Preparation method and application of organic phosphonic acid polymer retarder

Abstract

The application discloses a preparation method and application of an organic phosphonic acid polymer retarder, and the preparation method comprises the following steps: adding 2-acrylamide-2-methylpropane sulfonic acid, N,N-dimethyl acrylamide, itaconic acid and an olefin monomer containing a phosphono group into softened water to obtain a mixed raw material dispersion liquid A; adding a sodium hydroxide solution or a potassium hydroxide solution into the mixed raw material dispersion liquid A to obtain a mixed raw material dispersion liquid B; heating the mixed raw material dispersion liquid B, and adding an ammonium persulfate solution and a sodium bisulfite solution into the mixed raw material dispersion liquid B in sequence under the condition of heating and stirring; after the sodium bisulfite solution is completely added, a mixed reaction dispersion liquid is obtained; the mixed reaction dispersion liquid is continuously reacted at a constant temperature, and boric acid is added after the reaction is completed and is uniformly stirred, and the prepared product can be used for preparing a long sealing section cementing cement slurry. The application can solve the problems that an existing coagulant cannot completely eliminate the influence of a temperature difference effect on the strength of cement stones when the coagulant is used for cementing in a medium-high temperature long sealing section.

Description

Technical Field

[0001] This invention relates to the field of organophosphonic acid polymer retarder technology. Specifically, it relates to a method for preparing and applying an organophosphonic acid polymer retarder. Background Technology

[0002] With the continuous depletion of recoverable and easily accessible oil reserves, oil and gas exploration and development are shifting towards deep wells, ultra-deep wells, and complex wells, placing higher demands on the temperature resistance of cement slurries. To shorten well construction cycles and simplify wellbore structures, the length of the cementing section during cementing is inevitably increased. A longer cementing section means a larger temperature difference between the top and bottom of the cement slurry during setting; if the cement slurry at the top takes a long time to develop strength, it will affect subsequent operations.

[0003] The key to solving the above problems lies in retarders. Currently, there are many types of oil well cement retarders available in China, the most commonly used being: lignin sulfonates and their derivatives, low molecular weight cellulose and their derivatives, hydroxycarboxylic acids (salts), organophosphonic acids (salts), boric acid (salts), and complexes. Domestic and international efforts have continuously improved existing retarders to address their shortcomings, and some new retarders have also been developed.

[0004] Specific substances that can be used as retarder include: dextrin, various types of starch, casein, and certain protein-containing substances; sucrose, glucose, calcium or sodium lignosulfonate salts, sodium carboxymethyl cellulose (CMC), carboxyethyl cellulose (CHC), and mixtures thereof; additionally, tartaric acid, potassium tartrate, calcium tartrate, calcium sulfate dihydrate, calcium sulfite, ferrous sulfate, boric acid, mixtures of boric acid and tartaric acid, mixtures of tartaric acid and sodium bicarbonate, sodium hexametaphosphate, phosphoric acid, disodium phosphate, trisodium phosphate, tetrasodium phosphate, disodium hydrogen phosphate, sodium pyrophosphate, alkyl phosphates, disodium ethylenediaminetetraacetate, and various humic acids. However, the temperature range of use is generally narrow, broadly classified into medium-temperature (70–90℃) retarder and high-temperature (100–160℃) retarder.

[0005] In recent years, research on retarder slurries in my country has deepened. Since the 1990s, the focus has been on developing organic compounds and synthetic polymers, with hydroxycarboxylate salts and organophosphonates being the most frequently researched organic compounds. For example, Chinese patent "A High-Temperature Oil Well Cement Retarder that Can Inhibit Abnormal Gelation and its Preparation Method" (application publication number CN111662409A) discloses a quaternary copolymer retarder composed of 2-acrylamido-2-methylpropanesulfonic acid, itaconic acid, N,N-dimethyldiallylammonium chloride, and N,N-dimethylacrylamide. This retarder can inhibit the "bulging" and "core-forming" phenomena of cement slurry in the temperature range of 120℃ to 150℃. Chinese patent "High-Temperature Retardant Oil Well Cement" (application publication number CN111662409A) also discloses a similar retarder. Publication No. CN10698579B discloses a high-temperature resistant oil well cement retarder composed of hydroxyethylidene diphosphonic acid, citric acid, sodium chloride and water, which is resistant to high temperatures up to 210℃. Chinese Patent No. CN10698579B discloses a medium-high temperature oil well cement retarder that is resistant to high temperatures up to 210℃, which is formulated by polymerizing itaconic acid, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid in water in the presence of organophosphonates and initiators.

