A high-temperature retrogression agent, a cement paste containing the same, and a method for preparing the same

Abstract

The application belongs to the technical field of cementing, and particularly relates to a high-temperature-resistant decay agent, a cement slurry containing the same and a preparation method of the cement slurry. The high-temperature-resistant decay agent contains, by weight of 100 parts, 10-100 parts of spherical glass powder and 0-90 parts of quartz powder. The cementing cement slurry prepared by using the high-temperature-resistant decay agent can significantly improve the cement slurry mixing speed and the rheological property.

Description

Technical Field

[0001] This invention belongs to the field of cementing technology, specifically relating to a high-temperature degradation resistant agent, a cement slurry containing the same, and a method for preparing the same. Background Technology

[0002] In the oilfield cementing industry, high-temperature strength degradation of cement stone is a core issue affecting the long-term sealing integrity of cement sheaths, especially in the high-temperature and high-pressure environments of deep and ultra-deep wells. This phenomenon significantly weakens the interlayer sealing capacity of the cement sheath, leading to a decline in the cementing quality of oil and gas wells. Microscopic mechanism studies show that cement stone has two critical degradation temperature points: 110℃ and 150℃. When the temperature is >110℃, the cement hydration products undergo crystal transformation, generating low-strength phases such as α-C2SH, which destroys the dense structure of the cement stone, resulting in a positive correlation between the strength degradation rate and temperature. When the temperature is >150℃, the compressive strength can drop below 5MPa, and the mechanical properties are severely degraded. Under ultra-high temperature environments >200℃, the calcareous silicate (C5S6H) in the cement stone... 5.5 The transformation from siliceous calcium silicate (C6S6H) to hard calcium silicate is the core reason for the strength decline, as the parallel needle-like structure formed by the latter significantly increases the porosity; after the temperature is >210℃, hard calcium silicate further coarsens, accompanied by the formation of high-permeability, low-strength byproducts such as calcareous zeolite (C2S3H2) and columnar calcium silicate (C3S2H3); in a dynamic water environment >300℃, the dissolution of SiO2 and the decalcification reaction are intensified, leading to structural disintegration.

[0003] The key to improving the high-temperature resistance of cement stone lies in optimizing the silica-calcium ratio and regulating hydration products. Domestic and international research focuses on three technical approaches. First, improving high-temperature resistance by reducing the Ca(OH)2 content in sand-added oil well cement, i.e., appropriately reducing the amount of cement or adding pozzolanic active materials (such as silica fume), to form denser siliceous calcium silicate and hard siliceous calcium silicate in the early stages of high-temperature hydration. Second, improving the thermal stability of sand-added oil well cement stone by adding high-temperature reinforcing materials (such as inorganic whiskers and inorganic fibers), as whiskers and fibers can enhance the cement stone's resistance to thermal shock. Third, adding nanomaterials, which have high reactivity; for example, nano-SiO2 can react with Ca(OH)2 in a pozzolanic reaction, reducing the content of low-crystallinity Ca(OH)2, and the unreacted portion can fill the pores in the cement stone, making the microstructure of the cement stone denser.

[0004] Materials that improve the high-temperature resistance of cement stone mainly include quartz sand, aluminum-containing materials, glass powder, and materials containing non-crystalline silica such as liquid silica, calcium whiskers, rice husk ash, and potassium iron ore powder.

[0005] Traditional high-temperature strength degradation resistant materials, while able to improve the strength degradation problem of cement paste, may require the addition of large amounts of water loss reducers and other functional materials under extremely high temperature conditions, leading to difficulties in cement paste mixing and poor rheological properties; or in high-density formulations, the addition of high solids or functional materials may also lead to difficulties in cement paste mixing and poor rheological properties; or in low-density high-temperature formulations, the amount of weight-reducing agent may be increased to improve compressive strength, resulting in high solids and difficulties in cement paste mixing and poor rheological properties; or in high-temperature elastic and tough, self-healing cement pastes, the addition of functional materials may increase the solids and worsen the rheological properties of the paste.

