Temperature-resistant and salt-resistant retarder, preparation method and application thereof

Abstract

This invention provides a temperature- and salt-resistant retarder, its preparation method, and its application. The temperature- and salt-resistant retarder is copolymerized from prepolymer 1 and prepolymer 2. Prepolymer 1 is obtained by reacting an acrylamide monomer containing sulfonic acid groups with a diacid with 7-9 carbon atoms. Prepolymer 2 is obtained by reacting an aqueous styrene-acrylic emulsion containing sulfonic acid groups with a heterocyclic styrene-acrylic emulsion. The mass ratio of prepolymer 1 to prepolymer 2 is (0.85-1):(0.98-1.22), the mass ratio of the acrylamide monomer containing sulfonic acid groups to the diacid with 7-9 carbon atoms is (0.86-1.02):(1.90-2.2), and the mass ratio of the aqueous styrene-acrylic emulsion containing sulfonic acid groups to the heterocyclic styrene-acrylic emulsion is (1.0-1.5):(6.0-7.3). The temperature- and salt-resistant retarder exhibits excellent high-temperature and salt-water resistance.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well cementing technology, specifically relating to a temperature- and salt-resistant retarder, its preparation method, and its application. Background Technology

[0002] As oil exploration and development continues to advance towards deep and ultra-deep wells, the complex environments at the bottom of wells, including high temperatures and high salinity, pose severe challenges to cement slurry systems. These challenges manifest primarily in the following ways: 1) Cement slurry systems exhibit poor setting and regulation performance under high-temperature conditions; 2) Cement slurry experiences significant water loss in saturated brine, leading to increased system density and decreased workability. These complexities present new challenges to cementing technology and place higher performance demands on cement slurries and their admixtures.

[0003] Retarder is one of the main admixtures in cement slurry. It controls the thickening time of the cement slurry, ensuring its pumpability within a specified time, thereby guaranteeing the safety of cementing operations. Retarders are divided into traditional retarders and polymeric retarders. Traditional retarders include lignin sulfonates and their derivatives, organophosphates, and inorganic salts, which suffer from poor high-temperature stability and high dosage sensitivity. Polymeric retarders are formed by polymerizing monomers containing multiple functional groups, possessing a designable structure, thus exhibiting excellent high-temperature setting regulation.

[0004] CN116041601A discloses a polymer-based cement slurry retarder, the preparation method of which includes adding an initiator to a raw material liquid, heating to 60-70℃ to initiate a polymerization reaction to obtain the retarder. The raw material liquid includes styrene sulfonate, organophosphorus scale inhibitor, (meth)acrylate hydroxy ester, unsaturated dicarboxylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and water. Cement slurry with the added retarder maintains a low viscosity and does not thicken within 240 minutes at 220℃. CN117659311A discloses a cement slurry retarder, the preparation method of which includes using 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, and diallyl dimethylammonium chloride as monomers, and diallyl dimethylammonium chloride-modified montmorillonite as an active filler, synthesized by solution polymerization in situ intercalation method. Cement slurry with the added retarder can thicken for 322-547 minutes at 240℃. The aforementioned patent applications have achieved some success in high-temperature retarders; however, there are currently few reports on cement slurry retarders that simultaneously possess both high-temperature resistance and salt water resistance.

[0005] Therefore, how to develop a temperature- and salt-resistant retarder is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention provides a temperature- and salt-resistant retarder, which has excellent resistance to high temperatures and salt water.

[0007] The present invention also provides a method for preparing the above-mentioned temperature and salt resistant retarder. The preparation method is simple, easy to operate, and convenient for industrial production.

[0008] The present invention also provides a cement slurry comprising the above-mentioned temperature- and salt-resistant retarder, wherein the cement slurry has excellent high-temperature stability and salt water resistance.

[0009] In a first aspect, the present invention provides a temperature- and salt-resistant retarder, wherein the temperature- and salt-resistant retarder is copolymerized from prepolymer 1 and prepolymer 2;

[0010] The prepolymer 1 is obtained by reacting an acrylamide monomer containing sulfonic acid groups with a dicarboxylic acid having 7-9 carbon atoms;

[0011] The prepolymer 2 is obtained by reacting an aqueous styrene-acrylic emulsion containing sulfonic acid groups and a heterocyclic styrene-acrylic emulsion.

