product was obtained by distillation.

[0043] Example 10: To a 250ml three-necked flask, add 60g of dichloromethane and heat to 70°C. Then, add 10.0g of maleic anhydride and stir until the maleic anhydride is dissolved. Add 3.47g of hydrogen peroxide and continue stirring and reacting for 6 hours. Then, raise the temperature to 130°C, add 0.40g of sodium hydroxide and continue reacting for 6 hours. After the reaction is complete, cool the mixture to room temperature, then add 23.25g of thiourea, stir and react for 10 hours, and then distill to obtain the product.

[0044] Characterization and testing: In order to characterize the application performance of the slow-release scale inhibitor, the following tests were performed: 1. Electrochemical testing of corrosion and scale inhibitors at different concentrations At 80℃, the polarization curves of Q235 steel in sodium chloride solution containing different mass concentrations of corrosion and scale inhibitors are as follows: Figure 2 shown.

[0045] As can be seen from the figure, after adding corrosion inhibitors and scale inhibitors, the shape of the polarization curve did not change significantly compared with the blank sample. The polarization curves all moved toward the low current density direction, and the polarization curves of the two poles moved positively as a whole, indicating that the addition of corrosion inhibitors and scale inhibitors did not change the mechanism of the corrosion reaction, but only weakened the corrosion reaction rate.

[0046] 2. Test of the scale inhibition ability of corrosion and scale inhibitors on calcium carbonate Keeping other experimental conditions unchanged, the scale inhibition performance evaluation experiment was carried out by changing the dosage of scale inhibitor.

[0047] Depend on Figure 3 It can be seen that when the temperature is maintained at 80°C, the scale inhibition rate gradually increases with the increase in corrosion and scale inhibitor concentration. When the concentration is greater than 160 mg / L, the scale inhibition rate rises slowly. Therefore, the optimal addition amount of corrosion and scale inhibitor is 160 mg / L, at which the scale inhibition rate for calcium carbonate can reach 85%.

[0048] Depend on Figure 4 It can be seen that, with the concentration kept constant, the scale inhibition rate gradually increases with the continuous increase in reaction temperature. When the temperature is greater than 80 degrees Celsius, the upward trend of the scale inhibition rate slows down. The increase in the scale inhibition rate is because as the temperature rises, the amide bond breaks and a large number of carboxyl groups are generated, which can improve its scale inhibition efficiency.

[0049] In summary, the corrosion inhibitor and scale inhibitor prepared by the present invention undergoes a hydrolysis reaction under the action of high temperature to break the amide bond, thereby forming thiourea, polycarboxylic acid and macromolecular compounds with amino groups. The presence of carboxyl groups can chelate with calcium and magnesium ions to achieve a scale inhibition effect. The macromolecular compounds with amino groups and thiourea play a corrosion inhibition role through adsorption. The breakage of the amide bond will be affected by temperature, thereby playing a slow-release process, which can improve the efficiency of the use of the corrosion inhibitor and scale inhibitor. The generated macromolecules will also decompose under high temperature, thus being environmentally friendly. Compared with other corrosion inhibitors and scale inhibitors, the corrosion inhibitor prepared by the present invention can have an excellent scale inhibition effect, and the scale inhibition efficiency is still very high under high temperature conditions, which can meet the use conditions in high temperature environments.

[0050] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor, characterized in that: The following steps are involved: Maleic anhydride is added to dichloromethane, and then an oxidant is added to carry out an oxidation reaction; after the reaction is complete, the temperature is increased and a catalyst is added to carry out a ring-opening polymerization reaction to generate a polymer compound; the polymer compound is cooled to room temperature, and then thiourea is added to carry out an amidation reaction to obtain a high-temperature slow-release adsorption-type corrosion and scale inhibitor.

2. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: When the maleic anhydride is added, the temperature of the dichloromethane is 40° C.-70° C.; and the oxidation reaction time is 3-6 hours.

3. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The oxidant is any one of hydrogen peroxide, potassium hypochlorite and sodium hypochlorite.

4. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The mass ratio of the maleic anhydride to dichloromethane is 1:5-1:6; the molar ratio of the maleic anhydride to the oxidant is 1:1-1:

2.

5. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The heating temperature is 70-130° C.; the reaction time of the ring-opening polymerization reaction is 6-12 hours; and the reaction time of the amidation reaction is 10-24 hours.

6. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The catalyst is sodium hydroxide or hydroxylamine.

7. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The mass of the catalyst is 1%-3% of the sum of the mass of maleic anhydride and the oxidant.

8. The method for preparing a high-temperature slow-release adsorption-type corrosion and scale inhibitor according to claim 1, characterized in that: The molar ratio of maleic anhydride to thiourea is 1:1-1:

3.

9. A high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor prepared by the method for preparing a high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor according to any one of claims 1 to 8.

10. Use of the high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor prepared by the method for preparing the high-temperature slow-release adsorption type corrosion inhibitor and scale inhibitor according to any one of claims 1 to 8 in oilfield water system pipelines.

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