A temperature-resistant high-thermal-conductivity admixture for well cementing and a preparation method thereof

Abstract

The present application relates to oil and gas field resource development cementing material technical field, specifically to a kind of temperature-resistant high-thermal-conductivity external admixture for cementing cement and preparation method thereof, the temperature-resistant high-thermal-conductivity external admixture for cementing cement includes 40wt. 60wt. 30wt. 45wt. 10wt. 15wt. By percentage of weight, high-thermal-conductivity reinforcing material, reinforcing material and polyetherimide, the high-thermal-conductivity reinforcing material is the mixture formed after modification of the mixture of molybdenum disilicide, tungsten diboride, zirconium diboride, titanium diboride by mass ratio (5-7):(1-2):(1-2):1.This temperature-resistant high-thermal-conductivity external admixture for cementing cement has the characteristics of strong high-temperature resistance, high thermal conductivity, good toughness, etc., good compatibility with cement, does not affect the working performance of cementing cement slurry system, can participate in cement hydration reaction, improve the high-temperature resistance of cementing cement slurry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field resource development cementing materials, and particularly relates to a temperature-resistant high-thermal-conductivity external additive for cementing cement and a preparation method thereof. BACKGROUND

[0002] At present, the world energy pattern and consumption structure are undergoing tremendous changes, and energy cleaning, low carbonization and sustainability have become the main features of future energy development. Geothermal resources are a kind of green and clean energy with abundant reserves, safety and stability, and high utilization rate. As a tool for geothermal resource utilization, the quality of geothermal well itself is the key to the effective utilization of geothermal energy. The thermal resistance between the wellbore and the formation is an important factor affecting the heat extraction efficiency. The low thermal conductivity of conventional cementing cement seriously affects the heat extraction efficiency. At present, the most common method is to add thermal conductive fillers to cementing cement to improve the thermal conductivity of cementing cement, thereby improving the heat extraction efficiency. The commonly used fillers include non-metallic thermal conductive fillers such as graphite, graphene, silicon carbide and quartz sand, and metallic thermal conductive fillers such as copper, iron powder, steel fiber and aluminum.

[0003] Chinese patent CN113480265A discloses a high-thermal-conductivity cementing cement material for geothermal exploitation, which comprises the following components in parts by weight: 55-62 parts of cement, 6-8 parts of thermal conductive filler, 0.12-0.3 parts of water reducing agent, 0.02-0.08 parts of viscosity regulator and 25-38 parts of water. The method for preparing the cement material from the above-mentioned raw materials is also disclosed.

[0004] Chinese patent CN113800839A discloses a high-thermal-conductivity cementing material, a preparation method and application thereof. The high-thermal-conductivity cementing material comprises cement, silicon powder, water reducing agent, early strength agent and water, wherein the cement is 100 parts, the silicon powder is 15-30 parts, the water reducing agent is 0.4-0.6 parts, the early strength agent is 0.2-0.3 parts and the water is 70-80 parts.

[0005] Chinese patent CN108751870A discloses a high-thermal-conductivity cementing cement material for geothermal exploitation, which comprises water, ordinary Portland cement (P.042.5), thermal conductive strengthening material, JSS water reducing agent, sodium chloride (NaCl) and triethanolamine (TEA). The water-cement ratio is 0.5-0.7 by weight. The thermal conductive strengthening material accounts for 10% by mass of the ordinary Portland cement. The JSS water reducing agent accounts for 0.2-0.4% by mass of the ordinary Portland cement. The sodium chloride (NaCl) accounts for 0.3-1.3% by mass of the ordinary Portland cement. The triethanolamine (TEA) accounts for 0.01-0.03% by mass of the ordinary Portland cement.

[0006] Although the prior art considers the improvement of the heat conduction capacity of the cementing cement material, the geothermal well heat reservoir is deep and high in temperature, and the cementing cement will appear performance degradation in the process of drilling and exploiting geothermal resources in a harsh high temperature environment, therefore, it is an urgent problem for the person skilled in the art to provide a temperature-resistant and high-thermal-conductivity external additive for cementing cement. SUMMARY

[0007] The present application aims to solve the defects and deficiencies in the prior art, and provides a temperature-resistant and high-thermal-conductivity external additive for cementing cement and a preparation method thereof. The present application has the characteristics of high temperature resistance, high thermal conductivity and stable performance, and can effectively improve the heat conduction capacity and high temperature resistance of the cementing cement material.