[0006] Relatively speaking, organic retarders require less dosage but are more sensitive; polymer retarders require more dosage but have a better linear relationship between dosage and thickening time. Neither can completely eliminate the effect of temperature difference on the strength of cement paste. In order to obtain the best retardation and sealing effect, it is urgent to develop a retarder suitable for medium and high temperature long sealing sections. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to provide a method for preparing and applying an organophosphonic acid polymer retarder for medium- and high-temperature long cementing sections with high temperature resistance, a wide operating temperature range, and rapid strength development of cement stone at the top of the cement slurry column under large temperature difference conditions. This is to solve the problem that existing retarders cannot completely eliminate the influence of temperature difference on the strength of cement stone when used for cementing in medium- and high-temperature long cementing sections.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A method for preparing an organophosphonic acid polymer retarder includes the following steps:

[0010] Step A: Add 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylacrylamide, itaconic acid and phosphonoacrylic alkene monomers to softened water, stir and mix evenly to obtain mixed raw material dispersion A;

[0011] Step B: Add sodium hydroxide solution or potassium hydroxide solution to the mixed raw material dispersion A (the amount of sodium hydroxide solution or potassium hydroxide solution added should be such that the pH of the mixed raw material dispersion B is 4-5. If the pH of the mixed raw material dispersion B is lower than 4, it will cause abnormal gelation of cement slurry when the final prepared organophosphonic acid polymer retarder is used. However, if it is higher than 5, it will cause the final prepared organophosphonic acid polymer retarder to cause abnormally shortened thickening time of cement slurry when used, making the retarder ineffective and without retarding effect). Stir and mix evenly to obtain mixed raw material dispersion B. Compared with sodium hydroxide solution, using potassium hydroxide solution to neutralize the mixed raw material dispersion A using the method of the present invention is more conducive to preparing organophosphonic acid polymer retarder with good dispersibility.

[0012] Step C: Heat the mixed raw material dispersion B, and add ammonium persulfate solution and sodium bisulfite solution dropwise to the mixed raw material dispersion B while heating and stirring; after the sodium bisulfite solution has been added, a mixed reaction dispersion is obtained.

[0013] Step D: Continue the reaction of the mixed reaction dispersion at a constant temperature. After the reaction is completed, add boric acid to the reaction system and stir to mix well, thus preparing the organophosphonic acid polymer retarder.

[0014] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, in step A, 13-15 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 7-8 parts by weight of N,N-dimethylacrylamide (adding this part by weight of N,N-dimethylacrylamide is beneficial to improve the high temperature resistance of cementing mud for medium- and high temperature long sealing sections), 2-3 parts by weight of itaconic acid (adding this part by weight of itaconic acid can not only obtain organophosphonic acid polymer retarder with good retarding effect, but also effectively avoid the phenomenon of "the higher the temperature, the longer the thickening time of cement slurry" which affects the strength of cement slurry), 6-8 parts by weight of phosphonoyl group-containing olefin monomer (adding this part by weight of phosphonoyl group-containing olefin monomer can significantly improve the top strength of cementing mud for medium- and high temperature long sealing sections and give it a suitable thickening time), and 50-55 parts by weight of softened water.

[0015] In step B, the potassium hydroxide solution is 4 to 6 parts by weight, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40 to 48 wt%.

