Nitrogen injection driving and promoting gas extraction combined device

Abstract

The invention discloses a nitrogen injection, driving and gas extraction promoting combined device, which relates to the field of coal seam gas permeability increasing and gas extraction strengthening, and comprises a gas supply device, a pressure control and stabilization device and a nitrogen driving and carrying device which are connected with a gas injection pipeline through ball valves, and further comprises a main pipeline and a branch pipeline, and explosion valves and pressure relief valves are arranged on the main pipeline and the branch pipelines. A stable gas injection source is provided through the gas supply device, stable pressure in the gas injection pipeline is guaranteed through the pressure control and stabilization device, gas is stably injected into a gas injection drill hole through the nitrogen driving and carrying device, an explosion valve and a pressure relief valve additionally arranged on the gas injection pipeline serve as safety devices, and therefore the problem of overpressure unloading caused by man-made or equipment faults of a gas injection pipe network is solved; the three-plugging and two-injection hole sealing device has a better drilling and hole sealing effect on a soft coal seam. The invention provides an efficient and safe nitrogen injection driving and gas extraction promoting device.

Description

Technical Field

[0001] The invention relates to the field of coal seam gas permeability enhancement and enhanced gas extraction, and in particular to a nitrogen injection and driving gas extraction promotion combined device. Background Art

[0002] Gas is a mixed gas with methane as the main component. It is the first of the five major disasters that affect the safe and efficient production of coal mines. It is also a clean energy with high calorific value and clean properties. Gas extraction is the most direct, effective and practical way to control gas, and it is also an effective way to obtain clean energy.

[0003] As the depth and intensity of coal mining continue to increase, coal seam conditions become more complex, gas disasters become more serious, and the threat to miners' lives and mine production safety is also increasing. In particular, the extraction of coal mine gas in low-permeability coal seams still has problems such as small impact range, great extraction difficulty, and fast attenuation rate. Statistics show that more than 95% of the coal seams mined in my country's outburst and high-gas mines are low-permeability coal seams.

[0004] As a key technology to solve the problems of low permeability and difficult-to-drain coal seams, underground hydraulic permeability enhancement technology in coal mines has been promoted and applied in many large mining areas in China, especially in multi-coal seam high-gas outburst mines in the complex structural mining areas in the southwest, effectively curbing the occurrence of coal and gas outburst accidents and achieving significant economic benefits. However, the existing hydraulic fracturing technology is unstable. Under the action of ground stress, the fractured fissures will close quickly, and there will be insufficient drainage and insufficient pressure relief, which will affect the gas extraction effect.

[0005] As the depth of coal mining increases, shallow resources are increasingly depleted, and deep mining is imperative. In view of the characteristics of high gas, high stress and low permeability in deep coal seams, the rapid reduction technology of high gas coal seams has gradually received attention and become an important development direction. Nitrogen injection driving is also a coal seam permeability enhancement technology. By injecting gas, the amount of coal seam gas analysis is increased, thereby achieving the purpose of improving the gas extraction effect. Based on this, a nitrogen injection driving and gas extraction combined device is proposed. Summary of the invention

[0006] The present invention aims to provide a nitrogen injection and gas extraction combined device to solve the problems of unstable hydraulic fracturing effect, insufficient drainage and insufficient pressure relief.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A nitrogen injection and gas extraction combined device comprises a gas supply device, a pressure control and stabilizing device and a nitrogen driving device, wherein the gas supply device comprises a nitrogen generating device and an air injection pump, wherein the nitrogen generating device is connected to the air injection pump via an air injection pipeline, wherein the pressure control and stabilizing device comprises a pressure control system, a first pressure sensor, a bursting valve and a pressure relief valve, wherein the pressure sensor is arranged on the air injection pipeline at the outlet of the air injection pump and forms a data connection with the pressure control system, wherein the pressure control system is arranged on the air injection pump, wherein the bursting valve and the pressure relief valve are both arranged on the air injection pipeline at the outlet of the air injection pump, wherein the nitrogen driving device comprises a pressure control valve, a flow sensor, a second pressure sensor and an air injection device, wherein the pressure control and stabilizing device is connected to the pressure control valve, the flow sensor, the second pressure sensor and the air injection device in sequence via an air injection pipeline, wherein the air injection device and the coal seam gas injection borehole are sealed via a three-blocking and two-injection sealing device.

[0009] Furthermore, the gas supply device, the pressure control and stabilization device and the nitrogen driving device are interconnected by at least one ball valve.

[0010] Furthermore, the nitrogen generating device includes a nitrogen cylinder or a nitrogen generator.