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0009] A temperature-resistant and high-thermal-conductivity external additive for cementing cement, comprising the following raw materials in percentage by weight:

[0010] Thermal conduction strengthening material: 40wt.%~60wt.%;

[0011] Reinforcing material: 30wt.%~45wt.%;

[0012] Polyetherimide: 10wt.%~15wt.%;

[0013] The thermal conduction strengthening material is a mixture formed by mixing molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride in a mass ratio of (5-7):(1-2):(1-2):1 and then modifying.

[0014] Further, the reinforcing material is mixed by graphite quartz schist, andalusite and modified expanded graphite in a mass ratio of (4-6):(1-2):(3-4).

[0015] Further, the graphite quartz schist is in scale shape, and the graphite content is 15wt.%~20wt.%, the silicon dioxide content is 50wt.%~60wt.%, and the mica content is 10wt.%~20wt.%; the average particle size of the crushed and finely ground graphite quartz schist is ≤45μm.

[0016] Further, the andalusite has an Al2O3 content ≥50wt.%, a SiO2 content ≥40wt.%, and an average particle size ≤45μm.

[0017] Further, the modified expanded graphite is obtained by modifying the expanded graphite by low temperature plasma, and the modified expanded graphite has a volume of 600ml / g and an average particle size ≤74μm.

[0018] Further, the average particle size of the crushed and finely ground polyetherimide is ≤45μm.

[0019] Further, the effective substance content of the molybdenum disilicide is >99wt.%, the average particle size is 15μm; the effective substance content of the tungsten diboride is >99wt.%, the average particle size is 50nm; the effective substance content of the zirconium diboride is >99wt.%, the average particle size is 50nm; the effective substance content of the titanium diboride is >99wt.%, the average particle size is 15μm.

[0020] The application further provides a preparation method of the temperature-resistant high-thermal-conductivity external additive for cementing cement.

[0021] Further, the preparation of the thermal-conductivity strengthening material comprises: step a, mixing and grinding molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride in a mass ratio of (5-7):(1-2):(1-2):1 to form a mixture A; step b, placing the mixture A in an ethyl silicate ethanol solution with a concentration of 3wt.%-8wt.%, mechanically stirring and ultrasonic dispersing, and then placing in a constant-temperature water bath kettle for stirring reaction; step c, centrifugal separating the product after the reaction, repeatedly cleaning with anhydrous ethanol for 2-5 times, and vacuum drying to obtain the thermal-conductivity strengthening material.

[0022] Further, in the step a, the grinding is preferably performed by a ball mill, and the grinding time is preferably 30min; in the step b, the concentration of the ethyl silicate ethanol solution is preferably 6wt.%, the ultrasonic dispersing time is preferably 20min, and the stirring reaction time is preferably 10h; in the step c, the centrifugal separation speed is preferably 1200r / min, the centrifugal separation time is preferably 5min, the repeated cleaning times with anhydrous ethanol are preferably 3 times, and the vacuum drying time is preferably 24h.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The temperature-resistant high-thermal-conductivity external additive for cementing cement has the characteristics of strong high-temperature resistance, high thermal conductivity and good toughness, has good compatibility with cement, does not affect the working performance of the cementing cement slurry system, can participate in the cement hydration reaction, and improves the high-temperature resistance of the cementing cement slurry.

[0025] The temperature-resistant high-thermal-conductivity external additive for cementing cement is rationally designed, the raw materials such as molybdenum disilicide, tungsten diboride, zirconium diboride, titanium diboride and expanded graphite have excellent thermal conductivity and strong temperature resistance, the thermal-conductivity strengthening material and the reinforcing material reduce the gap between the cement particles through the small-size effect and the particle grading effect, increase the structure compactness of the cement stone, and reduce the decline of the thermal conductivity of the cement stone caused by the existence of pores.

