An ultra-high temperature cement slurry suspending stabilizer, a preparation method and application thereof

Abstract

The application provides an ultra-high temperature cement slurry suspension stabilizer and a preparation method and application thereof. The suspension stabilizer comprises a polymer prepared from 2-acrylamido-2-methylpropanesulfonic acid monomer, a vinyl multicyclic ring monomer, an unsaturated acrylamide monomer, an unsaturated cationic monomer and an unsaturated surfactant monomer. The preparation method of the suspension stabilizer comprises: polymerizing the 2-acrylamido-2-methylpropanesulfonic acid monomer, the vinyl multicyclic ring monomer, the unsaturated acrylamide monomer, the unsaturated cationic monomer and the unsaturated surfactant monomer in the presence of an initiator and a solvent to obtain the ultra-high temperature cement slurry suspension stabilizer. The application also provides application of the ultra-high temperature cement slurry suspension stabilizer as an additive of a cement slurry system for deep well and ultra-deep well cementing. The ultra-high temperature cement slurry suspension stabilizer can control the sedimentation stability of the cement slurry system at 240 DEG C to be 0.03 g / cm 3 The following.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas well cementing additives, and particularly relates to an ultrahigh-temperature cement slurry suspension stabilizer and a preparation method and application thereof. BACKGROUND

[0002] Deep and ultra-deep oil and gas resources have great potential and have become an important strategic field for increasing reserves and production of oil and gas. Oil and gas fields have successively proven deep oil and gas reservoirs above 8000m, and are moving towards 9000-10000m, with bottom hole temperatures crossing 200℃ from 180℃, and breaking through 240℃. Cementing is a key technology for ensuring well engineering quality and realizing safe and efficient development, and the quality of cementing directly relates to the success of drilling engineering and the service life of oil and gas wells. Deep and ultra-deep wells are necessary means to open deep oil and gas resources, but face complex geology and working conditions such as ultra-deep, ultra-high temperature and high pressure, and the difficulty of cementing increases sharply, and the operation risk is large. A high-performance ultra-high temperature cement slurry system is the core of ensuring the safety of cementing operations and the quality of cementing in complex deep and ultra-deep wells.

[0003] Settling stability is one of the important parameters for ensuring the comprehensive performance of a high-temperature cement slurry system, and is particularly important in deep and ultra-deep well ultra-high temperature cementing. Under high-temperature and ultra-high temperature conditions, the settling stability of the cement slurry faces severe challenges: ① the cement slurry viscosity decreases, the Brownian motion of the particles accelerates, the liquid phase suspension capacity deteriorates, and a large number of solid particles aggregate and settle; ② the system contains a large amount of polymer-based fluid loss additives and retarders, and has problems such as high-temperature thinning and even high-temperature degradation failure, which leads to a decrease in liquid phase viscosity and supporting capacity of the cement slurry, and aggravates the instability of the system; ③ the annular space of deep and ultra-deep well cementing is small, and the cementing segment is long, so the stability of the high-temperature cement slurry is extremely high, and if the cement slurry column is severely unstable, it will affect the safety and quality of cementing operations, and even cause gas channeling or cementing accidents. Therefore, improving the settling stability of the high-temperature and ultra-high temperature cementing slurry system plays a crucial role in ensuring the safety of deep and ultra-deep well cementing operations, the quality of cementing and long-term effective sealing.

[0004] The prior art has disclosed various methods to solve the above problems. CN102086386A discloses an anti-200℃ oil well cement anti-settling agent prepared by a method of aqueous phase free radical polymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylamide (AM), and N-vinylpyrrolidone (NVP). The anti-settling agent can effectively improve the high-temperature settling stability of the cement slurry, and has been successfully tested in the cementing of deep gas wells in Daqing Oilfield with a bottom hole temperature of 145℃, but it is not suitable for cementing working conditions with a bottom hole circulating temperature of 200℃ or higher. CN107629771A discloses an AMPS / DMAA / AA / NVP copolymer suspension stabilizer with a multi-branched structure, which does not thicken at low temperature and does not dilute at high temperature, but its temperature resistance is only 150℃, which cannot meet the downhole environment of deep and ultra-deep wells. CN109321219A discloses an oil well cement settling stabilizer, which introduces a hydrophobic monomer to improve the liquid viscosity by high-temperature hydrophobic bonding and phase separation, realizes low-temperature non-thickening and high-temperature thickening, and effectively solves the problem of cement slurry settling instability in deep and ultra-deep well cementing, but the use temperature is relatively low (200℃). CN114409845A provides a cement slurry suspension stabilizer resistant to 240℃ and a preparation method thereof, which uses an organic-inorganic nano-intercalation hybrid polymerization process to organically combine high molecular weight polymers with inorganic materials, and the cement slurry settling stability at 240℃ can be controlled within 0.03g / cm 3 At present, only by increasing the amount of polymer suspension stabilizer to improve the settling stability of the cement slurry system at ultra-high temperature, but often leads to serious thickening of the slurry and cannot be mixed, which is not conducive to the cementing operation of deep and ultra-deep wells.

[0005] The above-mentioned prior art has achieved certain results in improving the temperature resistance of the cement slurry system and the settling stability of the system, but most of them still cannot meet the technical requirements of the scale application of ultra-high temperature (200℃ or higher) cementing slurry in complex deep and ultra-deep wells. At present, only by increasing the amount of polymer suspension stabilizer to improve the settling stability of the cement slurry system at ultra-high temperature, but often leads to serious thickening of the slurry and cannot be mixed, which is not conducive to the cementing operation of deep and ultra-deep wells.

[0006] Therefore, it is urgent to develop an ultra-high temperature cement slurry suspension stabilizer to meet the requirements of safe operation and cementing quality in deep and ultra-deep well ultra-high temperature cementing. SUMMARY

[0007] To solve the above technical problems, the purpose of the present application is to provide an ultra-high temperature cement slurry suspension stabilizer, a preparation method and application thereof. The ultra-high temperature cement slurry suspension stabilizer of the present application can resist 240℃ high temperature, and can meet the requirements of safe operation and cementing quality in deep and ultra-deep well ultra-high temperature cementing.

[0008] To achieve the above object, the present application provides, in a first aspect, an ultra-high temperature cement slurry suspending stabilizer, which comprises a polymer prepared from 2-acrylamido-2-methylpropanesulfonic acid monomer, a vinyl multicyclic ring monomer, an unsaturated acrylamide monomer, an unsaturated cationic monomer and an unsaturated surfactant monomer containing long carbon side chains;

[0009] The mass ratio of the 2-acrylamido-2-methylpropanesulfonic acid monomer, the vinyl multicyclic ring monomer, the unsaturated acrylamide monomer, the unsaturated cationic monomer and the unsaturated surfactant monomer containing long carbon side chains is (18-25):(5-13):(15-25):(1.7-2.5):(0.5-1.5).

[0010] In the ultra-high temperature cement slurry suspending stabilizer described above, preferably, the vinyl multicyclic ring monomer comprises one or a combination of N-vinylpyrrolidone, N-vinylcaprolactam and sodium styrene sulfonate. The present application uses the vinyl multicyclic ring monomer, which is conducive to inhibiting the high-temperature hydrolysis of the molecular chain of the prepared polymer, increasing the rigidity of the molecular chain and improving the temperature resistance of the molecular structure of the polymer.

