Insulating material for downhole heater and method of making

Abstract

The application discloses an underground heater insulating material with improved insulation performance by manganese doping and a preparation method thereof. The insulating material is an insulating ceramic material prepared from mixed materials containing magnesium oxide, a doping material containing manganese elements and a modifying agent, and is prepared through ball milling, drying granulation, aging forming and plastic sintering. Since the doping material containing manganese elements and the magnesium oxide can form a solid solution, the lattice of the activated magnesium oxide crystal is improved, the compactness and strength of the material are improved, and the insulation performance is improved. The modifying agent reduces the vacancy defects of the MgO crystal grains, and the MgO-OH structure is not easily formed by moisture absorption, so that the volume resistivity is improved. Compared with the high-purity magnesium oxide ceramic material, the prepared insulating ceramic material has good high-temperature insulation performance, and can be used as an insulating material for a high-power underground heater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole high-power heater and insulating material, in particular to a downhole heater insulating material with improved insulation performance by manganese doping and a preparation method thereof. BACKGROUND

[0002] With the increasing demand for oil and gas and the continuous consumption of conventional oil and gas resources, the effective development of unconventional oil and gas resources has important strategic significance for relieving the supply pressure of oil and gas resources and promoting the low-carbon transformation and green development of energy structure. Unconventional oil and gas mainly includes heavy oil, shale oil, shale gas, coalbed methane, etc. Downhole electric heater technology is applied to new fields such as downhole heating assistance of heavy oil and in-situ coal gasification, which has important significance for promoting the implementation of major projects such as downhole electric heating assistance of heavy oil thermal recovery, in-situ conversion of shale oil, and in-situ coal gasification.

[0003] Downhole high-power electric heating technology uses the heat generated by electric resistance heating to continuously heat the wellbore heat transfer medium (steam, water or oil reservoir). Downhole high-power electric heater is the core equipment of electric heating technology. The electric heater (mineral insulation heating cable) mainly uses single or multiple electric resistance heating alloy wires as the heat source, magnesium oxide as the heat-conducting insulator, and stainless steel or copper as the sheath, which is manufactured by special production process. When the heating core wire passes through the electric current, the electric energy is converted into heat energy to heat the oil reservoir.

[0004] Currently, electric heating technology mainly uses MI cable, and the insulating material in the cable is high-purity magnesium oxide. However, due to the influence of factors such as purity, chemical properties, particle shape, particle size distribution, crystal shape, and filling process, the thermal conductivity, thermal stability, insulation performance, and long-term service performance of the insulating material are limited. Therefore, it is of great practical significance to develop a preparation method of downhole high-power heater insulating material with good insulation, mechanical strength, thermal conductivity, and stability. SUMMARY

[0005] In view of the above problems, the present application provides a downhole heater insulating material with improved insulation performance by manganese doping and a preparation method thereof, which overcomes the above problems or at least partially solves the above problems.

[0006] In a first aspect, the present application provides a downhole heater insulating material with improved insulation performance by manganese doping, which is an insulating ceramic material prepared from a mixture of magnesium oxide, manganese-containing doping material and modifying agent, through ball milling, drying and granulation, aging and molding, and plastic removal sintering.

[0007] Optionally, the mass content of the manganese-containing doping material in the mixture is 0.5-2.7%, and the mass content of the modifying agent in the mixture is 1-9%.

[0008] Optionally, the manganese element-containing doping material is a salt of manganese.

[0009] Optionally, the manganese element-containing doping material is an oxide of manganese.

[0010] Optionally, the manganese element-containing doping material is a manganate.

[0011] Optionally, the manganese element-containing doping material is a coordination compound of manganese.

[0012] Optionally, the modification reagent is at least one of sodium stearate, sodium dodecyl sulfate, sodium dodecyl sulfonate, CTAB, and butyl titanate.

[0013] In a second aspect, the embodiments of the present application provide a preparation method of an insulating material of a downhole heater by manganese doping to improve insulation performance, comprising:

[0014] The mixed material containing magnesium oxide, a manganese element-containing doping material, and a modification reagent is subjected to wet ball milling to obtain a slurry raw material;

[0015] The slurry raw material is dried and sieved to obtain a powder material;

[0016] The binder is added to the powder material for granulation, and then the powder material is pressed into a ceramic green body;

[0017] The ceramic green body is crushed, reformed, and aged to obtain a ceramic green sheet;

[0018] The ceramic green sheet is subjected to plastic arrangement sintering to obtain an insulating ceramic material.