[0016] In step C, the ammonium persulfate solution is prepared by mixing 1 to 1.5 parts by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 to 0.6 parts by weight of sodium bisulfite and 5 parts by weight of softened water.

[0017] In step D, the amount of boric acid added is 6-8 parts by weight. Adding this amount of boric acid can effectively improve the retarding effect and retarding stability of the final prepared organophosphonic acid polymer retarder. If boric acid is not added, or if the amount of boric acid added is too little or too much, the retarding effect of the organophosphonic acid polymer retarder will decrease. Especially in medium and high temperature environments with large temperature differences, its retarding effect on cementing slurry is unstable, which affects the development of the strength of the top cement stone.

[0018] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, in step A, 15 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 7.6 parts by weight of N,N-dimethylacrylamide, 3 parts by weight of itaconic acid, 6-8 parts by weight of phosphonoyl group-containing olefin monomer, and 50 parts by weight of softened water are used; in step B, 5 parts by weight of potassium hydroxide solution are used, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40 wt%; in step C, the ammonium persulfate solution is prepared by mixing 1 part by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 parts by weight of sodium bisulfite and 5 parts by weight of softened water; in step D, 6 parts by weight of boric acid are added.

[0019] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, in step C, the mixed raw material dispersion B is first heated to 75-85℃, and then ammonium sulfate solution and sodium bisulfite solution are added dropwise while stirring at 75-85℃ (heating and stirring at this temperature can avoid "self-polymerization" and significantly improve the conversion rate of raw materials); the ammonium sulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes; in step D, the mixed reaction dispersion is kept at a constant temperature of 75-85℃, and the reaction time is 3-3.5 hours.

[0020] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, in step C, the mixed raw material dispersion B is first heated to 80°C, and then ammonium sulfate solution and sodium bisulfite solution are added dropwise sequentially while stirring at 80°C; the ammonium sulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes; in step D, the mixed reaction dispersion is kept at a constant temperature of 80°C for 3 hours. Under these reaction conditions, not only can the conversion rate of the raw materials be significantly improved, but also a polymer with a suitable molecular weight and stable performance can be obtained.

[0021] The preparation method of the above-mentioned organophosphonic acid polymer retarder uses the following method to prepare the phosphonoyl group-containing olefin monomer: Step (A-1) Softened water, phosphorous acid and bromine chloride are added sequentially to a reaction vessel equipped with a distillation device and mixed evenly to obtain a mixed reaction system A; Step (A-2) The mixed reaction system is subjected to a constant temperature reaction, and after the constant temperature reaction is completed, a mixed reaction system B is obtained; Step (A-3) The temperature of the mixed reaction system B is further increased, and allyl chloride is added dropwise to the mixed reaction system B. After the allyl chloride is completely added, the reaction is stirred continuously, and the phosphonoyl group-containing olefin monomer is obtained after the reaction is completed.

[0022] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, in step (A-1), softened water is 20-25 parts by weight, phosphorous acid is 30-35 parts by weight, and bromine chloride is 3-4 parts by weight; in step (A-2), the constant temperature reaction temperature is 25-30℃, and the constant temperature reaction time is 1.5-2h; in step (A-3), the amount of allyl chloride added is 40-50 parts by weight; after the mixed reaction system B is heated to 80-85℃, allyl chloride is added dropwise to the mixed reaction system B, and the allyl chloride is added dropwise within 25-30min; after the allyl chloride is added dropwise, the reaction is stirred at 75-85℃ for 2.5-3.5h.