[0012] The mass ratio of prepolymer 1 to prepolymer 2 is (0.85-1):(0.98-1.22);

[0013] The mass ratio of the acrylamide monomer containing sulfonic acid groups to the dicarboxylic acid with 7-9 carbon atoms is (0.86-1.02):(1.9-2.2);

[0014] The mass ratio of the aqueous styrene-acrylic emulsion containing sulfonic acid groups to the heterocyclic styrene-acrylic emulsion is (1-1.5):(6-7.3).

[0015] The temperature- and salt-resistant retarder as described above, wherein the weight-average molecular weight of the temperature- and salt-resistant retarder is 450,000 to 500,000.

[0016] The temperature- and salt-resistant retarder as described above, wherein the sulfonic acid-containing acrylamide monomer comprises at least one selected from 2-acrylamido-2-phenylethanesulfonic acid, 2-acrylamido-dodecyl sulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid; and / or,

[0017] The dicarboxylic acid having 7-9 carbon atoms includes at least one of 1,7-heptanoic acid, octanoic acid, and azelaic acid; and / or,

[0018] The aqueous styrene-acrylic emulsion containing sulfonic acid groups includes at least one of silicone styrene-acrylic emulsion and elastic styrene-acrylic emulsion; and / or

[0019] The heterocyclic styrene-acrylic emulsion includes at least one of fused-ring styrene-acrylic emulsion and cross-linked modified styrene-acrylic emulsion.

[0020] Secondly, the present invention provides a method for preparing the above-mentioned temperature- and salt-resistant retarder, comprising the following steps:

[0021] (1) Mix an aqueous solution of acrylamide monomer containing sulfonic acid group and an aqueous solution of diacid with 7-9 carbon atoms, add alkali to adjust the pH to 6.5-7.5, heat to 60-80℃, and react to obtain prepolymer 1;

[0022] (2) Mix the aqueous styrene-acrylic emulsion containing sulfonic acid groups and the heterocyclic styrene-acrylic emulsion, and heat to 60-80℃ to react and obtain prepolymer 2;

[0023] (3) Mix prepolymer 1, prepolymer 2 and initiator, heat to 60-70℃, polymerize, add polymerization inhibitor, cool to 15-30℃, and obtain the temperature-resistant and salt-resistant retarder.

[0024] In the preparation method described above, the mass percentage concentrations of the aqueous solution of acrylamide monomer containing sulfonic acid group, the aqueous solution of dicarboxylic acid with 7-9 carbon atoms, the aqueous styrene-acrylic emulsion containing sulfonic acid group, and the heterocyclic styrene-acrylic emulsion in steps (1) and (2) are all 25%-30%.

[0025] The preparation method described above, wherein the alkali in step (1) includes at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate; and / or,

[0026] The reaction time described in step (1) is 30-40 min; and / or,

[0027] The reaction time described in step (2) is 60-80 min; and / or,

[0028] The polymerization reaction in step (3) takes 0.5-1.5 hours.

[0029] In the preparation method described above, the initiator includes ammonium persulfate, and the polymerization inhibitor includes at least one selected from resorcinol, p-benzoquinone, methylhydroquinone, and copper sulfate.

[0030] In the preparation method described above, the mass of the initiator is 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2, and the mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2.

[0031] The preparation method described above, wherein the polymerization reaction in step (3) is carried out under an inert gas; and / or,

[0032] The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or,

[0033] The cooling process described in step (3) also includes purification and drying.

[0034] Thirdly, the present invention provides a cement slurry comprising the above-mentioned temperature- and salt-resistant retarder.

