Low-temperature early-strength micro-expansion tough material for well cementation cement and preparation method thereof

Abstract

The invention discloses a low-temperature early-strength micro-expansion tough material for well cementation cement and a preparation method of the low-temperature early-strength micro-expansion tough material. The low-temperature early-strength micro-expansion tough material comprises the following raw materials in percentage by weight: 70-80wt% of an early-strength material; 10-15 wt% of an elastic and tough material; and 10-15 wt% of a micro-expansion material. The low-temperature early-strength micro-expansion tough material disclosed by the invention has the characteristics of good early-strength performance, good anti-channeling performance, high toughness and the like in a low-temperature environment, and other engineering performances of cement paste are not influenced after the material is added into cement. In addition, a large amount of solid waste is selected as the raw material for preparation, the solid waste absorption amount is increased, land resource waste and environmental pollution caused by solid waste stockpiling are reduced, and the method has the advantages of being environmentally friendly, low in cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas resource development, and particularly relates to a low-temperature early-strength, slightly expanding and tough material for well cementing and a preparation method thereof. Background Art

[0002] With the gradual development of oil and gas exploration and development towards deep-water oil and gas, coalbed methane, tight oil, etc., low-temperature well cementing operations have gradually increased. Low-temperature well cementing generally refers to a well cementing operation where the circulating temperature of the cement slurry is below 45°C and the well depth is less than 1500m. In a low-temperature environment, the hydration of conventional oil well cement is extremely slow, the early strength is low, and the waiting-for-set time is long, increasing the risk of annulus fluid channeling and affecting the well cementing quality and operation safety. In addition, when low-temperature wells that are later fractured require the cement stone to maintain strength development at low temperatures, the cement stone is also required to have a certain toughness to meet the sealing requirements after repeated impact loads.

[0003] Patent CN113387626A discloses a cement slurry for low-temperature well cementing and a preparation method thereof, which successively includes the following steps: (1) Pour 4.8 - 12 parts of a fluid loss reducer and 2.4 parts of a dispersant USZ into 352 parts of deionized water and stir evenly; (2) Dry-mix 800 parts of G-class oil well cement, 16 - 24 parts of calcium chloride, and 32 - 40 parts of microsilica; (3) Put the mixed dry powder into the solution in step (1) and stir evenly to obtain the cement slurry for low-temperature well cementing.

[0004] Patent CN110105030B discloses a well cementing material applicable to a low-temperature environment and a production method thereof. Its formula is mainly composed of the following raw materials mixed in weight percentages: 75 - 89% of portland cement clinker, 1 - 8% of sulfoaluminate cement clinker, 1 - 8% of high-alumina cement clinker, 2 - 4% of dihydrate gypsum, 0.5 - 1.2% of a dispersant, and 1 - 4% of a retarder.

[0005] Patent CN107540260B discloses a low-temperature cement early-strength agent for well cementing and cement containing it, which includes the following components in parts by weight: 23 - 27 parts of sodium sulfate, 5 - 7 parts of sodium nitrate, 3 - 5 parts of ferrous sulfate, 0.2 - 0.3 parts of diethanolamine, 0.4 - 0.5 parts of triethanolamine, 1.0 - 1.3 parts of a water reducer, 2 - 2.5 parts of ultrafine mica powder, 0.3 - 0.5 parts of lithium carbonate, and 0.8 - 1.0 parts of talc powder.

[0006] The above-mentioned existing technologies have achieved certain results in the low-temperature early strength of cement slurry, but there is still a lack of research on the anti-channeling performance and toughness of well cementing cement stone. Therefore, it is particularly important to develop a well cementing material that is applicable to a low-temperature environment, has early strength, anti-channeling performance, high toughness, and does not affect the engineering performance of the cement slurry system. Summary of the Invention

[0007] In order to overcome the above-mentioned technical difficulties of the cement slurry for well cementing, the present invention provides a low-temperature early-strength, slightly expanding and tough material for well cementing and a preparation method thereof, and provides a well cementing material applicable to low-temperature environments with early strength, good anti-channeling property, high toughness and no influence on the engineering properties of the cement slurry system to solve the technical problems of low-temperature well cementing technology.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] On the one hand, a low-temperature early-strength, slightly expanding and tough material for well cementing provided by the present invention includes the following raw materials by weight percentage:

[0010] Early-strength material: 70-80 wt%;

[0011] Elastic and tough material: 10-15 wt%;

[0012] Slightly expanding material: 10-15 wt%.

