High-temperature resistant retarder, preparation method thereof and high-temperature cement slurry

Abstract

The application provides a high-temperature-resistant retarder, a preparation method and a high-temperature-resistant cement slurry. Compositional monomers of the high-temperature-resistant retarder include monomers with structures shown in formula 1, monomers with structures shown in formula 2, monomers with structures shown in formula 3, monomers with structures shown in formula 4 and monomers with structures shown in formula 5. The high-temperature-resistant retarder has high structural stability at high temperatures, can effectively prolong the thickening time at high temperatures, and achieves a good retarding effect.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well development technology, and relates to a high-temperature resistant retarder, and more particularly to a high-temperature resistant retarder and its preparation method and high-temperature cement slurry. Background Technology

[0002] During drilling operations, cementing is required to seal complex formations, protect and support the casing inside oil and gas wells, and prevent fluid cross-contamination within the formation. This involves injecting cement into the annular space between the wellbore and the casing. However, as oil and gas resource development enters its later stages, the number of deep and ultra-deep wells continues to increase, with depths exceeding 10,000 meters. This causes bottom-hole temperatures to gradually rise from 200°C to 240°C; for example, the bottom-hole temperature of the "Jiantan 1 well" can reach as high as 235°C. This results in a large temperature difference between the bottom-hole and upper wellbore temperatures, requiring the cement slurry to have a low setting rate and a long thickening time at high temperatures. This presents significant challenges to cement slurry design.

[0003] Currently, adding retarders to cement slurry is commonly used to delay its setting time and adjust its thickening time. Among the many retarders, 2-acrylamide-2-methylpropanesulfonic acid (AMPS) polymers are widely used due to their good temperature resistance, diverse molecular structure design, and salt resistance. However, in high-temperature and ultra-high-temperature environments, the retardation effect remains unstable, affecting the settling stability of the cement slurry.

[0004] To address the above issues, CN102040987A discloses a 230℃-resistant retarder for oil well cement, which is prepared by free radical aqueous solution polymerization of AMPS and acrylic acid. Cement slurry containing this retarder can thicken in up to 330 minutes; however, the cement slurry system exhibits poor stability at high temperatures, affecting the thickening time.

[0005] CN101851317A discloses a polymer for use as a high-temperature cement retarder and its preparation method. This retarder is obtained by polymerization of 2-acrylamide-2-methylpropanesulfonic acid, styrene sulfonic acid, and itaconic acid, and exhibits good retarding effect when used at cycling temperatures above 180°C. However, the thickening time of cement slurry with this retarder is 244 min, indicating room for further improvement.

[0006] Therefore, it is necessary to further improve the retarder to enhance its retarding effect in high-temperature environments. Summary of the Invention

[0007] To address the aforementioned deficiencies, this invention provides a high-temperature resistant retarder that exhibits high structural stability at high temperatures and can achieve a good retarding effect.

[0008] The present invention also provides a method for preparing the above-mentioned high-temperature resistant retarder. The high-temperature resistant retarder prepared by this method has high structural stability at high temperatures and can achieve a good retarding effect.

[0009] The present invention also provides a high-temperature cement slurry, comprising the above-mentioned high-temperature resistant retarder or the high-temperature resistant retarder prepared by the above preparation method, having a longer thickening time.

[0010] The first aspect of this invention provides a high-temperature resistant retarder, wherein the constituent monomers of the high-temperature resistant retarder include: monomers with the structure shown in Formula 1, monomers with the structure shown in Formula 2, monomers with the structure shown in Formula 3, monomers with the structure shown in Formula 4, and monomers with the structure shown in Formula 5.

[0011]

[0012] Formula 1 Formula 2 Formula 3

[0013]

[0014] Formula 4 and Formula 5;

[0015] R1, R2, R3, R4, and R5 in Formulas 1, 2, 3, 4, and 5 may be the same or different, and each is independently selected from H or substituted or unsubstituted C1 to C30 alkyl groups; X includes any one of H, Na, and K.

[0016] The high-temperature retarder as described above, wherein, according to the mass fractions, the constituent monomers include: 32-76 parts of the monomer with the structure shown in Formula 1, 8-24 parts of the monomer with the structure shown in Formula 2, 2-12 parts of the monomer with the structure shown in Formula 3, 5-20 parts of the monomer with the structure shown in Formula 4, and 10-20 parts of the monomer with the structure shown in Formula 5.

[0017] Preferably, according to mass parts, the constituent monomers include: 40-66 parts of the monomer with the structure shown in Formula 1, 12-20 parts of the monomer with the structure shown in Formula 2, 5-10 parts of the monomer with the structure shown in Formula 3, 8-15 parts of the monomer with the structure shown in Formula 4, and 12-18 parts of the monomer with the structure shown in Formula 5.

[0018] The high-temperature retarder as described above, wherein the substituent in the alkyl group includes at least one selected from hydroxyl, alkenyl, alkynyl, and carboxyl groups;

[0019] And / or, the alkyl group is a C1 to C10 alkyl group.

[0020] The high-temperature resistant retarder as described above, wherein R1 is H, and / or, R2 is H, and / or, R3 is H, and / or, R4 is H, and / or, R5 is H.

[0021] A second aspect of this invention provides a method for preparing the high-temperature resistant retarder of the first aspect, comprising the following steps:

[0022] The raw materials, including the monomers with the structure shown in Formula 1, Formula 2, Formula 3, Formula 4 and Formula 5, are mixed with deionized water to obtain a mixed system.