[0006] Therefore, there is an urgent need in this field for a material that can improve the mixing ability and rheology of cement paste while maintaining its original resistance to high-temperature strength degradation. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an anti-high-temperature degradation agent, a cement slurry containing the same, and a method for preparing the same.

[0008] Specifically, the present invention is achieved through the following technical solutions: An anti-high temperature degradation agent, comprising, by total weight of 100 parts: 10-100 parts of spherical glass powder; and 0-90 parts of quartz powder.

[0009] The above-mentioned anti-high temperature degradation agent, based on a total weight of 100 parts, includes: 33-75 parts of spherical glass powder and 25-67 parts of quartz powder.

[0010] The density of the spherical glass powder in the aforementioned anti-high temperature degradation agent is 2.4 g / cm³. 3 ~2.6 g / cm 3 , the objects above the 70-mesh sieve are ≤10%, the objects under the 325-mesh sieve are ≤10%, and the roundness rate is ≥85%.

[0011] The aforementioned anti-high-temperature degradation agent contains quartz powder with a density of 2.55 g / cm³. 3 ~2.75 g / cm 3 The crystalline silica content is ≥95%, and the median particle size is 1-400 micrometers.

[0012] A method for preparing an anti-high temperature degradation agent includes: adding spherical glass powder and quartz powder into a mixer according to a certain ratio, and mixing until uniform, thereby obtaining the agent.

[0013] A cement slurry, based on 100 parts by weight of oil well cement, includes 27-50 parts of the above-mentioned anti-high temperature degradation agent, 0.3-2 parts of defoamer, and functional materials; wherein the functional materials are selected from one or more of the following: 0-50 parts of weight-reducing agent, 0-300 parts of weight-increasing agent, 0-30 parts of toughening agent, 0-30 parts of self-healing agent, 0-30 parts of anti-channeling agent, 0-15 parts of fluid loss reducing agent, 0.1-10 parts of retarder, 0-5 parts of dispersant, 0-5 parts of suspension stabilizer, and 0-10 parts of expansion agent.

[0014] The cement slurry mentioned above, wherein the oil well cement is Grade G oil well cement or Grade H oil well cement; and the defoamer is selected from one or more of organosilicon, polyether, polyether-modified organosilicon, and phosphate ester defoamers.

[0015] In the aforementioned cement slurry, the weight-reducing agent is selected from one or more of artificial hollow glass microspheres, natural cenospheres, expanded perlite, and rock asphalt; the weight-enhancing agent is selected from one or more of hematite powder, magnetite powder, spherical micro-manganese, barite, pyrite powder, reduced iron powder, and alloy powder.

[0016] In the aforementioned cement slurry, the toughening agent is selected from one or more of rubber, epoxy resin, asphalt, carbon fiber, basalt fiber, calcium carbonate whiskers, and polypropylene fiber; the self-healing agent is selected from one or more of polyacrylamide / acrylic acid copolymer salt-sensitive resin, styrene-butadiene rubber, SBS thermoplastic elastomer granules polyolefin elastomer, acrylate microspheres, epoxy resins, ettringite-based expanding agents, and sodium metasilicate.

[0017] The cement slurry described above contains an anti-channeling agent selected from styrene-butadiene latex, hydroxystyrene-butadiene latex, nitrile latex, styrene-acrylic latex, epoxy resin emulsion, microsilica and its emulsion, and nanosilica and its emulsion; and a water loss reducing agent selected from one or more of acrylamide-sodium acrylate copolymer, N,N-dimethylacrylamide and acrylamide-2-methylpropanesulfonate copolymer, and polyvinyl alcohol copolymer.

[0018] The cement slurry described above uses a retarder selected from one or more of sodium acrylamide-2-methylpropanesulfonate and acrylic acid copolymer, polyamino polyether organophosphate, and citric acid; and a dispersant selected from one or more of polycarboxylic acid polymers and aldehyde-ketone condensates.