[0013] Further, the elastic and tough material is obtained by pulverizing ethylene-butyl acrylate copolymer and cellulose acetate butyrate into fine powder according to a mass ratio of (2-3):1, mixing them, and then modifying them by low-temperature plasma;

[0014] Preferably, the mass ratio of ethylene-butyl acrylate copolymer to cellulose acetate butyrate is 5:2.

[0015] Further, the content of butyl acrylate in the ethylene-butyl acrylate copolymer is 33-37 wt%.

[0016] Further, the content of acetyl group in the cellulose acetate butyrate is 12-15 wt%, and the content of butyryl group is 32-35 wt%.

[0017] Further, the slightly expanding material is composed of sepiolite and magnesite tailings mixed according to a mass ratio of 1:3.

[0018] Further, the content of lithium magnesium silicate in the sepiolite > 99 wt%; the content of MgO in the magnesite tail is 38-42 wt%, and the content of SiO2 is 15-18 wt%.

[0019] Further, the early-strength material is composed of active component A, active component B and reinforcing component mixed according to a mass ratio of (1-2):6:(2-3), and the preparation method is as follows:

[0020] S1. Mix active component A and the reinforcing component to obtain powder A;

[0021] S2. Place active component B in a ball milling tank and ball mill it at a speed of 500 rpm for 6 h to obtain powder B;

[0022] S3. pneumatically mix powder A and powder B to obtain an early strength material.

[0023] The early strength material of the present invention can provide an alkaline environment for the initial hydration reaction of cement. On the one hand, it promotes the cement hydration reaction; on the other hand, it activates the activity of active component B, promotes the activation and decomposition of the solid waste in active component B, and promotes the release of Si 4+ 、Al 3+ and Ca 2+ plasma, accelerating the formation of hydration products. In addition, active component A in the present invention can act as crystal seeds of calcium silicate hydrate and calcium silicoaluminate hydrate in the early stage of hydration, providing a good nucleation effect during the cement hydration process, inducing the formation of calcium silicate hydrate and calcium silicoaluminate hydrate during the cement hydration process, promoting cement hydration and thus increasing the early strength of cement.

[0024] Further, the active component A is composed of carbide slag, biomass furnace slag and aerated concrete waste mixed in a mass ratio of 5:4:1, and the preparation method is as follows:

[0025] S11. Place carbide slag, biomass furnace slag and aerated concrete waste in a ball mill tank according to a mass ratio of 5:4:1, with a liquid-to-solid ratio of 1.0, and ball mill at a speed of 400 rpm for 72 h to obtain slurry A;

[0026] S12. Place slurry A in a sealed stirring tank, add a dispersant accounting for 1 wt% of the solid phase mass in slurry A and stir. The stirring temperature is 80 °C and the stirring time is 72 h to obtain slurry B;

[0027] S13. Place slurry B in a centrifugal device for liquid-solid separation, and dry the solid phase at the bottom of the liquid-solid separation into dry powder to obtain active component A;

[0028] Preferably, the CaO content in the carbide slag is 65-70 wt%, and the pH is 12-13; the SiO2 content of the biomass furnace slag is ≥65 wt%, the Al2O3 content is ≥15 wt%, and the particle size is less than 325 mesh; the aerated concrete waste is composed of tobermorite, semi-crystalline C-S-H(I), C-S-H gel and silica, and after being crushed and ground, the powder fineness is less than 600 mesh; the dispersion stabilizer is a mixture of ketone aldehyde condensate and microcrystalline cellulose;

[0029] The active component B is composed of modified zirconium silicate slag, ferrosilicon slag, phosphorus slag and alkali slag mixed in a mass ratio of 3:2:1:1. The modified zirconium silicate slag is a product obtained by making zirconium silicate slag into slurry C, subjecting slurry C to neutralization, water washing, impurity removal treatment, then performing liquid-solid separation, and then through high-temperature drying and grinding;