[0023] After adjusting the pH of the mixture to 2-6, a first reaction is carried out, and an initiator is added during the first reaction. After the first reaction is completed, a second reaction is carried out to obtain the high-temperature resistant retarder. The reaction temperature of the first reaction is 50-65℃, and the holding time is 20-30 min. The temperature of the second reaction is 70-90℃, and the holding time is 1.5-4 h.

[0024] In the preparation method of the high-temperature resistant retarder as described above, the mass ratio of the raw material to the deionized water is (20~40):100;

[0025] And / or, the mass ratio of the initiator to the raw material is (0.4~1.8):100.

[0026] The preparation method of the high-temperature resistant retarder as described above, wherein the first reaction is carried out under stirring conditions, and the stirring speed is 50~300 rpm;

[0027] And / or, the second reaction is carried out under stirring conditions, wherein the stirring speed is 50~300 rpm.

[0028] The preparation method of the high-temperature resistant retarder as described above, wherein the initiator includes at least one of potassium persulfate, ammonium persulfate, hydrogen peroxide, and azobisisobutyrazoline hydrochloride.

[0029] A third aspect of the present invention provides a high-temperature cement slurry, wherein the high-temperature cement slurry includes the high-temperature resistant retarder described in the first aspect, or the high-temperature resistant retarder prepared by the preparation method described in the second aspect.

[0030] The high-temperature cement slurry as described above, wherein the high-temperature cement slurry comprises cement, and the high-temperature resistant retarder accounts for 0.5~15% of the mass of the cement.

[0031] The high-temperature retarder in this invention is obtained by polymerizing monomers with structures shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5. Through optimization of molecular structure, effective intervention of heat-resistant groups, and rigid modification of molecular chains, the high-temperature resistance of the retarder polymer is effectively improved, which can effectively extend the thickening time of cement slurry at high temperatures. Attached Figure Description

[0032] Figure 1 This is a thickening curve of the cement slurry in Example 1 of the present invention at 240°C and 130MPa;

[0033] Figure 2 This is a thickening curve of the cement slurry in Comparative Example 1 of the present invention at 240°C and 130MPa. Detailed Implementation

[0034] 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.

[0035] With the increasing number of deep and ultra-deep wells, deep and ultra-deep formations have become an important area for increasing oil and gas reserves and production. However, as well depth gradually increases, the bottom-hole temperature gradually rises. The existing "Jiantan 1 well" has a bottom-hole temperature that can reach up to 235℃, resulting in a large temperature difference between the bottom-hole temperature and the upper part of the wellbore. In actual drilling operations, in order to ensure the safe construction and subsequent profitable development of deep and ultra-deep oil and gas wells, it is often necessary to inject cement into the annular space between the wellbore and the casing for cementing. Therefore, effectively controlling the thickening time of the cement slurry system under high-temperature conditions is the key to improving the safety of cementing operations.

[0036] Currently, the thickening time of cement slurry is typically controlled by adding retarders. The most commonly used retarder is 2-acrylamide-2-methylpropanesulfonic acid (AMPS) polymer retarders. However, these retarders generally suffer from unstable retardation effects at high temperatures and affect the settling stability of the cement slurry. The inventors discovered through analysis that the aforementioned problems may be caused by the fact that conventional AMPS polymer retarders are prone to conformational changes and molecular chain breakage under ultra-high temperature environments, leading to performance failure and an inability to efficiently control the thickening time of the cement slurry. This can also deteriorate the overall performance of the cement slurry, severely impacting its workability.

[0037] Based on the above analysis, the first aspect of the present invention provides a high-temperature resistant retarder, wherein the constituent monomers of the high-temperature resistant retarder include: monomers with the structure shown in Formula 1, monomers with the structure shown in Formula 2, monomers with the structure shown in Formula 3, monomers with the structure shown in Formula 4, and monomers with the structure shown in Formula 5.

[0038]

[0039] Formula 1 Formula 2 Formula 3

[0040]

[0041] Formula 4 and Formula 5;

[0042] R1, R2, R3, R4, and R5 in Formulas 1, 2, 3, 4, and 5 may be the same or different, and each is independently selected from H or substituted or unsubstituted C1 to C30 alkyl groups; X includes any one of H, Na, and K.

[0043] In this invention, "C1-C30 alkyl" refers to saturated straight-chain alkanes or saturated branched alkanes containing 1-30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0044] This invention does not specifically limit the type and position of substituents in C1-C30 alkyl groups. Any hydrogen atom in the alkyl group can be replaced by a substituent, and the number of substituents is not limited.

[0045] The present invention does not specifically limit the source of the monomers shown in Formula 1, Formula 2, Formula 3, Formula 4 and Formula 5, and can use commercially available products or products prepared by conventional preparation methods known to those skilled in the art.

[0046] The high-temperature retarder of this invention is obtained by polymerizing raw materials including the above-mentioned monomers. The sulfonate groups, carboxyl groups and hydroxyl groups included in the retarder can react with calcium ions in cement slurry simultaneously, effectively adsorbing cement particles, preventing cement particles from agglomerating too quickly, and delaying the thickening and solidification of cement slurry. At the same time, the five-membered ring and amide groups of the amide monomer side chains can form a hyperconjugated structure, which can effectively increase the rigidity of the polymer molecular chain, have high thermal energy, and make the molecular weight less prone to breakage, giving the retarder high high-temperature resistance, which can effectively improve the thickening time of cement slurry at ultra-high temperature (not lower than 205℃) and improve the retardation effect.