[0026] The heat-conducting reinforcing material in the temperature-resistant high-thermal-conductivity external additive for cementing cement is modified by a silane coupling agent (tetraethyl orthosilicate ethanol solution) to coat the surface of the heat-conducting reinforcing material with a layer of silicon dioxide, improve the hydrophilicity of the heat-conducting reinforcing material and participate in the hydration reaction, and enhance the cementing strength between the heat-conducting reinforcing material and the hydration product of cement and reduce the porosity. The main components of the reinforcing material are SiO2, Al2O3 and graphite, which can not only effectively reduce the calcium-silicon ratio (Ca / Si) of the cementing cement to prevent the strength of the cement stone from declining in a high-temperature environment, but also further enhance the thermal conductivity of the application by the synergistic effect of the graphite material and the heat-conducting reinforcing material. In addition, the modified expanded graphite has a loose and porous vermicular structure, which has a large surface area and softness. On the one hand, the large surface area provides a large number of crystallization points for the hydration product to promote hydration, and the hydrophilicity is improved after modification to enhance the cementing property between the hydration product and the heat-conducting reinforcing material. On the other hand, the softness of the modified expanded graphite is dispersed and inserted with the synergistic effect of the columnar muscovite and polyetherimide to relatively disperse the stress, reduce the brittleness of the cement stone and enhance the flexibility.

[0027] The temperature-resistant high-thermal-conductivity external additive for cementing cement can significantly enhance the high-temperature resistance, high-temperature toughness and thermal conductivity of the cementing cement by the mutual cooperation of the raw materials, ensure the quality of the geothermal well, improve the heat extraction efficiency and further promote the development and utilization of geothermal resources. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, further detailed description will be given. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0029] The cement slurries in the following embodiments are prepared according to the GB / T19139 standard, and the water-cement ratio is 0.44. The G-grade oil well cement is provided by Jiuhua Special Cement Co., Ltd., the high-temperature retarder is an AMPS polymer, the high-temperature fluid loss reducer is a 2-acrylamido-2-methylpropanesulfonic acid polymer, and the high-temperature stabilizer is a clay mineral. The proportions of the G-grade oil well cement, the high-temperature retarder, the high-temperature fluid loss reducer, the high-temperature stabilizer and the temperature-resistant high-thermal-conductivity external additive used in the following embodiments are the same.

[0030] The graphite quartz schist used in the embodiments of the present application is in the form of scales, and the graphite content is 15wt.% to 20wt.%, the silicon dioxide content is 50wt.% to 60wt.%, and the mica content is 10wt.% to 20wt.%. The average particle size of the crushed and finely ground graphite quartz schist is ≤45μm.

[0031] The andalusite used in the embodiment of the present application has an Al2O3 content of ≥50 wt.%, a SiO2 content of ≥40 wt.%, and an average particle size of ≤45 μm.

[0032] The modified expanded graphite used in the embodiment of the present application is formed by modifying expanded graphite at low temperature by plasma, and the modified expanded graphite has a specific surface area of 600 ml / g and an average particle size of ≤74 μm.

[0033] The polyetherimide used in the embodiment of the present application has an average particle size of ≤45 μm after being broken and finely ground.

[0034] The molybdenum disilicide used in the embodiment of the present application has an active substance content of >99 wt.% and an average particle size of 15 μm; the tungsten diboride used has an active substance content of >99 wt.% and an average particle size of 50 nm; the zirconium diboride used has an active substance content of >99 wt.% and an average particle size of 50 nm; and the titanium diboride used has an active substance content of >99 wt.% and an average particle size of 15 μm.

[0035] The preparation of the heat-conducting reinforcing material used in the embodiment of the present application comprises the following steps: step a, placing molybdenum disilicide, tungsten diboride, zirconium diboride, and titanium diboride in a ball mill in a mass ratio and mixing for 30 min to form a mixture A and increase the surface roughness thereof; step b, placing the mixture A in a 6 wt.% ethyl silicate ethanol solution, mechanically stirring and ultrasonically dispersing for 20 min, and then placing in a 60°C constant-temperature water bath and stirring for 10 h of sufficient reaction; and step c, centrifuging the product after the reaction at a speed of 1200 r / min for 5 min, repeatedly washing with anhydrous ethanol for 3 times, and vacuum drying for 24 h to obtain the heat-conducting reinforcing material.