[0019] Optionally, after the ceramic green sheet is obtained, the method further comprises:

[0020] It is judged whether the particle size of the current ceramic green sheet meets the particle size requirement;

[0021] If not, the current ceramic green sheet is used as a raw material, and the step of obtaining the slurry raw material by wet ball milling is returned.

[0022] Optionally, the step of obtaining the slurry raw material by wet ball milling comprises:

[0023] The wet ball milling is performed with agate balls and anhydrous ethanol as the medium to obtain the slurry raw material.

[0024] The above technical solutions provided by the present application have at least the following beneficial effects:

[0025] (1) The well heater insulating material with improved insulation performance by manganese doping provided by the present application is a mixed material containing magnesium oxide, a doping material containing manganese elements and a modifying agent, which is prepared by ball milling, drying, granulation, aging, molding and plastic sintering.

[0026] (2) The preparation method of the well heater insulating material with improved insulation performance by manganese doping provided by the present application is simple, easy to operate and suitable for industrial production.

[0027] The technical solutions of the present application will be further described in detail below through examples. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application and are used to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0029] Figure 1 The flow chart of the preparation method of the well heater insulating material with improved insulation performance by manganese doping in the present application. DETAILED DESCRIPTION

[0030] The exemplary embodiments of the present application will be described in detail below. Although exemplary embodiments are disclosed, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly and completely conveyed to those skilled in the art, and the scope of the present application can be fully conveyed to those skilled in the art.

[0031] In order to solve the problems in the prior art, the present application provides a well heater insulating material with improved insulation performance by manganese doping and a preparation method thereof.

[0032] The present application provides a well heater insulating material with improved insulation performance by manganese doping, which is a uniform, insulating ceramic material with good high-temperature electrical resistance, prepared from a mixed material containing magnesium oxide, a doping material containing manganese elements and a modifying agent, by ball milling, drying, granulation, aging, molding and plastic sintering.

[0033] Since the doping material containing manganese element and magnesium oxide can form a solid solution, the lattice of the activated magnesium oxide crystal is improved, the density and strength of the material are improved, and the insulation performance is improved; the modification reagent reduces the vacancy defects of the MgO crystal grains, and the MgO-OH structure is not easy to be formed by moisture absorption, thereby improving the volume resistivity; the prepared insulating ceramic material has good high-temperature insulation performance, can be used as an insulating material of a downhole high-power heater, and can ensure that the insulating material is not broken down at a high temperature of 650 DEG C.

[0034] Optionally, the purity of the magnesium oxide is not less than 80%.

[0035] Optionally, the mass content of the doping material containing manganese element in the mixed material is 0.5-2.7%, and the mass content of the modification reagent in the mixed material is 1-9%.

[0036] Optionally, the doping material containing manganese element can be in the following forms:

[0037] (1) The doping material containing manganese element is a salt of manganese

[0038] It can be manganese acetate or manganese stearate, and can also be manganese carbonyl, manganese tungstate, manganese citrate, manganese (II) triflate, manganese (II) carbonate, manganese perchlorate, etc.

[0039] (2) The doping material containing manganese element is an oxide of manganese

[0040] It can be an oxide of each valence state of manganese, such as manganese monoxide, manganese dioxide, manganese sesquioxide, manganese trioxide, etc.; and can also be an oxide form such as lithium manganese nickel oxide, lithium nickel manganese cobalt oxide, etc.

[0041] (3) The doping material containing manganese element is a manganate

[0042] For example, barium manganate, potassium permanganate, and lithium permanganate (III, IV) can also be used.

[0043] (4) The doping material containing manganese element is a coordination compound of manganese

[0044] It can be tricarbonyl cyclopentadienyl manganese (I), tetra-p-tolyl porphyrin manganese, and can also be di(ethylcyclopentadienyl) manganese (II), tris(2,2,6,6-tetramethyl-3,5-heptanedioic acid) manganese (III), etc.

[0045] Optionally, the above modification reagent can be at least one of sodium stearate, sodium dodecyl sulfate, sodium dodecyl sulfonate, CTAB and butyl titanate.

[0046] The application provides a preparation method of an insulating material of a downhole heater with improved insulation performance by manganese doping, as shown in Figure 1 The method comprises the following steps:

[0047] Step S11: wet ball milling the mixed material containing magnesium oxide, manganese element-containing doping material and modification reagent to obtain slurry raw material.

[0048] The specific materials of the magnesium oxide, the manganese element-containing doping material and the modification reagent and the mass ratio thereof are described above.