[0047] Furthermore, the high-temperature resistant retarder in this invention exhibits a good linear relationship with temperature and dosage, effectively controlling the thickening time of the cement slurry system under high-temperature conditions. It also shows good compatibility with other admixtures, has minimal impact on the mechanical properties of the cement paste, and is beneficial for improving the overall performance of the ultra-high temperature cement slurry system. Simultaneously, the retarder of this invention is highly applicable and adaptable, suitable for various types of cement slurry systems, including conventional density, low density, and high density systems. This effectively ensures cementing construction safety, reduces cementing operation risks, and meets the cementing technical requirements of deep wells, ultra-deep wells, and high-temperature, high-pressure gas wells under complex environments with large temperature differences in long cementing sections.

[0048] To further improve the high-temperature resistance and retarding performance of the retarder, it is necessary to control the proportion of the monomers in the retarder.

[0049] In one specific embodiment, the monomers comprise, by mass parts, 32 to 76 parts of the monomer with the structure shown in Formula 1, 8 to 24 parts of the monomer with the structure shown in Formula 2, 2 to 12 parts of the monomer with the structure shown in Formula 3, 5 to 20 parts of the monomer with the structure shown in Formula 4, and 10 to 20 parts of the monomer with the structure shown in Formula 5.

[0050] Preferably, according to the mass fractions, the monomers comprise: 40-66 parts of the monomer with the structure shown in Formula 1, 12-20 parts of the monomer with the structure shown in Formula 2, 5-10 parts of the monomer with the structure shown in Formula 3, 8-15 parts of the monomer with the structure shown in Formula 4, and 12-18 parts of the monomer with the structure shown in Formula 5.

[0051] When the mass fraction of each monomer in the composition is within the aforementioned range, the retarder exhibits good structural stability under high temperature conditions and can effectively extend the thickening time of cement slurry, demonstrating excellent overall performance.

[0052] For example, the mass parts of the monomers constituting the structure shown in Formula 1 in the monomer are 32, 36, 40, 44, 48, 52, 56, 60, 64 or 68, 72 or 76 parts, according to the mass parts.

[0053] For example, the number of parts by mass of the monomers constituting the structure shown in Formula 2 in the monomer is 8, 10, 12, 14, 16, 18, 20, 22 or 24.

[0054] For example, the number of parts by mass of the monomers that make up the structure shown in Formula 3 in the monomer is 2, 4, 6, 8, 10 or 12.

[0055] For example, the number of parts by mass of the monomers constituting the structure shown in Formula 4 in the monomer is 5, 8, 11, 14, 17 or 20.

[0056] For example, the number of parts by mass of the monomers constituting the structure shown in Formula 5 in the monomer is 10, 12, 14, 16, 18 or 20.

[0057] In one specific embodiment, the substituent in the alkyl group includes at least one selected from hydroxyl, alkenyl, alkynyl, and carboxyl groups. This can further improve the side chain structure of the retarder molecule and enhance its stability under high and ultra-high temperature environments.

[0058] In one specific embodiment, the alkyl group is a C1-C10 alkyl group, more preferably a C1-C4 alkyl group. In this case, the viscosity of the retarder is easier to control, which helps to ensure the dispersibility and stability of the retarder in the cement paste, thereby improving the retarding effect.

[0059] In one specific embodiment, R1 is H, R2 is H, R3 is H, R4 is H, and R5 is H. Specifically, when R1 is H, the monomer of the structure shown in Formula 1 is 2-acrylamido-2-methylpropanesulfonic acid; when R2 is H, the monomer of the structure shown in Formula 2 is itaconic acid; when R3 is H, the monomer of the structure shown in Formula 3 is N,N-dimethylacrylamide; when R4 is H, the monomer of the structure shown in Formula 4 is N-vinylpyrrolidone; and when R5 is H, the monomer of the structure shown in Formula 5 is 3-allyloxy-2-hydroxy-1-propanesulfonate.

[0060] A second aspect of this invention provides a method for preparing the high-temperature resistant retarder of the first aspect, comprising the following steps:

[0061] The raw materials, including the monomers with the structure shown in Formula 1, Formula 2, Formula 3, Formula 4 and Formula 5, are mixed with deionized water to obtain a mixed system.

[0062] After adjusting the pH of the mixed system to 2-6, the first reaction is carried out, and an initiator is added during the first reaction. After the first reaction is completed, the second reaction is carried out to obtain a high-temperature resistant retarder. The reaction temperature of the first reaction is 50-65℃ and the holding time is 20-30 min. The temperature of the second reaction is 70-90℃ and the holding time is 1.5-4 h.

[0063] Specifically, according to the set mass ratio, the raw materials including the monomers shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5 are added to deionized water and mixed evenly to obtain a mixed system. The pH of the mixed system is adjusted to pH=2~6 and then the temperature is raised to the temperature required for the first reaction, 50~65℃. At this temperature, the initiator is added and the reaction is maintained for 20~30 minutes. After the first reaction is completed, the temperature of the reaction system is raised to 70~90℃ and the reaction is maintained for 1.5~4 hours. After the reaction is completed, a high-temperature resistant retarder is obtained.