[0030] Preferably, the modified zirconium silicate slag has a SiO2 content of ≥90 wt%, a neutral pH, and a powder particle size less than 325 mesh; the powder particle size of the ferrosilicon slag is less than 325 mesh, with a SiO2 content of 35 - 40 wt%, an Al2O3 content of 9 - 12 wt%, a CaO content of 25 - 28 wt%, and a MgO content of 6 - 11 wt%; the phosphorus slag has a SiO2 content of 35 - 40 wt% and a CaO content of 42 - 48 wt%; the alkali slag has a CaCO3 content of 40 - 45 wt%, a CaSO4 content of 7 - 10 wt%, and a CaCl2 content of 10 - 14 wt%.

[0031] The reinforcing component is composed of lithium silicate and aluminum sulfate mixed in a mass ratio of 1:2; preferably, the purity of the lithium silicate is greater than 98 wt%, and the purity of the aluminum sulfate is greater than 98 wt%.

[0032] In the present invention, the active component A reacts under wet grinding conditions using carbide slag, biomass furnace slag, and aerated concrete waste to generate calcium silicate hydrate and calcium silicoaluminate hydrate. The aerated concrete waste contains a large amount of tobermorite, which can serve as the nucleation sites for calcium silicate hydrate and calcium silicoaluminate hydrate, greatly accelerating the formation of calcium silicate hydrate and calcium silicoaluminate hydrate and promoting the cement hydration reaction.

[0033] In the present invention, the active component B contains a large number of amorphous SiO2 particles, which have high activity and can rapidly undergo a hydration reaction with the cement hydration product Ca(OH)2 to accelerate cement hydration; at the same time, the active component B also contains a small amount of MgO, CaSO4, etc. On the one hand, it can promote the crystallization of ettringite through a synergistic effect with the reinforcing component, and on the other hand, it can form Mg(OH)2 during the cement hydration process, enhancing the cementation and sealing properties of the well - cemented stone, and thus improving the anti - channeling ability of the well - cemented stone.

[0034] The reinforcing component of the present invention can react with free hydroxide ions (OH - ) and calcium ions (Ca 2+ ) in the system to generate silicate gel and calcium silicate, filling the micropores and cracks of the hydration products, thereby improving the matrix density. The generated silicate gel and calcium silicate, through a synergistic strengthening effect with the active component A, further promote the formation of calcium silicate hydrate and calcium silicoaluminate hydrate; the reinforcing component can also jointly promote the crystallization of ettringite with various ions released by the active component B. Due to the consumption of a large amount of Si 4+ , Al 3+ , and Ca 2+ ions in the system, it further promotes the hydration of cement and the dissociation and release of the activity of the active component B, and thus promotes the formation of early strength. In addition, the Li + released by lithium silicate accelerates the destruction of the early hydration product film coating the cement particles and speeds up the hydration process.

[0035] On the other hand, a preparation method of a low-temperature early-strength, slightly expansive and tough material for well cementing includes: uniformly mixing early-strength materials, elastic and tough materials, and slightly expansive materials according to their respective mass ratios to obtain the low-temperature early-strength, slightly expansive and tough material for well cementing.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The low-temperature early-strength, slightly expansive and tough material of the present invention has the characteristics of good early-strength performance, good anti-channeling performance, and high toughness in a low-temperature environment. Moreover, after adding it to cement, it does not affect other engineering properties of the cement slurry. In addition, the present invention selects a large amount of solid waste as raw materials for preparation, which improves the consumption of solid waste, reduces the waste of land resources and environmental pollution caused by solid waste stacking, and has the characteristics of environmental protection and low cost.