[0011] In the ultra-high temperature cement slurry suspending stabilizer described above, preferably, the unsaturated acrylamide monomer comprises one or a combination of acrylamide, diacetone acrylamide, N,N-dimethyl acrylamide and N,N-diethyl acrylamide. The present application uses the unsaturated acrylamide monomer, which can improve the temperature resistance and salt resistance of the prepared polymer.

[0012] In the ultra-high temperature cement slurry suspending stabilizer described above, preferably, the unsaturated cationic monomer comprises one or a combination of dimethyldiallylammonium chloride, acryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl trimethyl ammonium chloride. The present application uses the unsaturated cationic monomer described above, which can adjust the molecular weight of the prepared polymer, solve the problem of cement slurry setting difficulty, form an ionic association structure in the polymer solution and further improve the temperature resistance and suspending capacity of the polymer.

[0013] In the ultra-high temperature cement slurry suspending stabilizer described above, preferably, the unsaturated surfactant monomer containing long carbon side chains comprises one or a combination of hexadecyl dimethyl diallyl ammonium chloride, 2-acrylamidohexadecane sulfonic acid and 2-acrylamidododecane sulfonic acid. The present application uses the unsaturated surfactant monomer containing long carbon side chains described above, which introduces a hydrophobic group, is conducive to improving the high-temperature tackifying capacity of the prepared polymer, reducing the molecular weight of the polymer and playing a solubilizing role, which is conducive to the solution polymerization reaction.

[0014] According to the specific embodiments of the present application, preferably, the ultra-high temperature cement slurry suspending stabilizer is prepared by the following steps:

[0015] The 2-acrylamido-2-methylpropanesulfonic acid monomer, the vinyl multicyclic monomer, the unsaturated acrylamide monomer, the unsaturated cationic monomer and the unsaturated surfactant monomer with long carbon side chain are polymerized in the presence of an initiator and a solvent to obtain a polymer solution, which is the ultra-high temperature cement slurry suspending stabilizer. In some specific embodiments of the present application, the solvent can be water. In some specific embodiments of the present application, the temperature of the polymerization reaction can be 70-85℃, and the time can be 4-6h.

[0016] More preferably, the ultra-high temperature cement slurry suspending stabilizer is prepared by the following steps:

[0017] In mass parts, 18-25 parts of the 2-acrylamido-2-methylpropanesulfonic acid monomer is dissolved in 20-30 parts of water, and the pH value is adjusted to 6-7 to obtain a first mixture; 0.5-1.5 parts of the unsaturated surfactant monomer with long carbon side chain is dissolved in 120-180 parts of water, and the pH value is optionally adjusted to 6-7 to obtain a second mixture; the first mixture and the second mixture are mixed, and then 15-25 parts of the unsaturated acrylamide monomer, 1.7-2.5 parts of the unsaturated cationic monomer and 5-13 parts of the vinyl multicyclic monomer are added and stirred uniformly to obtain a third mixture; then an initiator is added to the third mixture, and a polymer solution is obtained after polymerization, which is the ultra-high temperature cement slurry suspending stabilizer.

[0018] In some specific embodiments of the present application, the pH value adjusting agent used for adjusting the pH value to 6-7 can be a conventional pH value adjusting agent in the art, which is not particularly limited in the present application.

[0019] In some specific embodiments of the present application, when the unsaturated surfactant monomer with long carbon side chain is hexadecyldimethylammonium allyl chloride, the pH value of the solution thereof in water is generally 6-7, so that it is not necessary to adjust the pH value thereof with a pH value adjusting agent; when the unsaturated surfactant monomer with long carbon side chain is 2-acrylamidohexadecane sulfonic acid and / or 2-acrylamidododecane sulfonic acid, it is generally necessary to adjust the pH value thereof to 6-7 with a pH value adjusting agent.

[0020] In some embodiments of the present application, preferably, the amount of the initiator is 0.05-0.12% of the total mass of the third mixture. Specifically, the initiator can be in the form of a solution, which is added dropwise to the third mixture. The solution of the initiator can be prepared by the following steps: dissolving 0.05-0.12% of the initiator (based on the total mass of the third mixture) in an appropriate amount of water to obtain an initiator solution. Preferably, the concentration of the initiator in the initiator solution is 0.09-0.34%.

[0021] In some embodiments of the present application, preferably, the initiator comprises one or more of a combination of ammonium persulfate, potassium persulfate, and azobisdimethylvaleronitrile hydrochloride. The addition of the initiator facilitates the polymerization reaction.

[0022] In some embodiments of the present application, preferably, the dropping speed of the initiator solution is 10-20 mL / min.

[0023] In some embodiments of the present application, preferably, during the process of adding the initiator to the third mixture, the reaction temperature is controlled to be 50-65°C, and after the addition of the initiator is completed, the reaction temperature is controlled to be 70-85°C and the reaction is performed for 4-6 h.

[0024] By controlling the dropping speed of the initiator solution, as well as the temperature and time of the polymerization reaction, the present application can ensure the smooth progress of the polymerization reaction, thereby preparing the ultra-high temperature cement slurry suspension stabilizer of the present application.

[0025] According to the embodiments of the present application, preferably, the weight average molecular weight of the polymer in the ultra-high temperature cement slurry suspension stabilizer is 1,000,000-1,400,000, and the molecular weight distribution index is 1.8-2.3.

[0026] The super-high-temperature cement slurry suspension stabilizer of the present application is a polymer suspension stabilizer prepared by solution polymerization of the above-mentioned five monomers. The super-high-temperature cement slurry suspension stabilizer of the present application uses a vinyl multivalent ring monomer, which is beneficial to inhibit the high-temperature hydrolysis of the molecular chain of the prepared polymer, increase the rigidity of the molecular chain, and improve the temperature resistance of the molecular structure of the polymer. The use of the unsaturated acrylamide monomer in the present application can improve the temperature resistance and salt resistance of the prepared polymer. The use of the unsaturated cationic monomer and the unsaturated surfactant monomer containing a long carbon side chain in the present application can increase the polymerization steric hindrance between the monomers in the solution due to the ionic bond between the unsaturated cationic monomers, so as to adjust the size, charge distribution and molecular chain conformation of the polymer molecular chain, and at the same time, can form an ionic association structure to further improve the temperature resistance and suspension capacity of the polymer. The structure of the unsaturated surfactant monomer used in the present application contains a long carbon side chain and a hydrophobic group, which can increase the solubility of the polymerized monomer, improve the temperature resistance of the prepared polymer, and form a hydrophobic association structure in the solution, thereby further improving the high-temperature suspension capacity of the polymer solution.

[0027] The super-high-temperature cement slurry suspension stabilizer of the present application improves the super-high-temperature suspension stability of the polymer by means of molecular structure optimization design, synergistic effect of anion-cation-hydrophobic multifunctional groups, effective introduction of temperature-resistant and salt-resistant groups, and molecular weight control. The anion-cation-hydrophobic multifunctional groups can adjust the spatial structure of the polymer in the solution, the anion groups and the cation groups can improve the adsorption efficiency of the polymer on the surface of the cement particles and the adaptability to the material, and the hydrophobic groups can improve the spatial association capacity of the polymer at high temperature. The coupling effect of the above-mentioned ionic association, hydrophobic association and other effects can make the polymer prepared by the present application actively adapt to the temperature change in the well and the application environment of the cement slurry, so as to achieve the effect of not excessively thickening at low temperature and not significantly diluting at high temperature. The molecular weight and its distribution of the polymer are mainly realized by the polymerization steric hindrance effect of the unsaturated cationic monomer and the unsaturated surfactant monomer containing a long carbon side chain, so as to shorten the slurry mixing time and reduce the initial consistency, and improve the field adaptability of the cement slurry and the safety of the cementing operation in deep and ultra-deep wells.