[0064] This invention does not impose specific limitations on the mixing method; conventional methods in the art can be used for mixing, as long as the monomers in the mixture are uniformly mixed. For example, stirring can be used for mixing. This invention does not impose specific limitations on the stirring speed; a suitable stirring speed can be selected according to the actual situation.

[0065] This invention does not specifically limit the method of pH adjustment; conventional methods in the art can be used. For example, pH can be adjusted by adding an alkaline solution to the mixture; the alkaline solution can be an aqueous sodium hydroxide solution. This invention also does not specifically limit the concentration of the alkaline solution, as long as it can effectively adjust the pH of the mixture to between 2 and 6.

[0066] This invention does not specifically limit the heating rate for the first and second reactions; a suitable heating rate can be selected according to the actual situation. For example, the heating rate is 1~5℃ / min.

[0067] The present invention does not specifically limit the method of adding the initiator. For example, the initiator can be dissolved in deionized water to obtain an initiator aqueous solution, and the initiator aqueous solution can be added dropwise to the mixed system.

[0068] The present invention does not specifically limit the dropping rate of the initiator aqueous solution. A suitable dropping rate can be selected according to the actual situation. For example, the dropping rate is 5~10 mL / min.

[0069] The present invention does not specifically limit the mass fraction of the monomers shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5; furthermore, the retarding effect of the retarder can be further adjusted by controlling the mass fraction of the aforementioned five monomers.

[0070] This invention does not impose a specific limit on the ratio of raw materials including the aforementioned monomers to deionized water; a suitable ratio can be selected according to the actual situation.

[0071] The present invention does not impose a specific limit on the ratio of the initiator to the raw materials including the above-mentioned monomers, and an appropriate ratio can be selected according to the actual situation.

[0072] This invention does not specifically limit the type of initiator; a suitable initiator can be selected according to the actual situation.

[0073] The present invention does not specifically limit the source of the initiator, and can use commercially available products known to those skilled in the art or products prepared by conventional preparation methods.

[0074] The preparation method of the high-temperature resistant retarder in this invention firstly controls the polymerization rate and molecular weight of the retarder by adjusting the pH of the mixed system including the aforementioned monomers. Subsequently, the mixed system undergoes a staged heating reaction under the action of an initiator. This further controls the reaction rate and improves the regularity of the polymer. It also avoids local overheating, preventing dangerous situations such as explosive polymerization or decomposition caused by temperature runaway. Furthermore, it reduces the occurrence of side reactions and improves the selectivity and yield of the target product (retarder). The sulfonate groups, carboxyl groups, and hydroxyl groups in this high-temperature resistant retarder can adsorb cement particles, forming strong forces to prevent excessively rapid agglomeration of cement particles and delay the thickening and solidification of cement slurry. Simultaneously, the five-membered rings and amide groups on the side chains of the amide monomers can form a hyperconjugated structure, effectively increasing the rigidity of the polymer molecular chain and significantly improving the high-temperature resistance of the retarder. This significantly increases the thickening time of cement slurry at ultra-high temperatures (not lower than 205°C) and enhances the retarding effect.

[0075] Furthermore, the high-temperature resistant retarder of this invention has a simple preparation method, mild reaction conditions, is green, safe and environmentally friendly, and has low raw material and processing costs, making it potential for industrial production and large-scale application.

[0076] Furthermore, the mass ratio of raw materials to deionized water and the mass ratio of initiator to raw materials during the reaction process have a certain impact on the molecular weight and viscosity of the retarder.

[0077] If the mass ratio of raw materials to deionized water is too high, the molecular weight and viscosity of the retarder will be too high, which will reduce its dispersibility in the cement paste, leading to an increase in the initial consistency of the cement paste and affecting its flowability and other construction properties. If the mass ratio of raw materials to deionized water is too low, the molecular weight and viscosity of the retarder may be too low, which will increase production and usage costs.

[0078] The mass ratio of initiator to raw materials directly affects the polymerization rate. A high initiator-to-raw material ratio accelerates the polymerization rate and increases free radicals, thereby reducing the molecular weight of the retarder and affecting its stability at high temperatures. Furthermore, it may pose a risk of monomer burst polymerization, leading to safety accidents. Conversely, a low initiator-to-raw material ratio may result in a slow reaction, higher molecular weight, lower branching and cross-linking levels, or even difficulty in initiating the polymerization reaction, making it impossible to obtain a high-performance retarder. Therefore, further control of both ratios is necessary.

[0079] In one specific embodiment, the mass ratio of raw material to deionized water is (20~40):100. Within this range, the mass ratio of raw material to deionized water is suitable, resulting in a retarder with appropriate molecular weight and viscosity, which is beneficial for improving the dispersibility and stability of the retarder in cement paste, thereby enhancing the retarding effect of the retarder.

[0080] For example, the mass ratio of raw materials to deionized water is 20:100, 22:100, 24:100, 26:100, 28:100, 30:100, 32:100, 34:100, 36:100, 38:100 or 40:100.

[0081] In one specific embodiment, the mass ratio of initiator to raw material is (0.4~1.8):100. Within this range, the mass ratio of initiator to raw material is suitable, resulting in a retarder with appropriate molecular weight and viscosity. This is beneficial for improving the dispersibility of the retarder in cement paste and its stability under high-temperature conditions, thereby enhancing the retarding effect of the retarder.

[0082] For example, the mass ratio of initiator to raw material is 0.4:100, 0.6:100, 0.8:100, 1.0:100, 1.2:100, 1.4:100, 1.6:100 or 1.8:100.