[0011] Furthermore, the gas injection device includes a guard arm sleeve and a segmented gas injection pipe, the guard arm sleeve is sleeved on the outside of the segmented gas injection pipe, the guard arm sleeve is provided with a sleeve gas injection hole, and the lengths of several segmented gas injection pipes gradually increase.

[0012] Furthermore, the three-plugging and two-injection sealing device includes a plugging device, a grouting pump, a grouting pipeline, an air compressor and an air compressor pipe. The three plugging devices are mounted outside the air compressor pipe. A grouting cavity section is formed between the two plugging devices. The grouting pump is connected to the grouting cavity section through the grouting pipeline, and the air compressor is connected to the grouting cavity section through the air compressor pipe.

[0013] Furthermore, the blocking device is a pouch.

[0014] Furthermore, the combined device also includes a main pipeline and a branch pipeline, the gas supply device and the pressure control and stabilization device are arranged on the main pipeline, the nitrogen driving device is arranged on the branch pipeline, the main pipeline and the branch pipeline are connected through a three-way gas injection pipeline, and the multiple branch pipelines are respectively connected to multiple gas injection boreholes.

[0015] Furthermore, a bursting valve and a pressure relief valve are provided on the branch pipeline.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention provides a stable gas injection source through a gas supply device, and the pressure control system automatically adjusts the gas pressure value output by the gas injection pump through the pressure value in the pipe fed back by the first pressure sensor to ensure the stability of the pressure in the gas injection pipeline; secondly, the burst valve and pressure relief valve installed on the gas injection pipeline serve as safety devices to solve the problem of overpressure unloading caused by human or equipment failure in the gas injection pipeline network.

[0018] 2. The wall protection casing in the gas injection device of the present invention effectively avoids the problem of the hole wall of the gas injection borehole collapsing and clogging the borehole under stress concentration and the action of high-pressure gas, and solves the problem of rapid damage and short service life of the borehole in the soft coal seam due to continuous injection of high-pressure gas; and a number of segmented gas injection pipes with gradually increasing lengths solves the problem of the gradual attenuation of the gas injection pressure along the length of the borehole.

[0019] 3. The three-blocking and two-injection sealing device of the present invention divides a grouting section in the original traditional sealing process into two sections, inner and outer. The outer section grouting mainly achieves the function of filling the borehole and achieves small-scale sealing to a certain extent. It solves the problem that the traditional two-blocking and one-injection sealing technology is not ideal for drilling and sealing soft coal seams. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an overall schematic diagram of a nitrogen injection and gas extraction combined device;

[0021] Figure 2 A cross-sectional view of a gas injection device of a nitrogen injection driving and gas extraction combined device;

[0022] Figure 3 This is a schematic diagram of the structure of the three-blocking and two-injection sealing device.

[0023] The reference numerals in the drawings of the specification include:

[0024] 1. Gas supply device; 101. Nitrogen generating device; 102. Gas injection pump; 2. Pressure control and stabilizing device; 201. Pressure control system; 202. First pressure sensor; 203. Burst valve; 204. Pressure relief valve; 3. Nitrogen driving device; 301. Pressure control valve; 302. Flow sensor; 303. Second pressure sensor; 304. Gas injection device; 3041. Arm sleeve; 3042. Casing gas injection hole; 3043. Segmented gas injection pipe; 4. Ball valve; 5. Three-blocking and two-injection sealing device; 501. Sealing device; 502. Grouting pump; 503. Grouting pipeline; 504. Gas compression device; 505. Gas compression pipe; 506. Grouting cavity section; 6. Gas injection pipeline; 601. Main pipeline; 602. Branch pipeline; 7. Drilling. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0026] like Figure 1-3 As shown, a nitrogen injection driving and promoting gas extraction combined device includes a gas supply device 1, a pressure control and stabilizing device 2 and a nitrogen driving device 3. The gas supply device 1 includes a nitrogen generator 101 and an air injection pump 102. The nitrogen generator 101 includes a nitrogen cylinder or a nitrogen generator. The nitrogen generator 101 provides a stable gas injection source for the present invention. The nitrogen generator 101 is connected to the air injection pump 102 through an air injection pipeline 6. The air injection pump 102 can adjust the air injection pressure to ensure that the air injection pressure in the air injection pipeline 6 is stable and avoid safety problems caused by the use of high-pressure gas. The pressure control and stabilizing device 2 includes a pressure control system 201, a first pressure sensor 202, a burst valve 203 and a pressure relief valve 204. The pressure sensor is arranged on the air injection pipeline 6 at the outlet of the air injection pump 102, and forms a data connection with the pressure control system 201. The pressure control system 201 is arranged on the air injection pump 102. 01 The pressure value output by the gas injection pump 102 is automatically adjusted by the pressure value in the pipe fed back by the first pressure sensor 202 to ensure the stability of the pressure in the gas injection pipeline 6. The bursting valve 203 and the pressure relief valve 204 are both arranged on the gas injection pipeline 6 at the outlet of the gas injection pump 102. The pressure control and pressure stabilizing device 2 can adjust the pressure in the gas injection pipeline 6 in real time. The bursting valve 203 and the pressure relief valve 204 serve as safety devices to solve the problem of overpressure unloading caused by human or equipment failure in the gas injection pipeline network. The nitrogen driving device 3 includes a pressure control valve 301, a flow sensor 302, a second pressure sensor 303 and a gas injection device 304. The pressure control and pressure stabilizing device 2 is connected to the pressure control valve 301, the flow sensor 302, the second pressure sensor 303 and the gas injection device 304 in sequence through the gas injection pipeline 6. The gas injection device 304 and the coal seam gas injection borehole 7 are sealed by a three-blocking and two-injection sealing device 5. The pressure control valve 301 can control the pressure of the nitrogen gas injected into the gas injection borehole 7. The appropriate gas pressure can be selected according to the position of the coal seam where the borehole 7 is located. The flow sensor 302 and the second pressure sensor 303 can detect the gas pressure value in the gas injection borehole 7 and the flow rate of the gas in the injection hole in real time, so that the back-end control platform can adjust the gas injection pressure according to the real-time pressure value in the gas injection borehole 7. The gas injection device 304 is arranged in the coal seam gas injection borehole 7 to deliver the gas into the gas injection pipeline 6.

