Corrosion and scale inhibitor for oil field and preparation method of corrosion and scale inhibitor

Abstract

The invention discloses a corrosion and scale inhibitor for an oil field, and relates to the technical field of oil field exploitation, the corrosion and scale inhibitor comprises 10-500 parts of organic phosphate, 10-400 parts of polyaluminum chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water; the invention further discloses a preparation method of the corrosion and scale inhibitor for the oil field. Through the accurate raw material ratio and the advanced preparation process, the synergistic effect of all the components is ensured, the stability and effect of the corrosion and scale inhibitor are enhanced, and the corrosion and scale inhibitor can be used for a long time in a high-temperature and high-hardness water environment, has good water solubility and dispersity, can effectively reduce the maintenance cost of oil field facilities, and has good application prospects. The service life of equipment is prolonged. The technical scheme has high production efficiency and application value, and is suitable for various oil field environments.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield exploitation, and in particular to a corrosion and scale inhibitor for oilfields and a preparation method thereof. Background Art

[0002] During the exploitation of oil fields, scaling and corrosion often occur due to factors such as high water hardness and high temperature, which seriously affect the operating efficiency and life of oil field equipment. Although traditional corrosion and scale inhibitors can effectively prevent scaling and corrosion, most of them have strong toxicity and environmental pollution problems. Therefore, it is necessary to develop corrosion and scale inhibitors that can effectively alleviate the corrosion of oil field equipment and prevent scaling, while also having low toxicity and environmental protection. In recent years, researchers have made certain progress in the research and development of corrosion and scale inhibitors, especially through the composite of polymer materials and inorganic compounds, successfully improving their corrosion and scale inhibition effects.

[0003] In traditional corrosion and scale inhibitors, polyaluminium chloride is often used as the main component, but it has some limitations, such as insufficient corrosion inhibition ability or incompatibility with other ingredients. Therefore, developing an oilfield corrosion and scale inhibitor that has excellent corrosion and scale inhibition effects while also being environmentally friendly and economical has become an important task in the field of oilfield chemicals. Summary of the invention

[0004] In order to solve the above technical problems, a corrosion and scale inhibitor for oil fields and a preparation method thereof are provided. This technical solution solves the above problems.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A corrosion and scale inhibitor for oil fields, characterized in that it is prepared from the following materials:

[0007] 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water.

[0008] Preferably, it is prepared from the following materials: 500 parts of organic phosphate, 300 parts of polyaluminium chloride, 500 parts of polycarboxylate, 40 parts of sodium tripolyphosphate, 50 parts of metal oxide, 30 parts of amino acid derivative, 50 parts of ammonium chloride, 60 parts of phosphate, 80 parts of silicate, 50 parts of glycolic acid and 800 parts of water.

[0009] Preferably, the organic phosphate is one of a triester and a diester of phosphate, the polyaluminium chloride is generated by reacting aluminium chloride with an aqueous solution, and is obtained by filtering and drying, the polycarboxylate is one of a linear polymer and a branched polymer, and the metal oxide is one of titanium dioxide, silicon dioxide and aluminium oxide.

[0010] Preferably, sodium tripolyphosphate is one of anhydrous sodium tripolyphosphate and sodium tripolyphosphate decahydrate, the amino acid derivative is one of glycine and alanine derivatives, the silicate is one of hydrated silicate and non-hydrated silicate, and the water is one of deionized water and distilled water.

[0011] A method for preparing a corrosion and scale inhibitor for oil fields, the preparation steps comprising:

[0012] S1. Prepare materials, including: 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water;

[0013] S2, mixing polyaluminium chloride with water, stirring evenly and heating to 40-60°C to prepare a polyaluminium chloride solution for standby use;

[0014] S3, mixing the metal oxide with water, and stirring them fully to form a stable suspension for standby use;

[0015] S4, mixing sodium tripolyphosphate with water to form a transparent solution for standby use;

[0016] S5. Add all materials in proportion to the reactor, mix and stir, control the reaction temperature at 30-50°C, stir at 200-300r / min, and continue stirring for 2-4 hours;

[0017] S6, adjusting the pH of the stirred solution, adding amino acid derivatives and ammonium chloride for neutralization, until the pH value of the system reaches 6-8;

[0018] S7. After an appropriate reaction time, filter out impurities to obtain a corrosion and scale inhibitor solution;

[0019] S8. Store the filtered corrosion and scale inhibitor solution to obtain a final product.

