Organic-inorganic grafted suspension stabilizer, raw material composition thereof, and preparation method therefor

Abstract

The present invention provides an organic-inorganic grafted suspension stabilizer, a raw material composition thereof, and a preparation method therefor. The raw material composition comprises: 15-45 parts of a sulfonate monomer, 60-180 parts of a hydrophobic monomer, 1-15 parts of a cationic monomer, 1-15 parts of an allyl-containing ether monomer, and a modified inorganic material, wherein the modified inorganic material is obtained by modifying 0.1-1.5 parts of an inorganic material with 1-15 parts of a vinyl organosilicon monomer. The organic-inorganic grafted suspension stabilizer provided by the present invention can maintain relatively good sedimentation stability of a cement slurry at a relatively high bottom-hole circulating temperature, without affecting the formulation and feeding of the cement slurry, and has no adverse effect on properties, such as thickening and water loss, of the cement slurry.

Description

An organic-inorganic grafted suspension stabilizer, its raw material composition, and preparation method

[0001] Cross-reference information

[0002] This application claims priority to Chinese Patent Application No. 202411746330.5, filed on November 29, 2024, entitled "An Organic-Inorganic Grafted Suspension Stabilizer and Its Raw Material Composition and Preparation Method and Cement Slurry", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention belongs to the field of cementing slurry technology, specifically relating to an organic-inorganic grafted suspension stabilizer, its raw material composition, and preparation method. Background Technology

[0004] As exploration and development deepen, the targets become increasingly complex. More than 40% of remaining oil and gas resources are distributed in deep formations below 5000 meters, making deep and ultra-deep wells the primary source of future reserve and production increases for various oilfields. As exploration and development gradually moves towards deeper and ultra-deep wells, ensuring cementing quality and safety presents a severe challenge and key technical difficulty for oil and gas well cementing technology. Therefore, cementing is a crucial step in oil drilling. With increasing well depth and more complex well conditions, high temperatures can degrade the stability of cement slurry, leading to solid particle sedimentation and affecting cementing operations.

[0005] The stability of cement slurry directly affects the safety and quality of cementing operations. For example, poor slurry stability leads to uneven cement sheath development and varying compressive strength, thus negatively impacting the sealing performance of the cement sheath. With the development of downhole oil and gas resources, bottom-hole temperatures are increasing, placing higher demands on the stability of cement slurry. Furthermore, high-density cement slurries contain a large amount of inert weighting materials, making their poor stability at high temperatures even more pronounced.

[0006] Suspension stabilizers are key admixtures for improving the stability of cement slurries. Currently, common oil well cement suspension stabilizer materials fall into two main categories: inorganic materials and organic polymer materials. Inorganic suspension stabilizers offer good temperature resistance and primarily enhance cement slurry stability through thickening. Organic polymer materials, on the other hand, are added in small amounts and generally improve slurry stability by increasing the viscosity of the slurry and the adhesion between cement particles. In recent years, leveraging the unique characteristics of both materials, numerous research institutions have developed novel suspension stabilizers by combining organic and inorganic materials.

[0007] CN111154034A discloses a high-temperature suspension stabilizer for oil well cement and its preparation method. This suspension stabilizer comprises a ternary polymer of AMPS / NVP / AM and magnesium aluminum silicate. By mixing the polymer and inorganic materials through physical kneading, a high-temperature suspension stabilizer is prepared that can maintain good settling stability of conventional density cement slurry at 200℃ at a dosage of 1.5%. CN115975133A discloses a high-temperature, high-density cement slurry suspension stabilizer, its preparation method, and its application. This suspension stabilizer uses a grafting method, grafting a ternary polymer containing AMPS / DMAA / long-chain hydrophobic monomers obtained through free radical polymerization onto modified nano-SiO2, achieving a density of 2.6 g / cm³ at 210℃ at a dosage of 0.45%. 3 The density difference of the cement paste was reduced to 0.03 g / cm³. 3 CN115785926A discloses a polymer and its preparation method, as well as a high-temperature resistant, high-performance suspension stabilizer. This suspension stabilizer is prepared by mixing a polymer with a vinyl sulfonate main chain with a functional filler (a mixture of microsilica and ultrafine talc). This suspension stabilizer can maintain a density of 1.88 g / cm³ at 220°C with a 1% dosage. 3 The density difference between the top and bottom of the cement paste was reduced to 0.02 g / cm³. 3 CN114214048A discloses a high-temperature resistant suspension stabilizer for cementing working fluids and its preparation method. The high-temperature resistant suspension stabilizer of this invention is composed of two suspension stabilizing components: a graft-modified polymer and a polymer copolymer. The graft-modified polymer is obtained by grafting inorganic nanoparticles onto a polymer matrix (cellulose and bio-colloids) through graft chemical modification. The polymer copolymer is obtained by free radical polymerization of acrylic or propanesulfonic acid monomers with acrylamide monomers and macrocyclic side-chain ethylene monomers. This suspension stabilizer can maintain a density of 2.3 g / cm³ at 240°C with a dosage of 1.5%. 3 The density difference of the cement paste was reduced to 0.02 g / cm³. 3 However, none of the above technical solutions have explored the impact of mortar mixing and lime application, and there are no reports of their engineering applications.

[0008] Furthermore, CN114409845A discloses a cement slurry suspension stabilizer resistant to 240℃, its preparation method, and its application. This suspension stabilizer comprises a temperature-resistant and salt-resistant polymer and a modified inorganic layered material. It is prepared by free radical polymerization using acrylamide monomers, functionalized acrylamide monomers, and monomers with cyclic functional groups to obtain temperature-resistant polymer molecules. Subsequently, the obtained polymer molecules are intercalated into the modified inorganic layered material to obtain the cement slurry suspension stabilizer resistant to 240℃. This suspension stabilizer maintains a density of 1.85 g / cm³ at 240℃ at a dosage of 1.5%.3 The density difference of the cement paste was reduced to 0.05 g / cm³. 3 However, the cement slurry pouring time in this invention is relatively long (35-40 seconds), which has a certain impact on the cement slurry preparation.