[0027] The gas supply device 1, the pressure control and stabilization device 2 and the nitrogen driving device 3 are interconnected through a ball valve 4 to control the connection of the gas injection pipeline 6, which is convenient for changing the gas path and subsequent maintenance and overhaul.

[0028] The gas injection device 304 includes a guard arm sleeve 3041 and a segmented gas injection pipe 3043. The guard arm sleeve 3041 is sleeved on the outside of the segmented gas injection pipe 3043. The guard arm sleeve 3041 is provided with a sleeve gas injection hole 3042. The lengths of several segmented gas injection pipes 3043 gradually increase. The length of the segmented gas injection pipe 3043 can be fixed according to the actual situation on site, or the length can be set according to needs during production. The gas injection device 304 surrounds the segmented gas injection pipe 3043 by the arm sleeve 3041 arranged on the outer layer, effectively avoiding the problem of the hole wall of the gas injection borehole 7 collapsing and blocking the borehole 7 under the action of stress concentration and high-pressure gas, and solves the problem of fast damage and short service life of the soft coal seam borehole 7 due to continuous injection of high-pressure gas; the several segmented gas injection pipes 3043 with gradually increasing lengths in the arm sleeve 3041 make the injection pressure outlet located at different depths in the gas injection borehole 7, and the gas pressure of the injection gas in the segmented gas injection pipe 3043 is not easy to decay, which solves the problem of the gradual decay of the gas injection pressure along the length of the borehole 7.

[0029] The gas injection device 304 is sealed and connected with the gas injection borehole 7 through the three-blocking and two-injection sealing device 5. The three-blocking and two-injection sealing device 5 includes a grouting pipe, a plugging device 501, a grouting pump 502, a grouting pipeline 503, a compressed air device 504 and a compressed air pipe 505. The three plugging devices 501 are sleeved outside the gas injection pipeline 6, and a grouting cavity section 506 is formed between the two plugging devices 501. The grouting pump 502 is connected to the grouting cavity section 506 through the grouting pipeline 503, and the compressed air device 504 is connected to the grouting cavity section 506 through the compressed air pipe 505. The plugging device 501 is used to isolate the water, gas and soil inside and outside the borehole 7 to ensure the smooth progress of the grouting process. Three plugging devices 501 are set in the borehole 7 to form two grouting cavity sections 506. The grouting cavity section 506 located between the plugging devices 501 is used to inject inert gas and grouting materials. Grouting materials are usually selected with high strength, high sealing and corrosion resistance, such as cement slurry, epoxy resin, etc. During the grouting process, an inert gas (such as nitrogen, argon, etc.) is injected into the grouting cavity section 506 through the grouting pipe 503. The inert gas has the characteristic of not easily reacting chemically with other substances, which can ensure the stability and sealing of the grouting material. The injection of inert gas can also increase the pressure in the grouting cavity section 506, which helps the grouting material to better fill the cracks and gaps around the borehole 7. After grouting and injection of inert gas, the grouting material gradually solidifies and forms a stable plugging body. The plugging body can fit tightly to the wall of the borehole 7, effectively isolating the water, gas and soil inside and outside the borehole 7. The three-blocking and two-injection sealing device 5 divides a grouting section in the original traditional sealing process into two sections, the inner and outer sections. The grouting of the outer section mainly realizes the function of filling the borehole 7, and to a certain extent realizes small-scale plugging. It solves the problem that the traditional two-blocking and one-injection sealing technology is not ideal for the sealing effect of the borehole 7 in soft coal seams.

