Material for activating repairing function of self-repairing cement base and preparation method thereof

Abstract

The invention belongs to the technical field of oil well sealing cement, and particularly discloses a material for activating the repairing function of a self-repairing cement base and a preparation method thereof.The material comprises a rupturable hard shell, the rupturable hard shell is filled with a sodium bicarbonate solution, and a dilute sulphuric acid solution is wrapped in paraffin; and the paraffin coated with the dilute sulphuric acid solution is arranged in the rupturable hard shell filled with the sodium bicarbonate solution. Compared with the prior art, carbon dioxide is needed for the self-repairing cement to play a repairing role, and when the outside detects that an extraction drill hole has cracks, the material can provide carbon dioxide through mutual reaction of solutions to enable the self-repairing cement to generate a repairing product to block the cracks.

Description

Technical Field

[0001] This invention relates to the field of oil well cementing technology, and in particular to a material for activating the self-healing function of cement-based materials and its preparation method. Background Technology

[0002] Methane gas is a common and dangerous gas in coal mining. To improve gas extraction efficiency and reduce gas concentration, borehole sealing grouting technology is widely used in the sealing of gas extraction boreholes. Through the solidification and hardening process of the grouting material, the borehole is effectively sealed, ensuring the smooth progress of gas extraction.

[0003] With the continuous advancement of technology, grouting technology is also constantly being innovated and improved. To adapt to the complex and ever-changing geological environment and safety requirements in coal mining, a new type of self-healing cement grouting material for cracks has been developed. This is a material that can automatically generate repair products after damage, restoring its properties. It is typically dormant in the absence of carbon dioxide; its activity is activated in the presence of carbon dioxide, thus enabling it to function. However, this grouting material cannot perform its repair function in the absence of surrounding carbon dioxide, and cannot completely seal cracks, posing a safety hazard. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a material for activating the self-healing repair function of cement-based materials and its preparation method.

[0005] To achieve the above objectives, the present invention is implemented according to the following technical solution: One of the objectives of this invention is to provide a material for activating the self-healing function of cement-based repair, comprising a fractured hard shell filled with a sodium bicarbonate solution, a dilute sulfuric acid solution encapsulated in paraffin wax, and the paraffin wax encapsulated in the dilute sulfuric acid solution disposed within the fractured hard shell filled with sodium bicarbonate solution.

[0006] Furthermore, the mass percentages of the crackable hard shell, sodium bicarbonate solution, paraffin wax, and dilute sulfuric acid solution are as follows: crackable hard shell 15%~25%, sodium bicarbonate solution 20%~30%, paraffin wax 25%~35%, and dilute sulfuric acid solution 20%~30%.

[0007] Furthermore, the ruptureable hard shell is made of ethyl cellulose.

[0008] Furthermore, the concentration ratio of the sodium bicarbonate solution to the dilute sulfuric acid solution is 1:1 to 1.2.

[0009] The second objective of this invention is to provide a method for preparing a material to activate the self-healing repair function of cement-based materials, comprising the following steps: S1. Prepare hollow spherical paraffin wax, then inject dilute sulfuric acid solution into the hollow spherical paraffin wax and seal it with paraffin wax; S2. Paraffin wax coated with dilute sulfuric acid solution is placed into a crackable hard shell, then sodium bicarbonate solution is injected into the crackable hard shell, and the crackable hard shell is sealed; a material for activating the self-healing cement-based repair function is obtained.

[0010] Compared with existing technologies, the present invention addresses the issue that self-healing cement requires carbon dioxide to exert its repair function. When external factors detect cracks in the extraction borehole, the material can provide carbon dioxide through a solution reaction, allowing the self-healing cement to generate repair products that seal the cracks. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the materials used in this invention; Figure 2 A schematic diagram illustrating the mixing of a molten paraffin solution in a material; Figure 3 A schematic diagram illustrating the reaction between solutions to produce carbon dioxide; Figure 4 This is a schematic diagram illustrating the self-healing principle of cement-based cracks. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0013] like Figure 1 As shown in the figure, this embodiment exemplarily demonstrates a material for activating the self-healing function of cement-based repair, comprising a fractured hard shell 1, wherein the fractured hard shell 1 is filled with sodium bicarbonate solution 3, and a dilute sulfuric acid solution 4 is encapsulated in paraffin wax 2, wherein the paraffin wax 2 encapsulated with dilute sulfuric acid solution 4 is disposed in the fractured hard shell 1 filled with sodium bicarbonate solution 3; the fractured hard shell 1 is made of ethyl cellulose, and the concentration ratio of sodium bicarbonate solution 3 to dilute sulfuric acid solution 4 is 1:1~1.2.