[0028] The present application provides a preparation method of the above-mentioned super-high-temperature cement slurry suspension stabilizer, which comprises the following steps:

[0029] The 2-acrylamido-2-methylpropanesulfonic acid monomer, the vinyl multivalent ring monomer, the unsaturated acrylamide monomer, the unsaturated cationic monomer and the unsaturated surfactant monomer containing a long carbon side chain with a mass ratio of (18-25):(5-13):(15-25):(1.7-2.5):(0.5-1.5) are subjected to a polymerization reaction in the presence of an initiator and a solvent to obtain a polymer solution, which is the super-high-temperature cement slurry suspension stabilizer.

[0030] In some embodiments of the present application, the solvent can be water.

[0031] In the above preparation method, preferably, the temperature of the polymerization reaction can be 70-85℃, and the time can be 4-6h.

[0032] According to the embodiments of the present application, preferably, the preparation method of the ultra-high temperature cement slurry suspension stabilizer comprises the following steps:

[0033] In mass parts, 18-25 parts of 2-acrylamido-2-methylpropanesulfonic acid monomer is dissolved in 20-30 parts of water, and the pH value is adjusted to 6-7 to obtain a first mixture; 0.5-1.5 parts of unsaturated surfactant monomer containing long carbon side chains is dissolved in 120-180 parts of water, and the pH value is optionally adjusted to 6-7 to obtain a second mixture; the first mixture and the second mixture are mixed, and then 15-25 parts of unsaturated acrylamide monomer, 1.7-2.5 parts of unsaturated cationic monomer, and 5-13 parts of vinyl multiring monomer are added and stirred uniformly to obtain a third mixture; then an initiator is added to the third mixture, and after polymerization, a polymer solution is obtained, which is the ultra-high temperature cement slurry suspension stabilizer.

[0034] In the above preparation method, the pH value adjusting agent used for adjusting the pH value to 6-7 can be a conventional pH value adjusting agent in the art, which is not particularly limited in the present application.

[0035] In the above preparation method, preferably, the amount of the initiator is 0.05-0.12% of the total mass of the third mixture. Specifically, the initiator can be in the form of a solution, which is added dropwise to the third mixture. The solution of the initiator can be prepared by the following steps: 0.05-0.12% of the initiator based on the total mass of the third mixture is dissolved in an appropriate amount of water to obtain an initiator solution. Preferably, the concentration of the initiator in the initiator solution is 0.09-0.34%.

[0036] In the above preparation method, preferably, the initiator comprises one or a combination of several of ammonium persulfate, potassium persulfate, and azobisdimethylimidazoline hydrochloride.

[0037] In the above preparation method, preferably, the dropping speed of the initiator solution is 10-20 mL / min.

[0038] In the above preparation method, preferably, during the process of adding the initiator to the third mixture, the reaction temperature is controlled to be 50-65℃, and after the addition of the initiator is completed, the reaction temperature is controlled to be 70-85℃ and the reaction is performed for 4-6h.

[0039] The third aspect of the present application provides an application of the above-mentioned ultra-high temperature cement slurry suspension stabilizer as an additive of a cement slurry system for cementing high-temperature and high-pressure gas wells, unconventional oil and gas wells, gas storage wells, deep wells, ultra-deep wells and super-deep wells.

[0040] According to the specific embodiment of the present application, in the above-mentioned application, the depth of the deep well is generally 4500-6000 m, the depth of the ultra-deep well is generally 6000-9000 m, and the depth of the super-deep well is generally more than 9000 m.

[0041] In the above-mentioned application, preferably, the addition amount of the ultra-high temperature cement slurry suspension stabilizer is 3-5 parts based on 100 parts of the cement in the cement slurry system.

[0042] According to the specific embodiment of the present application, the specific formula of the above-mentioned cement slurry system can be routinely adjusted by those skilled in the art according to the actual situation. Generally, the raw material composition of the cement slurry system includes cement 100 parts, the ultra-high temperature cement slurry suspension stabilizer of the present application 3-5 parts, strength stabilizer 15-50 parts, density regulator 0 parts to an appropriate amount, dispersant 0-3 parts, fluid loss additive 2-9 parts, retarder 0.1-9 parts, defoamer 0-0.5 parts, and water in an appropriate amount, etc. Among them, the cement can use G-grade oil well cement, the strength stabilizer, the density regulator, the dispersant, the fluid loss additive, the retarder, the defoamer, etc. can all use the conventional cement slurry system additives in the art, and the present application does not specially limit them.

[0043] The existing cement slurry suspension stabilizer fails in performance under high temperature or ultra-high temperature conditions, resulting in deterioration of the settling stability of the cement slurry system, serious increase of the room temperature viscosity, and increase of the cementing operation risk due to difficult mixing on site. The ultra-high temperature cement slurry suspension stabilizer provided by the present application can significantly improve the ultra-high temperature settling stability of the cement slurry system, so that the settling stability of the cement slurry system under the condition of 240℃ can be controlled to be less than 0.03 g / cm 3 (the difference between the upper and lower densities), and has no adverse effect on the construction performance and mechanical properties, which can meet the technical requirements of deep well and ultra-deep well cementing under the bottom circulating temperature of 240℃ and below.

[0044] The super-high-temperature cement slurry suspension stabilizer of the present application generates a certain degree of intramolecular and intermolecular bonding through hydrophobic groups at room temperature (20-30 DEG C), reduces the hydrodynamic radius of the polymer molecular chain, prevents the polymer molecular chain from excessively stretching, a large amount of association into a network and strong adsorption on the surface of cement particles in water, etc., while the unsaturated cation monomer and the unsaturated surfactant monomer containing a long carbon side chain effectively regulate the molecular weight and its distribution, reduce the low-temperature tackifying property, and effectively solve the problem of cement slurry setting difficulty. With the increase of temperature (30-160 DEG C), the polymer molecular chain of the super-high-temperature cement slurry suspension stabilizer of the present application gradually stretches, the hydrophilicity increases, the hydrophobic side chain gradually exposes, and a polymer solution with a space network structure is formed through the hydrophobic association structure of the hydrophobic micro area; at the same time, the anion groups and cation groups in the polymer structure selectively adsorb on the surface of different types of cement minerals and solid particles, "lock" the solid particles in the slurry, and improve the settling stability of the cement slurry. At high temperature, super-high temperature (> 160 DEG C), the polybasic ring impedance group in the polymer of the super-high-temperature cement slurry suspension stabilizer of the present application protects the amide group from high-temperature hydrolysis, so the polymer molecular main chain, side chain and space network structure are not completely collapsed, and still have a strong solid phase suspension capacity. At the same time, the polymer space network structure formed by ionic association and hydrophobic association becomes more and more dense with the increase of temperature, can effectively alleviate the high-temperature dilution phenomenon of the cement slurry liquid phase, improve the liquid phase high-temperature suspension bearing capacity, thereby improving the rheological property of the slurry and the super-high-temperature stability of the cement slurry system, ensuring the comprehensive performance of the cement slurry system, and guaranteeing the safety and long-term stable sealing capacity of the cementing operation in deep wells and super-deep wells.

[0045] The technical scheme of the present application has at least the following beneficial effects:

[0046] (1) The super-high-temperature cement slurry suspension stabilizer of the present application improves the super-high-temperature resistance and suspension stability of the polymer suspension stabilizer through the effective introduction of temperature-resistant and salt-resistant groups, rigid ring structure suspension bearing, synergistic effect of anion-cation-hydrophobic multifunctional groups and self-regulation of molecular weight, and improves the construction performance of the cement slurry system and the complex environment adaptability of the cement slurry system in deep wells and super-deep wells.