[0038] 2. The early-strength material provided by the present invention provides an alkaline environment for the initial hydration reaction of cement. On the one hand, it promotes the cement hydration reaction and jointly promotes the formation of hydration products such as ettringite with the SO4 dissolved by itself; on the other hand, it provides seed crystals of calcium silicate hydrate and calcium silicoaluminate hydrate for the initial stage of cement hydration, provides a good nucleation effect during the cement hydration process, induces the formation of calcium silicate hydrate and calcium silicoaluminate hydrate during the cement hydration process, and further promotes cement hydration and thus improves the early strength of cement. 2- 3. The elastic and tough material provided by the present invention is obtained by co-mixing ethylene-butyl acrylate copolymer and cellulose acetate butyrate, crushing them and then mixing them in a Z-type kneader. Under the strong shearing action and thermal effect, the formed elastic and tough material has improved elasticity, toughness, strength, etc.; the surface of the elastic and tough material is modified by low-temperature plasma to improve the surface tension and hydrophilicity of the elastic and tough material, enhance the bonding property of the interface transition zone between the elastic and tough material and cement, and the internal pore structure. The surface of the elastic and tough material is covered with hydration products, and the bonding property with the cement matrix is stronger.

[0039] 4. The slightly expansive material provided by the present invention, through the combined action of hectorite and magnesite tailings, can not only improve the stability of the cement slurry and reduce the water loss of the cement slurry, but also lithium magnesium silicate can enhance the bonding property between cement hydration products, improve the density of the cement system, and thus improve its strength development. In addition, Mg(OH)2 formed by the alkaline environment hydration provided by the early-strength material of the present invention and ettringite generated under the promotion of the early-strength material synergistically enhance the expansibility of the well cementing stone, improve the bonding property and sealing property of the cement stone, and thus improve the anti-channeling ability of the well cementing stone.

[0040] 4. The slightly expansive material provided by the present invention, through the combined action of hectorite and magnesite tailings, can not only improve the stability of the cement slurry and reduce the water loss of the cement slurry, but also lithium magnesium silicate can enhance the bonding property between cement hydration products, improve the density of the cement system, and thus improve its strength development. In addition, Mg(OH)2 formed by the alkaline environment hydration provided by the early-strength material of the present invention and ettringite generated under the promotion of the early-strength material synergistically enhance the expansibility of the well cementing stone, improve the bonding property and sealing property of the cement stone, and thus improve the anti-channeling ability of the well cementing stone. Specific embodiments

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0042] Example 1

[0043] As a relatively preferred embodiment of the present invention, the specific composition of the low-temperature early-strength, slightly expanding and tough material for well cementing in this embodiment is shown in Table 1 below:

[0044] Table 1

[0045] Raw materials Weight ratio (wt%) Early strength material 70 Elastic material 15 Micro-expansion material 15

[0046] In this embodiment, the early-strength material is composed of active component A, active component B and reinforcing component, which are mixed in a mass ratio of 1:6:3.

[0047] In this embodiment, the elastic material is composed of ethylene-butyl acrylate copolymer and cellulose acetate butyrate. After being crushed into fine powder in a mass ratio of 5:2 and placed in a Z-type kneader for mixing, it is then modified by low-temperature plasma.

[0048] In this embodiment, the slightly expanding material is composed of hectorite and magnesite tailings, which are mixed in a mass ratio of 1:3.

[0049] According to the weight ratio in Table 1, the early-strength material, elastic and tough material, and slightly expanding material are mixed evenly to obtain the low-temperature early-strength, slightly expanding and tough material 1# for well cementing.

[0050] Example 2

[0051] As a relatively preferred embodiment of the present invention, the specific composition of the low-temperature early-strength, slightly expanding and tough material for well cementing in this embodiment is shown in Table 2 below:

[0052] Table 2

[0053] Raw materials Weight ratio (wt%) Early strength material 75 Elastic material 12.5 Micro-expansion material 12.5

[0054] In this embodiment, the early-strength material is composed of active component A, active component B and reinforcing component, which are mixed in a mass ratio of 1:6:3.

[0055] In this embodiment, the elastic material is composed of ethylene-butyl acrylate copolymer and cellulose acetate butyrate. After being crushed into fine powder in a mass ratio of 5:2 and placed in a Z-type kneader for mixing, it is then modified by low-temperature plasma.

[0056] In this embodiment, the slightly expanding material is composed of hectorite and magnesite tailings, which are mixed in a mass ratio of 1:3.