[0023] In the preparation method of the above-mentioned organophosphonic acid polymer retarder, step A includes 15 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 7.6 parts by weight of N,N-dimethylacrylamide, 3 parts by weight of itaconic acid, 6-8 parts by weight of phosphonoyl group-containing olefin monomer, and 50 parts by weight of softened water; the phosphonoyl group-containing olefin monomer is prepared by the following method:

[0024] Step (A-1): Add 20 parts by weight of softened water, 32 parts by weight of phosphorous acid, and 3 parts by weight of bromine chloride sequentially to a reaction vessel equipped with a distillation apparatus, mix thoroughly, and obtain mixed reaction system A; Step (A-2): React the mixed reaction system at a constant temperature of 30°C for 1.5 hours, and after the constant temperature reaction is completed, obtain mixed reaction system B; Step (A-3): Continue to heat mixed reaction system B to 80°C, and add 45 parts by weight of allyl chloride dropwise to mixed reaction system B, and the allyl chloride is added dropwise within 30 minutes; after the allyl chloride is added dropwise, continue to stir the reaction at 80°C for 3 hours, and after the reaction is completed, obtain the phosphonoyl alkene monomer;

[0025] In step B, the potassium hydroxide solution is 5 parts by weight, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40 wt%. In step C, the ammonium persulfate solution is prepared by mixing 1 part by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 parts by weight of sodium bisulfite and 5 parts by weight of softened water. First, the mixed raw material dispersion B is heated to 80°C (directly placed in an 80°C water bath for stirring and heating), and then the ammonium sulfate solution and sodium bisulfite solution are added dropwise while stirring at 80°C. The ammonium sulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes. In step D, the amount of boric acid added is 6 parts by weight. The constant temperature reaction temperature of the mixed reaction dispersion is 80°C, and the reaction time is 3 hours.

[0026] The application of organophosphonic acid polymer retarder involves using the organophosphonic acid polymer retarder prepared by the above-mentioned preparation method for the formulation of cement slurry in cementing sections with medium- and high-temperature large temperature differences and long sealing sections.

[0027] The above-mentioned organophosphonic acid polymer retarder is used in cementing slurry for medium- and high-temperature, large-temperature-difference, long-sealing sections, which consists of the following components in parts by weight: 100 parts by weight of Grade G high sulfate-resistant oil well cement, 12 parts by weight of weight-reducing agent CP-52, 8 parts by weight of weight-reducing agent CP-53, 1.5 parts by weight of anti-settling agent WH-10, 1.0 part by weight of drag-reducing agent USZ for oil well cement, 1.0 part by weight of expansion agent G401 for oil well cement, 1.0 part by weight of self-healing agent G406 for oil well cement, 2.5 parts by weight of water-based resin, 8.0 parts by weight of fluid loss reducing agent G310 for oil well cement, 70 parts by weight of tap water, and 3 to 4 parts by weight of the above-mentioned organophosphonic acid polymer retarder. Under this ratio, organophosphonic acid polymer retarder can work synergistically with anti-settling agents, water-based resins and fluid loss reducing agents in cementing slurry to improve the retarding effect of cementing slurry in long cementing sections under medium-high temperature and large temperature difference conditions, resulting in faster strength development of cement stone at the top of the cement slurry column and higher top strength.

[0028] The technical solution of the present invention achieves the following beneficial technical effects:

[0029] 1. The method for preparing the organophosphonic acid polymer retarder of the present invention, using 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylacrylamide, itaconic acid and self-made phosphonoyl group-containing olefin monomer raw materials, can provide a longer thickening time and higher top strength for cementing slurry in cementing sections with medium-high temperature and large temperature difference under medium-high temperature and large temperature difference conditions.

[0030] 2. Compared with existing organophosphoric acid derivatives, the retarder composed of organophosphonic acid polymers synthesized from phosphonoyl group-containing olefin monomers prepared using phosphorous acid, bromine chloride, and allyl chloride as raw materials, and synergistically formulated with boric acid in a specific ratio, exhibits better retarding effect under medium-high temperature and large temperature difference environments. Furthermore, the cement slurry prepared using this organophosphonic acid polymer retarder has the advantages of not thickening when cold and not reducing viscosity when hot compared with cement slurries prepared using commonly used large temperature difference retarders in the industry. Moreover, under medium-high temperature and large temperature difference conditions (85-145℃), the strength of the cement stone at the top of the cement slurry column develops faster, exceeding the top strength of cement slurries prepared using commonly used large temperature difference retarders in the industry after 48 hours within 24 hours. Attached Figure Description