[0036] Embodiment 1

[0037] As a preferred embodiment of the present application, the specific composition of the temperature-resistant and high-heat-conducting admixture for well cementing used in this embodiment is shown in Table 1.

[0038] Table 1

[0039] Component Weight percent (wt. %) Thermally conductive reinforcement material 40 Reinforcing material 45 Polyetherimide 15

[0040] In this embodiment, the heat-conducting reinforcing material is a mixture formed by mechanically mixing molybdenum disilicide, tungsten diboride, zirconium diboride, and titanium diboride in a mass ratio of 5:2:2:1 and then modifying the mixture.

[0041] In this embodiment, the reinforcing material is formed by mixing graphite quartz schist, andalusite, and modified expanded graphite in a mass ratio of 2:1:2.

[0042] The heat-conducting reinforcing material, the reinforcing material and the polyetherimide are mixed according to the above-mentioned proportions to obtain a temperature-resistant high-thermal-conductivity external additive 1# for cementing cement; according to the formula 79.5wt. % G-grade oil well cement + 20wt. % temperature-resistant high-thermal-conductivity external additive 1# + 0.5wt. % high-temperature stabilizer, and 4wt. % high-temperature fluid loss additive and 1.5wt. % high-temperature retarder accounting for 4wt. % of the total mass of the above solid phase, a cement slurry is prepared according to the GB / T19139 standard, the water-cement ratio is 0.44, and a cementing cement slurry system 1# is obtained.

[0043] Example 2

[0044] As a preferred embodiment of the present application, the specific composition of the temperature-resistant high-thermal-conductivity external additive for cementing cement used in this embodiment is shown in Table 2:

[0045] Table 2

[0046] Component Weight percent (wt. %) Thermally conductive reinforcement material 50 Reinforcing material 38 Polyetherimide 12

[0047] In this embodiment, the heat-conducting reinforcing material is a mixture formed by mechanically mixing and then modifying molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride in a mass ratio of 5:2:2:1.

[0048] In this embodiment, the reinforcing material is formed by mixing graphite quartz schist, andalusite and modified expanded graphite in a mass ratio of 2:1:2.

[0049] The heat-conducting reinforcing material, the reinforcing material and the polyetherimide are mixed according to the above-mentioned proportions to obtain a temperature-resistant high-thermal-conductivity external additive 1# for cementing cement; according to the formula 79.5wt. % G-grade oil well cement + 20wt. % temperature-resistant high-thermal-conductivity external additive 1# + 0.5wt. % high-temperature stabilizer, and 4wt. % high-temperature fluid loss additive and 1.5wt. % high-temperature retarder accounting for 4wt. % of the total mass of the above solid phase, a cement slurry is prepared according to the GB / T19139 standard, the water-cement ratio is 0.44, and a cementing cement slurry system 1# is obtained.

[0050] Example 3

[0051] As a preferred embodiment of the present application, the specific composition of the temperature-resistant high-thermal-conductivity external additive for cementing cement used in this embodiment is shown in Table 3:

[0052] Table 3

[0053] Component Weight percent (wt. %) Thermally conductive reinforcement material 60 Reinforcing material 30 Polyetherimide 10

[0054] In this embodiment, the heat-conducting reinforcing material is a mixture formed by mechanically mixing and then modifying molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride in a mass ratio of 5:2:2:1.

[0055] In the embodiment, the reinforcing material is formed by mixing graphite quartz schist, andalusite and modified expanded graphite at a mass ratio of 2:1:2.

[0056] The heat-conducting reinforcing material, the reinforcing material and the polyetherimide are mixed at the above-mentioned proportions to obtain a temperature-resistant high-thermal-conductivity external additive 3# for cementing cement; a cement slurry is prepared according to GB / T19139 standard, with a water-cement ratio of 0.44, according to a formula of 79.5wt.% G-grade oil well cement + 20wt.% temperature-resistant high-thermal-conductivity external additive 3# + 0.5wt.% high-temperature stabilizer, and 4wt.% high-temperature fluid loss additive and 1.5wt.% high-temperature retarder accounting for the total mass of the above solid phase.