[0057] Mix the early strength material, elastic and tough material, and slightly expanding material evenly according to the weight ratio in Table 2 to obtain the low-temperature early strength slightly expanding tough material 2# for well cementing.

[0058] Example 3

[0059] As a relatively preferred embodiment of the present invention, the specific composition of the low-temperature early strength slightly expanding tough material for well cementing in this embodiment is shown in Table 3 below:

[0060] Table 3

[0061] Raw materials Weight ratio (wt%) Early strength material 80 Elastic material 10 Micro-expansion material 10

[0062] In this embodiment, the early strength material is composed of active component A, active component B, and reinforcing component, which are mixed in a mass ratio of 1:6:3.

[0063] In this embodiment, the elastic material is obtained by crushing ethylene-butyl acrylate copolymer and cellulose acetate butyrate into fine powder in a mass ratio of 5:2, mixing them in a Z-type kneader, and then modifying them by low-temperature plasma.

[0064] In this embodiment, the slightly expanding material is composed of hectorite and magnesite tailings, which are mixed in a mass ratio of 1:3.

[0065] Mix the early strength material, elastic and tough material, and slightly expanding material evenly according to the weight ratio in Table 3 to obtain the low-temperature early strength slightly expanding tough material 3# for well cementing.

[0066] Example 4

[0067] As a relatively preferred embodiment of the present invention, the specific composition of the low-temperature early strength slightly expanding tough material for well cementing in this embodiment is shown in Table 4 below:

[0068] Table 4

[0069] Raw materials Weight ratio (wt%) Early strength material 80 Elastic material 10 Micro-expansion material 10

[0070] In this embodiment, the early strength material is composed of active component A, active component B, and reinforcing component, which are mixed in a mass ratio of 3:12:5.

[0071] In this embodiment, the elastic material is obtained by crushing ethylene-butyl acrylate copolymer and cellulose acetate butyrate into fine powder in a mass ratio of 5:2, mixing them in a Z-type kneader, and then modifying them by low-temperature plasma.

[0072] In this embodiment, the slightly expanding material is composed of hectorite and magnesite tailings, which are mixed in a mass ratio of 1:3.

[0073] Mix the early strength material, elastic and tough material, and slightly expanding material evenly according to the weight ratio in Table 4 to obtain the low-temperature early strength slightly expanding tough material 4# for well cementing.

[0074] Example 5

[0075] As a relatively preferred embodiment of the present invention, the specific composition of the low-temperature early strength slightly expanding tough material for well cementing in this embodiment is shown in Table 5 below:

[0076] Table 5

[0077] Raw materials Weight ratio (wt%) Early strength material 80 Elastic material 10 Micro-expansion material 10

[0078] In this embodiment, the early strength material is composed of active component A, active component B, and reinforcing component mixed in a mass ratio of 1:3:1.

[0079] In this embodiment, the elastic material is composed of ethylene-butyl acrylate copolymer and cellulose acetate butyrate crushed into fine powder in a mass ratio of 5:2, placed in a Z-type kneader for mixing, and then modified by low-temperature plasma.

[0080] In this embodiment, the slightly expanding material is composed of hectorite and magnesite tailings mixed in a mass ratio of 1:3.

[0081] Mix the early strength material, elastic and tough material, and slightly expanding material evenly according to the weight ratio in Table 5 to obtain the low-temperature early strength slightly expanding tough material 5# for well cementing.

[0082] Comparative Example 1

[0083] This comparative example uses G-grade cement as the blank group.

[0084] Comparative Example 2

[0085] In this comparative example, except that the reinforcing component is not included in the early strength material, the rest are the same as in Example 1, and the expanding tough material 1* is obtained.

[0086] Comparative Example 3

[0087] In this comparative example, except that cellulose acetate butyrate is not included in the elastic material, the rest are the same as in Example 1, and the expanding tough material 2* is obtained.

[0088] Comparative Example 4

[0089] In this comparative example, except that hectorite is not included in the slightly expanding material, the rest are the same as in Example 1, and the expanding tough material 3* is obtained.