[0047] (2) The super-high-temperature cement slurry suspension stabilizer of the present application has a temperature resistance of 240 DEG C, and can control the settling stability of the cement slurry system at 240 DEG C to be less than 0.03 g / cm 3 (density difference), has good compatibility with other cement slurry system additives, and has no adverse effect on the construction performance and mechanical properties of the cement slurry system.

[0048] (3) The preparation method of the super-high-temperature cement slurry suspending stabilizer is simple, green, safe, environmentally friendly, and low in production cost, and can realize industrial production and large-scale popularization and application.

[0049] (4) The super-high-temperature cement slurry suspending stabilizer has strong adaptability and can meet the cementing technical requirements of special wells such as high-temperature and high-pressure gas wells, unconventional oil and gas wells, gas storage wells, deep wells, super-deep wells and extra-deep wells.

[0050] In summary, the present application provides a super-high-temperature cement slurry suspending stabilizer, a preparation method and application thereof, in particular, a cement slurry polymer suspending stabilizer resistant to 240 DEG C high temperature and a preparation method and application thereof for cementing deep wells, super-deep wells. The super-high-temperature cement slurry suspending stabilizer provided by the present application has a wide temperature range and can control the sedimentation stability of the cement slurry system under the condition of 240 DEG C to 0.03 g / cm 3 In the following, the raw materials of the super-high-temperature cement slurry suspending stabilizer are cheap and easy to obtain, and the cement slurry system has good compatibility with other cementing cement slurry systems, significantly improves the comprehensive performance of the cement slurry system, and meets the requirements of safety operation and cementing quality of super-high-temperature cementing in deep wells, super-deep wells and the like. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The infrared spectrum of the polymer in the super-high-temperature cement slurry suspending stabilizer provided for Example 1.

[0052] Figure 2a 、 Figure 2b 、 Figure 2c and Figure 2d The ESEM images of the polymer solution prepared in Example 3 and Comparative Example 1 after being treated at 25 DEG C and 240 DEG C for 2h, respectively.

[0053] Figure 3 The thickening curve of the cement slurry system doped with the super-high-temperature cement slurry suspending stabilizer provided for Example 1 under the condition of 240 DEG C x 100 MPa.

[0054] Figure 4 The thickening curve of the cement slurry system doped with the high-temperature cement slurry suspending stabilizer provided for Comparative Example 1 under the condition of 240 DEG C x 100 MPa. DETAILED DESCRIPTION

[0055] In order to have a clearer understanding of the technical features, objects and beneficial effects of the present application, the technical solutions of the present application will be described in detail below, but it cannot be understood as limiting the scope of the present application.

[0056] According to the specific embodiment of the present application, preferably, the super-high-temperature cement slurry suspending stabilizer provided by the present application is prepared by at least the following steps:

[0057] 18-25 parts of 2-acrylamido-2-methylpropanesulfonic acid monomer is dissolved in 20-30 parts of deionized water, and the pH value is adjusted to 6-7 to obtain a first mixture;

[0058] 0.5-1.5 parts of an unsaturated surfactant monomer containing a long carbon side chain is dissolved in 120-180 parts of deionized water, and the pH value is optionally adjusted to 6-7 to obtain a second mixture;

[0059] The first mixture and the second mixture are thoroughly mixed, and then 15-25 parts of an unsaturated acrylamide monomer, 1.7-2.5 parts of an unsaturated cationic monomer, and 5-13 parts of a vinyl multicyclic monomer are sequentially added and stirred uniformly to obtain a third mixture;

[0060] 0.05-0.12% of an initiator based on the total mass of the third mixture is dissolved in 100 parts of deionized water to obtain an initiator solution (the concentration of the initiator in the initiator solution is 0.09-0.34%);

[0061] The initiator solution is added to the third mixture at a dropwise addition rate of 10-20 mL / min, and during the addition of the initiator solution to the third mixture, the reaction temperature is controlled at 50-65°C; after the addition of the initiator solution is completed, the reaction temperature is controlled at 70-85°C and reacted for 4-6 h to obtain a polymer solution, which is the super-high-temperature cement slurry suspension stabilizer.

[0062] Example 1

[0063] The present embodiment provides a super-high-temperature cement slurry suspension stabilizer, which is prepared by at least the following steps:

[0064] 25 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 30 g of deionized water, 4.5 g of sodium hydroxide is slowly added to adjust the pH value to 7 to obtain a first mixture;

[0065] 1.5 g of hexadecyl dimethyl allyl ammonium chloride is dissolved in 170 g of deionized water to obtain a second mixture;

[0066] The first mixture and the second mixture are thoroughly mixed, and then 25 g of N,N-dimethyl acrylamide, 2.5 g of acryloyloxyethyl trimethyl ammonium chloride, and 12 g of N-vinyl pyrrolidone are sequentially added and stirred uniformly to obtain a third mixture;

[0067] 0.318 g of potassium persulfate is dissolved in 100 g of deionized water to obtain an initiator solution;

[0068] The initiator solution is added to the third mixture at a dropwise adding speed of 10 mL / min, the water bath heating temperature is controlled at 65 ℃ during the dropwise adding of the initiator solution, after the dropwise adding is completed, the temperature is increased to 85 ℃ for reaction, and the reaction time is 4 h, to obtain a polymer solution, which is the ultra-high temperature cement slurry suspending stabilizer.

[0069] Example 2

[0070] The embodiment provides an ultra-high temperature cement slurry suspending stabilizer, which is prepared at least through the following steps:

[0071] 18 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 25 g of deionized water, 3.2 g of sodium hydroxide is slowly added to adjust the pH value to 6, and a first mixture is obtained;

[0072] 0.5 g of hexadecyl dimethyl allyl ammonium chloride is dissolved in 125 g of deionized water to obtain a second mixture;

[0073] The first mixture and the second mixture are fully mixed, and then 15 g of N,N-dimethyl acrylamide, 1.7 g of acryloyloxyethyl trimethyl ammonium chloride and 8 g of N-vinyl pyrrolidone are sequentially added and uniformly stirred to obtain a third mixture;

[0074] 0.147 g of potassium persulfate is dissolved in 100 g of deionized water to obtain an initiator solution;

[0075] The initiator solution is added to the third mixture at a dropwise adding speed of 10 mL / min, the water bath heating temperature is controlled at 65 ℃ during the dropwise adding of the initiator solution, after the dropwise adding is completed, the temperature is increased to 85 ℃ for reaction, and the reaction time is 4 h, to obtain a polymer solution, which is the ultra-high temperature cement slurry suspending stabilizer.

[0076] Example 3

[0077] The embodiment provides an ultra-high temperature cement slurry suspending stabilizer, which is prepared at least through the following steps:

[0078] 21 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 25 g of deionized water, 4.2 g of sodium hydroxide is slowly added to adjust the pH value to 6, and a first mixture is obtained;

[0079] 1 g of hexadecyl dimethyl allyl ammonium chloride is dissolved in 155 g of deionized water to obtain a second mixture;

[0080] The first mixture and the second mixture are mixed thoroughly, and then 20 g of N,N-dimethylacrylamide, 2.3 g of acryloyloxyethyl trimethyl ammonium chloride, and 10 g of N-vinyl pyrrolidone are sequentially added and stirred uniformly to obtain a third mixture;

[0081] 0.225 g of potassium persulfate is dissolved in 100 g of deionized water to obtain an initiator solution;

[0082] The initiator solution is added to the third mixture at a dripping speed of 10 mL / min, and the temperature of the water bath is controlled at 60°C during the dripping of the initiator solution. After the dripping is completed, the temperature is increased to 75°C for reaction, and the reaction time is 5 h, to obtain a polymer solution, which is the ultra-high temperature cement slurry suspending stabilizer.