[0031] Figure 1 Temperature thickening curve of "WL (4.2wt%)" cement slurry in Example 2 of this invention;

[0032] Figure 2 Temperature thickening curve (145℃) of "GH-10 (3wt%)" cement slurry in Example 2 of this invention;

[0033] Figure 3 Temperature thickening curve (135℃) of "GH-10 (3wt%)" cement slurry in Example 2 of this invention;

[0034] Figure 4 Temperature thickening curve (155℃) of "GH-10 (3wt%)" cement slurry in Example 2 of this invention. Detailed Implementation

[0035] Example 1

[0036] The preparation method of the organophosphonic acid polymer retarder in this embodiment includes the following steps:

[0037] Step A: Add 15g of 2-acrylamide-2-methylpropanesulfonic acid, 7.6g of N,N-dimethylacrylamide, 3g of itaconic acid and 6g of phosphonoacrylic alkene monomer to 50g of softened water, stir and mix evenly to obtain mixed raw material dispersion A.

[0038] Step B: Add 5g of 40wt% potassium hydroxide solution to the mixed raw material dispersion A, stir and mix evenly to obtain mixed raw material dispersion B; the pH of mixed raw material dispersion B is 4.6.

[0039] Step C: While stirring, heat the mixed raw material dispersion B to 80°C, and while heating and stirring at 80°C, add 6g of ammonium persulfate solution and 5.4g of sodium bisulfite solution dropwise to the mixed raw material dispersion B; the ammonium persulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes; after the sodium bisulfite solution is added dropwise, the mixed reaction dispersion is obtained.

[0040] Step D: Control the temperature of the mixed reaction dispersion to 80℃ and continue the reaction at 80℃ for 3 hours. After the reaction is completed, add 6g of boric acid to the reaction system and stir to mix well, thus preparing the organophosphonic acid polymer retarder.

[0041] Organophosphonates are excellent retarder slurries with good temperature resistance, are insensitive to temperature and dosage, and do not affect cement hydration. However, their retarding effect on cement weakens above 110℃, and the thickening curve is prone to bulging and step formation, shortening the thickening time and posing a significant threat to cementing operations. This embodiment uses self-made phosphonoyl group-containing olefin monomers to prepare organophosphonic acid polymer retarder, which can significantly improve the retarding effect of organophosphonic acid polymer retarder slurry, making it suitable for cementing slurries used in medium- and high-temperature, large-temperature-difference, long-sealing sections.

[0042] The preparation method of the phosphonoyl group-containing olefin monomer used in step A of this embodiment is as follows:

[0043] Step (A-1): Add 20g of softened water, 32g of phosphorous acid and 3g of bromine chloride to a reaction vessel equipped with a distillation apparatus in sequence, mix well to obtain mixed reaction system A;

[0044] Step (A-2): The mixed reaction system is kept at 30°C for 1.5 hours. After the isothermal reaction is completed, mixed reaction system B is obtained.

[0045] Step (A-3): Continue heating the mixed reaction system B to 80°C, and add 45g of allyl chloride dropwise to the mixed reaction system B. The allyl chloride should be added dropwise within 30 minutes. After the allyl chloride is added, continue stirring the reaction for 3 hours. The reaction ends to obtain the phosphonoyl alkene monomer.

[0046] Example 2

[0047] This embodiment uses the medium-organophosphonic acid polymer retarder (denoted as retarder GH-10) prepared by the preparation method of Example 1 to formulate cementing slurry for medium- and high-temperature long sealing sections. By changing the amount of medium-organophosphonic acid polymer retarder added, the strength development of the cement stone at the top of the cementing slurry column is compared.

[0048] The composition of the cement slurry for medium-high temperature long sealing sections prepared in this embodiment is shown in Table 1.

