Gas control equipment based on coal seam three-phase fracturing anti-reflection technology

Abstract

The utility model relates to gas control equipment based on a coal seam three-phase fracturing anti-reflection technology, which comprises a sand mixing device, a water supply device, a water / sand fracturing pump pry, a liquid carbon dioxide supply device, a liquid carbon dioxide fracturing pry, a confluence device and a control system, and is based on the water, sand and carbon dioxide three-phase fracturing anti-reflection technology breaking through the prior art. High-pressure water and liquid CO2 serve as fracturing fluid at the same time to conduct fracturing on the coal seam, native fractures are expanded in the coal seam, a large artificial fracture network is formed, the native fractures are expanded, the problems that an existing fracturing extraction method is large in construction difficulty, long in extraction time, poor in extraction effect, low in extraction amount and high in construction cost are solved, the gas permeability of the coal seam is greatly improved, and the coal seam quality is improved. The purpose of efficient extraction of the high-gas low-permeability coal seam is achieved, the gas treatment efficiency is remarkably improved, the gas treatment cost is reduced, coal seam gas is rapidly reduced, and extraction-excavation-extraction balance of high-gas and outburst mines is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mine gas control, in particular to a gas control device based on a coal seam three-phase fracturing and permeability enhancement technology, which is suitable for coal seam recovery in underground coal mines and can also be used for tunnel excavation. Background Art

[0002] At present, most mines in my country are facing the current situation of high gas content, poor coal seam permeability, great difficulty in gas extraction, and long gas extraction compliance period. In order to solve the above-mentioned gas control problems, mines must invest a lot of financial, human and material resources. Gas pre-extraction is the fundamental solution to mine gas disaster management, but most mines are faced with the difficulties of great extraction difficulty and long compliance time, which leads to the imbalance of mine extraction-digging-extraction and affects the economic benefits of mines. In order to improve the effect of gas extraction, the commonly used means include hydraulic cutting, hydraulic punching and cavitation, gas phase blasting, mechanical cavitation and other permeability enhancement measures. All kinds of measures have certain effects, but there are also many restrictions and even hidden dangers. Its applicable conditions are also affected by the occurrence of coal seam gas.

[0003] Whether gas can be efficiently extracted depends on the permeability of coal seams. Fracturing and permeability enhancement technology is a core technology that generates and expands macro and micro cracks in coal seams through fracturing to solve the problem of coal reservoir permeability. This technology has been widely used in the field of oil and gas, but in the coal mining industry, it is still mostly a measure of ground fracturing extraction. From the actual extraction results known so far, there are the following problems: difficult construction, long extraction time, poor extraction effect, low extraction volume, and high construction cost. Utility Model Content

[0004] The purpose of the utility model is to provide a gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology with reasonable configuration and reliable use, so as to solve the problems of existing fracturing and extraction means such as great construction difficulty, long extraction time, poor extraction effect, low extraction volume and high construction cost, form a large artificial fracture network in the coal seam, expand the original fracture, greatly improve the permeability of the coal seam, shorten the extraction time, achieve the purpose of efficient extraction of high-gas and low-permeability coal seams, significantly improve construction efficiency and reduce construction costs.

[0005] The technical solution of the utility model is:

[0006] A gas control equipment based on coal seam three-phase fracturing permeability enhancement technology, comprising a sand mixing device, a water supply device, a water / sand fracturing pump skid, a liquid carbon dioxide supply device, a liquid carbon dioxide fracturing skid, a confluence device and a control system, the technical key points of which are: the sand mixing device and the water supply device are connected by a first pipeline and a first liquid supply valve is arranged on the first pipeline, the sand mixing device and the water / sand fracturing pump skid are connected by a second pipeline and a first check valve is arranged on the second pipeline, a third pipeline is arranged between the water supply device and the outlet side pipe section of the first check valve and a first liquid inlet valve and a second check valve are arranged on the third pipeline, the liquid carbon dioxide supply device is connected to the water supply device by a first pipeline, and the first liquid supply valve and the second check valve are arranged on the third pipeline, and the liquid carbon dioxide supply device is connected to the water supply device by a second pipeline. The liquid tank is connected to the fourth pipeline by a liquid outlet pipeline, one end of the fourth pipeline is connected to the liquid supply tank by a back pressure pipeline, and the other end is connected to the inlet of the liquid carbon dioxide fracturing skid, a back pressure valve is provided on the back pressure pipeline, a second liquid supply valve is provided on the liquid outlet pipeline of the liquid supply tank, a second liquid inlet valve is provided on the fourth pipeline, the outlet of the water / sand fracturing pump skid is connected to the confluence device by a first high pressure pipeline, and a first filling valve is provided on the first high pressure pipeline, the outlet of the liquid carbon dioxide fracturing skid is connected to the confluence device by a second high pressure pipeline, and a second filling valve and a third check valve are provided on the second high pressure pipeline, and the outlet of the confluence device is connected to the high pressure manifold.

[0007] The above-mentioned gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology, the fourth pipeline includes a vacuum bus and an insulation pipeline connected to the vacuum bus, the vacuum bus is connected to the back pressure pipeline and the liquid outlet pipeline of the liquid supply tank, and the insulation pipeline is connected to the inlet of the liquid carbon dioxide fracturing skid.

[0008] The above-mentioned gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology has multiple liquid supply tanks, and the liquid outlet pipeline of each liquid supply tank is connected to the fourth pipeline respectively. One of the liquid supply tanks is provided with a back pressure connecting pipe connected to the back pressure pipeline, and the back pressure connecting pipe is provided with a first control valve. The back pressure pipeline is connected to a first bypass pipeline between the outlet and the inlet of the back pressure valve, and the first bypass pipeline is provided with a second control valve, and the back pressure pipeline is provided with a first pressure relief valve.

[0009] The above-mentioned gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology, the liquid outlet pipeline of the liquid supply tank is connected to the second bypass pipeline between the outlet and inlet of the second liquid supply valve, a third control valve is arranged on the second bypass pipeline, and two liquid outlet connecting pipes are arranged on the liquid supply tank, the ends of the two liquid outlet connecting pipes are connected to the inlet of the liquid outlet pipeline of the liquid supply tank by a tee, and a fourth control valve and a second pressure relief valve are arranged on the liquid outlet connecting pipe.

[0010] In the above-mentioned gas control equipment based on the coal seam three-phase fracturing and permeability enhancement technology, the back pressure pipeline and the liquid outlet pipeline of the liquid supply tank are respectively provided with a retractable and easily disassembled hose section.

[0011] The above-mentioned gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology, the control system includes a remote control end, a first electrical control box connected to the liquid carbon dioxide fracturing skid, and a second electrical control box connected to the water / sand fracturing pump skid, and the remote control end is connected to the first electrical control box, the second electrical control box, the first liquid supply valve, the second liquid supply valve, the first check valve, the second check valve, the third check valve, the first liquid inlet valve, the second liquid inlet valve, the first injection valve, the second injection valve and the back pressure valve.

[0012] The beneficial effects of the utility model are:

[0013] The utility model is based on the "water, sand, carbon dioxide" three-phase fracturing and permeability enhancement technology of the prior art, so that high-pressure water and liquid CO2 are simultaneously used as fracturing fluids to fracture the coal seam, thereby expanding the original cracks in the coal seam, forming a large artificial crack network, and expanding the original cracks. The problems of the existing fracturing and extraction methods such as the difficulty of construction, long extraction time, poor extraction effect, low extraction volume and high construction cost are solved, the permeability of the coal seam is greatly improved, the extraction time is shortened, and the purpose of efficient extraction of high-gas and low-permeability coal seams is achieved, the construction efficiency is significantly improved, the construction cost is reduced, and the imbalance of extraction-digging-extraction in high-gas and protruding mines is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] Figure 2 yes Figure 1 A partial enlarged view of

[0016] Figure 3 yes Figure 2 A partial enlarged view of .