[0009] Therefore, it is urgent and important to address the problems commonly associated with traditional suspension stabilizers, such as severe high-temperature dilution and prolonged cement slurry settling time, by resolving the issue of poor high-temperature settling stability of cement slurry without affecting the cement slurry preparation and settling time. Summary of the Invention

[0010] To address the aforementioned technical problems, the present invention aims to provide an organic-inorganic grafted suspension stabilizer, its raw material composition, and preparation method. The present invention also aims to provide a cement slurry. By modifying inorganic materials with vinyl organosilicon monomers and grafting long-chain polymers onto the surface of the modified inorganic materials, the resulting organic-inorganic grafted suspension stabilizer, when used in cement slurry, can ensure ideal settling stability of the cement slurry at high temperatures without affecting the normal mixing and discharging of the cement slurry.

[0011] To achieve the above objectives, the present invention provides a raw material composition for an organic-inorganic grafted suspension stabilizer, wherein, by weight, the raw material composition comprises: 15-45 parts of sulfonic acid monomer, 60-180 parts of hydrophobic monomer, 1-15 parts of cationic monomer, 1-15 parts of allyl ether monomer, and modified inorganic material.

[0012] The modified inorganic material is obtained by modifying 0.1-1.5 parts of inorganic material with 1-15 parts of vinyl organosilicon monomer.

[0013] According to a specific embodiment of the present invention, preferably, the vinyl organosilicon monomer comprises one or a combination of two or more of γ-(methacryloyloxy)propyltrimethoxysilane (KH570), vinyltriethoxysilane (A151), and vinyltrimethoxysilane (A171). For example, the vinyl organosilicon monomer can be KH570, a mixture of KH570 and A151, or a mixture of A151 and A171; wherein the amount of vinyl organosilicon monomer used can be 1, 5, 10, 15 parts, etc.

[0014] According to a specific embodiment of the present invention, preferably, the inorganic material includes one or a combination of two or more of magnesium aluminum hydroxysilicate, montmorillonite, bentonite, and nano silica.

[0015] According to a specific embodiment of the present invention, preferably, the sulfonic acid monomer includes one or a combination of two or more of 2-acrylamido-2-methylpropanesulfonic acid, sodium p-styrene sulfonate, and sodium vinyl sulfonate. For example, the sulfonic acid monomer can be 2-acrylamido-2-methylpropanesulfonic acid, a mixture of 2-acrylamido-2-methylpropanesulfonic acid and sodium p-styrene sulfonate, or a mixture of three sulfonic acid monomers: 2-acrylamido-2-methylpropanesulfonic acid, sodium p-styrene sulfonate, and sodium vinyl sulfonate; the amount of the sulfonic acid monomer is preferably 15-40 parts, wherein the amount of the sulfonic acid monomer can be 15, 30, 40, 45 parts, etc.

[0016] According to a specific embodiment of the present invention, preferably, the hydrophobic monomer includes two or more combinations of methacrylamide, N-ethylacrylamide, N-n-propylacrylamide, N-benzylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, N-tetradecylacrylamide, and N,N-diethyl-2-acrylamide. For example, the hydrophobic monomer can be a mixture of methacrylamide and N-ethylacrylamide, a mixture of three hydrophobic monomers such as N-n-propylacrylamide, N,N-dimethylacrylamide, and methacrylamide, a mixture of three hydrophobic monomers such as methacrylamide, N,N-dimethylacrylamide, and N-tetradecylacrylamide, or a mixture of five hydrophobic monomers such as methacrylamide, N-ethylacrylamide, N-n-propylacrylamide, N-benzylacrylamide, and N,N-dimethylacrylamide; wherein the amount of hydrophobic monomer used can be 60, 80, 100, 120, 150, 180 parts, etc.

[0017] According to a specific embodiment of the present invention, preferably, the cationic monomer includes one or a combination of two or more of dimethyl diallyl ammonium chloride, methacryloyloxyethyltrimethyl ammonium chloride, and octadecyl dimethyl allyl ammonium chloride. For example, the cationic monomer can be a mixture of dimethyl diallyl ammonium chloride, methacryloyloxyethyltrimethyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride, or a mixture of three cationic monomers such as dimethyl diallyl ammonium chloride, methacryloyloxyethyltrimethyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride; wherein, the amount of cationic monomer used can be 5, 10, 15 parts, etc.

[0018] According to a specific embodiment of the present invention, preferably, the allyl-containing ether monomer includes one or a combination of two or more of polyethylene glycol monoallyl ether, allyl ether, and allyl hydroxyethyl ether. For example, the allyl-containing ether monomer can be polyethylene glycol monoallyl ether, a mixture of polyethylene glycol monoallyl ether and allyl ether, or a mixture of polyethylene glycol monoallyl ether, allyl ether, and allyl hydroxyethyl ether; wherein the amount of the allyl-containing ether monomer can be 5, 10, 15 parts, etc.

[0019] According to a specific embodiment of the present invention, preferably, the initiator includes one or a combination of two or more of ammonium persulfate, potassium persulfate, azobisisobutyronitrile, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride. For example, the initiator may be a mixture of ammonium persulfate, potassium persulfate and azobisisobutyronitrile, a mixture of azobisisobutyronitrile and azobisisobutyramidine hydrochloride, or a mixture of four initiators: ammonium persulfate, potassium persulfate, azobisisobutyronitrile and azobisisobutyramidine hydrochloride.