[0049] The magnesium oxide raw material, the manganese element-containing doping material and the modification reagent can be wet ball milled for 6-12 h in a medium of agate ball and anhydrous ethanol to obtain the slurry raw material.

[0050] Step S12: drying the slurry raw material and sieving to obtain powder material.

[0051] The slurry raw material is dried and sieved through a 40-100 mesh sieve to obtain undersize powder material.

[0052] Step S13: adding a binder to the powder material to granulate, and then pressing to form a ceramic green body.

[0053] The binder is added to the powder to granulate, and the binder is fully mixed with the powder during the granulation process, and then the ceramic green body can be pressed.

[0054] Further, the binder can be polyvinyl alcohol (PVA), and the mass fraction thereof can be 5-10 wt.%; alternatively, another binder can be selected.

[0055] Step S14: crushing, reforming and aging the ceramic green body to obtain a ceramic green sheet.

[0056] Alternatively, after obtaining the ceramic green sheet, the following steps can be further included:

[0057] determining whether the particle size of the current ceramic green sheet meets the particle size requirement; if not, using the current ceramic green sheet as raw material and returning to the step of wet ball milling the slurry raw material.

[0058] During the preparation of the ceramic green sheet using the current ceramic green sheet as raw material, the previous preparation process can be kept unchanged, or a harder agate ball can be selected, and / or a smaller mesh size sieve can be selected.

[0059] Step S15: plastic sintering the ceramic green sheet to obtain an insulating ceramic material.

[0060] The method can include heating the formed ceramic green sheet to 500-700°C at a heating rate of 5°C / min, performing plastic removal treatment at the constant temperature for 30-120 min; and then heating to 1000-2000°C in a high-temperature muffle furnace, and performing high-temperature sintering of the ceramic green sheet at the constant temperature for 1-48 h to obtain the insulating ceramic material.

[0061] The preparation method of the downhole heater insulating material with improved insulation performance by manganese doping is simple, easy to operate, and suitable for industrial production.

[0062] Example 1

[0063] 1000 g of magnesium oxide (purity 99.99%), 10 g of manganese acetate, 10 g of sodium stearate, and an appropriate amount of anhydrous ethanol were weighed and added to a star-shaped ball mill for wet ball milling for 9 h. The above raw materials were transferred to an oven and dried at 120 DEG C for 24 h. The powder was sieved through a 40-mesh sieve. A mass fraction of 5 wt.% of polyvinyl alcohol (PVA) was used as a binder to granulate the powder. During the granulation process, the binder was mixed with the powder to make the mixture uniform. Then, the ceramic green body was pressed. The ceramic green body was crushed, reshaped, and aged to obtain a ceramic green sheet. The shaped ceramic green sheet was heated to 500 DEG C at a heating rate of 5 DEG C / min, and the temperature was maintained for 30 min for degassing treatment. Then, the ceramic green sheet was heated to 1400 DEG C in a high-temperature muffle furnace and maintained for 48 h for high-temperature sintering to obtain a ceramic sample.

[0064] Example 2

[0065] 1000 g of magnesium oxide (purity 99.99%), 20 g of manganese stearate, 20 g of sodium dodecyl sulfate, and an appropriate amount of anhydrous ethanol were weighed and added to a star-shaped ball mill for wet ball milling for 9 h. The above raw materials were transferred to an oven and dried at 120 DEG C for 24 h. The powder was sieved through a 40-mesh sieve. A mass fraction of 5 wt.% of polyvinyl alcohol (PVA) was used as a binder to granulate the powder. During the granulation process, the binder was mixed with the powder to make the mixture uniform. Then, the ceramic green body was pressed. The ceramic green body was crushed, reshaped, and aged to obtain a ceramic green sheet. The shaped ceramic green sheet was heated to 500 DEG C at a heating rate of 5 DEG C / min, and the temperature was maintained for 30 min for degassing treatment. Then, the ceramic green sheet was heated to 1400 DEG C in a high-temperature muffle furnace and maintained for 48 h for high-temperature sintering to obtain a ceramic sample.

[0066] Example 3

[0067] Take and add 1000 g of magnesium oxide (purity 99.99%), 5 g of manganese dioxide, 30 g of sodium dodecyl sulfate, an appropriate amount of absolute ethanol to the star-shaped ball mill, wet ball mill for 9 h, transfer the above raw materials to the oven, dry at 120℃ for 24 h, pass through a 40 mesh sieve, add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation, during the granulation process, the binder and the powder are fully mixed and uniform, then pressed into ceramic green body. The ceramic green body is broken, reshaped, and aged to obtain a ceramic green sheet. The shaped ceramic green sheet is heated to 500℃ at a heating rate of 5℃ / min, and held for 30 min for degassing treatment; then heated to 1400℃ in a high temperature muffle furnace and held for 48 h, the ceramic green sheet is high temperature sintered to obtain a ceramic sample.