[0017] In the figure: 1. Liquid supply tank, 2. Back pressure pipeline, 3. Vacuum bus, 4. Insulation pipeline, 5. Second liquid inlet valve, 6. First electric control box, 7. Liquid carbon dioxide fracturing skid, 8. Second high-pressure pipeline, 9. Second injection valve, 10. Third check valve, 11. Converging device, 12. High-pressure manifold, 13. First injection valve, 14. First high-pressure pipeline, 15. Water / sand fracturing pump skid, 16. Second electric control box, 17. First check valve, 18. Second pipeline, 19. Mixing Sand device, 20. first liquid supply valve, 21. water supply device, 22. second check valve, 23. first liquid inlet valve, 24. remote control end, 25. first pipeline, 26. third pipeline, 27. liquid outlet pipeline, 28. first bypass pipeline, 29. second bypass pipeline, 30. back pressure valve, 31. second control valve, 32. third control valve, 33. second liquid supply valve, 34. first control valve, 35. first pressure relief valve, 36. fourth control valve, 37. second pressure relief valve. DETAILED DESCRIPTION

[0018] The utility model is described in detail according to the accompanying drawings of the specification.

[0019] like Figure 1 to Figure 3 As shown, the gas control equipment based on the coal seam three-phase fracturing and permeability enhancement technology includes a sand mixing device 19, a water supply device 21, a water / sand fracturing pump skid 15, a liquid carbon dioxide supply device, a liquid carbon dioxide fracturing skid 7, a confluence device 11 and a control system.

[0020] Wherein: the sand mixing device 19 and the water supply device 21 are connected by a first pipeline 25 and a first liquid supply valve 20 is arranged on the first pipeline 25; the sand mixing device 19 and the water / sand fracturing pump skid 15 are connected by a second pipeline 18 and a first check valve 17 is arranged on the second pipeline 18; a third pipeline 26 is arranged between the water supply device 21 and the outlet side pipe section of the first check valve 17 and a first liquid inlet valve 23 and a second check valve 22 are arranged on the third pipeline 26.

[0021] The liquid supply tank 1 of the liquid carbon dioxide liquid supply device is connected to the fourth pipeline by means of the liquid outlet pipeline 27. One end of the fourth pipeline is connected to the liquid supply tank 1 by means of the back pressure pipeline 2, and the other end is connected to the inlet of the liquid carbon dioxide fracturing skid 7. The back pressure pipeline 2 is provided with a back pressure valve 30, the liquid outlet pipeline 27 of the liquid supply tank 1 is provided with a second liquid supply valve 33, and the fourth pipeline is provided with a second liquid inlet valve 5. In this embodiment, the fourth pipeline includes a vacuum bus 3 and an insulation pipeline 4 connected to the vacuum bus 3. The vacuum bus 3 is connected to the back pressure pipeline 2 and the liquid outlet pipeline 27 of the liquid supply tank 1, and the insulation pipeline 4 is connected to the inlet of the liquid carbon dioxide fracturing skid 15. The vacuum bus 3 is used to prevent the rapid gasification of liquid carbon dioxide. The back pressure pipeline 2 and the back pressure valve 30 are arranged to ensure that the pressure in the fourth pipeline reaches the set range before the liquid carbon dioxide is transported, so as to prevent the liquid carbon dioxide from condensing into dry ice under low pressure to block the pipeline. In this embodiment, there are three liquid supply tanks 1, and the liquid outlet pipeline 27 of each liquid supply tank 1 is connected to the vacuum bus 3 respectively. The first liquid supply tank 1 is provided with a back pressure pipe connected to the back pressure pipeline 2, and the back pressure pipe is provided with a first control valve 34. The back pressure pipeline 2 is connected with a first bypass pipeline 28 between the inlet and outlet of the back pressure valve 30, and the first bypass pipeline 28 is provided with a second control valve 31. The back pressure pipeline 2 is provided with a first pressure relief valve 35 to ensure maintenance safety. The liquid outlet pipeline 27 of the liquid supply tank 1 is connected to a second bypass pipeline 29 between the inlet and outlet of the second liquid supply valve 33, and the second bypass pipeline 29 is provided with a third control valve 32. In order to ensure the flow rate, the liquid supply tank 1 is provided with two liquid outlet pipes, and the ends of the two liquid outlet pipes are connected to the inlet of the liquid outlet pipeline 27 of the liquid supply tank 1 by a tee, and the liquid outlet pipe is provided with a fourth control valve 36 and a second pressure relief valve 37. The back pressure pipeline 2 and the liquid outlet pipeline 27 of the liquid supply tank 1 are respectively provided with a retractable and easily disassembled hose section.