[0030] The gas injection pipeline 6 of the present invention also includes a main pipeline 601 and a branch pipeline 602. The main pipeline 601 and the branch pipeline 602 together constitute a gas injection pipeline network. The gas supply device 1 and the pressure control and stabilization device 2 are arranged on the main pipeline 601, and the nitrogen driving device 3 is arranged on the branch pipeline 602. The main pipeline 601 and the branch pipeline 602 are connected through a three-way gas injection pipeline 6. The multiple branch pipelines 602 are respectively connected to multiple gas injection boreholes 7. The main pipeline 601 provides a stable source of gas pressure, and the branch pipeline 602 can select a suitable gas pressure size according to the position of the coal seam where the borehole 7 is located.

[0031] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A nitrogen injection and gas extraction combined device, characterized in that: The invention comprises an air supply device (1), a pressure control and stabilizing device (2) and a nitrogen driving device (3), wherein the air supply device (1) comprises a nitrogen generating device (101) and an air injection pump (102), wherein the nitrogen generating device (101) is connected to the air injection pump (102) via an air injection pipeline (6), and the pressure control and stabilizing device (2) comprises a pressure control system (201), a first pressure sensor (202), a burst valve (203) and a pressure relief valve (204), wherein the pressure sensor is arranged on the air injection pipeline (6) at the outlet of the air injection pump (102) and forms a data connection with the pressure control system (201), and the pressure control system (201) is arranged at the air injection pump. (102), the burst valve (203) and the pressure relief valve (204) are both arranged on the gas injection pipeline (6) at the outlet of the gas injection pump (102), the nitrogen driving device (3) comprises a pressure control valve (301), a flow sensor (302), a second pressure sensor (303) and a gas injection device (304), the pressure control and stabilizing device (2) is connected to the pressure control valve (301), the flow sensor (302), the second pressure sensor (303) and the gas injection device (304) in sequence through the gas injection pipeline (6), and the gas injection device (304) and the coal seam gas injection borehole (7) are sealed by a three-blocking and two-injection sealing device (5).

2. A nitrogen injection and gas extraction combined device according to claim 1, characterized in that: The gas supply device (1), the pressure control and stabilization device (2) and the nitrogen driving device (3) are connected to each other via at least one ball valve (4).

3. A nitrogen injection and gas extraction combined device according to claim 1, characterized in that: The nitrogen generating device (101) comprises a nitrogen cylinder or a nitrogen generator.

4. A nitrogen injection and gas extraction combined device according to claim 1, characterized in that: The gas injection device (304) comprises an arm guard sleeve (3041) and a segmented gas injection pipe (3043), wherein the arm guard sleeve (3041) is sleeved on the outside of the segmented gas injection pipe (3043), and a sleeve gas injection hole (3042) is provided on the arm guard sleeve (3041), and the lengths of a plurality of segmented gas injection pipes (3043) gradually increase.

5. A nitrogen injection and gas extraction combined device according to claim 1, characterized in that: The three-blocking and two-injection sealing device (5) comprises a blocking device (501), a grouting pump (502), a grouting pipeline (503), an air compressor (504) and an air compressor pipe (505); the three blocking devices (501) are sleeved outside the air compressor pipe (6); a grouting cavity section (506) is formed between the two blocking devices (501); the grouting pump (502) is connected to the grouting cavity section (506) via the grouting pipeline (503); and the air compressor (504) is connected to the grouting cavity section (506) via the air compressor pipe (505).

6. A nitrogen injection and gas extraction combined device according to claim 5, characterized in that: The blocking device (501) is a sac.

7. A nitrogen injection and gas extraction combined device according to claims 1-6, characterized in that: The gas injection pipeline (6) further comprises a main pipeline (601) and a branch pipeline (602); the gas supply device (1) and the pressure control and stabilization device (2) are arranged on the main pipeline (601); the nitrogen driving device (3) is arranged on the branch pipeline (602); the main pipeline (601) and the branch pipeline (602) are connected via a three-way gas injection pipeline (6); and a plurality of branch pipelines (602) are respectively connected to a plurality of gas injection boreholes (7).

8. A nitrogen injection and gas extraction combined device according to claim 7, characterized in that: The branch pipeline (602) is provided with a burst valve (203) and a pressure relief valve (204).

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