A high-pressure fracturing gas permeability enhancement device based on CO2 preparation

Abstract

The present invention discloses a high-pressure gas permeability enhancement device using CO2 as a fracturing agent. The device comprises a gas extraction pipe with a cover plate fixed to its upper portion. Multiple sealers are spaced apart beneath the cover plate. Each sealer has a side hole formed in the sidewall of the extraction pipe. Multiple heating strips are distributed along the outer wall of the extraction pipe. Compared to existing technologies, the present invention generates a thrust force that increases from top to bottom within the gas borehole, enhancing the fracturing effect deep within the borehole.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, in particular to a high-pressure fracturing gas permeability enhancement device based on CO2 preparation. Background Art

[0002] Hydraulic fracturing is used in coal mining to fracture the coal seams and extract gas from them. However, this method requires high water pressure and limits the fracturing range. Existing technologies also use rapid CO2 expansion to fracture coal seams, reducing the requirements for pumping equipment. However, the high CO2 expansion pressure can easily cause surface collapse in the borehole, and its performance in fracturing deeper layers is insufficient.

[0003] Therefore, it is necessary to provide a high-pressure fracturing gas permeability enhancement device based on CO2 preparation to solve the problems raised in the above background technology. Summary of the Invention

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-pressure fracturing gas permeability enhancement device based on CO2 preparation, comprising an extraction pipe, a cover plate fixed on the upper part of the extraction pipe, a plurality of sealers distributed at a certain interval under the cover plate, a side hole opened on the side wall of the extraction pipe on each sealer, and a plurality of heating strips distributed on the outer wall of the extraction pipe.

[0005] Furthermore, preferably, the hole sealer is an elastic rubber ring, and each hole sealer is fixed to the outer wall of the extraction tube through a fixing sleeve.

[0006] Furthermore, as a preference, a sealing sleeve is slidably provided on the outer wall of the extraction tube on each of the side holes, and a guide plate is fixed to the outside of the sealing sleeve.

[0007] Furthermore, preferably, a spring is provided between the guide plate and the hole sealer below, and the spring enables the guide plate to rise to a position where the sealing sleeve leaves the side hole.

[0008] Furthermore, as a preference, each of the hole sealers is connected together through an injection tube, the upper end of the injection tube passes through the top of the cover plate, and the injection tube is slidably connected to each guide plate.

[0009] Furthermore, as a preference, the upper end of the uppermost heating strip passes through the cover plate, and the cover plate is provided with an ignition ring which fits with a plurality of heating strips distributed circumferentially thereon.

[0010] Furthermore, as a preference, the heating strip is broken above each sealer so that the heating strip is divided into multiple sections, the bottom of each section of the heating strip is fixed to the corresponding sealing sleeve and passes through the bottom of the sealing sleeve, and the upper end of each section of the heating strip is fixed to the fixed sleeve and passes through the top of the fixed sleeve.

[0011] Furthermore, preferably, a circle of upper ignition plates is fixed to the bottom of the sealing sleeve, and the upper ignition plates are fitted with the end of each heating medicine strip, and a circle of lower ignition plates is fixed to the upper end of the fixed sleeve, and the lower ignition plates are fitted with the upper end of each heating medicine strip.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] In the present invention, the gas borehole is divided into multiple independent spaces, and liquid CO2 is distributed in the space of each gas borehole. The ignition ring is ignited to cause the uppermost heating strip to burn and generate heat. The liquid CO2 is instantly heated to generate a supercritical CO2 medium, which causes the gas pressure in this section of space to rise sharply, thereby cracking the gas borehole wall. At the same time, the corresponding guide plate moves downward to seal the side hole of this section, and the upper and lower ignition pieces are used to ignite the heating strip of the next section, so that a thrust that increases from top to bottom is generated in the gas borehole, thereby improving the cracking effect deep in the gas borehole. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of a high-pressure fracturing gas permeability enhancement device based on CO2 preparation;

[0015] Figure 2 It is a structural diagram of the fixing sleeve and the sealing sleeve;

[0016] In the figure: 1. Extraction tube; 2. Cover plate; 21. Ignition ring; 3. Sealer; 31. Fixing sleeve; 4. Liquid injection tube; 5. Heating strip; 51. Upper ignition plate; 52. Lower ignition plate; 6. Guide plate; 61. Sealing sleeve; 7. Side hole; 8. Spring. DETAILED DESCRIPTION

[0017] See also Figure 1 In an embodiment of the present invention, a high-pressure fracturing gas permeability enhancement device based on a CO2 agent includes an extraction pipe 1, a cover plate 2 is fixed on the upper part of the extraction pipe 1, a plurality of sealers 3 are distributed at a certain interval under the cover plate 2, a side hole 7 is opened on the side wall of the extraction pipe 1 on each sealer 3, and a plurality of heating strips 5 are distributed on the outer wall of the extraction pipe 1.

[0018] See also Figure 2 In this embodiment, the hole sealer 3 is an elastic rubber ring, and each hole sealer 3 is fixed to the outer wall of the extraction tube 1 through a fixing sleeve 31.

[0019] In this embodiment, a sealing sleeve 61 is slidably mounted on the outer wall of the extraction pipe 1 above each side hole 7. A guide plate 6 is fixed to the outside of the sealing sleeve 61. The diameter of the guide plate 6 is smaller than the diameter of the gas borehole. When the gas in the gas borehole between the two sealers 3 expands and the pressure suddenly rises, the guide plate 6 moves downward, allowing the sealing sleeve 61 to seal the side hole 7 and prevent gas pressure from flowing back into the extraction pipe 1.

[0020] In this embodiment, a spring 8 is provided between the guide plate 6 and the hole sealer 3 below, and the spring 8 is provided to raise the guide plate 6 to a position where the sealing sleeve 61 leaves the side hole 7. In other words, when the air pressure between the two hole sealers 3 is stable, the side hole 7 is opened.