[0019] In the aforementioned cement slurry, the suspension stabilizer is selected from one or more of high molecular weight polymers, xanthan gum, styrax, styrax, and sepiolite; the expansion agent is selected from one or more of magnesium oxide, calcium oxide, and ettringite-based expansion agents.

[0020] A method for preparing cement slurry, comprising: (1) Mix oil well cement and anti-high temperature degradation agent according to the ratio, and selectively add one or more of weighting agents or weight-reducing agents, expansion agents, toughening agents, self-repairing agents, and anti-channeling agents. Mix evenly according to the ratio to obtain dry mixture; (2) Mix the slurry water with the water loss reducer, retarder, dispersant, anti-channeling agent, suspension stabilizer and defoamer according to the ratio to obtain a liquid phase mixture; (3) At the work site, the dry mixture and the liquid mixture are mixed evenly to obtain the cement slurry.

[0021] The preparation method described above is characterized in that the slurry water is one of fresh water, seawater, or salt water.

[0022] The technical solution of the present invention has the following beneficial effects: (1) The high-temperature degradation agent of the present invention has good particle size distribution, good material flowability, and good stability during transportation, storage and mixing. (2) The high-temperature degradation agent of the present invention has uniform and stable material properties, and its use is not affected by long-term storage; (3) The cement slurry prepared using the high-temperature degradation agent of the present invention can be used to prepare cement with a strength of 1.20~2.80 g / cm³ by adjusting the weighting or weighting of the materials. 3 Density cement grout; (4) The cement slurry prepared using the anti-high temperature degradation agent of the present invention can significantly improve the cement slurry mixing speed and improve the rheological properties; (5) The cement slurry prepared using the anti-high temperature degradation agent of the present invention has no significant effect on the free fluid, API water loss, compressive strength and anti-high temperature strength degradation of the cement slurry. Detailed Implementation

[0023] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0024] The technical concept of this invention is as follows: using high-roundness spherical glass powder to replace traditional angular quartz powder, significantly reducing the friction between cement paste particles through the "ball bearing" effect, improving rheology and mixing efficiency; at the same time, it can be compounded with quartz powder to optimize the gradation, and while maintaining the resistance to high-temperature strength degradation (inhibiting high-temperature crystal transformation), it solves the problem of difficult paste adjustment in extremely high temperature, high / low density and complex functional systems of traditional materials, and achieves good workability and sealing integrity of cement paste in a wide density range.

[0025] Specifically, the high-temperature degradation resistant agent of the present invention comprises, by a total weight of 100 parts: 10-100 parts of spherical glass powder and 0-90 parts of quartz powder.

[0026] In some preferred embodiments, the density of the spherical glass powder is 2.4 g / cm³. 3 ~2.6 g / cm 3 , the objects above the 70-mesh sieve are ≤10%, the objects under the 325-mesh sieve are ≤10%, and the roundness rate is ≥85%.

[0027] This invention prepares a high-temperature strength degradation resistant material using spherical glass powder, which significantly improves the rheological properties of cement slurry while ensuring the high-temperature degradation resistance of traditional quartz materials.

[0028] In practice, when the density, particle size, and sphericity of spherical glass powder are not within the scope of protection of this invention, its improvement on the rheological properties of cement slurry system is not significant, or it significantly deteriorates the performance of cement slurry.

[0029] In some preferred embodiments, the spherical glass powder in the anti-high temperature degradation agent of the present invention is 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts or 100 parts, or any value between any two of the above, based on a total weight of 100 parts.

[0030] In practice, when the proportion of spherical glass powder in the anti-high temperature degradation agent of the present invention is less than 10 parts, the improvement on the rheological properties of the cement slurry system is not significant.

[0031] In a further preferred embodiment, the proportion of spherical glass powder in the anti-high temperature degradation agent of the present invention is 33 to 75 parts per 100 parts by weight.