[0020] In some specific implementations, preferably, the amount of the initiator is 0.05-0.4 parts, more preferably 0.05-0.25 parts; wherein, the amount of the initiator can be 0.1, 0.2, 0.3, 0.4 parts, etc.

[0021] This invention also provides a method for preparing an organic-inorganic grafted suspension stabilizer, wherein the preparation method uses the above-mentioned raw material composition of the organic-inorganic grafted suspension stabilizer and includes the following steps:

[0022] (1) Modified inorganic materials are obtained by using vinyl organosilicon monomers;

[0023] (2) Mix sulfonic acid monomers, hydrophobic monomers, cationic monomers, and allyl ether monomers in water to obtain an aqueous solution system of organic monomers containing carbon-carbon double bonds.

[0024] (3) The modified inorganic material is mixed with an aqueous solution system of organic monomers containing carbon-carbon double bonds, and an initiator is added dropwise to carry out a free radical polymerization reaction, so that the long-chain polymer is grafted onto the surface of the inorganic material to obtain an organic-inorganic grafted suspension stabilizer.

[0025] According to a specific embodiment of the present invention, preferably, in step (2), before adding the initiator, the step further includes adjusting the pH of the reaction system to 5-6 under ice bath conditions.

[0026] According to a specific embodiment of the present invention, preferably, the initiation temperature of the free radical polymerization reaction is 55-65℃ (preferably 55-60℃), and the reaction time is 2-8h (preferably 2-4h); the temperature is raised to the free radical polymerization temperature under nitrogen protection. For example, the free radical polymerization reaction time can be 4, 5, 6, 7, 8h, etc., and the initiation temperature can be 55, 60, 65℃, etc.

[0027] In the above preparation method, preferably, the preparation method of the organic-inorganic grafted suspension stabilizer specifically includes the following steps:

[0028] (a) Add 0.1-1.5 parts of magnesium aluminum hydroxysilicate and 1-15 parts of vinyl organosilicon monomer to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0029] (b) Add 15-45 parts of sulfonic acid monomer, 60-180 parts of hydrophobic monomer, 1-15 parts of cationic monomer, and 1-15 parts of allyl ether monomer to 500 parts of deionized water to obtain an aqueous solution system of organic monomers containing carbon-carbon double bonds; turn on the stirrer and after the components in the aqueous solution system have dissolved, add all the modified inorganic material obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6.

[0030] (c) Turn on the heating and raise the temperature to the initiation temperature of 55-60°C under nitrogen protection. Add 0.05-0.4 parts of initiator at one time and keep the temperature for 2-4 hours to obtain an organic-inorganic grafted liquid suspension stabilizer.

[0031] In this invention, the introduction of sulfonic acid monomers can improve the temperature and salt resistance of the polymer; the introduction of hydrophobic groups with carbon chains of different lengths can form a network structure by interlacing and associating with each other through intermolecular forces, thereby inhibiting the high-temperature dilution of cement slurry; the introduction of cationic monomers and ether monomers containing allyl groups can facilitate the wetting of cement particles, reduce surface tension, and thus reduce the cementing time.

[0032] The present invention also provides an organic-inorganic grafted suspension stabilizer, which is prepared by the above preparation method.

[0033] The present invention also provides a cement slurry, wherein the raw material composition of the cement slurry includes: cement, silica fume, water loss reducing agent, retarder, defoamer, liquid suspension stabilizer and water; wherein the liquid suspension stabilizer is the above-mentioned organic-inorganic grafted suspension stabilizer; wherein, based on the mass of cement as 100%, the dosage of the organic-inorganic grafted suspension stabilizer is 2.0%-5.0%, preferably 2.0%-3.5%.

[0034] According to a specific embodiment of the present invention, preferably, the raw material composition of the cement slurry includes: 600 parts of Grade G cement, 210 parts of silica fume, 20-30 parts of water loss reducing agent, 6-36 parts of retarder, 0.2-0.5 parts of defoamer, 12-30 parts of liquid suspension stabilizer, and 260-320 parts of water. More preferably, the raw material composition of the cement slurry includes: 600 parts of Grade G cement, 210 parts of silica fume, 24 parts of water loss reducing agent, 6-36 parts of retarder, 0.5 parts of defoamer, 12-30 parts of liquid suspension stabilizer, and 266-314 parts of water.

[0035] In some specific implementations, preferably, the water loss reducing agent includes one or more of BXF-200L(AF), BCG-200L, and BCF-230L, all manufactured by Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0036] In some specific embodiments, preferably, the retarder includes one or more of BCR-500L, BCR-300L, BCR-320L, BCR-290L, and BXR-200L, all manufactured by Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0037] In some specific implementations, preferably, the defoamer is G603, manufactured by Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] This invention employs an organic-inorganic grafting process. First, an inorganic material is modified using a vinyl organosilicon monomer to obtain a modified inorganic material. Then, by introducing monomers with different functions, long-chain polymers are grafted onto the surface of the modified inorganic material. During the preparation process, by modifying the inorganic material and grafting it onto its surface, the temperature resistance of the suspension stabilizer can be further improved, resulting in a composite temperature-resistant suspension stabilizer.

[0040] The organic-inorganic grafted suspension stabilizer provided by this invention can maintain good settling stability of cement slurry at a bottom hole circulation temperature (BHCT) of 100-200℃, effectively eliminate free fluid, does not affect cement slurry preparation and cementing, and has no adverse effects on the thickening and water loss properties of cement slurry, thus meeting the cementing needs of most deep wells. Attached Figure Description

[0041] Figure 1 shows the effect of the dosage of the suspension stabilizer prepared in Example 1 on the density difference between the upper and lower parts of the cement slurry.