[0035] The implementation of this invention has at least the following beneficial effects:

[0036] This invention uses specific types and amounts of raw materials to prepare a temperature- and salt-resistant retarder with a weight-average molecular weight of 450,000 to 500,000. This temperature- and salt-resistant retarder has good high-temperature resistance and salt water resistance. Cement slurry with the addition of the temperature- and salt-resistant retarder has excellent high-temperature stability and salt water resistance, and will not increase water loss in a salt water environment. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] A first aspect of the present invention provides a temperature- and salt-resistant retarder, which is copolymerized from prepolymer 1 and prepolymer 2;

[0039] Prepolymer 1 is obtained by reacting acrylamide monomer containing sulfonic acid groups with a dicarboxylic acid having 7-9 carbon atoms;

[0040] Prepolymer 2 is obtained by reacting an aqueous styrene-acrylic emulsion containing sulfonic acid groups with a heterocyclic styrene-acrylic emulsion;

[0041] The mass ratio of prepolymer 1 to prepolymer 2 is (0.85-1):(0.98-1.22);

[0042] The mass ratio of acrylamide monomers containing sulfonic acid groups to dicarboxylic acids with 7-9 carbon atoms is (0.86-1.02):(1.9-2.2);

[0043] The mass ratio of aqueous styrene-acrylic emulsion containing sulfonic acid groups to heterocyclic styrene-acrylic emulsion is (1-1.5):(6-7.3).

[0044] This invention uses the above-mentioned specific types and proportions of polymer monomers to prepare a temperature and salt resistant retarder with excellent high temperature and salt water resistance.

[0045] In this invention, the weight-average molecular weight of the temperature- and salt-resistant retarder is 450,000 to 500,000, which enables the temperature- and salt-resistant retarder to form a spatial network structure at high temperatures.

[0046] In some embodiments, the sulfonic acid-containing acrylamide monomer includes at least one selected from 2-acrylamido-2-phenylethanesulfonic acid, 2-acrylamido-dodecylsulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid; and / or,

[0047] Dicarboxylic acids with 7-9 carbon atoms include at least one of 1,7-heptanediol, octanoic acid, and azelaic acid.

[0048] This invention introduces sulfonic acid groups, amide groups, and carboxyl groups with strong adsorption capacity into a temperature- and salt-resistant retarder by using acrylamide containing sulfonic acid groups and dicarboxylic acids with 7-9 carbon atoms. This helps to adsorb cement particles and reduce the hydration rate of cement.

[0049] Furthermore, the aqueous styrene-acrylic emulsion containing sulfonic acid groups includes at least one of silicone styrene-acrylic emulsion and elastic styrene-acrylic emulsion; and / or,

[0050] Heterocyclic styrene-acrylic emulsions include at least one of fused-ring styrene-acrylic emulsions and cross-linked modified styrene-acrylic emulsions.

[0051] This invention introduces high-temperature resistant benzene rings and heterocyclic rings into a temperature- and salt-resistant retarder by using an aqueous styrene-acrylic emulsion containing sulfonic acid groups and a styrene-acrylic emulsion containing heterocyclic rings. This makes the retarder less prone to agglomeration at high temperatures, which is beneficial to improving the high-temperature and salt-water resistance of the retarder.

[0052] Secondly, the present invention provides a method for preparing the above-mentioned temperature- and salt-resistant retarder, the preparation method comprising the following steps:

[0053] (1) Mix an aqueous solution of acrylamide monomer containing sulfonic acid group and an aqueous solution of diacid with 7-9 carbon atoms, add alkali to adjust the pH to 6.5-7.5, heat to 60-80℃, and react to obtain prepolymer 1;

[0054] (2) Mix the aqueous styrene-acrylic emulsion containing sulfonic acid groups and the heterocyclic styrene-acrylic emulsion, and heat to 60-80℃ to react and obtain prepolymer 2;

[0055] (3) Mix prepolymer 1, prepolymer 2 and initiator, heat to 60-70℃, polymerize, add polymerization inhibitor, cool to 15-30℃, and obtain the temperature-resistant and salt-resistant retarder.

[0056] In step 1) of this invention, the pH value of the mixed system is adjusted to 6.5-7.5 by adding alkali to avoid insufficient polymerization of the monomers under acidic conditions.