[0083] Furthermore, to make the reaction more complete and uniform, stirring can be carried out during the reaction process; and the stirring speed has a great influence on the polymerization reaction. A suitable stirring speed can not only avoid the reaction runaway and the occurrence of side reactions, but also prevent uneven heat and mass transfer in the reaction system, which would affect the reaction rate and the molecular weight uniformity of the reaction product retarder.

[0084] In one specific embodiment, the first reaction is carried out under stirring conditions at a stirring speed of 50-300 rpm; the second reaction is carried out under stirring conditions at a stirring speed of 50-300 rpm. Within this range, the reaction can be carried out under relatively mild conditions, which not only allows the monomers to react fully but also prevents side reactions or even thermal runaway, thus facilitating the formation of a retarder with a relatively uniform molecular weight.

[0085] For example, in the first reaction, the stirring speed is 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm or 300 rpm; in the second reaction, the stirring speed is 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm or 300 rpm.

[0086] In one specific embodiment, the initiator includes at least one selected from potassium persulfate, ammonium persulfate, hydrogen peroxide, and azobisisobutyrazoline hydrochloride. When the initiator is a mixture of the aforementioned compounds, the present invention does not specifically limit the proportion of each compound in the mixture.

[0087] A third aspect of the present invention provides a high-temperature cement slurry comprising the high-temperature resistant retarder of the first aspect, or the high-temperature resistant retarder prepared by the preparation method of the second aspect. Because the cement slurry comprises the aforementioned high-temperature resistant retarder, it can achieve a longer thickening time at high temperatures.

[0088] In one specific embodiment, the high-temperature cement slurry includes cement, and the high-temperature resistant retarder accounts for 0.5% to 15% of the cement by mass. Within this range, it not only plays a role in retarding the setting process, but also avoids the cement slurry taking too long to develop strength or even failing to develop strength at low temperatures due to excessive content. This can improve the safety and quality of cementing in deep wells and ultra-deep wells with long cementing sections.

[0089] For example, the high-temperature resistant retarder accounts for 0.5%, 1%, 3%, 5%, 7%, 9%, 12%, or 15% of the cement by mass.

[0090] The high-temperature retarder of the present invention will be described in detail below through specific embodiments.

[0091] Example 1

[0092] 1) Weigh out 63.6 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 16 parts by weight of itaconic acid, 6.4 parts by weight of N,N-dimethylacrylamide, 14 parts by weight of N-vinylpyrrolidone, and 12 parts by weight of 3-allyloxy-2-hydroxy-1-propanesulfonic acid. Dissolve the aforementioned monomers in 360 parts by weight of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 4-5 using sodium hydroxide.

[0093] 2) The above mixture was heated to 60°C at a stirring rate of 200 r / min and a heating rate of 2°C / min. 0.8 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 5 mL / min. After reacting for 30 min, the reaction system was heated to 75°C at a heating rate of 0.5°C / min. The reaction was continued at this temperature for 3 h. After naturally cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight-average molecular weight of the retarder was found to be 120,000.

[0094] Example 2

[0095] 1) Weigh out 50.4 parts of 2-acrylamido-2-methylpropanesulfonic acid, 14 parts of itaconic acid, 8.6 parts of N,N-dimethylacrylamide, 12 parts of N-vinylpyrrolidone, and 15 parts of 3-allyloxy-2-hydroxy-1-propanesulfonic acid according to the mass fractions. Dissolve the aforementioned monomers in 320 parts of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 4-5 using sodium hydroxide.

[0096] 2) The above mixture was heated to 50°C at a stirring rate of 50 r / min and a heating rate of 2°C / min. 0.58 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 5 mL / min. After reacting for 20 min, the reaction system was heated to 70°C at a heating rate of 0.5°C / min. The reaction was continued at this temperature for 2.5 h. After naturally cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight average molecular weight of the retarder was found to be 200,000.

[0097] Example 3

[0098] 1) Weigh out 65.8 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 14 parts by weight of itaconic acid, 5.2 parts by weight of N,N-dimethylacrylamide, 15 parts by weight of N-vinylpyrrolidone, and 14 parts by weight of 3-allyloxy-2-hydroxy-1-propanesulfonic acid. Dissolve the aforementioned monomers in 400 parts by weight of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 4-5 using sodium hydroxide.

[0099] 2) The above mixture was heated to 55°C at a stirring rate of 100 r / min and a heating rate of 2°C / min. 1.2 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 5 mL / min. After reacting for 25 min, the reaction system was heated to 80°C at a heating rate of 0.5°C / min. The reaction was continued at this temperature for 2 h. After naturally cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight average molecular weight of the retarder was found to be 100,000.

[0100] Example 4

[0101] 1) Weigh out 63.6 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 16 parts by weight of itaconic acid, 6.4 parts by weight of N,N-dimethylacrylamide, 14 parts by weight of N-vinylpyrrolidone, and 13 parts by weight of 3-allyloxy-2-hydroxy-1-propanesulfonic acid. Dissolve the aforementioned monomers in 360 parts by weight of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 2-3 using sodium hydroxide.

[0102] 2) The above mixture was heated to 65°C at a stirring rate of 150 r / min and a heating rate of 3°C / min. 0.8 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 8 mL / min. After reacting for 20 min, the reaction system was heated to 90°C at a heating rate of 0.5°C / min. The reaction was continued at this temperature for 1.5 h. After naturally cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight average molecular weight of the retarder was found to be 130,000.