[0042] Figure 2 is a comparison of cement slurry settlement test and BP settlement test conducted at 150℃.

[0043] Figure 3 is a thermogravimetric analysis curve of the suspension stabilizer prepared in Example 1.

[0044] Figure 4 shows the water loss of the suspension stabilizer prepared in Example 1 when combined with different water loss reducing agents at high temperature.

[0045] Figure 5 shows the effect curves of different types of retarder dosage on thickening time.

[0046] Figure 6 shows the trend of the effect of the dosage of the suspension stabilizer prepared in Example 1 on the thickening time. Detailed Implementation

[0047] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0048] Example 1:

[0049] This embodiment provides a method for preparing an organic-inorganic grafted suspension stabilizer, specifically including the following steps:

[0050] (a) Add 0.5 parts magnesium aluminum hydroxysilicate and 5 parts vinyltriethoxysilane (A151) to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0051] (b) Add 30 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5 parts of sodium vinyl sulfonate, 100 parts of N,N-dimethylacrylamide, 10 parts of N-ethylacrylamide, 5 parts of N-tert-butylacrylamide, 10 parts of dimethyldiallylammonium chloride, and 5 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water to obtain an aqueous solution system; turn on the stirrer, and after all the components in the aqueous solution system have dissolved, add all the modified inorganic material obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6;

[0052] (c) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at one time and keep the reaction at the temperature for 3 hours to obtain a liquid organic-inorganic grafted suspension stabilizer, which is labeled as sample A.

[0053] Example 2:

[0054] This embodiment provides a method for preparing an organic-inorganic grafted suspension stabilizer, specifically including the following steps:

[0055] (a) Add 0.5 parts magnesium aluminum hydroxysilicate and 5 parts vinyltriethoxysilane (A151) to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0056] (b) Add 20 parts of 2-acrylamido-2-methylpropanesulfonic acid, 10 parts of sodium p-styrenesulfonate, 80 parts of N,N-dimethylacrylamide, 10 parts of N-benzylacrylamide, 10 parts of N,N-diethyl-2-acrylamide, 5 parts of dimethyldiallylammonium chloride, and 5 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water to obtain an aqueous solution system; turn on the stirrer, and after all the components in the aqueous solution system have dissolved, add all the modified inorganic materials obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6;

[0057] (c) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at one time and keep the reaction at the temperature for 3 hours to obtain a liquid organic-inorganic grafted suspension stabilizer, which is labeled as sample B.

[0058] Example 3:

[0059] This embodiment provides a method for preparing an organic-inorganic grafted suspension stabilizer, specifically including the following steps:

[0060] (a) Add 0.5 parts magnesium aluminum hydroxysilicate and 5 parts vinyltriethoxysilane (A151) to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0061] (b) Add 15 parts of 2-acrylamido-2-methylpropanesulfonic acid, 10 parts of sodium p-styrenesulfonate, 5 parts of sodium vinylsulfonate, 100 parts of N,N-dimethylacrylamide, 5 parts of N-benzylacrylamide, 5 parts of N,N-diethyl-2-acrylamide, 5 parts of N-tetradecylacrylamide, 5 parts of N-tert-butylacrylamide, 5 parts of dimethyl diallyl ammonium chloride, 5 parts of methacryloyloxyethyltrimethylammonium chloride, and 10 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water to obtain an aqueous solution system; turn on the stirrer, and after all the components in the aqueous solution system have dissolved, add all the modified inorganic materials obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6;

[0062] (c) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at one time and keep the reaction at the temperature for 3 hours to obtain a liquid organic-inorganic grafted suspension stabilizer, which is labeled as sample C.

[0063] Example 4:

[0064] This embodiment provides a method for preparing an organic-inorganic grafted suspension stabilizer, specifically including the following steps:

[0065] (a) Add 0.5 parts magnesium aluminum hydroxysilicate and 5 parts vinyltriethoxysilane (A151) to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0066] (b) Add 40 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5 parts of sodium vinyl sulfonate, 75 parts of N,N-dimethylacrylamide, 5 parts of N-benzylacrylamide, 5 parts of N,N-diethyl-2-acrylamide, 5 parts of N-n-propylacrylamide, 5 parts of N-tetradecylacrylamide, 5 parts of N-tert-butylacrylamide, 5 parts of dimethyldiallylammonium chloride, 5 parts of methacryloyloxyethyltrimethylammonium chloride, 5 parts of octadecyldimethylallylammonium chloride, and 10 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water to obtain an aqueous solution system; turn on the stirrer, and after all the components in the aqueous solution system have dissolved, add all the modified inorganic materials obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6;

[0067] (c) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at one time and keep the reaction at the temperature for 3 hours to obtain a liquid organic-inorganic grafted suspension stabilizer, which is labeled as sample D.

[0068] Comparative Example 1:

[0069] This comparative example provides a method for preparing a liquid suspension stabilizer, specifically including the following steps:

[0070] (a) Add 0.5 parts magnesium aluminum hydroxysilicate and 5 parts vinyltriethoxysilane (A151) to 100 parts of anhydrous ethanol, stir and soak at room temperature for 12 hours, filter and dry to obtain modified inorganic material.

