Static expansion fracturing material for upward drilling and use method

Abstract

According to the static expansion fracturing material for upward drilling and the using method, calcium oxide serves as a main material, magnesium oxide, titanium oxide and citric acid serve as auxiliary materials, the main material and the auxiliary materials are both dry materials, and the main material and the auxiliary materials are evenly stirred, mixed and ground to obtain the static expansion fracturing material. The mass ratios of the calcium oxide, the magnesium oxide, the titanium oxide and the citric acid are 85.5%, 5.5%, 7.5% and 1.5% respectively. The invention has the advantages of scientific principle, easily available ingredients, simple manufacturing process, low cost, good cracking effect, advanced injection or installation, slow expansion cracking after encountering water, and safe and reliable use process.

Description

Technical Field

[0001] The invention belongs to the technical field of static fracturing of coal and rock strata in coal mine roofs, and in particular relates to a static expansion fracturing material for upward drilling and a use method thereof. Background Art

[0002] Static fracturing coal-rock technology is increasingly used in fracturing projects of coal and rock in mines, especially in civil engineering and construction industries, due to its advantages of no noise, no dust, no harmful gas, inherent safety of materials, and ease of use. The commonly used static fracturing materials are mainly materials with CaO as the main ingredient, which are mixed with a certain amount of water into slurry and poured into the borehole. After a few hours, the slurry material expands and cracks the rock. This kind of material generates heat during the CaO reaction. If too much slurry is poured in at one time, the heat will not be released in time and will produce spray holes, which will bring safety hazards and affect the fracturing effect. Therefore, it is required that the fracturing borehole should not be too large, generally with a diameter of no more than 50mm and a depth of no more than 1m. Therefore, the fracturing range of a single hole is limited. When a large range of coal and rock needs to be fractured, a large number of boreholes need to be constructed, and the engineering workload is large.

[0003] During coal mining, the cracking of the tunnel or working face roof is quite different from the working conditions of the ground construction industry. First, it is necessary to implement an upward hole, and the drilling depth is relatively long, generally ranging from a few meters to dozens of meters; second, it is inconvenient to drill long holes in the roof. In order to achieve the cracking effect, the diameter of the drill hole is relatively large, generally ranging from 40mm to 90mm, and a large amount of charge is required for a single hole; third, the reaction time of the roof cracking to the expansion agent is more flexible, ranging from a few hours to dozens of hours; fourth, if the upward drilling hole is injected with expansion agent slurry, a grouting pump is required, which has high requirements for the fluidity of the slurry. Summary of the invention

[0004] In order to adapt to the working conditions required for roof fracturing drilling in a coal mine environment, the present invention provides a static expansion fracturing material with good fluidity, long reaction time, slow heat generation, low reaction temperature, and applicable to large-diameter deep holes, and a method of using the material.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a static expansion fracturing material for upward drilling, characterized in that: calcium oxide is used as a main ingredient, magnesium oxide, titanium oxide and citric acid are used as auxiliary ingredients, the main ingredient and the auxiliary ingredients are all dry materials, and the main ingredient and the auxiliary ingredients are stirred and evenly mixed and ground to obtain the static expansion fracturing material.

[0006] In terms of mass ratio, the mass proportions of calcium oxide, magnesium oxide, titanium oxide and citric acid are 85.5%, 5.5%, 7.5% and 1.5% respectively.

[0007] A method for using a static expansion fracturing material for upward drilling comprises the following steps: (1) Use sealing devices or sealing materials to seal the top plate drilling holes in advance, and reserve grouting pipes and return pipes; (2) Mix the prepared static expansion cracking material and water in a weight ratio of 1:3 and stir evenly in a mixing bucket; (3) Use a mud pump or grouting pump to inject the evenly stirred slurry into the top plate borehole through the grouting pipe until slurry flows out of the outer port of the return pipe, and then turn off the mud pump or grouting pump; (4) The slurry solidifies in the borehole and expands slowly until it reaches the maximum expansion force.

[0008] A method for using a static expansion cracking material for upward drilling, the specific process is as follows: the prepared static expansion cracking material is packaged into a medicine roll with cotton cloth or non-woven fabric at a density of 1.7-1.8, the diameter of the medicine roll does not exceed 70mm, the medicine roll is placed in water within 5 minutes to absorb water saturation, and then the medicine roll is installed in a top plate drilling hole within 20 minutes, if the drilling hole inclination angle is too large, the medicine roll can be wrapped with anti-skid barbs or steel wire to prevent it from sliding down during installation in the drilling hole; after 30 minutes, the medicine roll reacts and starts to expand slowly until it reaches the maximum expansion force.