[0090] Comparative Example 5

[0091] In this comparative example, except that the ethylene-butyl acrylate copolymer and cellulose acetate butyrate are not modified after mixing, the rest are the same as in Example 1, and the expanding tough material 4* is obtained.

[0092] Test Example

[0093] 1. Prepare cement slurry according to the standard of GB / T 19139-2003, with a water-cement ratio of 0.44. The dosage of the expansive toughness material in Examples 1 to 5 and Comparative Examples 2 to 5 is 5wt%. Test the engineering properties of each prepared cement slurry and the G-class cement of Comparative Example 1, such as water loss, fluidity, anti-channeling coefficient, thickening time, etc. The results are shown in Table 6.

[0094] Table 6

[0095]

[0096] According to the data in Table 6 above, it can be concluded that the water loss of the cement slurry prepared with the expansive toughness material of Examples 1 to 5 is less than 50 ml and the fluidity is greater than 18 cm, which can better meet the construction requirements; and compared with Comparative Example 1, the thickening time of the slurry is greatly shortened. The SPN value (anti-gas-channeling performance parameter) shows that the present invention can improve the anti-channeling property of the cement slurry and greatly shorten the setting time of the cement slurry. The present invention can be well adapted to the cement slurry without affecting the construction performance of the cement slurry body. The engineering properties of Comparative Examples 2 to 5 are better than those of Comparative Example 1, but compared with Example 1, the thickening time of the cement slurry in Comparative Examples 2 to 5 is prolonged, and the gas anti-channeling ability of the slurry is greatly reduced.

[0097] 2. Prepare cement slurry according to the standard of GB / T 19139-2003, with a water-cement ratio of 0.44. The dosage of the expansive toughness material in Examples 1 to 5 and Comparative Examples 2 to 5 is 5wt%. Test the compressive strength and elastic modulus of each prepared cement slurry and the G-class cement of Comparative Example 1 at different curing temperatures and curing times. The results are shown in Table 7.

[0098] Table 7

[0099]

[0100] It can be seen from the data in Table 7 above that the present invention can significantly improve the compressive strength of G-class oil well cement under low-temperature conditions, indicating that the present invention has excellent low-temperature early strength effect and is beneficial to shortening the setting time of shallow oil and gas well cementing. The present invention can significantly reduce the elastic modulus of the cement stone and improve the toughness of the cement stone. The compressive strength of the cement stone formed by incorporating the expansive toughness material of Comparative Examples 2 to 5 is much greater than that of Comparative Example 1, but less than that of Example 1, indicating that the low-temperature early strength effect of the materials formed by Comparative Examples 2 to 5 is weaker.

[0101] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solutions of the present invention, rather than limiting it, and certainly not limiting the patent scope of the present invention; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention; that is to say, any meaningless changes or polishing made in the main design concept and spirit of the present invention, as long as the technical problems solved are still the same as those of the present invention, should be included in the protection scope of the present invention; in addition, directly or indirectly applying the technical solutions of the present invention to other related technical fields shall similarly be included in the patent protection scope of the present invention.

Claims

1. A low-temperature early-strength and slightly expanding ductile material for well cementing, characterized in that, Comprising the following raw materials by weight percentage: Early strength material: 70 - 80 wt%; Elastoplastic material: 10 - 15 wt%; Micro - expansion material: 10 - 15 wt%.

2. The low-temperature early-strength slightly expanding and tough material for well cementing according to claim 1, wherein, The elastoplastic material is obtained by crushing ethylene - butyl acrylate copolymer and cellulose acetate butyrate into fine powder according to the mass ratio of (2 - 3):1, mixing them, and then modifying them by low - temperature plasma; Preferably, the mass ratio of ethylene - butyl acrylate copolymer to cellulose acetate butyrate is 5:

2.

3. The low-temperature early-strength slightly-expandable tough material for well cementing according to claim 2, wherein The content of butyl acrylate in the ethylene - butyl acrylate copolymer is 33 - 37 wt%.

4. A low-temperature early-strength, slightly expanding and tough material for well cementing according to claim 2, characterized in that, The content of acetyl group in the cellulose acetate butyrate is 12 - 15 wt%, and the content of butyryl group is 32 - 35 wt%.