[0020] Preferably, the S2 specifically includes:

[0021] Before mixing polyaluminium chloride with water, heat the water to 40-45°C. The polyaluminium chloride can be divided into several small portions and gradually added to the water while stirring to ensure that each portion of the polyaluminium chloride is completely dissolved before adding the next batch;

[0022] During the stirring process, a circulating stirring method is used, and the stirring speed is set to 100-150r / min to maintain uniform stirring;

[0023] After adding polyaluminium chloride, continue heating to 40-60°C, using gradual heating and keep stirring during the heating process;

[0024] Take samples regularly and monitor the solubility of polyaluminium chloride to ensure that the solution reaches the required concentration and transparency. If agglomerates and impurities are found during the dissolution process, adjust the amount of water added and the temperature;

[0025] After the dissolution is completed, preliminary filtration is performed through a filter to remove particulate impurities to ensure that a transparent and uniform polyaluminium chloride solution is obtained in the end.

[0026] Preferably, the S3 specifically includes:

[0027] The metal oxide and water are stirred, and during the stirring process, the water temperature is controlled between 20-30°C by temperature control measures;

[0028] Adding dispersants can reduce the cohesion between metal oxide particles and ensure the stability of the suspension;

[0029] The stirring speed is adjusted periodically, first using a stirring speed of 200-400 r / min for preliminary mixing, and then gradually increasing to 500-700 r / min for uniform dispersion to ensure uniform distribution of the metal oxide in the water.

[0030] Preferably, the S4 specifically includes:

[0031] Heat water to a temperature range of 35-45°C, mix part of the sodium tripolyphosphate with the water, and gradually add the remaining sodium tripolyphosphate during stirring;

[0032] Ultrasonic wave assisted dissolution was used and a dissolution promoter was added;

[0033] The pH of the solution was monitored in real time, and insoluble matter and tiny particles were found during the dissolution process. The solution was clarified by standing for a period of time to obtain a transparent sodium tripolyphosphate solution.

[0034] Preferably, the S5 specifically includes:

[0035] The raw materials were added to the reactor in stages in sequence, and the temperature was controlled by a temperature gradient, maintaining 30-40°C in the initial stage, and then gradually increasing the temperature to 40-50°C;

[0036] An intelligent stirring system is introduced to automatically adjust the stirring speed according to the change of viscosity during the reaction. A pH sensor is used to monitor the change of the solution, and the reaction progress is judged according to the pH change, and the stirring time is adjusted;

[0037] During the reaction time of 2-4 hours, the corrosion and scale inhibition performance of the product is tested in stages. During the reaction process, nitrogen is introduced for stirring.

[0038] Preferably, the S6 specifically includes:

[0039] The amino acid derivatives and ammonium chloride are added to the reaction system in batches, and the pH changes of the solution are monitored in real time using an online pH sensor, which is automatically fed back to the adjustment system to ensure that the pH value is accurately controlled between 6 and 8;

[0040] Automatic control technology is used to accurately control the addition rate of amino acid derivatives and ammonium chloride;

[0041] When adjusting the pH value, control the reaction temperature, and when the pH is close to 6.5, gradually increase the reaction temperature to close to 50°C;

[0042] Through experimental optimization, the optimal pH range is determined to obtain the best corrosion and scale inhibition effect. The type and dosage of amino acid derivatives are optimized according to the characteristics of different types of amino acid derivatives and their synergistic effect with ammonium chloride.

[0043] The pH of the reaction system is monitored and if there is any change, a regulator is added to maintain the pH stability to ensure the consistency of the final product quality.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The formula of the oilfield corrosion and scale inhibitor proposed by the invention effectively solves the shortcomings of the traditional oilfield corrosion and scale inhibitor through accurate material ratio and multi-step reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a framework diagram of the preparation steps of the present invention. DETAILED DESCRIPTION

[0047] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0048] Reference Figure 1As shown, a corrosion inhibitor and scale inhibitor for oil fields and a preparation method thereof include: a corrosion inhibitor and scale inhibitor for oil fields, characterized in that it is prepared from the following materials:

[0049] 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water.