[0071] (b) Add 45 parts of 2-acrylamido-2-methylpropanesulfonic acid, 80 parts of N,N-dimethylacrylamide, 10 parts of N-ethylacrylamide, and 10 parts of N,N-diethyl-2-acrylamide to 500 parts of deionized water and mix to obtain an aqueous solution system; turn on the stirrer and wait for all the components in the aqueous solution system to dissolve, then add all the modified inorganic material obtained in step (a), and adjust the pH of the mixed solution obtained after dissolving the components with NaOH under ice bath conditions to 5-6;

[0072] (c) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at once and keep the reaction at the temperature for 3 hours to obtain a liquid suspension stabilizer, which is labeled as sample E.

[0073] Comparative Example 2:

[0074] This comparative example provides a method for preparing a liquid suspension stabilizer, specifically including the following steps:

[0075] (1) Add 45 parts of 2-acrylamido-2-methylpropanesulfonic acid, 80 parts of N,N-dimethylacrylamide, 10 parts of N-ethylacrylamide, 10 parts of N,N-diethyl-2-acrylamide, 10 parts of dimethyldiallylammonium chloride, and 10 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water and mix to obtain an aqueous solution system; turn on the stirrer and wait for each component in the aqueous solution system to dissolve. Then, under ice bath conditions, use NaOH to adjust the pH of the mixed solution obtained after dissolving each component to 5-6.

[0076] (2) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at once and keep the reaction at the temperature for 3 hours to obtain a liquid polymer, which is labeled as sample F.

[0077] Comparative Example 3:

[0078] This comparative example provides a method for preparing a liquid suspension stabilizer, specifically including the following steps:

[0079] (1) Add 30 parts of 2-acrylamido-2-methylpropanesulfonic acid, 60 parts of N,N-dimethylacrylamide, 15 parts of N-ethylacrylamide, 5 parts of N-benzylacrylamide, 10 parts of N-tert-butylacrylamide, 10 parts of dimethyldiallylammonium chloride, and 5 parts of polyethylene glycol monoallyl ether to 500 parts of deionized water and mix to obtain an aqueous solution system; turn on the stirrer and wait for each component in the aqueous solution system to dissolve. Then, under ice bath conditions, use NaOH to adjust the pH of the mixed solution obtained after dissolving each component to 5-6.

[0080] (2) Turn on the heating and raise the temperature to the initiation temperature of 60°C under nitrogen protection. Add 0.2 parts of ammonium persulfate at one time and keep the reaction at the temperature for 3 hours to obtain a liquid polymer.

[0081] (3) Subsequently, 0.5 parts of magnesium aluminum hydroxysilicate were added to the liquid polymer and stirred for 2 hours to obtain an organic-inorganic compound liquid suspension stabilizer, which was labeled as sample G.

[0082] The following investigation explores the various properties of the suspension stabilizers prepared in Examples 1-4 and Comparative Examples 1-3 when used in cement slurry. The cement slurry in each of the following test examples was prepared in accordance with the standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells".

[0083] Experimental Example 1

[0084] This experiment compares the settling stability evaluation results of cement slurry prepared with suspension stabilizers (AD samples) in Examples 1-4, suspension stabilizers prepared with suspension stabilizers (EG samples) in Comparative Examples 1-3, and cement slurry without suspension stabilizers at a bottom hole circulation temperature (BHCT) of 200°C. The data results are shown in Table 1.

[0085] The cement slurry formulation, by weight, includes: 600 parts of Grade G oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer (BXF-200L(AF)), 36 parts of retarder (BCR-500L), 0.5 parts of defoamer (G603), 21 parts of liquid suspension stabilizer, and 276 parts of fresh water; the liquid-to-solid ratio of the cement slurry is 0.44, resulting in a density of 1.90 g / cm³. 3 Cement grout.

[0086] Among them, Grade G oil well cement is a product of Jiahua Special Cement Co., Ltd.; silica fume is 140-300 mesh silica fume produced by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; water loss reducer BXF-200L(AF), retarder BCR-500L and defoamer G603 are products of Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0087] The test method for the settlement stability of cement slurry is as follows: Cement slurry is cured according to the test method specified in Section 3 of Chapter 15 of standard GB / T 19139-2012. The cured cement slurry is stirred at 4000 r / min for 15 seconds. Then, 400 mL is poured directly into a clean, dry 500 mL graduated cylinder within 1 minute. The cylinder opening is sealed with plastic film, and the cylinder is immediately placed in a water bath preheated to 90℃ for 2 hours. Following the test method specified in Chapter 6 of GB / T 19139-2012, a digital liquid density meter is used to test and record the density of the top and bottom 200 mL of cement slurry in the graduated cylinder. The density difference between the top and bottom 200 mL of cement slurry is obtained by subtracting the density of the top 200 mL from the density of the bottom 200 mL of cement slurry, and this difference is used to determine the settlement stability of the cement slurry.

[0088] Table 1. Settlement stability test results of cement grout at 200℃ (BHCT)

[0089] As shown in Table 1, the density difference between the upper and lower sections of the cement slurry without a suspending stabilizer at a curing temperature of 200℃ (BHCT) is 0.365 g / cm³. 3 The free liquid was 15 mL, and the settling stability was extremely poor; the density difference between the upper and lower parts of the cement slurry in sample E of Comparative Example 1 was 0.065 g / cm³. 3 However, its settling time is relatively long; using the cement slurry from the FG sample in Comparative Examples 2-3 at a curing temperature of 200℃ (BHCT), the settling stability of the cement slurry was 0.115 g / cm³. 3 and 0.105 g / cm 3 Furthermore, it contains a small amount of free liquid; therefore, the above results are not ideal.

[0090] In comparison, the cement slurry prepared using the suspension stabilizer AD samples from Examples 1-4 exhibited better settling stability, with a density difference between the upper and lower sections of the cement slurry ≤ 0.025 g / cm³. 3 It can effectively eliminate free liquid without affecting the preparation and application of cement slurry. The application time is ≤18s, and it can maintain good settling stability of cement slurry at 200℃ (BHCT).