5. A low-temperature early-strength, slightly expanding and tough material for well cementing, as claimed in claim 1, characterized in that, The micro - expansion material is composed of sepiolite and magnesite tailings mixed according to the mass ratio of 1:

3.

6. The low-temperature early-strength slightly expanding and tough material for well cementing according to claim 5, characterized in that, The content of lithium magnesium silicate in the sepiolite > 99 wt%; the content of MgO in the magnesite tailings is 38 - 42 wt%, and the content of SiO2 is 15 - 18 wt%.

7. A low-temperature early-strength slightly expanding and tough material for well cementing, according to claim 1, characterized in that The early strength material is composed of active component A, active component B and reinforcing component mixed according to the mass ratio of (1 - 2):6:(2 - 3), and the preparation method is as follows: S1. Mix active component A and the reinforcing component to obtain powder A; S2. Place active component B in a ball - milling tank and ball - mill at a speed of 500 rpm for 6 h to obtain powder B; S3. Mix powder A and powder B pneumatically to obtain the early strength material.

8. The low-temperature early-strength slightly expanding tough material for well cementing according to claim 7, characterized in that, The active component A is composed of carbide slag, biomass furnace slag and aerated concrete waste mixed according to the mass ratio of 5:4:1, and the preparation method is as follows: S11. Place carbide slag, biomass furnace slag and aerated concrete waste according to the mass ratio of 5:4:1 in a ball - milling tank, with a liquid - to - solid ratio of 1.0, and ball - mill at a speed of 400 rpm for 72 h to obtain slurry A; S12. Place slurry A in a sealed stirring tank, add a dispersant accounting for 1 wt% of the solid phase mass in slurry A and stir. The stirring temperature is 80 °C and the stirring time is 72 h to obtain slurry B; S13. Place slurry B in a centrifugal device for liquid - solid separation, and dry the solid phase at the bottom of the liquid - solid separation into dry powder to obtain active component A; Preferably, the content of CaO in the carbide slag is 65 - 70 wt%, and the pH is 12 - 13; the content of SiO2 in the biomass furnace slag ≥ 65 wt%, the content of Al2O3 ≥ 15 wt%, and the particle size is less than 325 mesh; the aerated concrete waste is composed of tobermorite, semi - crystalline C - S - H (I), C - S - H gel and silica, and after being crushed and ground, the powder fineness is less than 600 mesh; the dispersion stabilizer is a mixture of ketone - aldehyde condensate and microcrystalline cellulose; The active component B is composed of modified zirconium - silicon slag, silicon - manganese slag, phosphorus slag and alkali slag mixed according to the mass ratio of 3:2:1:

1. The modified zirconium - silicon slag is a product obtained by making zirconium - silicon slag into slurry C, subjecting slurry C to neutralization, washing, impurity removal treatment, then performing solid - liquid separation, and finally through high - temperature drying and grinding; Preferably, the content of SiO2 in the modified zirconium silicate slag is ≥90wt%, the pH is neutral, and the powder particle size is less than 325 mesh; the powder particle size of the silicomanganese slag is less than 325 mesh, the SiO2 content is 35-40wt%, the Al2O3 content is 9-12wt%, the CaO content is 25-28wt%, and the MgO content is 6-11wt%; the SiO2 content in the phosphorus slag is 35-40wt%, and the CaO content is 42-48wt%; the CaCO3 content in the alkali slag is 40-45wt%, the CaSO4 content is 7-10wt%, and the CaCl2 content is 10-14wt%; The reinforcing component is composed of lithium silicate and aluminum sulfate mixed in a mass ratio of 1:2; preferably, the purity of the lithium silicate is greater than 98wt%, and the purity of the aluminum sulfate is greater than 98wt%.

9. The preparation method of a low-temperature early-strength slightly-expansive tough material for well cementing cement according to any one of claims 1 to 8, characterized in that, It includes: Mix the early strength material, elastic and ductile material, and micro-expansion material evenly according to each mass ratio to obtain the low-temperature early strength micro-expansion ductile material for well cementing.

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