[0050] Specifically, it is prepared from the following materials: 500 parts of organic phosphate, 300 parts of polyaluminium chloride, 500 parts of polycarboxylate, 40 parts of sodium tripolyphosphate, 50 parts of metal oxide, 30 parts of amino acid derivative, 50 parts of ammonium chloride, 60 parts of phosphate, 80 parts of silicate, 50 parts of glycolic acid and 800 parts of water.

[0051] The organic phosphate is one of a phosphate triester and a phosphate diester, the polyaluminium chloride is generated by reacting aluminium chloride with an aqueous solution, and is obtained by filtering and drying, the polycarboxylate is one of a linear polymer and a branched polymer, and the metal oxide is one of titanium dioxide, silicon dioxide and aluminium oxide;

[0052] The sodium tripolyphosphate is one of anhydrous sodium tripolyphosphate and sodium tripolyphosphate decahydrate, the amino acid derivative is one of glycine and alanine derivative, the silicate is one of hydrated silicate and non-hydrated silicate, and the water is one of deionized water and distilled water;

[0053] A method for preparing a corrosion and scale inhibitor for oil fields, the preparation steps comprising:

[0054] S1. Prepare materials, including: 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water;

[0055] S2, mixing polyaluminium chloride with water, stirring evenly and heating to 40-60°C to prepare a polyaluminium chloride solution for standby use;

[0056] S3, mixing the metal oxide with water, and stirring them fully to form a stable suspension for standby use;

[0057] S4, mixing sodium tripolyphosphate with water to form a transparent solution for standby use;

[0058] S5. Add all materials in proportion to the reactor, mix and stir, control the reaction temperature at 30-50°C, stir at 200-300r / min, and continue stirring for 2-4 hours;

[0059] S6, adjusting the pH of the stirred solution, adding amino acid derivatives and ammonium chloride for neutralization, until the pH value of the system reaches 6-8;

[0060] S7. After an appropriate reaction time, filter out impurities to obtain a corrosion and scale inhibitor solution;

[0061] S8. Store the filtered corrosion and scale inhibitor solution to obtain a final product.

[0062] The S2 specifically includes:

[0063] Before mixing polyaluminium chloride with water, heat the water to 40-45°C. The polyaluminium chloride can be divided into several small portions and gradually added to the water while stirring to ensure that each portion of the polyaluminium chloride is completely dissolved before adding the next batch;

[0064] During the stirring process, a circulating stirring method is used, and the stirring speed is set to 100-150r / min to maintain uniform stirring;

[0065] After adding polyaluminium chloride, continue heating to 40-60°C, using gradual heating and keep stirring during the heating process;

[0066] Take samples regularly and monitor the solubility of polyaluminium chloride to ensure that the solution reaches the required concentration and transparency. If agglomerates and impurities are found during the dissolution process, adjust the amount of water added and the temperature;

[0067] After the dissolution is completed, preliminary filtration is performed through a filter to remove particulate impurities to ensure that a transparent and uniform polyaluminium chloride solution is obtained in the end.

[0068] Heat the water to 40-45℃ and add polyaluminium chloride in batches, ensuring that each batch of polyaluminium chloride is completely dissolved before adding the next batch, which helps to improve the dissolution efficiency of polyaluminium chloride. This batch addition method can avoid adding too much solid at one time, resulting in incomplete dissolution or agglomeration;

[0069] Using a circulating stirring method and maintaining the stirring speed at 100-150r / min helps to achieve uniformity of the solution. Uniform stirring ensures that polyaluminium chloride is completely dissolved in water, avoiding the phenomenon of incomplete local dissolution, thereby improving the stability of the final solution;

[0070] After adding polyaluminium chloride, continue heating to 40-60°C and use gradual heating to effectively control temperature changes, avoid uneven dissolution caused by rapid heating or decomposition caused by overheating, and keep stirring to accelerate dissolution and promote uniformity of the solution;

[0071] Regularly sample and monitor the solubility of polyaluminium chloride to ensure that the solution reaches the required concentration and transparency. During the dissolution process, if lumps or impurities are found, the amount of water added and the temperature can be adjusted in time to avoid the production of insoluble matter and improve the purity of the final product.