[0057] In some embodiments, the mass percentage concentrations of the aqueous solution of acrylamide monomer containing sulfonic acid groups, the aqueous solution of dicarboxylic acid with 7-9 carbon atoms, the aqueous styrene-acrylic emulsion containing sulfonic acid groups, and the heterocyclic styrene-acrylic emulsion in steps (1) and (2) are all 25%-30%.

[0058] Preparing monomer solutions of a specific mass percentage concentration before polymerization can further control the reaction efficiency and ensure stable polymerization. Specifically, sulfonic acid-containing acrylamide monomers can be added to water to prepare an aqueous solution of sulfonic acid-containing acrylamide monomers with a mass percentage concentration of 25%-30%; diacids with 7-9 carbon atoms can be added to water to prepare an aqueous solution of diacids with 7-9 carbon atoms with a mass percentage concentration of 25%-30%; an aqueous styrene-acrylic emulsion containing sulfonic acid groups can be added to water to prepare an aqueous styrene-acrylic emulsion containing sulfonic acid groups with a mass percentage concentration of 25%-30%; and a heterocyclic styrene-acrylic emulsion can be added to water to prepare a heterocyclic styrene-acrylic emulsion with a mass percentage concentration of 25%-30%.

[0059] In some embodiments, the alkali includes at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate, which allows the monomers to undergo a more complete polymerization reaction.

[0060] Furthermore, the reaction time in step (1) is 30-40 min; and / or, the reaction time in step (2) is 60-80 min; and / or, the polymerization reaction time in step (3) is 0.5-1.5 h, so as to ensure that the monomers fully undergo polymerization reaction while saving energy.

[0061] In this invention, ammonium persulfate is added as an initiator to the polymer monomer. Ammonium persulfate has the advantages of fast initiation speed, fast dissolution, fast dispersion, and low price, which enables the polymer monomer to carry out the polymerization reaction efficiently.

[0062] Furthermore, the polymerization inhibitor includes at least one of resorcinol, p-benzoquinone, methylhydroquinone, and copper sulfate, which terminates the polymerization reaction.

[0063] In some embodiments, the mass of the initiator is 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2, which can improve the efficiency of the polymerization reaction while saving initiator.

[0064] Furthermore, the mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2, so as to terminate the polymerization reaction in a timely manner while conserving the polymerization inhibitor.

[0065] In this invention, the polymerization reaction in step (3) is carried out under an inert gas, which includes at least one of helium, argon, and nitrogen, which can further improve the polymerization reaction efficiency.

[0066] Furthermore, step (3) includes purifying and drying the reaction system sequentially after cooling to separate a higher purity temperature and salt resistant retarder.

[0067] Thirdly, the present invention provides a cement slurry comprising the temperature- and salt-resistant retarder described in the first aspect.

[0068] The present invention does not limit the other components and contents of the cement slurry, and can be the cement slurry commonly used in the art, such as cement, quartz sand, water loss reducing agent, defoamer, retarder and water.

[0069] The cement slurry exhibits excellent high-temperature stability and salt water resistance, and will not increase water loss in a salt water environment.

[0070] The present invention will be described in detail below through specific embodiments:

[0071] Example 1

[0072] The preparation method of the temperature- and salt-resistant retarder provided in this embodiment includes the following steps:

[0073] (1) Mix 2-acrylamido-2-phenylethanesulfonic acid aqueous solution and azelaic acid aqueous solution, add sodium hydroxide to adjust the pH value to 7, heat to 70℃, react for 30 min, and obtain prepolymer 1;

[0074] (2) Mix silicone styrene-acrylic emulsion (model 707, Henan Tianchou Chemical Products Co., Ltd.) and polycyclic styrene-acrylic emulsion (model BJ806, Beijing Jiahuitongda Chemical Products Co., Ltd.), heat to 65℃, and react for 60 min to obtain prepolymer 2;

[0075] (3) Under nitrogen protection, prepolymer 1, prepolymer 2 and ammonium persulfate are mixed, heated to 70°C, and polymerized for 1 hour. Resorcinol is added, cooled to 15°C, and purified and dried to obtain the temperature and salt resistant retarder.

