CN107939364B - A device and method for integrating electric pulse fracturing, anti-reflection and gas seepage - Google Patents

Abstract

An integrated device and method for electric pulse fracturing, anti-reflection and gas seepage, which is suitable for improving the gas drainage rate of low-permeability and high-adsorption coal seams, including a high-voltage charging power supply, a high-voltage energy storage capacitor, a high-voltage discharge switch, and a coal sample fixing device , Hydraulic control system, vacuum pump device, gas cylinder, pressure gauge. First, use the high-voltage charging power supply to charge the high-voltage energy storage capacitor, turn on the high-voltage discharge switch, and discharge the coal sample through the positive electrode and the negative electrode, generating huge energy directly on the coal body, forming cracks in the coal body, and then passing through the coal. The gas seepage device built into the coal sample fixture measures the permeability of the coal sample after breakdown. The invention can realize the integrated operation of electric pulse cracking and anti-reflection and gas seepage measurement, the method has accurate measurement and convenient operation, and can provide a reliable basis for electric pulse cracking effect.

Description

A device and method for integrating electric pulse fracturing, anti-reflection and gas seepage

technical field

The invention relates to the technical field of gas drainage in coal mines, in particular to an integrated experimental device and method for electric pulse fracturing, permeation enhancement and gas seepage, which is suitable for studying problems such as difficulty in coal seam gas drainage.

Background technique

In recent years, as my country's coal mining has gradually entered the stage of deep mining, problems such as high ground stress and difficulty in gas extraction are particularly prominent. The key to solving this problem is gas extraction. At present, the commonly used gas extraction methods mainly include hydraulic fracturing, deep hole blasting, hydraulic slitting, and protective layer mining. However, there are some defects in the application of these technologies. For example, hydraulic fracturing can easily cause water lock phenomenon, block gas The channel for migration; it is difficult for deep hole blasting to deliver medicine; the application effect of hydraulic slitting in soft coal seam is poor; the mining of protective layer is not suitable for mining in a single coal seam. Therefore, it is particularly important to develop a wider range of coal seam permeability enhancement methods to solve the problem of difficult gas drainage in low-permeability coal seams.

SUMMARY OF THE INVENTION

Technical problem: The purpose of the present invention is to overcome the problems in the prior art, and to provide a simple, reliable and easy-to-operate method that can accurately measure the permeability of coal samples after electric pulse cracking. The invention directly acts on the coal seam by applying high voltage electricity to generate a discharge channel between the positive electrode and the negative electrode, and the huge energy passes through the discharge channel instantaneously to form a strong stress wave to break the coal sample, and then passes through the gas seepage measurement experimental device. A gas permeability measurement was performed.

Technical scheme: The electric pulse fracturing, anti-reflection and gas seepage integrated device of the present invention includes a high-voltage charging power supply, a high-voltage energy storage capacitor, a high-voltage discharge switch, a coal sample fixing device, a hydraulic control system, a vacuum pump device, a gas cylinder, and a pressure gauge. and the air inlet control valve, the air outlet end of the gas cylinder is connected with a pressure gauge and an air outlet control valve; it is characterized in that: the output end of the high-voltage charging power supply is connected with the positive electrode of the high-voltage energy storage capacitor, and the high-voltage energy storage capacitor The output end is connected with the input end of the high-voltage discharge switch, the output end of the high-voltage discharge switch is connected with the coal sample fixing device, and the output end of the coal sample fixing device is connected with the negative electrode of the high-voltage energy storage capacitor; The sample fixing device is connected with the hydraulic control system, the vacuum pump device and the gas cylinder.

The coal sample fixing device includes a support table and a cavity arranged on the support table, a high-pressure rubber sleeve is arranged in the cavity, and a gap filled with hydraulic oil is left between the outer circular surface of the high-pressure rubber sleeve and the inner circular surface of the cavity. , the bottom of the cavity is provided with an oil inlet pipe for injecting hydraulic oil into the gap, and the oil inlet pipe is connected to the hydraulic control system. The middle of the high-pressure rubber sleeve is provided with a coal sample, and the upper end surface of the coal sample is provided with an upper shaft pressure column. There is a lower axial compression column on the lower end surface of the upper axial compression column, the lower axial compression column and the upper axial compression column each have a central hole and a side hole, and the central hole of the upper axial compression column is embedded with a spring-loaded coal sample. The upper needle-shaped positive electrode, the central hole of the lower axial compression column is embedded with a needle-shaped negative electrode supported by two springs on the coal sample; the needle-shaped positive electrode and the needle-shaped negative electrode are covered with insulating sleeves. The pipe is embedded in the upper and lower axial compression columns; the side hole of the lower axial compression column is provided with an air intake pipe which is connected with the vacuum pump device. An air outlet pipe is arranged in the side hole; the lower shaft pressing column and the upper shaft pressing column are respectively connected with the hydraulic control system through the hydraulic pipeline, and the hydraulic pipeline is connected with the hydraulic control valve; the air inlet pipe is connected with the gas cylinder, and the gas outlet pipe is provided with Outlet control valve and gas flow meter to measure flow.

The diameters of the central holes of the lower axial compression column and the upper axial compression column are determined by the outer diameter of the insulating sleeve, and the diameters of the side holes are determined by the diameters of the air inlet pipe and the air outlet pipe.