[0103] Example 5

[0104] 1) Weigh out 40.6 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 20 parts by weight of itaconic acid, 9.4 parts by weight of N,N-dimethylacrylamide, 10 parts by weight of N-vinylpyrrolidone, and 18 parts by weight of 3-allyloxy-2-hydroxy-1-propanesulfonic acid. Dissolve the aforementioned monomers in 360 parts by weight of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 4-5 using sodium hydroxide.

[0105] 2) The above mixture was heated to 60°C at a stirring rate of 200 r / min and a heating rate of 2 / min. 1.2 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 6 mL / min. After reacting for 30 min, the reaction system was heated to 75°C at a heating rate of 0.5°C / min. The reaction was continued at this temperature for 4 h. After naturally cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight average molecular weight of the retarder was found to be 90,000.

[0106] Example 6

[0107] 1) Weigh out 63.6 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 16 parts by weight of itaconic acid, 6.4 parts by weight of N,N-dimethylacrylamide, 14 parts by weight of N-vinylpyrrolidone, and 12 parts by weight of 3-allyloxy-2-hydroxy-1-propanesulfonic acid. Dissolve the aforementioned monomers in 360 parts by weight of deionized water and mix them evenly with a stirrer to obtain a mixed system. Then adjust the pH value of the mixed system to 4-5 using sodium hydroxide.

[0108] 2) The above mixture was heated to 60°C at a stirring rate of 200 r / min and a heating rate of 4°C / min. 0.8 parts of potassium persulfate were dissolved in 10 parts of deionized water to obtain an initiator aqueous solution. The initiator aqueous solution was added to the above mixture at a dropping rate of 6 mL / min and reacted for 30 min. Then the reaction system was heated to 85°C at a heating rate of 0.5°C / min and reacted at this temperature for 4 h. After natural cooling to room temperature, the high-temperature resistant retarder of this embodiment was obtained. The weight average molecular weight of the retarder was found to be 130,000.

[0109] Example 7

[0110] The preparation method of the retarder in this embodiment is basically the same as that in Example 1. The difference is that in step 1), 32.6 parts of 2-acrylamido-2-methylpropanesulfonic acid, 8.2 parts of itaconic acid, 2.8 parts of N,N-dimethylacrylamide, 5.9 parts of N-vinylpyrrolidone, and 10 parts of 3-allyloxy-2-hydroxy-1-propanesulfonic acid are weighed according to the mass fractions. The aforementioned monomers are dissolved in 192 parts of deionized water and mixed evenly with a stirrer to obtain a mixed system. Then, the pH value of the mixed system is adjusted to 4-5 using sodium hydroxide.

[0111] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 80,000.

[0112] Example 8

[0113] The preparation method of the retarder in this embodiment is basically the same as that in Example 1. The difference is that in step 1), 75.6 parts of 2-acrylamido-2-methylpropanesulfonic acid, 23.2 parts of itaconic acid, 11.1 parts of N,N-dimethylacrylamide, 19.9 parts of N-vinylpyrrolidone, and 20 parts of 3-allyloxy-2-hydroxy-1-propanesulfonic acid are weighed according to the mass fractions. The aforementioned monomers are dissolved in 380 parts of deionized water and mixed evenly with a stirrer to obtain a mixed system. Then, the pH value of the mixed system is adjusted to 4-5 using sodium hydroxide.

[0114] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 150,000.

[0115] Example 9

[0116] The preparation method of the retarder in this embodiment is basically the same as that in Example 1, except that in step 1), 80.5 parts of 2-acrylamido-2-methylpropanesulfonic acid are used.

[0117] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 140,000.

[0118] Example 10

[0119] The preparation method of the retarder in this embodiment is basically the same as that in Example 1, except that in step 1), the amount of itaconic acid is 26 parts and the pH of the system is 4-5.

[0120] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 130,000.

[0121] Example 11

[0122] The preparation method of the retarder in this embodiment is basically the same as that in Example 1, except that in step 1), N,N-dimethylacrylamide is 18 parts.

[0123] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 170,000.

[0124] Example 12

[0125] The preparation method of the retarder in this embodiment is basically the same as that in Example 1, except that in step 1), N-vinylpyrrolidone is 24 parts.

[0126] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 130,000.

[0127] Example 13

[0128] The preparation method of the retarder in this embodiment is basically the same as that in Example 1, except that in step 1), 3-allyloxy-2-hydroxy-1-propanesulfonic acid is 25 parts.

[0129] Tests showed that the weight-average molecular weight of the high-temperature retarder in this embodiment is 120,000.

[0130] Comparative Example 1

[0131] The preparation method of the retarder in this comparative example is basically the same as that in Example 1, except that in step 1), N-vinylpyrrolidone is not included in the reaction monomer; at the same time, sodium hydroxide is used to adjust the pH of the mixed system to 4-5.

[0132] The weight-average molecular weight of the retarder in this comparative example was found to be 130,000, according to the test results.

[0133] Comparative Example 2

[0134] The preparation method of the retarder in this comparative example is basically the same as that in Example 1, except that in step 1), N,N-dimethylacrylamide is not included in the reaction monomer; at the same time, sodium hydroxide is used to adjust the pH of the mixed system to 4-5.

[0135] The weight-average molecular weight of the retarder in this comparative example was found to be 70,000, according to the test results.