[0076] The mass ratio of prepolymer 1 to prepolymer 2 is 1:1.22, the mass ratio of 2-acrylamido-2-phenylethanesulfonic acid to azelaic acid is 1:2.2, and the mass ratio of silicone styrene-acrylic emulsion to fused ring styrene-acrylic emulsion is 1:7.3.

[0077] The mass percentage concentrations of the aqueous solutions of 2-acrylamido-2-phenylethanesulfonic acid, azelaic acid, silicone styrene-acrylic emulsion, and fused ring styrene-acrylic emulsion were all 25%.

[0078] The mass of ammonium persulfate is 1% of the total mass of prepolymer 1 and prepolymer 2, and the mass of resorcinol is 0.9% of the total mass of prepolymer 1 and prepolymer 2.

[0079] Example 2

[0080] The preparation method of the temperature- and salt-resistant retarder provided in this embodiment includes the following steps:

[0081] (1) Mix 2-acrylamido-2-methylpropanesulfonic acid aqueous solution and succinic acid aqueous solution, add potassium hydroxide to adjust the pH value to 6.5, heat to 75℃, react for 40 min to obtain prepolymer 1;

[0082] (2) Mix the elastic styrene-acrylic emulsion (model 707H, Henan Tianchou Chemical Products Co., Ltd.) and the crosslinked modified styrene-acrylic emulsion (BJ-806H, Beijing Jiahuitongda Chemical Products Co., Ltd.), heat to 65℃, and react for 80 min to obtain prepolymer 2;

[0083] (3) Under nitrogen protection, prepolymer 1, prepolymer 2 and ammonium persulfate were mixed, heated to 65°C, and polymerized for 1.5 h. Then p-benzoquinone was added, cooled to 15°C, and purified and dried to obtain the temperature and salt resistant retarder.

[0084] Among them, the mass ratio of prepolymer 1 to prepolymer 2 is 1:1, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid to octanoic acid is 1:2, and the mass ratio of elastic styrene-acrylic emulsion to crosslinked modified styrene-acrylic emulsion is 1:6.

[0085] The mass percentage concentrations of the aqueous solutions of 2-acrylamido-2-methylpropanesulfonic acid, succinic acid, elastic styrene-acrylic emulsion, and crosslinked modified styrene-acrylic emulsion were all 26%.

[0086] The mass of ammonium persulfate is 1.5% of the total mass of prepolymer 1 and prepolymer 2, and the mass of p-benzoquinone is 1.1% of the total mass of prepolymer 1 and prepolymer 2.

[0087] Example 3

[0088] The preparation method of the temperature- and salt-resistant retarder provided in this embodiment includes the following steps:

[0089] (1) Mix 2-acrylamidododecyl sulfonic acid aqueous solution and azelaic acid aqueous solution, add sodium carbonate to adjust the pH value to 7.5, heat to 80℃, react for 35 min to obtain prepolymer 1;

[0090] (2) Mix the elastic styrene-acrylic emulsion and the fused cyclic styrene-acrylic emulsion, heat to 65°C, and react for 75 min to obtain prepolymer 2;

[0091] (3) Under nitrogen protection, prepolymer 1, prepolymer 2 and ammonium persulfate are mixed, heated to 70°C, and polymerized for 1 hour. Resorcinol is added, cooled to 15°C, and purified and dried to obtain the temperature and salt resistant retarder.

[0092] The mass ratio of prepolymer 1 to prepolymer 2 is 0.9:1.22, the mass ratio of 2-acrylamido-2-phenylethanesulfonic acid to azelaic acid is 1:1.9, and the mass ratio of elastic styrene-acrylic emulsion to fused ring styrene-acrylic emulsion is 1:6.

[0093] The mass percentage concentrations of the aqueous solutions of 2-acrylamidododecyl sulfonic acid, azelaic acid, elastic styrene-acrylic emulsion, and fused ring styrene-acrylic emulsion were all 27%.

[0094] The mass of ammonium persulfate is 2% of the total mass of prepolymer 1 and prepolymer 2, and the mass of resorcinol is 1.3% of the total mass of prepolymer 1 and prepolymer 2.