[0068] Example 4

[0069] Take and add 1000 g of magnesium oxide (purity 99.99%), 30 g of lithium manganese nickel oxide, 50 g of CTAB, an appropriate amount of absolute ethanol to the star-shaped ball mill, wet ball mill for 9 h, transfer the above raw materials to the oven, dry at 120℃ for 24 h, pass through a 40 mesh sieve, add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation, during the granulation process, the binder and the powder are fully mixed and uniform, then pressed into ceramic green body. The ceramic green body is broken, reshaped, and aged to obtain a ceramic green sheet. The shaped ceramic green sheet is heated to 500℃ at a heating rate of 5℃ / min, and held for 30 min for degassing treatment; then heated to 1400℃ in a high temperature muffle furnace and held for 48 h, the ceramic green sheet is high temperature sintered to obtain a ceramic sample.

[0070] Example 5

[0071] Take and add 1000 g of magnesium oxide (purity 99.99%), 10 g of barium manganate, 100 g of butyl titanate, an appropriate amount of absolute ethanol to the star-shaped ball mill, wet ball mill for 9 h, transfer the above raw materials to the oven, dry at 120℃ for 24 h, pass through a 40 mesh sieve, add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation, during the granulation process, the binder and the powder are fully mixed and uniform, then pressed into ceramic green body. The ceramic green body is broken, reshaped, and aged to obtain a ceramic green sheet. The shaped ceramic green sheet is heated to 500℃ at a heating rate of 5℃ / min, and held for 30 min for degassing treatment; then heated to 1400℃ in a high temperature muffle furnace and held for 48 h, the ceramic green sheet is high temperature sintered to obtain a ceramic sample.

[0072] Example 6

[0073] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 10 g of potassium permanganate, 10 g of sodium dodecyl sulfonate, and an appropriate amount of absolute ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0074] Example 7

[0075] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 10 g of potassium permanganate, 10 g of sodium dodecyl sulfonate, and an appropriate amount of absolute ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0076] Example 8

[0077] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 10 g of potassium permanganate, 10 g of sodium dodecyl sulfonate, and an appropriate amount of absolute ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0078] Example 9

[0079] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 5 g of manganese trioxide, 30 g of sodium dodecyl sulfate, and an appropriate amount of anhydrous ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then, press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then, heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0080] Example 10

[0081] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 5 g of manganese trioxide, 30 g of sodium dodecyl sulfate, and an appropriate amount of anhydrous ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then, press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then, heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0082] Example 11

[0083] Take and add 1000 g of magnesium oxide (purity 99.99%) to the star-shaped ball mill, 5 g of manganese trioxide, 30 g of sodium dodecyl sulfate, and an appropriate amount of anhydrous ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Sieve through a 40 mesh sieve. Add 5wt.% polyvinyl alcohol (PVA) as a binder to the powder for granulation. During the granulation process, the binder and the powder are mixed evenly. Then, press into ceramic blanks. Break the ceramic blanks, re-form, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then, heat to 1400°C in a high-temperature muffle furnace and hold for 48 h for high-temperature sintering to obtain ceramic samples.

[0084] Example 12

[0085] Take and add 1000 g of magnesium oxide (purity 95.00%) to the star-shaped ball mill, 5 g of manganese dioxide, 30 g of sodium dodecyl sulfate, and an appropriate amount of anhydrous ethanol, and wet ball mill for 9 h. Transfer the above raw materials to an oven and dry at 120°C for 24 h. Screen through a 40 mesh sieve. Add 5 wt.% polyvinyl alcohol (PVA) as a binder to the powder and granulate. During the granulation process, mix the binder and the powder evenly, and then press into ceramic blanks. Break and reform the ceramic blanks, and age to obtain ceramic green sheets. Heat the formed ceramic green sheets to 500°C at a heating rate of 5°C / min, and hold for 30 min for degassing. Then heat to 1400°C in a high-temperature muffle furnace and hold for 48 h to sinter the ceramic green sheets to obtain ceramic samples.

[0086] According to the sample size requirements of the properties to be tested, machine process the ceramic sheets. For samples for electrical property testing, coat the surface of the processed ceramic sheets with silver electrodes, and fire the electrodes at 800°C for 30 min. Then perform the corresponding electrical property tests.