[0136] Comparative Example 3

[0137] The preparation method of the retarder in this comparative example is basically the same as that in Example 1, except that in step 1), N-vinylpyrrolidone and N,N-dimethylacrylamide are not included in the reaction monomers; at the same time, sodium hydroxide is used to adjust the pH of the mixed system to 4~5.

[0138] The weight-average molecular weight of the retarder in this comparative example was found to be 60,000, according to the test results.

[0139] Comparative Example 4

[0140] The preparation method of the retarder in this comparative example is basically the same as that in Example 1, except that in step 1), itaconic acid is not included in the reaction monomer; at the same time, sodium hydroxide is used to adjust the pH of the mixed system to 4-5.

[0141] The weight-average molecular weight of the retarder in this comparative example was found to be 90,000, according to the test results.

[0142] Comparative Example 5

[0143] The preparation method of the retarder in this comparative example is basically the same as that in Example 1. The difference is that in step 1), 3-allyloxy-2-hydroxy-1-propanesulfonic acid is not included in the reaction monomer; at the same time, sodium hydroxide is used to adjust the pH of the mixed system to 4~5.

[0144] The weight-average molecular weight of the retarder in this comparative example was found to be 130,000, according to the test results.

[0145] Comparative Example 6

[0146] The preparation method of the retarder in this comparative example is basically the same as that in Example 1. The difference is that in step 2), after the initiator aqueous solution is added to the above-mentioned mixed system at a dropping rate of 5 mL / min, the mixed system is allowed to react at 60°C for 3.5 h, and finally naturally cooled to room temperature to obtain the retarder of this example.

[0147] The weight-average molecular weight of the retarder in this comparative example was found to be 60,000, according to the test results.

[0148] Test case

[0149] According to the relevant provisions of the petroleum and natural gas industry standards SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder" and GB / T 19139-2012 "Test Methods for Oil Well Cement", the high-temperature resistant retarders prepared in Examples 1-13 and Comparative Examples 1-6 were mixed into cement slurry. The thickening performance, fluidity, rheological properties, API water loss, stability, and compressive strength of the cement slurry system were comprehensively evaluated. The main experimental instruments included:

[0150] 30-60 type corrugated agitator, product of Shenyang Tiger Petroleum Instrument Equipment Manufacturing Co., Ltd.; 8240 type high pressure thickener, product of American Chemdale Industrial Instruments Co., Ltd.; TG-71 type water loss meter, product of Shenyang Tiger Petroleum Instrument Equipment Manufacturing Co., Ltd.; YJ-2001 uniform loading pressure testing machine, product of Shenyang Tiger Petroleum Instrument Equipment Manufacturing Co., Ltd.

[0151] The cement slurry used includes the following components by weight percentage:

[0152] Cement slurry 1: Jiahua G-grade oil well cement (HSR) + silica fume + microsilica + fluid loss reducer + dispersant + high-temperature stabilizer + water. Silica fume accounts for 35% of the cement mass, microsilica for 3%, fluid loss reducer for 4%, dispersant for 1.2%, and high-temperature stabilizer for 3%. The cement slurry density is 1.89 g / cm³. 3 It is mainly used to evaluate the performance of cement paste at temperatures of 110~180℃;

[0153] Cement slurry 2: Jiahua G-grade oil well cement (HSR) + silica fume + microsilica + anti-fading material + fluid loss reducer + dispersant + high-temperature stabilizer + water. Silica fume accounts for 50% of the cement mass, microsilica for 3%, anti-fading material for 8%, fluid loss reducer for 5%, dispersant for 1.6%, and high-temperature stabilizer for 5%. The cement slurry density is 1.89 g / cm³. 3 It is mainly used to evaluate the performance of cement paste at temperatures of 200~240℃.

[0154] Among them, the silica powder is 200-mesh quartz sand with a microsilica particle size range of 0.1~0.3μm, the water loss reducing agent is AMPS-type multi-component copolymer product DRF-3L, the dispersant is sulfonated aldehyde-ketone condensate DRS-1S (weight average molecular weight of 30,000~40,000), the high temperature stabilizer is AMPS-type multi-component copolymer and ultrafine mineral material compound product DRK-5S, and the anti-fading material is high aluminate inorganic mineral material FST-1, all of which are from China Petroleum Engineering Technology Research Institute Co., Ltd.

[0155] The test results are shown in Tables 1-3. Figure 1 and Figure 2 .

[0156] Table 1

[0157]

[0158] As shown in Table 1:

[0159] Compared to Comparative Examples 1-6, the cement slurries in Examples 1-13 exhibited better settling stability and water loss performance at different temperatures; the API water loss of the cement slurry system including the retarder in Example 1 was <50 mL, and the settling stability was ≤0.05 g / cm³. 3 This indicates that the retarder in this invention helps cement particles in cement slurry maintain good dispersibility, does not damage the stability of cement slurry under different temperature environments, and has no adverse effect on the water loss reduction performance of cement slurry.

[0160] Table 2

[0161]

[0162] Note: * indicates that the cement stone strength curing temperature is the experimental temperature.

[0163] As shown in Table 2:

[0164] The retarders in Examples 1-13 have little impact on the strength of cement stone. When the cement stone was cured at different temperatures ranging from 120 to 240°C for 1 day, 2 days, and 7 days, it exhibited high strength, meeting the requirements for cementing operations. However, the cement stone with the added retarder showed relatively good initial compressive strength at high temperatures, but its compressive strength tended to deteriorate with prolonged high-temperature curing time. This could pose a potential threat to the safety of cementing operations and long-term safe and efficient operation. This indicates that the retarder in this invention has good compatibility with other admixtures in cement slurry (such as fluid loss reducers, dispersants, and high-temperature stabilizers), and has minimal impact on the system's settling stability and the mechanical strength of the cement stone.