[0057] Embodiment 4

[0058] As a preferred embodiment of the present application, the temperature-resistant high-thermal-conductivity external additive for cementing cement used in the embodiment has the specific composition shown in Table 4.

[0059] Table 4

[0060] Component Weight percent (wt. %) Thermally conductive reinforcement material 50 Reinforcing material 38 Polyetherimide 12

[0061] In the embodiment, the heat-conducting reinforcing material is a mixture formed by mechanically mixing and then modifying molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride at a mass ratio of 12:3:3:2.

[0062] In the embodiment, the reinforcing material is formed by mixing graphite quartz schist, andalusite and modified expanded graphite at a mass ratio of 10:3:7.

[0063] The heat-conducting reinforcing material, the reinforcing material and the polyetherimide are mixed at the above-mentioned proportions to obtain a temperature-resistant high-thermal-conductivity external additive 4# for cementing cement; a cement slurry is prepared according to GB / T19139 standard, with a water-cement ratio of 0.44, according to a formula of 79.5wt.% G-grade oil well cement + 20wt.% temperature-resistant high-thermal-conductivity external additive 4# + 0.5wt.% high-temperature stabilizer, and 4wt.% high-temperature fluid loss additive and 1.5wt.% high-temperature retarder accounting for the total mass of the above solid phase.

[0064] Embodiment 5

[0065] As a preferred embodiment of the present application, the temperature-resistant high-thermal-conductivity external additive for cementing cement used in the embodiment has the specific composition shown in Table 5.

[0066] Table 5

[0067] Component Weight percent (wt. %) Thermally conductive reinforcement material 50 Reinforcing material 38 Polyetherimide Component Weight percent (wt. %) Thermally conductive reinforcement material Reinforcing material Polyetherimide 12

[0068] In the embodiment, the heat-conducting reinforcing material is a mixture of molybdenum disilicide, tungsten diboride, zirconium diboride and titanium diboride in a mass ratio of 7:1:1:1, which is mechanically mixed and then modified.

[0069] In the embodiment, the reinforcing material is a mixture of graphite quartz schist, andalusite and modified expanded graphite in a mass ratio of 6:1:3.

[0070] The heat-conducting reinforcing material, the reinforcing material and the polyetherimide are mixed in the above proportions to obtain a temperature-resistant high-thermal-conductivity external additive 5# for cementing cement. According to the formula 79.5wt. % G-grade oil well cement + 20wt. % temperature-resistant high-thermal-conductivity external additive 5# + 0.5wt. % high-temperature stabilizer, and 4wt. % high-temperature fluid loss additive and 1.5wt. % high-temperature retarder accounting for 4wt. % of the total mass of the above solid phase, the cement slurry is prepared according to GB / T19139 standard, the water-cement ratio is 0.44, and the cementing cement slurry system 5# is obtained.

[0071] Comparative Example 1

[0072] According to the formula 99.5wt. % G-grade oil well cement + 0.5wt. % high-temperature stabilizer, and 4wt. % high-temperature fluid loss additive and 1.5wt. % high-temperature retarder accounting for 4wt. % of the total mass of the above solid phase, the cement slurry is prepared according to GB / T19139 standard, the water-cement ratio is 0.44, and the cementing cement slurry system 6# is obtained.

[0073] Comparative Example 2

[0074] In the present comparative example, except that the temperature-resistant high-thermal-conductivity external additive does not contain the heat-conducting reinforcing material, the rest of the proportions and conditions are the same as those of Example 1, and the cementing cement slurry system 7# is obtained.

[0075] Comparative Example 3

[0076] In the present comparative example, except that the temperature-resistant high-thermal-conductivity external additive does not contain the reinforcing material, the rest of the proportions and conditions are the same as those of Example 1, and the cementing cement slurry system 8# is obtained.