[0021] In this embodiment, each of the hole sealers 3 is connected together via an injection tube 4. The upper end of the injection tube 4 extends above the cover plate 2 and is slidably connected to each guide plate 6. High-pressure water can be injected into the hole sealer 3 through the injection tube 4 to expand it and seal the gas borehole.

[0022] In this embodiment, the upper end of the topmost heating strip 5 penetrates the cover plate 2. The cover plate 2 has an ignition ring 21 that fits over the circumference of the plurality of heating strips 5. The ignition ring 21 can simultaneously ignite the plurality of heating strips 5, causing the temperature between the two sealers 3 to rise sharply.

[0023] In this embodiment, the heating strip 5 is broken above each sealer 3 so that the heating strip 5 is divided into multiple sections. The bottom of each section of the heating strip 5 is fixed to the corresponding sealing sleeve 61 and passes through the bottom of the sealing sleeve 61. The upper end of each section of the heating strip 5 is fixed to the fixing sleeve 31 and passes through the top of the fixing sleeve 31.

[0024] In this embodiment, a circle of upper ignition pieces 51 is fixed to the bottom of the sealing sleeve 61. The upper ignition pieces 51 are in contact with the end of each heating strip 5. A circle of lower ignition pieces 52 is fixed to the upper end of the fixed sleeve 31. The lower ignition pieces 52 are in contact with the upper end of each heating strip 5. When the upper section of heating strips 5 ignites, the gas in the gas borehole between the two corresponding sealers 3 expands. The corresponding upper ignition piece 51 is ignited, and the corresponding sealing sleeve 61 moves down to the lower fixed sleeve 31, igniting the corresponding lower ignition piece 52, thereby igniting the next section of heating strips 5. In other words, the gas in the gas borehole between the two sealers 3 expands sequentially from top to bottom at regular intervals, generating a thrust force that increases from top to bottom in the gas borehole, thereby improving the fracturing effect deep in the gas borehole.

[0025] During specific implementation, a gas borehole is drilled on the coal mine excavation face, the extraction pipe 1 is extended into the gas borehole, and the cover plate 2 is fitted to the surface of the gas borehole. High-pressure water is injected into the sealer 3 through a high-pressure water pump to expand and seal the gas borehole, so as to divide the gas borehole into multiple independent spaces. Liquid CO2 is injected into the extraction pipe 1 to distribute the liquid CO2 in the space of each gas borehole. The ignition ring 21 is ignited to make the uppermost heating strip 5 burn and generate heat. The liquid CO2 is instantly heated to generate a supercritical CO2 medium, which causes the gas pressure in this section of space to rise sharply, and the wall of the gas borehole is cracked. At the same time, the corresponding guide plate 6 moves downward to seal the side hole 7 of this section, and the upper ignition piece 51 and the lower ignition piece 52 are used to ignite the heating strip 5 of the next section, so that a thrust that increases from top to bottom is generated in the gas borehole, thereby improving the cracking effect deep in the gas borehole.

[0026] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A high-pressure fracturing gas permeability enhancement device based on CO2 preparation, comprising a pumping pipe (1), characterized in that: A cover plate (2) is fixed on the upper part of the extraction tube (1), and a plurality of sealers (3) are distributed at a certain interval under the cover plate (2). A side hole (7) is opened on the side wall of the extraction tube (1) on each sealer (3), and a plurality of heating medicine strips (5) are distributed on the outer wall of the extraction tube (1); Each of the hole sealers (3) is fixed to the outer wall of the extraction tube (1) via a fixing sleeve (31); The outer wall of the extraction tube (1) on each side hole (7) is slidably covered with a sealing sleeve (61); The heating strip (5) is broken above each sealer (3) so that the heating strip (5) is divided into multiple sections, the bottom of each section of the heating strip (5) is fixed to the corresponding sealing sleeve (61) and penetrates to the bottom of the sealing sleeve (61), and the upper end of each section of the heating strip (5) is fixed to the fixing sleeve (31) and penetrates to the top of the fixing sleeve (31); A circle of upper ignition pieces (51) is fixed to the bottom of the sealing sleeve (61), and the upper ignition pieces (51) are fitted with the end of each heating medicine strip (5). A circle of lower ignition pieces (52) is fixed to the upper end of the fixing sleeve (31), and the lower ignition pieces (52) are fitted with the upper end of each heating medicine strip (5).

2. A high-pressure fracturing gas permeability enhancement device based on CO2 preparation according to claim 1, characterized in that: The hole sealer (3) is an elastic rubber ring.

3. A high-pressure fracturing gas permeability enhancement device based on CO2 preparation according to claim 1, characterized in that: A guide plate (6) is fixed outside the sealing sleeve (61).

4. A high-pressure fracturing gas permeability enhancement device based on CO2 formulation according to claim 3, characterized in that: A spring (8) is provided between the guide plate (6) and the hole sealer (3) below, and the spring (8) enables the guide plate (6) to rise to a position where the sealing sleeve (61) leaves the side hole (7).

5. A high-pressure fracturing gas permeability enhancement device based on CO2 formulation according to claim 3, characterized in that: Each of the hole sealers (3) is connected together through an injection pipe (4), the upper end of the injection pipe (4) penetrates above the cover plate (2), and the injection pipe (4) is slidably connected to each guide plate (6).

6. A high-pressure fracturing gas permeability enhancement device based on CO2 formulation according to claim 1, characterized in that: The upper end of the uppermost heating strip (5) penetrates the cover plate (2), and the cover plate (2) is provided with an ignition ring (21) which is in contact with a plurality of heating strips (5) distributed circumferentially thereon.

Images