[0049] Table 1

[0050] Components weight Actual dosage / g Grade G cement 100 400 Reducer CP-52 12 48 Reducer CP-53 8 32 anti-settling agent WH-10 1.5 6 USZ drag reducer for oil well cement 1.0 4 Oil well cement expansion agent G401 1.0 4 G406 self-healing agent for oil well cement 1.0 4 water-based resin 2.5 10 Oil well cement fluid loss reducer G310 8.0 32 GH-10 retarder 3.0 12 tap water 70 280

[0051] In Table 1, Grade G cement is Grade G high sulfate-resistant oil well cement produced by Sichuan Jiahua Cement Plant; Lightening agent CP-52 is a hollow microsphere-type lightening agent produced by Weihui Chemical Co., Ltd.; Lightening agent CP-53 is a water-absorbing and viscosity-enhancing lightening agent produced by Weihui Chemical Co., Ltd.; Anti-settling agent WH-10 is produced by Weihui Chemical Co., Ltd. (in some other embodiments, products from other companies with similar performance can also be used instead); Oil well cement drag reducer USZ is produced by Weihui Chemical Co., Ltd.; Oil well cement expansion agent G401 is produced by Weihui Chemical Co., Ltd. (in... In some other embodiments, products from other companies with similar performance can be used instead; the self-healing agent G406 for oil well cement is produced by Weihui Chemical Co., Ltd. (in some other embodiments, products from other companies with similar performance can be used instead); the water-based resin is produced by Weihui Chemical Co., Ltd. (in some other embodiments, products from other companies with similar performance can be used instead); the water loss reducing agent G310 for oil well cement is produced by Weihui Chemical Co., Ltd.; the retarder GH-10 is the organophosphonic acid polymer retarder prepared by the preparation method of Example 1.

[0052] Tests showed that the cement slurry prepared according to Table 1 developed its cement stone strength rapidly at the top of the slurry column under medium-high temperature and large temperature difference conditions, and reached a relatively high strength within 24 hours. When a commonly used large temperature difference retarder (denoted as "WL", which produces cement slurry with the best strength index of cement stone at the top of the slurry column, achieved in 48 hours under medium-high temperature and large temperature difference conditions) was used instead of "retarder GH-10" in the cement slurry preparation in Table 1, and the thickening time of the cement slurry was adjusted within the same range, the cement stone strength development of the prepared cement slurry at the top of the slurry column under medium-high temperature and large temperature difference conditions was always one day slower than that of the cement slurry prepared with "retarder GH-10". Moreover, when the dosage of "WL" was 4.2 wt% of the cement mass, the cement slurry thickening time was within the required range, and the cement stone strength at the top of the slurry column was the highest under medium-high temperature and large temperature difference conditions.

[0053] Table 2 compares the performance of cement slurries prepared according to GB / T19139 with different retarders within the same thickening time requirement range. "WL (4.2wt%)" represents cement slurry prepared using an external high-temperature retarder accounting for 4.2wt% of the ash weight, i.e., the performance of cement slurry prepared using a commonly used large temperature difference retarder in the industry; "GH-10 (3wt%)" represents cement slurry prepared using an additional 3.0wt% of the ash weight. The performance comparison results of the two cement slurries are shown in Table 2. Figures 1 to 4 The thickening time-temperature curve is shown in Table 2.

[0054] Table 2

[0055]