[0077] Comparative Example 4

[0078] In the present comparative example, except that the temperature-resistant high-thermal-conductivity external additive does not contain the polyetherimide, the rest of the proportions and conditions are the same as those of Example 1, and the cementing cement slurry system 9# is obtained.

[0079] The engineering properties of the cementing cement slurry obtained in Examples 1-5 and Comparative Examples 1-4 are tested according to GB / T19139 oil well cement test method, and the test results are shown in Table 6.

[0080] Table 6

[0081]

[0082] According to the experimental data in Table 6, the cement slurry configured in Examples 1-5 has a water loss of ≤35 ml, the fluidity and free liquid meet the construction requirements, the slurry stability is good, the thickening time is controllable, and the engineering performance is good. Compared with Examples 1-5, the water loss and free liquid of Comparative Examples 1-4 increase, indicating that the temperature-resistant high-thermal-conductivity external additive for cementing used in the application has good compatibility with the external additive, and can improve the slurry stability, reduce the system water loss and reduce the free liquid under the synergistic effect of the thermal-conductivity strengthening material, the reinforcing material and the polyether polyimide.

[0083] The cement slurry obtained in Examples 1-5 and Comparative Examples 1-4 was tested at 150°C. The NYSQ-2017 pressure testing machine was used to test the compressive strength; the cored cement stone was obtained after curing and molding, and then the triaxial mechanical property test was performed. The cement stone mechanical test standard is based on GB / T50266-2013 "Engineering rock mass test method standard", the experimental equipment is RTR-1000 type triaxial rock mechanics test; the DRE-2C type thermal conductivity tester is used, the transient plane heat source method is adopted, the thermal conductivity of the cement stone for well cementing is tested, and the test results are shown in Table 7.

[0084] Table 7

[0085]

[0086] According to the performance data of the cementing slurry systems 1-9 obtained in Examples 1-5 and Comparative Examples 1-4, the cementing slurry systems 1-5 have a 2d compressive strength of >35 MPa, a 7d compressive strength of >36 MPa, a 2d elastic modulus of ≤7.4 GPa, and a thermal conductivity of ≥1.9 W / (m·K); compared with the cementing slurry system 6 obtained in Comparative Example 1, the cementing slurry of Examples 1-5 with the temperature-resistant high-thermal-conductivity external additive of the application has improved compressive strength, no strength decay at high temperature, improved toughness, and significantly increased thermal conductivity; compared with the cementing slurry systems 7-9 obtained in Comparative Examples 2-4, it is shown that the temperature-resistant high-thermal-conductivity external additive of the application effectively improves the temperature resistance, toughness and thermal conductivity of the cement stone under the synergistic effect of the thermal-conductivity strengthening material, the reinforcing material and the polyether polyimide.

[0087] Finally, it should be noted that: the above embodiments are merely the preferred embodiments of the present application to illustrate the technical solutions of the present application, rather than limit, of course, is not to limit the scope of the patent of the present application; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still be modified to the technical solutions recorded in the foregoing embodiments, or part or all of the technical features are replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application; that is to say, but whatever is made in the main design idea and spirit of the present application has no substantial significance of the change or polish, the technical problem solved is still consistent with the present application, and should be included in the protection scope of the present application; in addition, the technical solutions of the present application are directly or indirectly applied to other related technical fields, which are also included in the patent protection scope of the present application.

Claims

1. A temperature-resistant high-thermal-conductivity admixture for cementing cement, characterized by, The raw materials include the following by weight percentage: Thermal conductive reinforcing material: 40wt.%~60wt.%; Reinforcing material: 30wt.%~45wt.%; Polyetherimide: 10wt.%~15wt.%; The reinforcing material is mixed by graphite quartz schist, andalusite, modified expanded graphite in a mass ratio of (4~6):(1~2):(3~4); the modified expanded graphite is modified by low-temperature plasma from expanded graphite; The thermal conductive reinforcing material is a mixture formed by mixing molybdenum disilicide, tungsten diboride, zirconium diboride, titanium diboride in a mass ratio of (5~7):(1~2):(1~2):1 and then modifying; The preparation of the thermal conductive reinforcing material includes: step a, mixing and pulverizing molybdenum disilicide, tungsten diboride, zirconium diboride, titanium diboride in a mass ratio of (5~7):(1~2):(1~2):1 to form a mixture A; step b, placing the mixture A in an ethyl silicate ethanol solution with a concentration of 3wt.%~8wt.%, mechanically stirring and ultrasonic dispersing, and then placing it in a constant-temperature water bath to stir and react; step c, centrifuging the product after the reaction, repeatedly cleaning it with anhydrous ethanol for 2~5 times, and vacuum drying to obtain the thermal conductive reinforcing material.