[0014] In the actual formulation, the mass percentages of the crackable hard shell 1, sodium bicarbonate solution 3, paraffin wax 2, and dilute sulfuric acid solution 4 are as follows: crackable hard shell 15%~25%, sodium bicarbonate solution 20%~30%, paraffin wax 25%~35%, and dilute sulfuric acid solution 20%~30%. For example, the formulation contains 20g of crackable hard shell, 25g of sodium bicarbonate solution, 30g of paraffin wax, and 25g of dilute sulfuric acid solution.

[0015] The specific process for preparing this material used to activate the self-healing repair function of cement-based materials is as follows: S1. Prepare hollow spherical paraffin 2, then inject dilute sulfuric acid solution 4 into the hollow spherical paraffin 2 and seal it with paraffin; S2. Paraffin 2 containing dilute sulfuric acid solution 4 is placed into a spherical crackable shell 1. Then, sodium bicarbonate solution 3 is injected into the crackable shell 1 and the crackable shell 1 is sealed. The material used to activate the self-healing cement-based repair function is obtained.

[0016] When using this solution, if a leak is found in the extraction borehole, to ensure extraction efficiency and safety, the self-healing cement needs to perform its repair function to seal the cracks. When preparing the cement slurry, 5%~8% of a material to activate the self-healing cement-based repair function is added and stirred evenly. Then, the cracks are sealed. When a leak is found in the extraction borehole, to ensure extraction efficiency and safety, the self-healing cement needs to perform its repair function to seal the cracks. The cracks are surrounded by a material to activate the self-healing cement-based repair function. Because paraffin wax has a low melting point, external heating is used to melt the paraffin wax 2, which contains a dilute sulfuric acid solution 4 within its fractured hard shell 1. This allows the sodium bicarbonate solution 3 to mix with the dilute sulfuric acid solution 4 to form a mixed solution 5. Figure 2 As shown, the mixed solution 5 reacts to produce carbon dioxide. As the reaction proceeds, the gas produced by the reaction causes the ruptureable hard shell 1 to break, thereby releasing carbon dioxide, as shown. Figure 3 As shown. Then, the self-healing cement comes into contact with carbon dioxide, triggering the self-healing mechanism and generating repair products to seal the cracks, such as... Figure 4 As shown.

[0017] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A material for activating the self-healing function of cement-based repair, characterized in that, It includes a fractured hard shell filled with a sodium bicarbonate solution, and a dilute sulfuric acid solution encapsulated in paraffin wax, with the paraffin wax encapsulated in the dilute sulfuric acid solution disposed within the fractured hard shell filled with sodium bicarbonate solution.

2. The material for activating the self-healing cement-based repair function according to claim 1, characterized in that, The mass percentages of the fractured hard shell, sodium bicarbonate solution, paraffin wax, and dilute sulfuric acid solution are as follows: fractured hard shell 15%~25%, sodium bicarbonate solution 20%~30%, paraffin wax 25%~35%, and dilute sulfuric acid solution 20%~30%.

3. The material for activating the self-healing cement-based repair function according to claim 1, characterized in that, The fractured hard shell is made of ethyl cellulose.

4. The material for activating the self-healing cement-based repair function according to claim 1, characterized in that: The concentration ratio of the sodium bicarbonate solution to the dilute sulfuric acid solution is 1:1 to 1.

2.

5. A method for preparing a material for activating the self-healing repair function of cement-based materials as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Prepare hollow spherical paraffin wax, then inject dilute sulfuric acid solution into the hollow spherical paraffin wax and seal it with paraffin wax; S2. Place the paraffin containing dilute sulfuric acid solution into a crackable hard shell, then inject sodium bicarbonate solution into the crackable hard shell and seal the crackable hard shell. Materials were obtained for activating the self-healing cement-based repair function.

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