[0095] Application Examples 1-3

[0096] The temperature- and salt-resistant retarder prepared in Examples 1-3 was added to the cement slurry formulation. The cement slurry consisted of the following components by weight: 100 parts cement (Dalian Cement), 40 parts quartz sand (Chaoyang Minghua), 8 parts water loss reducer (DS-1, Liaoning Hengao), 0.5 parts defoamer (Panjin Hongbo), 5 parts temperature- and salt-resistant retarder, and 46 parts water.

[0097] Application Example 4

[0098] This application example provides a cement slurry that, compared to application example 1, reduces the content of the temperature and salt resistant retarder to 4 parts, while keeping other conditions unchanged.

[0099] Application Example 5

[0100] This application example provides a cement slurry. Compared with application example 4, the water loss reducing agent DS-1 is replaced with an equal amount of DRG (Panjin Hongbo Petroleum Technology Service Co., Ltd.), while other conditions remain unchanged.

[0101] Application Example 6

[0102] This application example provides a cement slurry. Compared with application example 4, the water loss reducing agent DS-1 is replaced with an equal amount of D181 (Schlumberger), while other conditions remain unchanged.

[0103] Application Example 7

[0104] This application example provides a cement slurry. Compared with application example 4, the fluid loss reducing agent DS-1 is replaced with an equal amount of GWF-200L (Great Wall Drilling Cementing Company), while other conditions remain unchanged.

[0105] Application Example 8

[0106] This application example provides a cement slurry that, compared to application example 4, increases the content of the temperature- and salt-resistant retarder to 6 parts, while keeping other conditions unchanged.

[0107] Performance testing

[0108] (1) Thickening time test: The same mass of cement slurry prepared in Application Examples 1-3 was weighed and thickened at 220℃ according to the requirements of GB / T10238. The results are shown in Table 1.

[0109] (2) Sensitivity test of retarder dosage: The thickening time of cement slurry in Examples 4-8 was tested, and the results are shown in Table 2.

[0110] (3) Salt water resistance test: Weigh the same mass of cement slurry prepared in Application Examples 1-3, replace the water in the above cement slurry with an equal amount of 18wt% sodium salt water, and test the thickening time at 220℃ according to the requirements of GB / T10238. The results are shown in Table 3.

[0111] Table 1

[0112]

[0113] As can be seen from the analysis of Table 1, the cement slurry prepared by applying Examples 1-3 has a longer thickening time.

[0114] Table 2

[0115]

[0116] As shown in Table 2, the cement slurry prepared by using the water loss reducing agent GWF-200L in Application Example 7 and the temperature and salt resistant retarder in Example 1 has a longer thickening time and a right-angle thickening trend, and the sensitivity response is ideal.

[0117] Table 3

[0118]

[0119] As shown in Table 3, when the NaCl content in the slurry preparation water of the cement slurry prepared in Examples 1-3 is 18wt%, the cement slurry still has a relatively long thickening time, indicating that the cement slurry has a strong resistance to salt water.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature- and salt-resistant retarder, characterized in that, The temperature- and salt-resistant retarder is copolymerized from prepolymer 1 and prepolymer 2; The prepolymer 1 is obtained by reacting an acrylamide monomer containing sulfonic acid groups with a dicarboxylic acid having 7-9 carbon atoms; The prepolymer 2 is obtained by reacting an aqueous styrene-acrylic emulsion containing sulfonic acid groups and a heterocyclic styrene-acrylic emulsion. The mass ratio of prepolymer 1 to prepolymer 2 is (0.85-1):(0.98-1.22). The mass ratio of the acrylamide monomer containing sulfonic acid groups to the dicarboxylic acid with 7-9 carbon atoms is (0.86-1.02):(1.90-2.2). The mass ratio of the aqueous styrene-acrylic emulsion containing sulfonic acid groups to the heterocyclic styrene-acrylic emulsion is (1.0-1.5):(6.0-7.3). The weight-average molecular weight of the temperature- and salt-resistant retarder is 450,000 to 500,000.