[0032] In some preferred embodiments, the density of the quartz powder is 2.55 g / cm³. 3 ~2.75 g / cm 3 The crystalline silica content is ≥95%, and the median particle size is 1-400 micrometers.

[0033] This invention, by mixing quartz powder and spherical glass powder in a certain proportion, achieves resistance to high-temperature strength degradation and significantly improves the rheological properties of cement paste, while reducing the cost of use.

[0034] In practice, when the density, silica content, and particle size of the quartz powder are outside the scope of protection of this invention, the quality of the quartz powder will be lower than the reasonable range of commonly used anti-high temperature degradation agents in oilfield cementing, significantly deteriorating the performance of cement slurry.

[0035] In some optional embodiments, the quartz powder in the anti-high temperature degradation agent of the present invention is 0 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts or 50 parts by total weight of 100 parts, or any value between any two of the above values.

[0036] In a further preferred embodiment, the proportion of quartz powder in the anti-high temperature degradation agent of the present invention is 25 to 67 parts per 100 parts by weight.

[0037] On the other hand, the present invention also provides a method for preparing an anti-high temperature degradation agent, comprising: mixing spherical glass powder and quartz powder evenly according to a certain ratio.

[0038] In another aspect, the present invention also provides a cement slurry, based on 100 parts by weight of oil well cement, comprising 27-50 parts of the above-mentioned anti-high temperature degradation agent, 0.3-2 parts of defoamer, and functional materials; wherein the functional materials are selected from one or more of the following: 0-50 parts of weight-reducing agent, 0-300 parts of weight-increasing agent, 0-30 parts of toughening agent, 0-30 parts of self-healing agent, 0-30 parts of anti-channeling agent, 0-15 parts of fluid loss reducing agent, 0.1-10 parts of retarder, 0-5 parts of dispersant, 0-5 parts of suspension stabilizer, and 0-10 parts of expansion agent.

[0039] This invention, through adjusting the weight or weight of the material, can be used to prepare materials with a strength of 1.20~2.80 g / cm³. 3 Cement slurry with a density range.

[0040] The defoamer, weight-reducing agent, weight-increasing agent, toughening agent, self-healing agent, anti-channeling agent, water loss reducing agent, retarder, dispersant, suspension stabilizer, and expansion agent in the cement slurry of the present invention can all be obtained through conventional selection according to actual production needs.

[0041] In some preferred embodiments, the oil well cement is Grade G or Grade H oil well cement; the defoamer is selected from one or more of organosilicon, polyether, polyether-modified organosilicon, and phosphate ester defoamers; the weight-reducing agent is selected from one or more of artificial hollow glass microspheres, natural cenospheres, expanded perlite, and rock asphalt; the weighting agent is selected from one or more of hematite powder, magnetite powder, spherical micro-manganese, barite, pyrite powder, reduced iron powder, and alloy powder; the toughening agent is selected from one or more of rubber, epoxy resin, asphalt, carbon fiber, basalt fiber, calcium carbonate whiskers, and polypropylene fiber; and the self-healing agent is selected from polyacrylamide (AM) / acrylic acid (AA) copolymer salt-sensitive resin, styrene-butadiene rubber, and SBS. The product comprises one or more of the following: thermoplastic elastomer particles, polyolefin elastomers, acrylate microspheres, epoxy resins, ettringite-based expanding agents, and sodium metasilicate; the anti-channeling agent is selected from latex (including styrene-butadiene latex, hydroxystyrene-butadiene latex, nitrile latex, and styrene-acrylic latex), epoxy resin emulsions, microsilica and its emulsions, and nanosilica and its emulsions; the water loss reducing agent is selected from one or more of the following: acrylamide-sodium acrylate copolymer, N,N-dimethylacrylamide and acrylamide-2-methylpropanesulfonate copolymer, and polyvinyl alcohol copolymer; the retarder is selected from one or more of the following: acrylamide-2-methylpropanesulfonate and acrylic acid copolymer, polyamino polyether organophosphates, and citric acid; the dispersant is selected from one or more of the following: polycarboxylic acid polymers and aldehyde-ketone condensates; the suspension stabilizer is selected from one or more of the following: polymers, xanthan gum, styrene gum, styrene gum, and sepiolite; and the expanding agent is selected from one or more of the following: magnesium oxide, calcium oxide, and ettringite-based expanding agents.