[0083] Example 4

[0084] The ultra-high temperature cement slurry suspending stabilizer is prepared by at least the following steps:

[0085] 25 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 30 g of deionized water, and 4.5 g of sodium hydroxide is slowly added to adjust the pH value to 6 to obtain a first mixture;

[0086] 1.5 g of 2-acrylamidohexadecanesulfonic acid is dissolved in 170 g of deionized water, and 0.2 g of sodium hydroxide is slowly added to adjust the pH value to 6 to obtain a second mixture;

[0087] The first mixture and the second mixture are mixed thoroughly, and then 25 g of N,N-dimethylacrylamide, 2 g of methacryloyloxyethyl trimethyl ammonium chloride, and 5 g of N-vinyl caprolactam are sequentially added and stirred uniformly to obtain a third mixture;

[0088] 0.318 g of potassium persulfate is dissolved in 100 g of deionized water to obtain an initiator solution;

[0089] The initiator solution is added to the third mixture at a dripping speed of 10 mL / min, and the temperature of the water bath is controlled at 65°C during the dripping of the initiator solution. After the dripping is completed, the temperature is increased to 85°C for reaction, and the reaction time is 4 h, to obtain a polymer solution, which is the ultra-high temperature cement slurry suspending stabilizer.

[0090] Example 5

[0091] The ultra-high temperature cement slurry suspending stabilizer is prepared by at least the following steps:

[0092] dissolve 25 g of 2-acrylamido-2-methylpropanesulfonic acid in 30 g of deionized water, slowly add sodium hydroxide to adjust the pH value to 7 to obtain a first mixture;

[0093] dissolve 1.5 g of hexadecyl dimethyl allyl ammonium chloride in 170 g of deionized water to obtain a second mixture;

[0094] mix the first mixture and the second mixture well, and then sequentially add 25 g of N,N-dimethyl acrylamide, 2.5 g of acryloyloxyethyl trimethyl ammonium chloride, and 12 g of N-vinyl pyrrolidone, and stir uniformly to obtain a third mixture;

[0095] dissolve 0.318 g of potassium persulfate in 100 g of deionized water to obtain an initiator solution;

[0096] control the initiator solution to be added to the third mixture at a dropping speed of 10 mL / min, control the water bath heating temperature to be 50°C during the process of adding the initiator solution, and then increase the temperature to 70°C after the addition of the initiator solution is completed to perform reaction, the reaction time is 6 h, and a polymer solution is obtained, which is the ultra-high temperature cement slurry suspending stabilizer.

[0097] Comparative Example 1

[0098] The present comparative example provides a high-temperature cement slurry suspending stabilizer, which is different from Example 1 in that no unsaturated cationic monomer is added. Specifically, the high-temperature cement slurry suspending stabilizer of the present comparative example is prepared at least by the following steps:

[0099] dissolve 25 g of 2-acrylamido-2-methylpropanesulfonic acid in 30 g of deionized water, slowly add 4.5 g of sodium hydroxide to adjust the pH value to 7 to obtain a first mixture;

[0100] dissolve 1.5 g of hexadecyl dimethyl allyl ammonium chloride in 170 g of deionized water to obtain a second mixture;

[0101] mix the first mixture and the second mixture well, and then sequentially add 25 g of N,N-dimethyl acrylamide, 2.5 g of acryloyloxyethyl trimethyl ammonium chloride, and 12 g of N-vinyl pyrrolidone, and stir uniformly to obtain a third mixture;

[0102] dissolve 0.318 g of potassium persulfate in 100 g of deionized water to obtain an initiator solution;

[0103] The initiator solution is added to the third mixture at a dropwise adding speed of 10 mL / min, the water bath heating temperature is controlled at 65°C during the dropwise adding of the initiator solution, after the dropwise adding is completed, the temperature is increased to 85°C for reaction, the reaction time is 4 h, and a polymer solution is obtained, which is the high temperature cement slurry suspension stabilizer.

[0104] Comparative Example 2

[0105] The present comparative example provides a high temperature cement slurry suspension stabilizer, which is different from that of Example 1 in that no unsaturated surfactant monomer containing a long carbon side chain is added. Specifically, the high temperature cement slurry suspension stabilizer of the present comparative example is prepared at least by the following steps:

[0106] 25 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 30 g of deionized water, 4.5 g of sodium hydroxide is slowly added to adjust the pH value to 7, and then 170 g of deionized water is added, and then 25 g of N,N-dimethyl acrylamide, 2.5 g of acryloyloxyethyl trimethyl ammonium chloride, and 12 g of N-vinyl pyrrolidone are sequentially added, and stirred uniformly to obtain a mixture;

[0107] 0.318 g of potassium persulfate is dissolved in 100 g of deionized water to obtain an initiator solution;

[0108] The initiator solution is added to the third mixture at a dropwise adding speed of 10 mL / min, the water bath heating temperature is controlled at 65°C during the dropwise adding of the initiator solution, after the dropwise adding is completed, the temperature is increased to 85°C for reaction, the reaction time is 4 h, and a polymer solution is obtained, which is the high temperature cement slurry suspension stabilizer.

[0109] Comparative Example 3

[0110] The present comparative example provides a high temperature cement slurry suspension stabilizer, which is different from that of Example 1 in that the amount of the unsaturated surfactant monomer containing a long carbon side chain is 2 g. Specifically, the high temperature cement slurry suspension stabilizer of the present comparative example is prepared at least by the following steps:

[0111] 25 g of 2-acrylamido-2-methylpropanesulfonic acid is dissolved in 30 g of deionized water, 4.5 g of sodium hydroxide is slowly added to adjust the pH value to 7, and then 170 g of deionized water is added, and then 25 g of N,N-dimethyl acrylamide, 2.5 g of acryloyloxyethyl trimethyl ammonium chloride, and 12 g of N-vinyl pyrrolidone are sequentially added, and stirred uniformly to obtain a mixture;

[0112] 2 g of hexadecyl dimethyl allyl ammonium chloride is dissolved in 170 g of deionized water to obtain a second mixture;

[0113] The first mixture and the second mixture are thoroughly mixed, and then 25g of N,N-dimethylacrylamide, 2.5g of acryloyloxyethyltrimethylammonium chloride and 12g of N-vinylpyrrolidone are added in sequence and stirred until homogeneous to obtain the third mixture;

[0114] Dissolve 0.318 g of potassium persulfate in 100 g of deionized water to obtain an initiator solution;

[0115] The initiator solution is added to the third mixture at a dropping rate of 10 mL / min. During the dropping of the initiator solution, the water bath heating temperature is controlled at 65°C. After the dropping is completed, the temperature is raised to 85°C for reaction. The reaction time is 4 hours to obtain a polymer solution, which is the high-temperature cement slurry suspension stabilizer.