[0022] The outlet of the water / sand fracturing pump skid 15 is connected to the confluence device 11 via a first high-pressure pipeline 14, and a first filling valve 13 is provided on the first high-pressure pipeline 14. The outlet of the liquid carbon dioxide fracturing skid 7 is connected to the confluence device 11 via a second high-pressure pipeline 8, and a second filling valve 9 and a third check valve 10 are provided on the second high-pressure pipeline 8. The outlet of the confluence device 11 is connected to the high-pressure manifold 12.

[0023] The control system includes a remote control end 24, a first electrical control box 6 connected to the liquid carbon dioxide fracturing pry 7, and a second electrical control box 16 connected to the water / sand fracturing pump pry 15. The remote control end 24 is connected to the first electrical control box 6, the second electrical control box 16, the first liquid supply valve 20, the second liquid supply valve 33, the first check valve 17, the second check valve 22, the third check valve 10, the first liquid inlet valve 33, the second liquid inlet valve 5, the first filling valve 13, the second filling valve 9 and the back pressure valve 30.

[0024] Working process:

[0025] like Figure 1 As shown, the utility model can be arranged in a tunnel hole when in use, and can be isolated by using an exposure-proof wall to play a role of explosion isolation.

[0026] 1. Pilot water preparatory fracturing: see Figure 1 , open the first liquid inlet valve 23 and the first injection valve 13, and start the water / sand fracturing pump skid 15. At this time, the fracturing fluid (water) of the water supply device 21 is pressurized by the water / sand fracturing pump skid 15, and is pressed into the coal seam to be fractured through the first high-pressure pipeline 14, the confluence device 11, and the high-pressure manifold 12. As the pressure increases, the coal seam initially cracks, and then the pressure drops. As the fracturing fluid (water) is continuously injected, the pressure rises back to the initial cracking value of the coal seam, causing the coal seam to crack stably, and at this time, sand and LCO2 can be carried.

[0027] 2. Water-sand fracturing operation: close the first liquid inlet valve 23, open the first liquid supply valve 20, water enters the sand mixing device 19 (which can suspend sand) to form a water-sand mixed liquid, which is sent to the water / sand fracturing pump skid 15 for pressurization, and the high-pressure water-sand mixed fracturing fluid is generated. It enters the confluence device 11 through the first high-pressure pipeline 14, and is then pressed into the coal seam through the high-pressure manifold 12.

[0028] 3. Operation of liquid carbon dioxide fracturing system: water-carrying sand-carrying LCO2 fracturing operation. First open the back pressure valve 30, wait for the back pressure in the vacuum bus 3 and the insulation pipeline 4 to reach 1.2MPa or more, then open the second liquid supply valve 33 and the second liquid inlet valve 5, wait for the pump head temperature of the liquid carbon dioxide fracturing skid 7 to be lower than -5°C, start the liquid carbon dioxide fracturing skid 7, open the second injection valve 9, when the pressure is higher than the water-carrying sand fracturing operation pressure, LCO2 flows into the confluence device 11 through the second high-pressure pipeline 8, mixes with the water-sand mixture, forms a high-pressure mixture of water, sand and liquid CO2, and is pressed into the coal seam to achieve three-phase fracturing and permeability enhancement of the coal seam.

[0029] 4. End the fracturing operation: When the water, sand and liquid CO2 injection volume reaches the design requirements of the coal seam fracturing, the liquid carbon dioxide fracturing skid 7 is shut down, the first liquid inlet valve 23 is opened, and the first liquid supply valve 20 is closed. At this time, the high-pressure manifold 12 only injects clean water into the coal seam to flush the sand and liquid CO2 in the first high-pressure pipeline 14 and the high-pressure manifold 12. After the set flushing time, the water / sand fracturing pump skid 15 is shut down to complete the fracturing operation.