[0087] Using the existing high-purity magnesium oxide ceramic material as a comparative example, the electrical property test results of the ceramic samples obtained in the above 12 examples and the 4 comparative examples at the corresponding temperatures are shown in Table 1:

[0088] Table 1: Raw material composition of Examples 1-12 and statistical table of electrical property test results of Examples 1-12 and comparative examples

[0089]

[0090]

[0091] It can be seen that the ceramic samples obtained in Examples 1-12 have a volume resistivity higher than 160 MΩ·cm even at a high temperature of 650°C. The ceramic samples obtained in this example have high insulation performance and can meet the working condition requirements of not being broken down at high temperatures. The high-purity magnesium oxide ceramic material has a high risk of being broken down at high temperatures.

[0092] From the comparison of Examples 3 and 10-12, it can also be found that the higher the purity of magnesium oxide in the mixed material, the better the insulation of the insulating ceramic material obtained.

[0093] Further, in more embodiments, it is found that, in the preparation process, the modification reagent is selected from at least two of sodium stearate, sodium dodecyl sulfate, sodium dodecyl sulfonate, CTAB and butyl titanate, the formed ceramic green sheet is selected by 40-100 mesh sieve, the ceramic green sheet is degassed at constant temperature of 500-700 DEG C for 30-120 min, and the ceramic green sheet is sintered at high temperature of 1000-2000 DEG C for 1-48 h, so that the insulating ceramic material with required insulating performance can be obtained.

[0094] It should be further noted that the raw materials used for preparing the insulating ceramic material in the embodiments of the present application and the materials involved in the comparative examples are all commercially available general products.

[0095] The above description includes examples of one or more embodiments. Of course, those of ordinary skill in the art should recognize that various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations falling within the scope of the appended claims. In addition, the term "comprising" used in the specification or claims is intended to have the same meaning as the term "including" and is interpreted as if the term "including" was used in the claims as an open-ended transitional phrase, as interpreted under 35 U.S.C. § 112(f). In addition, the use of any one term "or" in the specification or claims is intended to mean "non-exclusive or".

[0096] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the concept and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A downhole heater insulating material with improved insulation properties by manganese doping, characterized in that, The insulating material is an insulating ceramic material prepared by mixing a magnesium oxide, a manganese element-containing doping material and a modifying agent, ball milling, drying and granulating, aging and forming, and plastic removal sintering; The modifying agent is at least one of sodium stearate, sodium dodecyl sulfate, sodium dodecyl sulfonate, CTAB and butyl titanate; The mass content of the manganese element-containing doping material in the mixed material is 0.5-2.7%, and the mass content of the modifying agent in the mixed material is 1-9%.

2. The insulation material for downhole heater by manganese doping to improve insulation performance according to claim 1, wherein, The manganese element-containing doping material is a salt of manganese.

3. The insulation material for downhole heater insulation with improved insulation properties by manganese doping as claimed in claim 1, wherein, The manganese element-containing doping material is an oxide of manganese.

4. The insulation material for downhole heaters with improved insulation properties by manganese doping as claimed in claim 1, wherein, The manganese element-containing doping material is a manganate.

5. The insulation material for downhole heaters with improved insulation properties by manganese doping as claimed in claim 1, wherein, The manganese element-containing doping material is a coordination compound of manganese.

6. A method for preparing the downhole heater insulating material with improved insulation properties by doping with manganese as claimed in any one of claims 1 to 5, wherein, The method comprises the steps of: mixing a magnesium oxide, a manganese element-containing doping material and a modifying agent to obtain slurry raw materials by wet ball milling; drying the slurry raw materials and sieving to obtain powder materials; adding a binder to the powder materials to granulate, and then pressing to form ceramic blanks; breaking the ceramic blanks, re-forming and aging to obtain ceramic green sheets; performing plastic removal sintering on the ceramic green sheets to obtain the insulating ceramic material.

7. The production method according to claim 6, wherein After the ceramic green sheets are obtained, the method further comprises the steps of: determining whether the particle size of the current ceramic green sheets meets the particle size requirement; if not, returning to the step of obtaining the slurry raw materials by wet ball milling, and using the current ceramic green sheets as raw materials.

8. The production method according to claim 6, wherein The step of obtaining the slurry raw materials by wet ball milling comprises the steps of: performing wet ball milling on the mixed materials by taking agate balls and anhydrous ethanol as the medium to obtain the slurry raw materials.

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