[0165] Table 3

[0166]

[0167] As shown in Table 3:

[0168] Within the temperature range of 120~240℃, the retarder prepared in Example 1 can effectively prolong the thickening time of cement slurry. By changing the dosage of the retarder, the thickening time of cement slurry can be linearly adjusted within the range of 200~600 min, and it shows a good linear relationship with temperature and dosage (i.e., the mass percentage of retarder in cement). Meanwhile, compared with Comparative Examples 1-6, the retarders in Examples 2-13 all exhibit good high-temperature setting regulation performance and temperature adaptability, which helps to improve the stability of cement slurry under high-temperature conditions and achieve efficient control of ultra-high temperature cement slurry.

[0169] Figure 1 This is a thickening curve of the cement slurry in Example 1 at 240℃ and 130MPa. Figure 1 In the test, the cement slurry thickening curve was normal, with no abnormal gelation phenomena such as bulging or "core encapsulation". The initial consistency was 23 Bc. Although the slurry consistency decreased with increasing temperature, it eventually remained at around 10 Bc. The thickening time of the system was 429 min, and the thickening curve was basically "right angle".

[0170] Figure 2 The thickening curve of the cement slurry in Comparative Example 1 at 240℃ and 130MPa is shown in the figure. Figure 2 It can be seen that the initial consistency of the cement slurry is 28 Bc, and the consistency gradually decreases with the increase of temperature. The thickening time is 204 min, indicating that the retarder prepared in Comparative Example 1 has lost its retarding performance at 240℃.

[0171] 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 high-temperature resistant retarder, characterized in that, The high-temperature resistant retarder comprises monomers with the structure shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5. Formula 1 Formula 2 Formula 3 Formula 4 and Formula 5; R1, R2, R3, R4, and R5 in Formulas 1, 2, 3, 4, and 5 may be the same or different, and each is independently selected from H or substituted or unsubstituted C1 to C30 alkyl groups; X includes any one of H, Na, and K.

2. The high-temperature resistant retarder according to claim 1, characterized in that, According to the mass fractions, the constituent monomers include: 32 to 76 parts of the monomer with the structure shown in Formula 1, 8 to 24 parts of the monomer with the structure shown in Formula 2, 2 to 12 parts of the monomer with the structure shown in Formula 3, 5 to 20 parts of the monomer with the structure shown in Formula 4, and 10 to 20 parts of the monomer with the structure shown in Formula 5. Preferably, according to mass parts, the constituent monomers include: 40-66 parts of the monomer with the structure shown in Formula 1, 12-20 parts of the monomer with the structure shown in Formula 2, 5-10 parts of the monomer with the structure shown in Formula 3, 8-15 parts of the monomer with the structure shown in Formula 4, and 12-18 parts of the monomer with the structure shown in Formula 5.

3. The high-temperature resistant retarder according to claim 1 or 2, characterized in that, The substituents in the alkyl group include at least one selected from hydroxyl, alkenyl, alkynyl, and carboxyl groups; And / or, the alkyl group is a C1 to C10 alkyl group.

4. The high-temperature resistant retarder according to claim 3, characterized in that, R1 is H, and / or, R2 is H, and / or, R3 is H, and / or, R4 is H, and / or, R5 is H.

5. A method for preparing the high-temperature resistant retarder according to any one of claims 1-4, characterized in that, Includes the following steps: The raw materials, including the monomers with the structure shown in Formula 1, Formula 2, Formula 3, Formula 4 and Formula 5, are mixed with deionized water to obtain a mixed system. After adjusting the pH of the mixture to 2-6, a first reaction is carried out, and an initiator is added during the first reaction. After the first reaction is completed, a second reaction is carried out to obtain the high-temperature resistant retarder. The reaction temperature of the first reaction is 50-65℃, and the holding time is 20-30 min. The temperature of the second reaction is 70-90℃, and the holding time is 1.5-4 h.

6. The method for preparing the high-temperature resistant retarder according to claim 5, characterized in that, The mass ratio of the raw material to the deionized water is (20~40):100; And / or, the mass ratio of the initiator to the raw material is (0.4~1.8):

100.

7. The method for preparing the high-temperature resistant retarder according to claim 5 or 6, characterized in that, The first reaction is carried out under stirring conditions, wherein the stirring speed is 50~300 rpm; And / or, the second reaction is carried out under stirring conditions, wherein the stirring speed is 50~300 rpm.

8. The method for preparing the high-temperature resistant retarder according to any one of claims 5-7, characterized in that, The initiator includes at least one of potassium persulfate, ammonium persulfate, hydrogen peroxide, and azobisisobutyrazoline hydrochloride.

9. A high-temperature cement slurry, characterized in that, The high-temperature cement slurry includes the high-temperature resistant retarder as described in any one of claims 1-4, or the high-temperature resistant retarder prepared by the preparation method described in any one of claims 5-8.

10. The high-temperature cement slurry according to claim 9, characterized in that, The high-temperature cement slurry includes cement, and the high-temperature resistant retarder accounts for 0.5-15% of the mass of the cement.

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