[0091] Experimental Example 2

[0092] This experiment used the suspension stabilizer A sample prepared in Example 1. The effect of different dosages of the suspension stabilizer on the stability of cement paste was tested at a temperature of 100-200℃ (BHCT). The test results are shown in Figure 1.

[0093] The cement slurry had a liquid-to-solid ratio of 0.44, resulting in a density of 1.90 g / cm³.3 The cement slurry contains G-grade oil well cement produced by Jiahua Special Cement Co., Ltd.; silica fume is 140-300 mesh silica fume produced by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; and water loss reducer BXF-200L(AF), retarder BCR-300L and defoamer G603 are products produced by Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0094] The cement slurry formulations with different amounts of suspending stabilizer, based on parts by weight, are as follows:

[0095] When the dosage of suspension stabilizer is 1.5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6-36 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 9 parts of suspension stabilizer, and 276-320 parts of fresh water;

[0096] When the dosage of suspension stabilizer is 2.0% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6-36 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 12 parts of suspension stabilizer, and 276-320 parts of fresh water;

[0097] When the dosage of suspension stabilizer is 2.5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6-36 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 15 parts of suspension stabilizer, and 276-320 parts of fresh water;

[0098] When the dosage of suspension stabilizer is 3.0% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6-36 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 18 parts of suspension stabilizer, and 276-320 parts of fresh water;

[0099] When the dosage of suspension stabilizer is 3.5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6-36 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 21 parts of suspension stabilizer, and 276-320 parts of fresh water.

[0100] In Figure 1, when the dosage of the suspension stabilizer is fixed, the corresponding retarder dosage at different temperatures is shown in Table 2. Taking the mass of Grade G cement as 100%, the retarder dosage is calculated, and the fresh water dosage is determined by the liquid-to-solid ratio. Fresh water dosage = (mass of Grade G oil well cement + mass of silica fume) × liquid-to-solid ratio - mass of other liquid admixtures.

[0101] Table 2. Retarder dosage at different temperatures as shown in Figure 1

[0102] As can be seen from the comparison of the test results in Figure 1, the density difference between the upper and lower parts of the cement slurry gradually decreases with the increase of the dosage of the suspension stabilizer, proving that the settling stability of the cement slurry can be significantly improved. Therefore, the suspension stabilizer provided by the present invention can maintain good settling stability of conventional density cement slurry at a temperature of 100-200℃ (BHCT) with a dosage of 2.0%-3.5%.

[0103] Experimental Example 3

[0104] This experiment uses the BP settlement test to determine the static stability of cement slurry and compares it with the settlement stability results of cement slurry to verify the settlement stability results of cement slurry.

[0105] The test method for the BP settlement test is as follows: Cement slurry is cured according to the test method specified in Section 3 of Chapter 15 of standard GB / T 19139-2012. After the cured cement slurry is stirred at 4000 r / min for 15 seconds, it is poured into the settling pipe to a depth of approximately 20 mm from the top. The inner diameter of the settling pipe should be 25 mm ± 5 mm, and the minimum length should be 100 mm. A thin layer of grease should be applied to the inner surface of the settling pipe and all joints to ensure no leakage of cement slurry and to prevent damage to the cement stone during disassembly. During the test, the settling pipe should not react with the well cement and should not deform. Simultaneously, the cement slurry in the settling pipe should be stirred to remove air bubbles, and then the settling pipe should be filled with cement slurry. The top of the settling tube should be covered to prevent cement slurry from overflowing. The top cover should have a pressure transmission hole. The settling tube filled with cement slurry should be placed vertically in a heating / cooling container filled with water. The container should be preheated or precooled to the test temperature. If the test temperature is higher than 90°C, the curing container should be preheated or precooled to 90°C. Cure the cement slurry for 24 hours or until it solidifies. Remove the settling tube from the curing container and place it in a water bath at 27°C ± 6°C. After the settling tube has cooled, remove the cement stone sample and immerse it in water to prevent it from drying out. The length of the cement stone sample should be measured, and two marks should be made approximately 20 mm from the bottom and top of the sample. Divide the sample into approximately equal parts (at least two parts) between these two marks and mark them. Cut the sample at these marks and arrange the cut pieces in order.

[0106] Before weighing each test block, keep them submerged in water. The balance accuracy should be 0.01g, preferably 0.001g. The preferred method for determining the density of each cement test block is as follows: Place a beaker containing water on a balance, remove the tare weight to zero the balance; remove a section of the test block from the water bath and gently dry it with a paper towel, place the test block next to the beaker on the balance, and record its mass as mi, then remove the test block from the balance; remove the tare weight again to zero the balance; tie a thin rope around the test block, suspend the test block with the rope, and place it in the water in the beaker, ensuring that the entire test block is completely submerged in the water without touching the bottom or side of the beaker, and without any air bubbles adhering to the test block; record the mass of the test block in the water as mi(w), then remove the test block from the water and remove the tare weight from the balance; repeat the above steps to determine the density of each section of the cement test block; using Archimedes' principle, calculate the relative density of each section of the cement test block according to the formula drel = mi / mi(w), and finally calculate the density difference between the top and bottom sections to determine the density distribution and settlement stability of the cement sample.

[0107] This test example uses cement slurry prepared from sample A of suspension stabilizer in Example 1. The results of cement slurry sedimentation test and BP sedimentation test were compared when the dosage of suspension stabilizer was changed at 150℃. The test results are shown in Figure 2.