[0030] The above is a detailed description of the embodiments of the utility model, but the above contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of the invention of the utility model should still fall within the scope of this patent.

Claims

1. A gas control equipment based on coal seam three-phase fracturing permeability enhancement technology, comprising a sand mixing device, a water supply device, a water / sand fracturing pump skid, a liquid carbon dioxide supply device, a liquid carbon dioxide fracturing skid, a confluence device and a control system, characterized in that: The sand mixing device and the water supply device are connected by a first pipeline, and a first liquid supply valve is arranged on the first pipeline. The sand mixing device and the water / sand fracturing pump skid are connected by a second pipeline, and a first check valve is arranged on the second pipeline. A third pipeline is arranged between the water supply device and the outlet side pipe section of the first check valve, and a first liquid inlet valve and a second check valve are arranged on the third pipeline. The liquid supply tank of the liquid carbon dioxide liquid supply device is connected with a fourth pipeline by a liquid outlet pipeline. One end of the fourth pipeline is connected with the liquid supply tank by a back pressure pipeline, and the other end is connected with the inlet of the liquid carbon dioxide fracturing skid. A back pressure valve is arranged on the back pressure pipeline. A second liquid supply valve is arranged on the liquid outlet pipeline of the liquid supply tank. A second liquid inlet valve is arranged on the fourth pipeline. The outlet of the water / sand fracturing pump skid is connected with a confluence device by a first high pressure pipeline, and a first filling valve is arranged on the first high pressure pipeline. The outlet of the liquid carbon dioxide fracturing skid is connected with a confluence device by a second high pressure pipeline, and a second filling valve and a third check valve are arranged on the second high pressure pipeline. The outlet of the confluence device is connected with a high pressure manifold.

2. The gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology according to claim 1 is characterized by: The fourth pipeline includes a vacuum bus and a heat-insulating pipeline connected to the vacuum bus. The vacuum bus is connected to the back pressure pipeline and the liquid outlet pipeline of the liquid supply tank. The heat-insulating pipeline is connected to the inlet of the liquid carbon dioxide fracturing skid.

3. The gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology according to claim 1 is characterized in that: There are multiple liquid supply tanks, and the liquid outlet pipeline of each liquid supply tank is connected to the fourth pipeline respectively. One of the liquid supply tanks is provided with a back pressure connecting pipe connected to the back pressure pipeline, and the back pressure connecting pipe is provided with a first control valve. The back pressure pipeline is connected to a first bypass pipeline between the outlet and the inlet of the back pressure valve, and the first bypass pipeline is provided with a second control valve. The back pressure pipeline is provided with a first pressure relief valve.

4. The gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology according to claim 1 is characterized by: The liquid outlet pipeline of the liquid supply tank is connected to the second bypass pipeline between the outlet and inlet of the second liquid supply valve, and a third control valve is arranged on the second bypass pipeline. The liquid supply tank is provided with two liquid outlet connecting pipes, and the ends of the two liquid outlet connecting pipes are connected to the inlet of the liquid outlet pipeline of the liquid supply tank by a tee, and the liquid outlet connecting pipes are provided with a fourth control valve and a second pressure relief valve.

5. The gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology according to claim 1 is characterized in that: The back pressure pipeline and the liquid outlet pipeline of the liquid supply tank are respectively provided with flexible hose sections which are retractable and easy to disassemble.

6. The gas control equipment based on coal seam three-phase fracturing and permeability enhancement technology according to claim 1 is characterized by: The control system includes a remote control end, a first electrical control box connected to the liquid carbon dioxide fracturing skid, and a second electrical control box connected to the water / sand fracturing pump skid. The remote control end is connected to the first electrical control box, the second electrical control box, the first liquid supply valve, the second liquid supply valve, the first check valve, the second check valve, the third check valve, the first liquid inlet valve, the second liquid inlet valve, the first injection valve, the second injection valve and the back pressure valve.

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