[0056] As shown in Table 2, when 3.0 wt% of GH-10 (based on the weight of Grade G cement) is added to the cement slurry, the strength of the cement stone at the top of the cement slurry column develops rapidly under medium-high temperature and large temperature difference conditions (85-145℃). Furthermore, it can exceed the top strength of cement slurry prepared using commonly used large temperature difference retarders within 24 hours, which is achieved after 48 hours. The thickening time of "GH-10 (3 wt%)" at 135℃ is 466.5℃, at 145℃ it is 417.9℃, and at 155℃ it is 405.8℃. This indicates that the cement slurry prepared with the organophosphate polymer retarder prepared in this embodiment will not exhibit a thickening time inversion phenomenon during cementing. In addition, the comparison of rheological readings in Table 2 proves that this cement slurry, compared to "WL (4.2 wt%)" cement slurry, has the advantages of not thickening on cold slurry and not reducing viscosity on hot slurry, which helps adjust the settling stability of the cement slurry.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for preparing an organophosphonic acid polymer retarder, characterized in that, Includes the following steps: Step A: Add 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylacrylamide, itaconic acid, and phosphonoacrylic acid-containing olefin monomers to softened water and stir to mix evenly to obtain mixed raw material dispersion A; wherein, 13-15 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 7-8 parts by weight of N,N-dimethylacrylamide, 2-3 parts by weight of itaconic acid, 6-8 parts by weight of phosphonoacrylic acid-containing olefin monomers, and 50-55 parts by weight of softened water; Step B: Add sodium hydroxide solution or potassium hydroxide solution to the mixed raw material dispersion A, stir and mix evenly to make the pH of the mixed raw material dispersion B 4-5, thus obtaining mixed raw material dispersion B; Step C: Heat the mixed raw material dispersion B, and add ammonium persulfate solution and sodium bisulfite solution dropwise to the mixed raw material dispersion B while heating and stirring; after the sodium bisulfite solution has been added, a mixed reaction dispersion is obtained. Step D: Continue the reaction of the mixed reaction dispersion at a constant temperature. After the reaction is completed, add boric acid to the reaction system and stir to mix. The amount of boric acid added is 6-8 parts by weight, and the organophosphonic acid polymer retarder is thus prepared. Phosphonoyl group-containing alkene monomers are prepared by the following method: Step (A-1): Softened water, phosphorous acid, and bromine chloride are added sequentially to a reaction vessel equipped with a distillation apparatus and mixed thoroughly to obtain a mixed reaction system A. Step (A-2): The mixed reaction system is subjected to a constant temperature reaction. After the constant temperature reaction is completed, mixed reaction system B is obtained. Step (A-3): Continue heating the mixed reaction system B and add allyl chloride dropwise to the mixed reaction system B. After the allyl chloride has been added, continue stirring the reaction. Once the reaction is complete, the phosphonoyl alkene monomer is obtained.

2. The method for preparing the organophosphonic acid polymer retarder according to claim 1, characterized in that, In step B, the potassium hydroxide solution is 4-6 parts by weight, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40-48 wt%. In step C, the ammonium persulfate solution is prepared by mixing 1 to 1.5 parts by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 to 0.6 parts by weight of sodium bisulfite and 5 parts by weight of softened water.

3. The method for preparing the organophosphonic acid polymer retarder according to claim 2, characterized in that, In step A, there are 15 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 7.6 parts by weight of N,N-dimethylacrylamide, 3 parts by weight of itaconic acid, 6-8 parts by weight of phosphonoacrylyl olefin monomers, and 50 parts by weight of softened water. In step B, the potassium hydroxide solution is 5 parts by weight, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40 wt%. In step C, the ammonium persulfate solution is prepared by mixing 1 part by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 parts by weight of sodium bisulfite and 5 parts by weight of softened water. In step D, the amount of boric acid added is 6 parts by weight.

4. The method for preparing the organophosphonic acid polymer retarder according to claim 1, characterized in that, In step C, the mixed raw material dispersion B is first heated to 75-85°C while stirring. Then, ammonium persulfate solution and sodium bisulfite solution are added dropwise while stirring at 75-85°C. The ammonium persulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes. In step D, the mixed reaction dispersion is kept at a constant temperature of 75–85°C for 3–3.5 h.

5. The method for preparing the organophosphonic acid polymer retarder according to claim 4, characterized in that, In step C, the mixed raw material dispersion B is first heated to 80°C while stirring, and then ammonium persulfate solution and sodium bisulfite solution are added dropwise while stirring at 80°C. The ammonium persulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes. In step D, the mixed reaction dispersion is kept at a constant temperature of 80°C for 3 hours.