[0108] The cement slurry had a liquid-to-solid ratio of 0.44, resulting in a density of 1.90 g / cm³. 3 The cement slurry formulations, by weight, for different amounts of suspending stabilizer are as follows:

[0109] When the dosage of suspension stabilizer is 2.3% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 13.8 parts of suspension stabilizer, and 300.1 parts of fresh water;

[0110] When the dosage of suspension stabilizer is 2.5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 15 parts of suspension stabilizer, and 298.9 parts of fresh water;

[0111] When the dosage of suspension stabilizer is 2.7% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 parts of retarder BCR-300L, 0.5 parts of defoamer G603, 16.2 parts of suspension stabilizer, and 297.7 parts of fresh water.

[0112] Among them, Grade G oil well cement is a product of Jiahua Special Cement Co., Ltd.; silica fume is 140-300 mesh silica fume produced by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; water loss reducer BXF-200L(AF), retarder BCR-500L and defoamer G603 are products of Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0113] As shown in Figure 2, by comparing the suspension performance of the suspension stabilizer at high temperature using two different test methods, it can be seen that the results of the two test methods are similar. Therefore, the suspension stabilizer provided by this invention can maintain good settling stability of cement slurry at high temperature.

[0114] Test Example 4

[0115] This experiment tested the thermogravimetric analysis (TG-DTG) curve of the suspension stabilizer A sample prepared in Example 1. The specific results are shown in Figure 3, where TG is thermogravimetric analysis and DTG is the rate of weight loss of the substance per unit time.

[0116] As can be seen from Figure 3, the thermal decomposition of suspension stabilizer molecules mainly consists of two stages:

[0117] The first stage is thermal degradation within a temperature range of 251-333℃, during which the mass loss of the suspension stabilizer is 23.1%. The DTG curve for this stage shows a trough at 298℃. The main reason for this weight loss is the extensive decomposition and breakage of side chain groups such as amide and sulfonic acid groups in the suspension stabilizer molecule.

[0118] The second stage involves thermal degradation within a temperature range of 333-507℃, during which the mass loss of the suspension stabilizer is 39.1%. A trough is observed on the DTG curve for this stage, at a temperature of 398℃. The main reason for this weight loss is the breakage of the main chain in the suspension stabilizer molecule. After the temperature rises above 507℃, the thermogravimetric curve tends to stabilize, leaving only a small amount of carbonaceous residue.

[0119] Therefore, the suspension stabilizer provided by this invention has high temperature resistance and can meet the cementing needs of most deep wells.

[0120] Experimental Example 5

[0121] During cementing operations, cement slurry can "leak" as it passes through permeable formations under formation pressure, leading to water loss, reduced fluidity, and compromised on-site safety. Therefore, different types of admixtures may exhibit synergistic or incompatible behaviors in cement slurry.

[0122] In this study, the effect of the suspension stabilizer A sample prepared in Example 1 on the water loss performance of cement slurry after being used in combination with different water loss reducing agents at high temperature was tested. The results are shown in Figure 4.

[0123] The cement slurry had a liquid-to-solid ratio of 0.44, resulting in a density of 1.90 g / cm³. 3 The cement slurry formulations, by weight, when combined with different water loss reducing agents are as follows:

[0124] By weight, the cement slurry formulation containing a suspension stabilizer includes: 600 parts of Grade G oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer, 36 parts of retarder (BCR-500L), 0.5 parts of defoamer (G603), 15 parts of liquid suspension stabilizer, and 282 parts of fresh water. Among these, the fluid loss reducers selected in different cement slurries are, in order, BXF-200L(AF), BCG-200L, and BCF-230L.

[0125] Without a suspending stabilizer, the cement slurry formulation includes: 600 parts Grade G oil well cement, 210 parts silica fume, 24 parts fluid loss reducer, 36 parts retarder (BCR-500L), 0.5 parts defoamer (G603), and 297 parts fresh water. The fluid loss reducers selected in different cement slurries are, in descending order: BXF-200L(AF), BCG-200L, and BCF-230L.

[0126] Among them, Grade G oil well cement is a product of Jiahua Special Cement Co., Ltd.; silica fume is 140-300 mesh silica fume produced by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; and water loss reducing agent (BXF-200L(AF), BCG-200L, BCF-230L), retarder BCR-500L and defoamer G603 are products of Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0127] As shown in Figure 4, at 150℃, the suspension stabilizer can be used in combination with different types of water loss reducing agents. The water loss of cement slurry without the suspension stabilizer is (50-60) mL / 30 min. In contrast, the water loss of cement slurry can be further reduced after the suspension stabilizer is added.

[0128] Therefore, the suspension stabilizer provided by the present invention can be successfully formulated with different types of water loss reducing agents without damaging the water loss performance of cement slurry.

[0129] Experimental Example 6

[0130] In cement paste systems, due to the differences in structure between different types of retarders, when they are mixed with suspension stabilizers, they may exhibit competitive adsorption behavior on the surface of cement particles, which can affect the performance of individual admixtures.

[0131] In this study, the effect of the suspension stabilizer A sample prepared in Example 1 on the thickening time of cement slurry was tested when it was used in combination with different types of retarders. The results are shown in Figures 5 and 6.

[0132] The cement slurry had a liquid-to-solid ratio of 0.44, resulting in a density of 1.90 g / cm³. 3 The cement slurry, grade G oil well cement is a product of Jiahua Special Cement Co., Ltd.; the silica fume is 140-300 mesh silica fume produced by Tianjin Yuyang Ultrafine Mineral Powder Processing Co., Ltd.; the water loss reducing agent BXF-200L(AF), retarders (BCR-300L, BCR-500L, BCR-320L, BCR-290L, BXR-200L) and defoamer G603 are products of Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0133] In Figure 5, the cement slurry formulation, by weight, includes: 600 parts of Grade G oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 6 to 36 parts of retarder, 0.5 parts of defoamer G603, 15 parts of suspension stabilizer, and 280.9 to 310.9 parts of fresh water. The amount of retarder added is calculated based on 100% of the weight of Grade G cement, and the amount of fresh water added is determined by the liquid-to-solid ratio.