[0009] A method for using a static expansion fracturing material for upward drilling. Since the coal mining face in a coal mine is a process of dynamic forward advancement, the roof needs to remain stable in the tunnel or mining area to ensure normal production safety. When the roof enters the goaf, it needs to be actively artificially fractured to make it collapse in time. Therefore, some roof fracturing projects have special requirements for the timing of fracturing, and it is necessary to load the medicine roll into the fracturing borehole in advance, retain the medicine roll in the borehole for standby use, and seal the hole mouth to reserve a water injection pipe; when the roof is about to enter the goaf, inject water into the borehole; the medicine roll reacts and expands after meeting water; the medicine roll is designed to be a hollow structure, the outside of the medicine roll is sealed, and a water pipe is arranged in the center of the medicine roll, and the static expansion fracturing material is loaded in the annular space between the medicine roll and the water pipe, and fine holes are opened on the water pipe for medicine powder to absorb water, that is, the medicine powder absorbs water from the inner hole to react, so that the medicine roll can be retained in the borehole for standby use. When the medicine roll needs to react and expand, it only needs to inject water into the water pipe in the borehole, which further expands the scope of use of static expansion fracturing materials, which is particularly suitable for the fracturing of the roof at both ends of the coal mine.

[0010] By adopting the above technical solution, compared with the prior art, the present invention has the following beneficial effects: (1) The role of calcium oxide in the raw materials of the present invention is to expand when it comes into contact with water; the role of magnesium oxide is to absorb heat and increase fluidity; the role of titanium oxide is to increase fluidity and increase reaction stability; the role of citric acid is to slow down the setting, that is, to extend the reaction time and avoid rapid and large-scale accumulation of heat. After the four raw materials are mixed, they need to be ground and crushed to a particle size of less than 200 meshes, so as to ensure the fluidity of the slurry after the product is stirred with water.

[0011] (2) The static expansion cracking material is ground into a material with a mass ratio of 85.5%, 5.5%, 7.5% and 1.5% of calcium oxide, magnesium oxide, titanium oxide and citric acid respectively, and mixed with water in a weight ratio of 1:3. After being injected into the borehole, it can slowly react and expand. After 12 to 16 hours, the expansion force exceeds 20MPa, and the expansion force continues to increase for more than 100 hours. The maximum expansion force exceeds 40MPa, and the fluidity is less than 50mPa·s. Using an ordinary pneumatic grouting pump, a head of more than 20m can be achieved. This method is generally suitable for boreholes with a diameter not exceeding 50mm. If the borehole diameter exceeds 50mm, it is easy to cause blowout, and a special sealing process is required to seal the hole.

[0012] (3) The static expansion material of the present invention has good water absorption. The static expansion material is packaged into a medicine roll with cotton cloth, non-woven fabric or permeable paper at a certain density (specific gravity 1.7-1.8). It can be saturated with water within 5 minutes when placed in water, and the water absorption rate reaches more than 20%. The medicine roll after absorbing water can also expand and crack coal and rock when quickly placed in a borehole.

[0013] In summary, the present invention has a scientific principle, easily available ingredients, simple manufacturing process, low cost, good fracturing effect, can be injected or installed in advance, slowly expands and fractures after encountering water, and is safe and reliable in use. DETAILED DESCRIPTION

[0014] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0015] The static expansion fracturing material for upward drilling of the present invention is mainly composed of calcium oxide, magnesium oxide, titanium oxide and citric acid as ingredients, the main ingredient and the ingredients are all dry materials, and the main ingredient and the ingredients are stirred and evenly mixed and ground to obtain the static expansion fracturing material. In terms of mass ratio, the mass proportions of calcium oxide, magnesium oxide, titanium oxide and citric acid are 85.5%, 5.5%, 7.5% and 1.5% respectively.

[0016] A method for using a static expansion fracturing material for upward drilling includes the following three embodiments: Embodiment 1: The method comprises the following steps: (1) using a sealing device or sealing material to seal the top plate drilling hole in advance, and reserving a grouting pipe and a return pipe; (2) Mix the prepared static expansion cracking material and water in a weight ratio of 1:3 and stir evenly in a mixing bucket; (3) Use a mud pump or grouting pump to inject the evenly stirred slurry into the top plate borehole through the grouting pipe until slurry flows out of the outer port of the return pipe, and then turn off the mud pump or grouting pump; (4) The slurry solidifies in the borehole and expands slowly until it reaches the maximum expansion force.

[0017] Embodiment 2: The specific process is as follows: the prepared static expansion cracking material is packed into a medicine roll with cotton cloth or non-woven fabric at a density of 1.7 to 1.8. The diameter of the medicine roll shall not exceed 70 mm. The medicine roll shall be placed in water for 5 minutes to be saturated with water. Then the medicine roll shall be loaded into the top plate drilled hole within 20 minutes. If the inclination angle of the drill hole is too large, the outside of the medicine roll can be wrapped with anti-slip barbs or steel wire to prevent it from sliding down during installation in the drill hole. After 30 minutes, the medicine roll will react and start to expand slowly until it reaches the maximum expansion force.