[0042] Furthermore, the present invention also provides a method for preparing the above-mentioned cement slurry, comprising: (1) Mix oil well cement and anti-high temperature degradation agent according to the ratio, and selectively add one or more of weighting agents or weight-reducing agents, expansion agents, toughening agents, self-repairing agents, and anti-channeling agents. Mix evenly according to the ratio to obtain dry mixture; (2) Mix the slurry water with the water loss reducer, retarder, dispersant, anti-channeling agent, suspension stabilizer and defoamer according to the ratio to obtain a liquid phase mixture; (3) At the work site, the dry mixture and the liquid mixture are mixed evenly to obtain the cement slurry.

[0043] In some preferred embodiments, the slurry water is one of fresh water, seawater, or salt water.

[0044] Through practice, the high-temperature degradation resistant agent proposed in this invention is applicable to ultra-high temperature cement slurry formulations, high-temperature high-density formulations, low-density high-temperature formulations, high-temperature elasticity and toughness formulations, and self-healing formulations. While maintaining the high-temperature degradation resistant function of traditional high-temperature degradation resistant agents, it can significantly improve the rheological properties of slurry, providing a new means of improving the rheological properties of cement slurries with high rheological performance requirements and high adjustment difficulty in oilfield cementing operations.

[0045] Example The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments, unless otherwise specified, are performed according to conventional methods and conditions.

[0046] Defoamer: Purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250316; Water loss reducer: Purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250327; High-temperature retarder: purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250421; Self-healing agent: Purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250318; Dispersant: Purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250312; Low-temperature retarder: purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250618; Microsilicone-based anti-channeling enhancer: purchased from Blue Ocean Boda Technology Co., Ltd., batch number: 20250628; Micro-manganese weighting agent: purchased from Aiken Company, batch number: 20250706.

[0047] Example 1 Novel high-temperature degradation resistant agent formulation 1: spherical glass powder, density 2.45 g / cm³ 3 , the objects on the 100 mesh sieve are ≤10%, the objects on the 180 mesh sieve are ≤10%, the roundness rate is ≥85%, accounting for 100%.

[0048] Example 2 New high-temperature degradation resistant agent formulation 2: spherical glass powder, density 2.50 g / cm³ 3 ≤10% of the material passed through a 70-mesh sieve, ≤10% of the material passed through a 325-mesh sieve, sphericity ≥85%, accounting for 50%; Quartz powder C-Si300 (density 2.63g / cm³) 3 , with a silica content ≥95.0%, D

[50] 25~50 micrometers), accounting for 50%.

[0049] Example 3 Novel high-temperature degradation resistant agent formulation 3: spherical glass powder, density 2.50 g / cm³ 3 ≤10% of the material passed through a 70-mesh sieve, ≤10% of the material passed through a 325-mesh sieve, sphericity ≥85%, accounting for 75%; Quartz powder C-Si800 (density 2.65 g / cm³) 3 , with a silica content ≥95.0%, D

[50] 1~3 micrometers), accounting for 25%.

[0050] Example 4 Novel high-temperature degradation resistant agent formulation 4: spherical glass powder, density 2.50 g / cm³ 3 ≤10% of the material passed through a 70-mesh sieve, ≤10% of the material passed through a 325-mesh sieve, sphericity ≥85%, accounting for 67%; Quartz powder C-Si800 (density 2.65 g / cm³) 3 , with a silica content ≥95.0%, D

[50] 1~3 micrometers), accounting for 33%.