2. The temperature resistant and high thermal conductive admixture for cementing cement of claim 1, characterized in that, The graphite quartz schist is in the form of flake, with a graphite content of 15wt.%~20wt.%, a silicon dioxide content of 50wt.%~60wt.%, and a mica content of 10wt.%~20wt.%; the average particle size of the graphite quartz schist after crushing and grinding is ≤45μm.

3. The temperature resistant and high thermal conductive admixture for cementing cement of claim 1, characterized in that, The andalusite has an Al2O3 content of ≥50wt.%, a SiO2 content of ≥40wt.%, and an average particle size of ≤45μm.

4. The temperature resistant and high thermal conductive admixture for cementing cement of claim 1, characterized in that, The modified expanded graphite has a specific surface area of 600mL / g and an average particle size of ≤74μm.

5. The temperature resistant and high thermal conductive admixture for cementing cement of claim 1, characterized in that, The polyetherimide has an average particle size of ≤45μm after crushing and grinding.

6. The temperature resistant and high thermal conductive admixture for cementing cement of claim 1, characterized in that, The effective substance content of the molybdenum disilicide is >99wt.%, and the average particle size is 15μm; the effective substance content of the tungsten diboride is >99wt.%, and the average particle size is 50nm; the effective substance content of the zirconium diboride is >99wt.%, and the average particle size is 50nm; the effective substance content of the titanium diboride is >99wt.%, and the average particle size is 15μm.

7. The method according to any one of claims 1 to 6, characterized in that, The preparation of the thermal conductive reinforcing material includes: step a, mixing and pulverizing molybdenum disilicide, tungsten diboride, zirconium diboride, titanium diboride in a mass ratio of (5~7):(1~2):(1~2):1 to form a mixture A; step b, placing the mixture A in an ethyl silicate ethanol solution with a concentration of 3wt.%~8wt.%, mechanically stirring and ultrasonic dispersing, and then placing it in a constant-temperature water bath to stir and react; step c, centrifuging the product after the reaction, repeatedly cleaning it with anhydrous ethanol for 2~5 times, and vacuum drying to obtain the thermal conductive reinforcing material.

8. The method according to claim 7, wherein the temperature resistant and high thermal conductive admixture for cementing is prepared by the following steps: 1) mixing the components of the admixture, 2) heating and stirring, 3) cooling, 4) screening, 5) packaging. In the step a, the ball mill is used for pulverizing, and the pulverizing time is 30min.

9. The method according to claim 8, wherein the temperature resistant and high thermal conductive admixture for cementing is prepared by the following steps: 1) mixing the components of the admixture, and 2) mixing the components of the admixture in the order of the components of the admixture in claim 8. In the step a, the ball mill is used for pulverizing, and the pulverizing time is 30min.

10. A method for preparing a high-temperature resistant and thermally conductive admixture for cementing according to claim 8, characterized in that, In the step b, the concentration of the ethyl orthosilicate ethanol solution is 6 wt.%, the ultrasonic dispersion time is 20 min, and the stirring reaction time is 10 h.

11. The method according to claim 8, wherein the temperature resistant and high thermal conductive admixture for cementing is prepared by the following steps: 1) mixing the components of the admixture, 2) heating and stirring, 3) cooling, 4) screening, 5) packaging. In the step c, the centrifugal separation speed is 1200 r / min, the centrifugal separation time is 5 min, the number of repeated cleaning with anhydrous ethanol is 3 times, and the vacuum drying time is 24 h.

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