6. The method for preparing the organophosphonic acid polymer retarder according to claim 1, characterized in that, In step (A-1), softened water is 20-25 parts by weight, phosphorous acid is 30-35 parts by weight, and bromine chloride is 3-4 parts by weight; in step (A-2), the isothermal reaction temperature is 25-30℃, and the isothermal reaction time is 1.5-2 hours; in step (A-3), the amount of allyl chloride added is 40-50 parts by weight; after the mixed reaction system B is heated to 80-85℃, allyl chloride is added dropwise to the mixed reaction system B, and the allyl chloride is added dropwise within 25-30 minutes; after the allyl chloride is added dropwise, the reaction is stirred at 75-85℃ for 2.5-3.5 hours.

7. The method for preparing the organophosphonic acid polymer retarder according to claim 1, characterized in that, In step A, there are 15 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 7.6 parts by weight of N,N-dimethylacrylamide, 3 parts by weight of itaconic acid, 6-8 parts by weight of phosphonoacrylyl olefin monomers, and 50 parts by weight of softened water. Phosphonoyl group-containing alkene monomers are prepared by the following method: Step (A-1): Add 20 parts by weight of softened water, 32 parts by weight of phosphorous acid and 3 parts by weight of bromine chloride to a reaction vessel equipped with a distillation apparatus in sequence, mix well to obtain mixed reaction system A; Step (A-2): The mixed reaction system is kept at 30°C for 1.5 hours. After the isothermal reaction is completed, mixed reaction system B is obtained. Step (A-3): Continue heating the mixed reaction system B to 80°C, and add 45 parts by weight of allyl chloride to the mixed reaction system B. The allyl chloride is added dropwise within 30 minutes. After the allyl chloride is added, continue stirring the reaction at 80°C for 3 hours. The reaction ends to obtain phosphonoyl alkene monomers. In step B, the potassium hydroxide solution is 5 parts by weight, and the mass fraction of potassium hydroxide in the potassium hydroxide solution is 40 wt%. In step C, the ammonium persulfate solution is prepared by mixing 1 part by weight of ammonium persulfate and 5 parts by weight of softened water, and the sodium bisulfite solution is prepared by mixing 0.4 parts by weight of sodium bisulfite and 5 parts by weight of softened water. First, the mixed raw material dispersion B is heated to 80°C while stirring, and then the ammonium persulfate solution and sodium bisulfite solution are added dropwise sequentially while stirring at 80°C. The ammonium persulfate solution is added dropwise within 1 minute, and the sodium bisulfite solution is added dropwise within 10 minutes. In step D, the amount of boric acid added is 6 parts by weight; the constant temperature reaction temperature of the mixed reaction dispersion is 80℃, and the reaction time is 3h.

8. The application of organophosphonic acid polymer retarder, characterized in that, The organophosphonic acid polymer retarder prepared by the preparation method of the organophosphonic acid polymer retarder as described in any one of claims 1-7 is used in the preparation of cement slurry for cementing sections with medium- and high-temperature large temperature differences and long sealing sections.

9. The application of the organophosphonic acid polymer retarder according to claim 8, characterized in that, The cement slurry for cementing wells in medium- and high-temperature, large-temperature-difference, long-sealing sections is composed of the following components in parts by weight: 100 parts by weight of Grade G high-sulfate-resistant oil well cement, 12 parts by weight of weight-reducing agent CP-52, 8 parts by weight of weight-reducing agent CP-53, 1.5 parts by weight of anti-settling agent WH-10, 1.0 part by weight of drag-reducing agent USZ for oil well cement, 1.0 part by weight of expansion agent G401 for oil well cement, 1.0 part by weight of self-healing agent G406 for oil well cement, 2.5 parts by weight of water-based resin, 8.0 parts by weight of fluid loss reducing agent G310 for oil well cement, 70 parts by weight of tap water, and 3 to 4 parts by weight of the organophosphonic acid polymer retarder prepared by the preparation method of the organophosphonic acid polymer retarder as described in any one of claims 1-7.

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