[0051] Example 5 The novel high-temperature degradation resistant agent formulation 5: spherical glass powder with a density of 2.40 g / cm³ 3 ≤10% of the material passed through a 70-mesh sieve, ≤10% of the material passed through a 180-mesh sieve, sphericity ≥85%, accounting for 50%; Quartz powder C-Si880 (density 2.61 g / cm³) 3 The silica content is ≥95.0%, and the composite particle size (D

[50] 1~3 micrometers:D

[50] 20~45 micrometers:D

[50] 50~80 micrometers mass ratio is about 1:1:1) accounts for 50%.

[0052] Example 6 The novel high-temperature degradation resistant agent has the following formulation ratio: 6: spherical glass powder with a density of 2.40 g / cm³. 3 The content of the material on a 70-mesh sieve is ≤10%, the content of the material under a 180-mesh sieve is ≤10%, the roundness rate is ≥85%, and the proportion is 33%; Quartz powder C-Si880 (density 2.61g / cm³) 3 The silica content is ≥95.0%, and the composite particle size (D

[50] 1~3 micrometers:D

[50] 20~45 micrometers:D

[50] 50~80 micrometers mass ratio is about 1:1:1) accounts for 67%.

[0053] Example 7 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% of the novel high-temperature degradation resistant agent prepared in Example 2; 0.5% defoamer; 6% fluid loss reducer; 1.5% high-temperature retarder; density adjusted to 1.90 g / cm³ using tap water. 3 .

[0054] Example 8 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% of the novel high-temperature degradation resistant agent prepared in Example 5; 0.5% defoamer; 6% fluid loss reducer; 8% self-healing agent; 1% dispersant; 1.5% high-temperature retarder; density adjusted to 1.90 g / cm³ using tap water. 3 .

[0055] Example 9 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% high-temperature fading resistant agent prepared in Example 1; 100% hematite powder weighting agent; 0.5% defoamer; 6% fluid loss reducer; 0.5% dispersant; 1.0% high-temperature retarder; density adjusted to 2.30 g / cm³ using semi-saturated sodium chloride brine. 3 .

[0056] Example 10 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% of the novel high-temperature degradation resistant agent prepared in Example 6; 60% hematite powder weighting agent; 60% micro-manganese weighting agent; 0.5% defoamer; 6% fluid loss reducer; 1.0% dispersant; 3.0% high-temperature retarder; 1.5% medium- and low-temperature retarder; density adjusted to 2.40 g / cm³ using tap water. 3 .

[0057] Example 11 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% of the novel high-temperature degradation resistant agent prepared in Example 3; 20% of the artificial glass microsphere weight-reducing agent; 2% of the microsilica-based anti-channeling reinforcing agent; 0.5% of the defoamer; 6% of the fluid loss reducing agent; 2.0% of the dispersant; 2.0% of the high-temperature retarder; and 1.0% of the medium- and low-temperature retarder. The density was adjusted to 1.50 g / cm³ using tap water. 3 .

[0058] Example 12 Cement slurry: 100% Grade G high sulfate-resistant oil well cement; 35% of the novel high-temperature degradation resistant agent prepared in Example 4; 55% of the artificial glass microsphere weight-reducing agent; 5% of the microsilica-based anti-channeling reinforcing agent; 1.0% of the defoamer; 12% of the fluid loss reducing agent; 5.0% of the dispersant; 3.0% of the high-temperature retarder; and 1.5% of the medium- and low-temperature retarder. The density was adjusted to 1.20 g / cm³ using tap water. 3 .

[0059] Comparative Example 7-1 The novel anti-high-temperature degradation agent in Example 7 was replaced with conventional quartz powder with a density of 2.63 g / cm³. 3The median particle size is 20-50 micrometers, and the silica content is ≥97%.

[0060] Comparative Example 8-1 The novel anti-high-temperature degradation agent in Example 8 was replaced with conventional quartz powder with a density of 2.61 g / cm³. 3 The silica content is ≥95.0%, and the composite particle size (D

[50] 1~3 micrometers:D

[50] 20~45 micrometers:D

[50] 50~80 micrometers mass ratio is about 1:1:1).