[0116] Comparative Example 4

[0117] This comparative example provides a high-temperature cement slurry suspension stabilizer, which differs from Example 1 in that the amount of unsaturated cationic monomer added is 3g. Specifically, the high-temperature cement slurry suspension stabilizer of this comparative example is prepared by at least the following steps:

[0118] Dissolve 25g of 2-acrylamido-2-methylpropanesulfonic acid in 30g of deionized water, and slowly add 4.5g of sodium hydroxide to adjust the pH to 7 to obtain the first mixture;

[0119] Dissolve 1.5g of hexadecyldimethylallylammonium chloride in 170g of deionized water to obtain a second mixture;

[0120] The first mixture and the second mixture were thoroughly mixed, and then 25g of N,N-dimethylacrylamide, 3g of acryloyloxyethyltrimethylammonium chloride and 12g of N-vinylpyrrolidone were added in sequence and stirred until homogeneous to obtain the third mixture.

[0121] Dissolve 0.318 g of potassium persulfate in 100 g of deionized water to obtain an initiator solution;

[0122] The initiator solution is added to the third mixture at a dropping rate of 10 mL / min. During the dropping of the initiator solution, the water bath heating temperature is controlled at 65°C. After the dropping is completed, the temperature is raised to 85°C for reaction. The reaction time is 4 hours to obtain a polymer solution, which is the high-temperature cement slurry suspension stabilizer.

[0123] Test Example 1

[0124] In this test example, the cement slurry suspension stabilizers prepared in Examples 1-5 and Comparative Examples 1-4 were analyzed by gel permeation chromatography. The results are shown in Table 1.

[0125] Table 1

[0126] Number average molecular weight Weight average molecular weight Distribution index Example 1 560415 1058652 1.88905 Example 2 677219 1295621 1.91315 Example 3 677969 1302683 1.92145 Example 4 603983 1353682 2.24126 Example 5 510608 1152401 2.25692 Comparative Example 1 851710 2265156 2.65954 Comparative Example 2 278460 502654 1.80512 Comparative Example 3 278460 1401458 2.64056 Comparative Example 4 278503 656892 2.35865

[0127] As shown in Table 1, the weight-average molecular weights of the polymers prepared in Examples 1-5 are all between 1 million and 1.4 million, and the molecular weight distribution index is between 1.8 and 2.3. In the comparative examples, Comparative Example 1 did not add an unsaturated cationic monomer, so it was impossible to effectively control the molecular weight and molecular weight distribution of the polymer, resulting in a molecular weight and distribution index that were much larger than the recommended range. This could lead to excessively strong thickening ability of the polymer, which might affect the cement ash setting. Comparative Example 2 did not add an unsaturated surfactant monomer containing long carbon side chains. Although the polymer had a suitable molecular weight distribution index, the molecular weight was too small. This is because the polymer without the introduction of unsaturated surfactant monomers with long carbon side chains has fewer long-chain alkyl groups distributed on the side chains, resulting in a lower molecular weight. A low molecular weight and fewer alkane groups on the side chains can lead to poor polymer suspension ability. Comparative Example 3 added an excessive amount of unsaturated surfactant monomer, resulting in a larger molecular weight distribution index. This is because unsaturated surfactant monomers themselves contain multiple functional groups, and the excessive introduction makes the polymerization process more complex and the product more heterogeneous. Comparative Example 4 added an excessive amount of unsaturated cationic monomer. The steric hindrance of the cationic monomer affected the polymerization reaction, thus reducing the molecular weight of the polymer.

[0128] Test Example 2

[0129] In this test example, the ultra-high temperature cement slurry suspension stabilizer prepared in Example 1 was analyzed by infrared spectroscopy. The obtained infrared spectrum is shown below. Figure 1 As shown.

[0130] The KBr pelleting method was used to perform infrared spectroscopy on the purified polymer prepared in Example 1 using a Fourier transform infrared spectrometer, with a wavenumber range of 4000-400 cm⁻¹. -1 The steps for purifying the polymer solution prepared in Example 1 include: precipitating the polymer solution with an appropriate amount of ethanol solution, then washing and drying it, repeating this process three times, and finally pulverizing it to obtain the purified polymer.

[0131] Depend on Figure 1 It can be determined that 3439.8cm -1 1543.3cm -1 The peak represents the stretching vibration of the NH group in the amide group, at 1640.9 cm⁻¹. -1 This is the stretching vibration peak of the C=O group in the amide group, at 1700 cm⁻¹. -1 The absorption in the vicinity is due to the stretching vibration of the -C=O ring on the pyrrole ring, 2920.1 cm⁻¹. -1 2065.6cm -11443.8cm -1 1404.1cm -1 The peak is a characteristic CH peak for methyl (-CH3), at 1188.7 cm⁻¹. -1 1043.9cm -1 and 977.2cm -1 The peak is the characteristic peak of S=O in sulfonic acid groups, at 651.8 cm⁻¹. -1 The characteristic peak of SO in sulfonic acid groups is 1291 cm⁻¹. -1 The peak is a CN- stretching vibration peak, 720.2 cm⁻¹. -1 The peak is a characteristic -CH2- peak of long-chain alkanes, and it is located at 1650 cm⁻¹. -1 The absence of characteristic peaks for C=C double bonds in the vicinity indicates that all monomers in Example 1 participated in the copolymerization reaction, and the product was the target product, namely a pentagonal copolymer of 2-acrylamido-2-methylpropanesulfonic acid, hexadecyl dimethyl allyl ammonium chloride, N,N-dimethylacrylamide, acryloyloxyethyl trimethyl ammonium chloride, and N-vinylpyrrolidone.

[0132] Test Example 3

[0133] In this test example, the microstructure of the polymers obtained after treating the polymer solutions prepared in Example 3 and Comparative Example 1 at 25°C and 240°C for 2 hours was analyzed by environmental scanning electron microscopy (ESEM).

[0134] Figure 2a and Figure 2b The microstructures of the polymer solution prepared in Comparative Example 1 after treatment at 25℃ and 240℃ are shown. Figure 2a and Figure 2b It can be seen that at room temperature, the polymer prepared in Comparative Example 1 has a basically linear structure, and the molecular chains form a network structure through hydrophobic association with reactive surfactants. However, as the temperature increases, the hydrophobic association structure between molecules is gradually destroyed, and the molecular chains undergo partial chain breakage and conformational transformation. The microstructure of the polymer treated at 240℃ is spherical, resulting in the polymer-type suspension stabilizer having virtually no suspension support capacity at ultra-high temperatures and thus failing in performance. Therefore, the cement slurry system containing the high-temperature cement slurry suspension stabilizer prepared in Comparative Example 1 experienced severe sedimentation after curing at 240℃.

[0135] Figure 2c and Figure 2d The microstructures of the polymer solution prepared in Example 3 after treatment at 25°C and 240°C, respectively. Figure 2c and Figure 2dIt is evident that at room temperature, the polymer prepared in Example 3 exhibits a layered, porous, mucosal conformation in water. This is because the polymer molecules, through ion association and hydrophobic association, possess a spatial network structure, which significantly increases the viscosity and support capacity of the polymer solution, preventing the settling of solid particles such as cement. The polymer treated at 240℃ still maintains a spatial network structure, and the interactions between molecular chain segments are strong, indicating that the microstructure of the polymer prepared in Example 3 undergoes minimal change after ultra-high temperature treatment, or only some chain segments are damaged without affecting its overall performance. Therefore, the ultra-high temperature cement slurry suspension stabilizer provided in Example 3 possesses strong temperature resistance and ultra-high temperature suspension stability.