[0072] S3 specifically includes:

[0073] The metal oxide and water are stirred, and during the stirring process, the water temperature is controlled between 20-30°C by temperature control measures;

[0074] Adding dispersants can reduce the cohesion between metal oxide particles and ensure the stability of the suspension;

[0075] The stirring speed is adjusted periodically, first using a stirring speed of 200-400 r / min for preliminary mixing, and then gradually increasing to 500-700 r / min for uniform dispersion to ensure uniform distribution of the metal oxide in the water.

[0076] By controlling the water temperature between 20-30°C, the risk of decomposition or aggregation of metal oxide particles due to excessively high temperatures is avoided. At the same time, this temperature range helps maintain the stability of the dispersant and metal oxide particles and avoids the adverse effects of excessively high or low temperatures on the suspension.

[0077] The addition of dispersants effectively reduces the cohesive force between metal oxide particles, making the particles more dispersed. The role of dispersants helps maintain the stability of the suspension and prevents metal oxide particles from settling or agglomerating in water, thereby maintaining a uniform distribution, avoiding particle agglomeration, and improving the long-term stability of the suspension.

[0078] S4 specifically includes:

[0079] Heat water to a temperature range of 35-45°C, mix part of the sodium tripolyphosphate with the water, and gradually add the remaining sodium tripolyphosphate during stirring;

[0080] Ultrasonic wave assisted dissolution was used and a dissolution promoter was added;

[0081] The pH of the solution was monitored in real time, and insoluble matter and tiny particles were found during the dissolution process. The solution was clarified by standing for a period of time to obtain a transparent sodium tripolyphosphate solution.

[0082] S5 specifically includes:

[0083] The raw materials were added to the reactor in stages in sequence, and the temperature was controlled by a temperature gradient, maintaining 30-40°C in the initial stage, and then gradually increasing the temperature to 40-50°C;

[0084] An intelligent stirring system is introduced to automatically adjust the stirring speed according to the change of viscosity during the reaction. A pH sensor is used to monitor the change of the solution, and the reaction progress is judged according to the pH change, and the stirring time is adjusted;

[0085] During the reaction time of 2-4 hours, the corrosion and scale inhibition performance of the product is tested in stages. During the reaction process, nitrogen is introduced for stirring.

[0086] S6 specifically includes:

[0087] The amino acid derivatives and ammonium chloride are added to the reaction system in batches, and the pH changes of the solution are monitored in real time using an online pH sensor, which is automatically fed back to the adjustment system to ensure that the pH value is accurately controlled between 6 and 8;

[0088] Automatic control technology is used to accurately control the addition rate of amino acid derivatives and ammonium chloride;

[0089] When adjusting the pH value, control the reaction temperature, and when the pH is close to 6.5, gradually increase the reaction temperature to close to 50°C;

[0090] Through experimental optimization, the optimal pH range is determined to obtain the best corrosion and scale inhibition effect. The type and dosage of amino acid derivatives are optimized according to the characteristics of different types of amino acid derivatives and their synergistic effect with ammonium chloride.

[0091] The pH of the reaction system is monitored and if there is any change, a regulator is added to maintain the pH stability to ensure the consistency of the final product quality.

[0092] In summary, the advantages of the present invention are:

[0093] In the present invention, the organic phosphate, polyaluminium chloride, polycarboxylate, metal oxide and other ingredients used work synergistically to significantly improve the corrosion and scale inhibition effects. By accurately adjusting the pH value and using a suitable combination of amino acid derivatives and ammonium chloride, good protection of oilfield equipment is achieved;

[0094] Compared with traditional corrosion and scale inhibitors, the corrosion and scale inhibitor of the present invention uses environmentally friendly inorganic and organic composite components in its formula, which greatly reduces the impact on the environment. In particular, in the process of adjusting the pH value, amino acid derivatives and ammonium chloride are used, which can not only effectively adjust the pH, but also have good biodegradability;

[0095] By carefully controlling the order of adding components and the steps of stirring, heating, dissolving, etc., we ensure that each ingredient can maximize its effect, while reducing the generation of by-products and improving the purity and stability of the final product;

[0096] The corrosion and scale inhibitor of the present invention is suitable for a variety of oil field environments, including complex conditions such as high-hardness water, high temperature, and high salt, and can adapt to different oil field production requirements, and has strong applicability and market potential;

[0097] Compared with other similar products, the raw materials used in the present invention have lower costs, and the utilization rate of the raw materials is improved through optimized production processes, so that the final product has a higher cost performance.