[0061] Comparative Example 9-1 The novel anti-high-temperature degradation agent in Example 9 was replaced with conventional quartz powder with a density of 2.63 g / cm³. 3 The median particle size is 20-50 micrometers, and the silica content is ≥97%.

[0062] Comparative Example 10-1 The novel anti-high-temperature degradation agent in Example 10 was replaced with conventional quartz powder with a density of 2.61 g / cm³. 3 The silica content is ≥95.0%, and the composite particle size (D

[50] 1~3 micrometers:D

[50] 20~45 micrometers:D

[50] 50~80 micrometers mass ratio is about 1:1:1).

[0063] Comparative Example 11-1 The novel anti-high-temperature degradation agent in Example 11 was replaced with conventional quartz powder with a density of 2.65 g / cm³. 3 , with a silica content ≥95.0% and a D

[50] of 1~3 micrometers.

[0064] Comparative Example 12-1 The novel anti-high-temperature degradation agent in Example 12 was replaced with conventional quartz powder with a density of 2.65 g / cm³. 3 , with a silica content ≥95.0% and a D

[50] of 1~3 micrometers.

[0065] Comparative Example 7-2 The novel anti-high-temperature degradation agent in Example 7 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0066] Comparative Example 8-2 The novel anti-high temperature degradation agent in Example 8 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0067] Comparative Example 9-2 The novel anti-high-temperature degradation agent in Example 9 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0068] Comparative Example 10-2 The novel anti-high-temperature degradation agent in Example 10 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0069] Comparative Example 11-2 The novel anti-high temperature degradation agent in Example 11 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0070] Comparative Example 12-2 The novel anti-high-temperature degradation agent in Example 12 was replaced with conventional glass powder with a density of 2.45 g / cm³. 3 The median particle size is 20-50 micrometers, with an irregular morphology.

[0071] Performance testing The conventional slurry properties of cement pastes in Examples 7-12 and Comparative Examples 7-1-12-1 and 7-2-12-2 were tested respectively.

[0072] The cement slurry test method was carried out in accordance with the relevant requirements of GB / T 19139-2012 standard, and the test results are shown in Table 1.

[0073] Table 1 Summary of test results for conventional cement grout properties

[0074] Note: A "-" indicates that it cannot be measured.

[0075] in conclusion: The high-temperature degradation resistant agent of this invention has good particle size distribution, good material flowability, and good stability during transportation, storage, and mixing. The material is uniform and stable, and its use is not affected by long-term storage.

[0076] The cement slurry formulated with the high-temperature degradation agent of this invention can achieve a strength of 1.20~2.80 g / cm³ by adjusting the weighting or weighting of the materials. 3 Density cement grout; The cement slurry formulated with the anti-high temperature degradation agent of the present invention can significantly improve the cement slurry mixing speed and improve the rheological properties. The cement slurry formulated with the anti-high temperature degradation agent of the present invention has no significant effect on the free fluid, API water loss, compressive strength, and anti-high temperature strength degradation of the cement slurry.

[0077] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0079] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-temperature degradation resistant agent, characterized in that, Based on a total weight of 100 parts, it includes: 10-100 parts of spherical glass powder; and 0-90 parts of quartz powder.

2. The anti-high temperature degradation agent according to claim 1, characterized in that, Based on a total weight of 100 parts, it includes: 33-75 parts of spherical glass powder; and 25-67 parts of quartz powder.

3. The anti-high temperature degradation agent according to claim 1, characterized in that, The density of the spherical glass powder is 2.4 g / cm³. 3 ~2.6 g / cm 3 , the objects above the 70-mesh sieve are ≤10%, the objects under the 325-mesh sieve are ≤10%, and the roundness rate is ≥85%.

4. The anti-high temperature degradation agent according to claim 1, characterized in that, The density of the quartz powder is 2.55 g / cm³. 3 ~2.75 g / cm 3 The crystalline silica content is ≥95%, and the median particle size is 1-400 micrometers.