[0136] Test Example 4

[0137] According to the relevant provisions of the petroleum and natural gas industry standard GB / T 19139-2012 "Test Methods for Oil Well Cement", the performance of the suspension stabilizers prepared in Examples 1-5 and Comparative Examples 1-4 were evaluated, and the results are shown in Table 2. The sedimentation stability of the cement slurry system was investigated by: curing the cement slurry system under experimental temperature and pressure for 30 minutes using a high-temperature and high-pressure thickener, then cooling it to 90°C, removing it, removing the surface oil, and measuring the density difference d between the upper and lower parts of the cement slurry. m1 After mixing thoroughly, the mixture was left to stand at 90℃ for 2 hours. The density difference d between the upper and lower parts of the cement slurry was then measured. m2 And at the same time, the free liquid was examined.

[0138] To simulate the settling stability of the cement slurry system when pumping is interrupted due to unforeseen circumstances during cementing operations in deep and ultra-deep wells at ultra-high temperatures, the consistency change of the cement slurry system containing the suspension stabilizer of the present invention and the comparative examples was investigated at the experimental temperature and pressure after a 30-minute interruption. If the consistency backflushing value at the moment of restart is greater than 40 Bc, it will significantly increase the fluid pumping pressure, posing a risk of formation leakage. If it is less than 40 Bc, the settling stability of the cement slurry system is considered to be good.

[0139] Therefore, this test case investigates the effect of suspension stabilizers on the settling stability of ultra-high temperature cement slurry systems by combining the above methods.

[0140] Table 2

[0141]

[0142] Note: # represents the percentage of cement by mass; d m1 After the cement slurry system was cured at the experimental temperature and pressure for 30 minutes and then cooled to 90°C, it was removed, the surface oil was removed, and the density difference between the upper and lower parts was directly measured; d m2The difference in density between the top and bottom of the cement slurry system after it has been thoroughly mixed with high temperature and placed in a 90℃ water bath for 2 hours is the result of the mixture being uniformly stirred.

[0143] The cement slurry system used in this test, conducted at an experimental temperature above 160℃, had the following formulation by mass: 100 parts Jiahua G-grade oil well cement (HSR) + 50 parts quartz sand (200 mesh) + 1.2 parts primary dispersant + 1.2 parts secondary dispersant + 4 parts water loss reducer + 5 parts retarder + x parts (i.e., % bwoc in Table 2) suspension stabilizer + (56-x) parts water; the density of the cement slurry system was 1.90 g / cm³. 3 .

[0144] The cement slurry system used in this test, conducted at an experimental temperature of 120-160℃, had the following formulation by mass: 100 parts Jiahua G-grade oil well cement (HSR) + 35 parts quartz sand (200 mesh) + 3 parts microsilica + 0.8 parts primary dispersant + 4 parts water loss reducer + 2 parts retarder + x parts (i.e., % bwoc in Table 2) suspension stabilizer + (53-x) parts water; the density of the cement slurry system was 1.90 g / cm³. 3 .

[0145] Among them, the first dispersant, the second dispersant, the retarder, and the water loss reducer are respectively aldehyde-ketone condensate dispersant DRS-1S, polycarboxylic acid dispersant DRS-2S, acrylamide retarder DRH-3L, and acrylamide water loss reducer DRF-3L, all of which are products manufactured by China Petroleum Engineering Technology Research Institute Co., Ltd.

[0146] As shown in Table 2, under the experimental conditions of 240℃, the cement slurry system containing the ultra-high temperature cement slurry suspension stabilizer provided in Examples 1-5 of this invention has a settling time of less than 35 seconds, good fluidity, and a settling stability controlled at 0.03 g / cm³. 3 Below, there is no free liquid, and the ultra-high temperature thickening experiment stops normally.

[0147] However, the cement slurry systems containing the high-temperature cement slurry suspension stabilizers provided in Comparative Example 1 and Comparative Example 2, respectively, experienced difficulties in cement slurry loading (>60s), severe slurry thickening, and poor settling stability (>0.1g / cm³). 3 The free liquid content is high (>1.4%) and the viscosity rebounds sharply when the machine is restarted after a 30-minute interruption.

[0148] Although the cement slurry systems containing the high-temperature cement slurry suspension stabilizers provided by Comparative Example 3 and Comparative Example 4 were easy to apply and had good fluidity, their system stability, free fluid, and stoppage tests could not meet the requirements for cementing operations.

[0149] The preliminary analysis of the reasons for the above differences is as follows: The suspension stabilizer prepared in Comparative Example 1 lacks groups provided by unsaturated cationic monomers in its molecular structure. Its polymer molecular weight is high, and it cannot form ion-associated structures at high temperatures. Therefore, it exhibits characteristics of room-temperature thickening and high-temperature dilution, thus affecting the mixing and sedimentation stability of the high-temperature cement slurry system. The suspension stabilizer prepared in Comparative Example 2 did not use unsaturated surfactant monomers containing long carbon side chains. Its polymer molecular weight is large, and it lacks hydrophobic associative structures. Therefore, the cement slurry system exhibits severe room-temperature thickening and poor high-temperature sedimentation stability. Severe sedimentation leads to thickening and shutdown problems, posing a significant challenge to the safety of cementing operations in deep and ultra-deep wells at ultra-high temperatures. The suspension stabilizers prepared in Comparative Examples 3 and 4 introduced excessive amounts of unsaturated cationic monomers and excessive amounts of unsaturated surfactant monomers containing long carbon side chains, respectively. The monomer polymerization has significant steric hindrance, affecting the polymer reaction process. The resulting polymer-type suspension stabilizers have lower molecular weights, and the excessive cationic groups act on the surface of cement particles, altering their surface charge distribution, thus causing instability of the cement slurry system under ultra-high temperature conditions. The comparison of the above embodiments and comparative examples also verifies the superiority of the molecular structure of the ultra-high temperature cement slurry suspension stabilizer prepared in the embodiments of the present invention, which ultimately determines its excellent performance.

[0150] Figure 3 The thickening curve of the cement slurry system containing the ultra-high temperature cement slurry suspension stabilizer provided in Example 1 is shown at 240℃ × 100MPa. Figure 3 It can be seen that the consistency curve of the cement slurry system with the ultra-high temperature cement slurry suspension stabilizer prepared in Example 1 is stable, with an initial consistency of about 18 Bc. As the temperature increases, the consistency decreases only slightly, and there are no adverse phenomena such as abnormal gelation during the thickening process.

[0151] Figure 4 Thickening curve of the cement slurry system containing the high-temperature cement slurry suspension stabilizer provided in Comparative Example 1 at 240℃ × 100MPa. Figure 4 It can be seen that the installed consistency of the cement slurry system is 35 Bc, which cannot meet the requirements for on-site mixing. Moreover, the consistency decreases significantly with increasing temperature. This phenomenon indicates that the high-temperature cement slurry suspension stabilizer prepared in Comparative Example 1 has obvious room temperature thickening properties, making it difficult to mix the cement slurry system on-site. In addition, the polymer solution in the liquid phase of the cement slurry is severely diluted at high temperature, and the sedimentation stability of the system gradually deteriorates, thereby affecting the overall performance of the cement slurry system and increasing the risk of cementing operations.

[0152] Therefore, the ultra-high temperature cement slurry suspension stabilizer provided in this embodiment of the invention has a temperature resistance of over 240℃, which can significantly improve the settling stability of the ultra-high temperature cement slurry system, and its overall performance is superior to the suspension stabilizer provided in the comparative example. Meanwhile, the ultra-high temperature cement slurry suspension stabilizer prepared in this embodiment of the invention has a wide applicable temperature range. Within the experimental temperature range of 120-240℃, adjusting the dosage of the ultra-high temperature cement slurry suspension stabilizer can significantly improve the construction performance of the cement slurry system, thereby ensuring the safety of cementing operations in deep and ultra-deep wells.