2. The temperature- and salt-resistant retarder according to claim 1, characterized in that, The sulfonate-containing acrylamide monomer includes at least one selected from 2-acrylamido-2-phenylethanesulfonic acid, 2-acrylamido-dodecyl sulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid; and / or, The dicarboxylic acid having 7-9 carbon atoms includes at least one of 1,7-heptanoic acid, octanoic acid, and azelaic acid; and / or, The aqueous styrene-acrylic emulsion containing sulfonic acid groups includes at least one of silicone styrene-acrylic emulsion and elastic styrene-acrylic emulsion; and / or The heterocyclic styrene-acrylic emulsion includes at least one of fused-ring styrene-acrylic emulsion and cross-linked modified styrene-acrylic emulsion.

3. A method for preparing the temperature- and salt-resistant retarder according to claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Mix an aqueous solution of acrylamide monomer containing sulfonic acid group and an aqueous solution of diacid with 7-9 carbon atoms, add alkali to adjust the pH to 6.5-7.5, heat to 60-80℃, and react to obtain prepolymer 1; (2) Mix the aqueous styrene-acrylic emulsion containing sulfonic acid groups and the heterocyclic styrene-acrylic emulsion, and heat to 60-80℃ to react and obtain prepolymer 2; (3) Mix prepolymer 1, prepolymer 2 and initiator, heat to 60-70℃, polymerize, add polymerization inhibitor, cool to 15-30℃, and obtain the temperature-resistant and salt-resistant retarder; The weight-average molecular weight of the temperature- and salt-resistant retarder is 450,000 to 500,000.

4. The preparation method according to claim 3, characterized in that, The mass percentage concentrations of the aqueous solution of acrylamide monomer containing sulfonic acid group, the aqueous solution of dicarboxylic acid with 7-9 carbon atoms, the aqueous styrene-acrylic emulsion containing sulfonic acid group, and the heterocyclic styrene-acrylic emulsion mentioned in steps (1) and (2) are all 25%-30%.

5. The preparation method according to claim 3 or 4, characterized in that, The alkali mentioned in step (1) includes at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate; and / or, The reaction time described in step (1) is 30-40 min; and / or, The reaction time described in step (2) is 60-80 min; and / or, The polymerization reaction in step (3) takes 0.5-1.5 hours.

6. The preparation method according to claim 3 or 4, characterized in that, The initiator includes ammonium persulfate; and / or, The polymerization inhibitor includes at least one of resorcinol, p-benzoquinone, methylhydroquinone, and copper sulfate.

7. The preparation method according to claim 5, characterized in that, The initiator includes ammonium persulfate; and / or, The polymerization inhibitor includes at least one of resorcinol, p-benzoquinone, methylhydroquinone, and copper sulfate.

8. The preparation method according to claim 3 or 4, characterized in that, The initiator is present in an amount of 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2; and / or, The mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2.

9. The preparation method according to claim 5, characterized in that, The initiator is present in an amount of 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2; and / or, The mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2.

10. The preparation method according to claim 6, characterized in that, The initiator is present in an amount of 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2; and / or, The mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2.

11. The preparation method according to claim 7, characterized in that, The initiator is present in an amount of 1%-2.5% of the total mass of prepolymer 1 and prepolymer 2; and / or, The mass of the polymerization inhibitor is 0.9%-1.3% of the total mass of prepolymer 1 and prepolymer 2.

12. The preparation method according to claim 3 or 4, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

13. The preparation method according to claim 5, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

14. The preparation method according to claim 6, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

15. The preparation method according to claim 7, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

16. The preparation method according to claim 8, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

17. The preparation method according to claim 9, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

18. The preparation method according to claim 10, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

19. The preparation method according to claim 11, characterized in that, The polymerization reaction described in step (3) is carried out under an inert gas; and / or, The inert gas mentioned in step (3) includes at least one of helium, argon, and nitrogen; and / or, The cooling process described in step (3) also includes purification and drying.

20. A cement grout, characterized in that, The cement slurry contains the temperature- and salt-resistant retarder as described in claim 1 or 2.

Images