5. The method for preparing the anti-high temperature degradation agent according to any one of claims 1 to 4, characterized in that, include: Add spherical glass powder and quartz powder to a mixer according to the specified ratio, and mix until homogeneous.

6. A cement grout, characterized in that, Based on 100 parts by weight of oil well cement, the product includes 27-50 parts of the high-temperature degradation resistant agent as described in any one of claims 1-4, 0.3-2 parts of the defoamer, and functional materials; wherein the functional materials are selected from one or more of the following: 0-50 parts of a weight-reducing agent, 0-300 parts of a weight-increasing agent, 0-30 parts of a toughening agent, 0-30 parts of a self-healing agent, 0-30 parts of an anti-channeling agent, 0-15 parts of a fluid loss reducing agent, 0.1-10 parts of a retarder, 0-5 parts of a dispersant, 0-5 parts of a suspension stabilizer, and 0-10 parts of an expanding agent.

7. The cement grout according to claim 6, characterized in that, The oil well cement is either Grade G or Grade H; the defoamer is selected from one or more of the following: organosilicon, polyether, polyether-modified organosilicon, and phosphate ester defoamers.

8. The cement grout according to claim 6, characterized in that, The weight-reducing agent is selected from one or more of artificial hollow glass microspheres, natural cenospheres, expanded perlite, and rock asphalt; the weight-enhancing agent is selected from one or more of hematite powder, magnetite powder, spherical micro-manganese, barite, pyrite powder, reduced iron powder, and alloy powder.

9. The cement grout according to claim 6, characterized in that, The toughening agent is selected from one or more of rubber, epoxy resin, asphalt, carbon fiber, basalt fiber, calcium carbonate whiskers, and polypropylene fiber; the self-healing agent is selected from one or more of polyacrylamide / acrylic acid copolymer salt-sensitive resin, styrene-butadiene rubber, SBS thermoplastic elastomer granules polyolefin elastomer, acrylate microspheres, epoxy resins, ettringite-based expanding agents, and sodium metasilicate.

10. The cement grout according to claim 6, characterized in that, The anti-channeling agent is selected from styrene-butadiene latex, hydroxystyrene-butadiene latex, nitrile latex, styrene-acrylic latex, epoxy resin emulsion, microsilicone and its emulsion, nanosilicone and its emulsion; the water loss reducing agent is selected from one or more of acrylamide-sodium acrylate copolymer, N,N-dimethylacrylamide and acrylamide-2-methylpropanesulfonate copolymer, and polyvinyl alcohol copolymer.

11. The cement grout according to claim 6, characterized in that, The retarder is selected from one or more of sodium acrylamide-2-methylpropanesulfonate and acrylic acid copolymer, polyamino polyether organophosphate, and citric acid; the dispersant is selected from one or more of polycarboxylic acid polymers and aldehyde-ketone condensates.

12. The cement grout according to claim 6, characterized in that, The suspension stabilizer is selected from one or more of high molecular weight polymers, xanthan gum, zeolite, styrax, sepiolite, and other similar materials; the swelling agent is selected from one or more of magnesium oxide, calcium oxide, and ettringite-based swelling agents.

13. The method for preparing cement slurry according to any one of claims 6 to 12, characterized in that, include: (1) Mix oil well cement and anti-high temperature degradation agent according to the ratio, and selectively add one or more of weighting agents or weight-reducing agents, expansion agents, toughening agents, self-repairing agents, and anti-channeling agents. Mix evenly according to the ratio to obtain dry mixture; (2) Mix the slurry water with the water loss reducer, retarder, dispersant, anti-channeling agent, suspension stabilizer and defoamer according to the ratio to obtain a liquid phase mixture; (3) At the work site, the dry mixture and the liquid mixture are mixed evenly to obtain the cement slurry.

14. The preparation method according to claim 13, characterized in that, The slurry preparation water is one of fresh water, seawater, or salt water.

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