[0153] In summary, the ultra-high temperature cement slurry suspension stabilizer of the present invention has a wide applicable temperature range and stable performance. It can ensure the comprehensive performance of cement slurry systems with bottom hole circulation temperatures of 240℃ and below, as well as the safety of ultra-high temperature cementing operations. It has good application prospects in cementing operations in deep wells, ultra-deep wells, extra-deep wells, as well as high-temperature and high-pressure gas wells, unconventional oil and gas wells, and gas storage wells.

[0154] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A super-high temperature cement slurry suspension stabilizer, wherein the suspension stabilizer comprises a polymer prepared from 2-acrylamido-2-methylpropanesulfonic acid monomer, vinyl polycyclic monomer, unsaturated acrylamide monomer, unsaturated cationic monomer and unsaturated surfactant monomer containing long carbon side chains; in, The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid monomer, vinyl polycyclic monomer, unsaturated acrylamide monomer, unsaturated cationic monomer, and unsaturated surfactant monomer containing long carbon side chains is (18-25):(5-13):(15-25):(1.7-2.5):(0.5-1.5); The vinyl polycyclic monomer includes one or a combination of several of N-vinylpyrrolidone, N-vinylcaprolactam, and sodium styrene sulfonate; the unsaturated surfactant monomer containing a long carbon side chain includes one or a combination of several of hexadecyl dimethyl allyl ammonium chloride, 2-acrylamidohexadecanesulfonic acid, and 2-acrylamidododecanesulfonic acid.

2. The ultra-high temperature cement slurry suspension stabilizer according to claim 1, wherein, The unsaturated acrylamide monomers include one or a combination of several of acrylamide, diacetone acrylamide, N,N-dimethylacrylamide and N,N-diethylacrylamide.

3. The ultra-high temperature cement slurry suspension stabilizer according to claim 1, wherein, The unsaturated cationic monomer includes one or a combination of several of dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, and methacryloyloxyethyl trimethyl ammonium chloride.

4. The ultra-high temperature cement slurry suspension stabilizer according to claim 1, wherein, The ultra-high temperature cement slurry suspension stabilizer is prepared through the following steps: A polymer solution is obtained by polymerizing 2-acrylamido-2-methylpropanesulfonic acid monomer, vinyl polycyclic monomer, unsaturated acrylamide monomer, unsaturated cationic monomer, and unsaturated surfactant monomer containing long carbon side chains in a mass ratio of (18-25):(5-13):(15-25):(1.7-2.5):(0.5-1.5) in the presence of an initiator and a solvent, which is the ultra-high temperature cement slurry suspension stabilizer.

5. The ultra-high temperature cement slurry suspension stabilizer according to claim 4, wherein, The ultra-high temperature cement slurry suspension stabilizer is prepared through the following steps: By weight, 18-25 parts of 2-acrylamido-2-methylpropanesulfonic acid monomer are dissolved in 20-30 parts of water, and the pH is adjusted to 6-7 to obtain a first mixture; 0.5-1.5 parts of unsaturated surfactant monomer containing long carbon side chains are dissolved in 120-180 parts of water, and the pH is selectively adjusted to 6-7 to obtain a second mixture; the first mixture and the second mixture are mixed, and then 15-25 parts of unsaturated acrylamide monomer, 1.7-2.5 parts of unsaturated cationic monomer, and 5-13 parts of vinyl polycyclic monomer are added and stirred evenly to obtain a third mixture; then an initiator is added to the third mixture, and after polymerization reaction, a polymer solution is obtained, which is the ultra-high temperature cement slurry suspension stabilizer.

6. The ultra-high temperature cement slurry suspension stabilizer according to claim 5, wherein, The amount of the initiator is 0.05-0.12% of the total mass of the third mixture.

7. The ultra-high temperature cement slurry suspension stabilizer according to claim 4 or 5, wherein, The initiator includes one or a combination of several of ammonium persulfate, potassium persulfate, and azobisisobutyrazoline hydrochloride.

8. The ultra-high temperature cement slurry suspension stabilizer according to claim 5, wherein, The initiator is added dropwise to the third mixture in the form of a solution; the concentration of the initiator in the initiator solution is 0.09-0.34%; and the dropping rate of the initiator solution is 10-20 mL / min.

9. The ultra-high temperature cement slurry suspension stabilizer according to claim 5, wherein, During the process of adding the initiator to the third mixture, the reaction temperature is controlled at 50-65℃. After the initiator is completely added, the reaction temperature is controlled at 70-85℃ and the reaction is carried out for 4-6 hours.

10. A method for preparing an ultra-high temperature cement slurry suspension stabilizer according to any one of claims 1-9, comprising the following steps: A polymer solution is obtained by polymerizing 2-acrylamido-2-methylpropanesulfonic acid monomer, vinyl polycyclic monomer, unsaturated acrylamide monomer, unsaturated cationic monomer, and unsaturated surfactant monomer containing long carbon side chains in a mass ratio of (18-25):(5-13):(15-25):(1.7-2.5):(0.5-1.5) in the presence of an initiator and a solvent, which is the ultra-high temperature cement slurry suspension stabilizer.

11. The preparation method according to claim 10, wherein, The ultra-high temperature cement slurry suspension stabilizer is prepared through the following steps: By weight, 18-25 parts of 2-acrylamido-2-methylpropanesulfonic acid monomer are dissolved in 20-30 parts of water, and the pH is adjusted to 6-7 to obtain a first mixture; 0.5-1.5 parts of unsaturated surfactant monomer containing long carbon side chains are dissolved in 120-180 parts of water, and the pH is selectively adjusted to 6-7 to obtain a second mixture; the first mixture and the second mixture are mixed, and then 15-25 parts of unsaturated acrylamide monomer, 1.7-2.5 parts of unsaturated cationic monomer, and 5-13 parts of vinyl polycyclic monomer are added and stirred evenly to obtain a third mixture; then an initiator is added to the third mixture, and after polymerization reaction, a polymer solution is obtained, which is the ultra-high temperature cement slurry suspension stabilizer.

12. The preparation method according to claim 11, wherein, The amount of the initiator is 0.05-0.12% of the total mass of the third mixture.

13. The preparation method according to claim 10 or 11, wherein, The initiator includes one or a combination of several of ammonium persulfate, potassium persulfate, and azobisisobutyrazoline hydrochloride.

14. The preparation method according to claim 11, wherein, The initiator is added dropwise to the third mixture in the form of a solution; the concentration of the initiator in the initiator solution is 0.09-0.34%; and the dropping rate of the initiator solution is 10-20 mL / min.

15. The preparation method according to claim 11, wherein, During the process of adding the initiator to the third mixture, the reaction temperature is controlled at 50-65℃. After the initiator is completely added, the reaction temperature is controlled at 70-85℃ and the reaction is carried out for 4-6 hours.

16. The application of the ultra-high temperature cement slurry suspension stabilizer as described in any one of claims 1-9 as an additive in cement slurry systems for cementing high-temperature and high-pressure gas wells, unconventional oil and gas wells, gas storage wells, deep wells, ultra-deep wells, and extra-deep wells.

17. The application according to claim 16, wherein, Based on 100 parts of cement in the cement slurry system, the amount of ultra-high temperature cement slurry suspension stabilizer added is 3-5 parts.

Images