[0018] Embodiment 3: Since the coal mining face in a coal mine is a process of dynamic forward advancement, the roof needs to remain stable in the tunnel or mining area to ensure normal production safety. When the roof enters the goaf, it needs to be actively artificially fractured to make it collapse in time. Therefore, some roof fracturing projects have special requirements for the timing of fracturing, and it is necessary to load the medicine roll into the fracturing borehole in advance, retain the medicine roll in the borehole for standby use, and seal the hole mouth to reserve a water injection pipe; when the roof is about to enter the goaf, inject water into the borehole; the medicine roll reacts and expands after meeting water; the medicine roll is designed to be a hollow structure, the outside of the medicine roll is sealed, and a water pipe is arranged in the center of the medicine roll, and the static expansion fracturing material is loaded in the annular space between the medicine roll and the water pipe, and fine holes are opened on the water pipe for medicine powder to absorb water, that is, the medicine powder absorbs water from the inner hole to react, so that the medicine roll can be retained in the borehole for standby use. When the medicine roll needs to react and expand, it only needs to inject water into the water pipe in the borehole, which further expands the scope of use of static expansion fracturing materials, which is particularly suitable for the fracturing of the roof at both ends of the coal mine.

[0019] The above embodiments illustrate the basic principles and features of the present invention, but the above only illustrates the preferred embodiments of the present invention and is not limited to the embodiments. Under the inspiration of this patent, a person skilled in the art can make many forms of deformation and improvement without departing from the scope of protection of the present invention and the claims, which are all within the protection scope of the present invention. Therefore, the patent and protection scope of the present invention shall be subject to the attached claims.

Claims

1. A static expansion fracturing material for upward drilling, characterized in that: The main material is calcium oxide, and the auxiliary materials are magnesium oxide, titanium oxide and citric acid. The main material and the auxiliary materials are all dry materials. The main material and the auxiliary materials are uniformly mixed and ground to obtain a static expansion cracking material.

2. The static expansion fracturing material for upward drilling according to claim 1, characterized in that: In terms of mass ratio, the mass proportions of calcium oxide, magnesium oxide, titanium oxide and citric acid are 85.5%, 5.5%, 7.5% and 1.5% respectively.

3. A method for using a static expansion fracturing material for upward drilling as claimed in claim 1 or 2, characterized in that: The following steps are involved: (1) Use sealing devices or sealing materials to seal the top plate drilling holes in advance, and reserve grouting pipes and return pipes; (2) Mix the prepared static expansion cracking material and water in a weight ratio of 1:3 and stir evenly in a mixing bucket; (3) Use a mud pump or grouting pump to inject the evenly stirred slurry into the top plate borehole through the grouting pipe until slurry flows out of the outer port of the return pipe, and then turn off the mud pump or grouting pump; (4) The slurry solidifies in the borehole and expands slowly until it reaches the maximum expansion force.

4. A method for using a static expansion fracturing material for upward drilling as claimed in claim 1 or 2, characterized in that: The specific process is as follows: the prepared static expansion cracking material is packed into a medicine roll with cotton cloth or non-woven fabric at a density of 1.7 to 1.

8. The diameter of the medicine roll shall not exceed 70 mm. The medicine roll shall be placed in water for 5 minutes to be saturated with water. Then the medicine roll shall be loaded into the top plate drilled hole within 20 minutes. If the inclination angle of the drill hole is too large, the outside of the medicine roll can be wrapped with anti-slip barbs or steel wire to prevent it from sliding down during installation in the drill hole. After 30 minutes, the medicine roll will react and start to expand slowly until it reaches the maximum expansion force.

5. A method for using a static expansion fracturing material for upward drilling as claimed in claim 1 or 2, characterized in that: Since the coal mining face of a coal mine is a process of dynamic forward advancement, the roof needs to remain stable in the tunnel or mining area to ensure normal production safety. When the roof enters the goaf, it needs to be actively artificially fractured to make it collapse in time; therefore, some roof fracture projects have special requirements for the timing of fracture, and it is necessary to load the medicine roll into the fracture borehole in advance, retain the medicine roll in the borehole for standby, and seal the hole to reserve a water injection pipe; when the roof is about to enter the goaf, inject water into the borehole; the medicine roll reacts and expands after meeting water; the medicine roll is designed to be a hollow structure, the outside of the medicine roll is sealed, a water pipe is set in the center of the medicine roll, and static expansion fracture material is loaded in the annular space between the medicine roll and the water pipe, and fine holes are opened on the water pipe for medicine powder to absorb water, that is, the medicine powder absorbs water from the inner hole to react, so that the medicine roll can be retained in the borehole for standby use, and when the medicine roll needs to react and expand, it is only necessary to inject water into the water pipe in the borehole, which further expands the scope of use of static expansion fracture materials, and is particularly suitable for the fracture of the roof at both ends of the coal mine mining area.