[0134] As shown in Figure 5, under the same dosage of suspension stabilizer (2.5%), the thickening time of cement paste can be adjusted by changing the dosage of retarder.

[0135] Figure 6 further explores the effect of the dosage of suspension stabilizer on the thickening time of cement paste by selecting different retarders (types and dosages are shown in Table 3) at different temperatures.

[0136] Table 3 shows the types and dosages of retarder at different temperatures as shown in Figure 6.

[0137] Calculate the amount of retarder to be added based on the mass of Grade G cement (100%), and determine the amount of fresh water to be added based on the liquid-to-solid ratio. The cement paste formula, by mass, is as follows:

[0138] Without the suspension stabilizer, the cement slurry includes: 600 parts of Grade G oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 to 36 parts of retarder, 0.5 parts of defoamer G603, and 295.9 to 313.9 parts of fresh water.

[0139] When the dosage of suspension stabilizer is 2.5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 to 36 parts of retarder, 0.5 parts of defoamer G603, 15 parts of suspension stabilizer, and 280.9 to 298.9 parts of fresh water.

[0140] When the dosage of suspension stabilizer is 5% (based on the mass of G-grade cement as 100%), the cement slurry includes: 600 parts of G-grade oil well cement, 210 parts of silica fume, 24 parts of fluid loss reducer BXF-200L(AF), 18 to 36 parts of retarder, 0.5 parts of defoamer G603, 30 parts of suspension stabilizer, and 265.9 to 283.9 parts of fresh water.

[0141] As shown in Figure 6, when the retarder dosage is kept constant at the same temperature, adjusting the dosage of the suspension stabilizer results in a small increase in the cement slurry thickening time, with no significant impact.

[0142] Therefore, based on the results in Figures 5 and 6, the suspension stabilizer provided by this invention has no adverse effect on the thickening performance of cement slurry.

Claims

1. A raw material composition for an organic-inorganic grafted suspension stabilizer, wherein, By weight, the raw material composition comprises: 15-45 parts of sulfonic acid monomer, 60-180 parts of hydrophobic monomer, 1-15 parts of cationic monomer, 1-15 parts of allyl ether monomer, and modified inorganic material. The modified inorganic material is obtained by modifying 0.1-1.5 parts of inorganic material with 1-15 parts of vinyl organosilicon monomer.

2. The raw material composition according to claim 1, wherein, The vinyl organosilicon monomers include one or more of γ-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, and vinyltrimethoxysilane.

3. The raw material composition according to claim 1, wherein, The inorganic material includes one or more of magnesium aluminum hydroxysilicate, montmorillonite, bentonite, and nano silica.

4. The raw material composition according to claim 1, wherein, The sulfonic acid monomer includes one or more of 2-acrylamido-2-methylpropanesulfonic acid, sodium p-styrenesulfonate, and sodium vinylsulfonate.

5. The raw material composition according to claim 1, wherein, The hydrophobic monomer includes two or more combinations of methacrylamide, N-ethylacrylamide, N-n-propylacrylamide, N-benzylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, N-tetradecylacrylamide, and N,N-diethyl-2-acrylamide.

6. The raw material composition according to claim 1, wherein, The cationic monomer includes one or more of dimethyl diallyl ammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and octadecyl dimethyl allyl ammonium chloride.

7. The raw material composition according to claim 1, wherein, The allyl-containing ether monomers include one or more of polyethylene glycol monoallyl ether, allyl ether, and allyl hydroxyethyl ether.

8. A method for preparing an organic-inorganic grafted suspension stabilizer, wherein, The preparation method uses the raw material composition of the organic-inorganic grafted suspension stabilizer according to any one of claims 1-7, and includes the following steps: (1) Modified inorganic materials are obtained by using vinyl organosilicon monomers; (2) Mix sulfonic acid monomers, hydrophobic monomers, cationic monomers, and allyl ether monomers in water to obtain an aqueous solution system of organic monomers containing carbon-carbon double bonds. (3) The modified inorganic material is mixed with an aqueous solution system of organic monomers containing carbon-carbon double bonds, and an initiator is added dropwise to carry out a free radical polymerization reaction, so that the long-chain polymer is grafted onto the surface of the inorganic material to obtain an organic-inorganic grafted suspension stabilizer.

9. The preparation method according to claim 8, wherein, In step (3), before adding the initiator, the pH of the reaction system is adjusted to 5-6 under ice bath conditions.

10. The preparation method according to claim 8, wherein, The initiation temperature of the free radical polymerization reaction is 55-65℃, and the reaction time is 2-8h.

11. An organic-inorganic grafted suspension stabilizer, which is prepared by the preparation method according to any one of claims 8-10.

12. A cement grout, wherein, The raw materials of this cement slurry include: cement, silica fume, water loss reducer, retarder, defoamer, liquid suspension stabilizer and water; The liquid suspension stabilizer is the organic-inorganic grafted suspension stabilizer as described in claim 11; The dosage of the organic-inorganic grafted suspension stabilizer is 2.0%-5.0% based on the mass of cement (100%).

13. The cement grout according to claim 12, wherein, The raw material composition of the cement slurry includes: 600 parts of Grade G cement, 210 parts of silica fume, 20-30 parts of water loss reducing agent, 6-36 parts of retarder, 0.2-0.5 parts of defoamer, 12-30 parts of liquid suspension stabilizer, and 260-320 parts of water.

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