[0098] Experimental steps for scale inhibition efficiency of corrosion and scale inhibitors

[0099] Prepare experimental materials:

[0100] Prepare the corrosion and scale inhibitor samples to be tested, select artificially prepared water samples containing calcium, magnesium and other ions, and prepare reagents for adjusting the ion concentration in the water to simulate the actual water quality.

[0101] Experimental equipment: constant temperature water bath, stirrer, filter, pH meter, titrator, spectrophotometer;

[0102] Prepare a water sample containing metal ions such as calcium and magnesium at a certain concentration, prepare a corrosion and scale inhibitor solution according to the experimental needs, adjust the temperature of the water sample, set up a stirrer, and maintain a certain stirring speed to ensure that the solution is uniform;

[0103] Add the corrosion and scale inhibitor solution gradually into the water sample and react for 1-2 hours. During the experiment, pay attention to whether there is a scale layer formed, analyze the clarity of the water sample, and observe the precipitation to preliminarily judge the scaling situation;

[0104] Filter water samples, collect scale, use gravimetric method to determine the type and amount of scale, use ion chromatography to analyze the changes in calcium and magnesium ion concentrations in water, evaluate the effect of corrosion and scale inhibitors, and record the pH value of water samples.

[0105] The scale inhibition efficiency is calculated by comparing the changes in calcium and magnesium ions in the water sample before and after the addition of corrosion and scale inhibitors.

[0106] Comparative experiment: A blank control group was set up, that is, only ordinary scale inhibitor experiments were carried out without injecting corrosion and scale inhibitor solution, in order to compare and evaluate the effect of surfactants on improving the recovery rate.

[0107] Table 1 below is the data table obtained during the experiment

[0108]

[0109] Table 1

[0110] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A corrosion and scale inhibitor for oil fields, characterized in that: Prepared from the following materials: 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water.

2. The corrosion and scale inhibitor for oil fields according to claim 1, characterized in that: Specifically, it is prepared from the following materials: 500 parts of organic phosphate, 300 parts of polyaluminium chloride, 500 parts of polycarboxylate, 40 parts of sodium tripolyphosphate, 50 parts of metal oxide, 30 parts of amino acid derivative, 50 parts of ammonium chloride, 60 parts of phosphate, 80 parts of silicate, 50 parts of glycolic acid and 800 parts of water.

3. A corrosion and scale inhibitor for oil fields according to claim 2, characterized in that: The organic phosphate is one of triester and diester phosphates, the polyaluminium chloride is generated by reacting aluminium chloride with an aqueous solution, and is obtained by filtering and drying, the polycarboxylate is one of a linear polymer and a branched polymer, and the metal oxide is one of titanium dioxide, silicon dioxide and aluminium oxide.

4. The corrosion and scale inhibitor for oil fields according to claim 3, characterized in that: Sodium tripolyphosphate is one of anhydrous sodium tripolyphosphate and sodium tripolyphosphate decahydrate, the amino acid derivative is one of glycine and alanine derivatives, the silicate is one of hydrated silicate and non-hydrated silicate, and the water is one of deionized water and distilled water.

5. A method for preparing a corrosion and scale inhibitor for oil fields, characterized in that: The preparation steps are: S1. Prepare materials, including: 10-500 parts of organic phosphate, 10-400 parts of polyaluminium chloride, 5-500 parts of polycarboxylate, 1-60 parts of sodium tripolyphosphate, 1-80 parts of metal oxide, 2-50 parts of amino acid derivative, 5-70 parts of ammonium chloride, 1-80 parts of phosphate, 5-90 parts of silicate, 5-60 parts of glycolic acid and 100-1000 parts of water; S2, mixing polyaluminium chloride with water, stirring evenly and heating to 40-60°C to prepare a polyaluminium chloride solution for standby use; S3, mixing the metal oxide with water, and stirring them fully to form a stable suspension for standby use; S4, mixing sodium tripolyphosphate with water to form a transparent solution for standby use; S5. Add all materials in proportion to the reactor, mix and stir, control the reaction temperature at 30-50°C, stir at 200-300r / min, and continue stirring for 2-4 hours; S6, adjusting the pH of the stirred solution, adding amino acid derivatives and ammonium chloride for neutralization, until the pH value of the system reaches 6-8; S7. After an appropriate reaction time, filter out impurities to obtain a corrosion and scale inhibitor solution; S8. Store the filtered corrosion and scale inhibitor solution to obtain a final product.

6. The method for preparing a corrosion and scale inhibitor for oil fields according to claim 5, characterized in that: The S2 specifically includes: Before mixing polyaluminium chloride with water, heat the water to 40-45°C. The polyaluminium chloride can be divided into several small portions and gradually added to the water while stirring to ensure that each portion of the polyaluminium chloride is completely dissolved before adding the next batch; During the stirring process, a circulating stirring method is used, and the stirring speed is set to 100-150r / min to maintain uniform stirring; After adding polyaluminium chloride, continue heating to 40-60°C, using gradual heating and keep stirring during the heating process; Take samples regularly and monitor the solubility of polyaluminium chloride to ensure that the solution reaches the required concentration and transparency. If agglomerates and impurities are found during the dissolution process, adjust the amount of water added and the temperature; After the dissolution is completed, preliminary filtration is performed through a filter to remove particulate impurities to ensure that a transparent and uniform polyaluminium chloride solution is obtained in the end.

7. The method for preparing a corrosion and scale inhibitor for oil fields according to claim 6, characterized in that: The S3 specifically includes: The metal oxide and water are stirred, and during the stirring process, the water temperature is controlled between 20-30°C by temperature control measures; Adding dispersants can reduce the cohesion between metal oxide particles and ensure the stability of the suspension; The stirring speed is adjusted periodically, first using a stirring speed of 200-400 r / min for preliminary mixing, and then gradually increasing to 500-700 r / min for uniform dispersion to ensure uniform distribution of the metal oxide in the water.

8. The method for preparing a corrosion and scale inhibitor for oil fields according to claim 7, characterized in that: The S4 specifically includes: Heat water to a temperature range of 35-45°C, mix part of the sodium tripolyphosphate with the water, and gradually add the remaining sodium tripolyphosphate during stirring; Ultrasonic wave assisted dissolution was used and a dissolution promoter was added; The pH of the solution was monitored in real time, and insoluble matter and tiny particles were found during the dissolution process. The solution was clarified by standing for a period of time to obtain a transparent sodium tripolyphosphate solution.

9. The method for preparing a corrosion and scale inhibitor for oil fields according to claim 8, characterized in that: The S5 specifically includes: The raw materials were added to the reactor in stages in sequence, and the temperature was controlled by a temperature gradient, maintaining 30-40°C in the initial stage, and then gradually increasing the temperature to 40-50°C; An intelligent stirring system is introduced to automatically adjust the stirring speed according to the change of viscosity during the reaction. A pH sensor is used to monitor the change of the solution, and the reaction progress is judged according to the pH change, and the stirring time is adjusted; During the reaction time of 2-4 hours, the corrosion and scale inhibition performance of the product is tested in stages. During the reaction process, nitrogen is introduced for stirring.

10. The method for preparing a corrosion and scale inhibitor for oil fields according to claim 9, characterized in that: The S6 specifically includes: The amino acid derivatives and ammonium chloride are added to the reaction system in batches, and the pH changes of the solution are monitored in real time using an online pH sensor, which is automatically fed back to the adjustment system to ensure that the pH value is accurately controlled between 6 and 8; Automatic control technology is used to accurately control the addition rate of amino acid derivatives and ammonium chloride; When adjusting the pH value, control the reaction temperature, and when the pH is close to 6.5, gradually increase the reaction temperature to close to 50°C; Through experimental optimization, the optimal pH range is determined to obtain the best corrosion and scale inhibition effect. The type and dosage of amino acid derivatives are optimized according to the characteristics of different types of amino acid derivatives and their synergistic effect with ammonium chloride. The pH of the reaction system is monitored and if there is any change, a regulator is added to maintain the pH stability to ensure the consistency of the final product quality.

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