The method for integrating the seepage flow of the above-mentioned electric pulse cracking and anti-reflection integrated device with gas seepage flow includes the following steps:

a. Fix the coal sample in the middle of the high-pressure rubber sleeve, then put the high-pressure rubber sleeve containing the coal sample into the cavity, and set the upper and lower axial compression columns on the upper and lower end faces of the coal sample respectively. Under the action of the second spring, the needle-shaped positive electrode and the needle-shaped negative electrode arranged in the central holes of the upper and lower axial compression columns are close to the coal sample;

b. Open the hydraulic control system, and after applying the preset confining pressure and axial pressure to the coal sample by adjusting the hydraulic control valve and the hydraulic control valve, close the hydraulic control system, hydraulic control valve and hydraulic control valve;

c. Charge the preset voltage into the high-voltage energy storage capacitor through the high-voltage charging power supply, turn on the high-voltage discharge switch, and discharge the coal sample;

d. After repeating step c for many times to rupture the coal sample, turn off the high-voltage charging power supply and the high-voltage discharging switch;

e. Use a sealing sleeve to seal the connection between the wire and the lower and upper axial compression columns;

f. Open the inlet control valve, close the outlet control valve, and use the vacuum pump device to evacuate the coal sample fixing device;

g. After vacuuming, close the intake control valve, remove the vacuum pump device, then connect the gas cylinder to the intake pipe, open the gas cylinder, and set the intake pressure to 1MPa by adjusting the intake control valve to saturate the adsorption of the coal sample. 3-5 days;

h. Open the air outlet control valve, maintain the air inlet pressure at 2MPa by adjusting the air inlet control valve, and measure the gas flow at the outlet end through a gas flow meter;

i. By changing the confining pressure, axial pressure, inlet gas pressure and the preset voltage of the high-voltage charging power supply during the experiment, the crushing effect and gas permeability of coal samples after electric pulse breakdown were studied.

Beneficial effects: Due to the adoption of the above technical scheme, the present invention can realize the integrated experimental operation of electric pulse antireflection and gas seepage, and can accurately test the effect of electric pulse cracking. Through the hydraulic control system, the electric pulse fracturing experiment can be carried out under the condition of triaxial loading, which can better clear the gas seepage channel. The effect of electric pulse cracking was tested. The device is simple in structure and convenient in operation, can effectively solve the problem of difficulty in checking the effect of electric pulse crushing coal samples, and has wide practicability in the field.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention.

FIG. 2 is a sectional view taken along line I-I in FIG. 1 .

In the figure: 1—high voltage charging power supply, 2—high voltage energy storage capacitor, 3—high voltage discharge switch, 4—coal sample fixing device, 5—hydraulic control system, 6—vacuum pump device, 7—gas cylinder, 8—pressure gauge, 9—Intake control valve, 10—Inlet pipe, 11—Outlet pipe, 12—Hydraulic oil, 13—Coal sample, 14—High pressure rubber sleeve, 15—Cavity, 16—Lower axial pressure column, 17—Upper axial pressure Column, 18—support table, 19—gas flow meter, 20—insulation sleeve, 21—sealing sleeve, 22—gas outlet control valve, 23—needle positive electrode, 24—needle negative electrode, 25—spring one, 26 - Spring two, 27 - hydraulic control valve one, 28 - hydraulic control valve two.

Detailed ways

Below in conjunction with accompanying drawing, an embodiment of the present invention is further described:

The integrated device of electric pulse cracking and anti-reflection and gas seepage of the present invention is mainly composed of a high-voltage charging power supply 1, a high-voltage energy storage capacitor 2, a high-voltage discharge switch 3, a coal sample fixing device 4, a hydraulic control system 5, a vacuum pump device 6, a gas Bottle 7, pressure gauge 8 and air inlet control valve 9, the gas outlet end of gas bottle 7 is connected with pressure gauge 8 and gas outlet control valve 9; The output end of the high-voltage energy storage capacitor 2 is connected to the input end of the high-voltage discharge switch 3, the output end of the high-voltage discharge switch 3 is connected to the coal sample fixing device 4, and the output end of the coal sample fixing device 4 is connected. It is connected with the negative pole of the high-voltage energy storage capacitor 2; the coal sample fixing device 4 is connected with the hydraulic control system 5, the vacuum pump device 6 and the gas cylinder 7.

The coal sample fixing device 4 includes a support table 18 and a cavity 15 arranged on the support table 18 . The cavity 15 is provided with a high-pressure rubber sleeve 14 , the outer circular surface of the high-pressure rubber sleeve 14 and the inner circular surface of the cavity 15 There is a gap filled with hydraulic oil 12 between them. The bottom of the cavity 15 is provided with an oil inlet pipe for injecting hydraulic oil into the gap. The oil inlet pipe is connected to the hydraulic control system 5. The middle of the high pressure rubber sleeve 14 is provided with a coal sample 13. The upper end surface of the coal sample 13 is provided with an upper axial compression column 17, and the lower end surface of the coal sample 13 is provided with a lower axial compression column 16. The lower axial compression column 16 and the upper axial compression column 17 each have a central hole and a The side hole, the central hole of the upper axial compression column 17 is embedded with a needle-shaped positive electrode 23 pushed by the spring 1 25 on the coal sample, and the central hole of the lower axial compression column 16 is embedded with a spring 2 26 pushed against the coal sample. The needle-shaped negative electrode 24 on the sample; the needle-shaped positive electrode 23 and the needle-shaped negative electrode 24 are sheathed with an insulating sleeve 20, and the insulating sleeve 20 is embedded in the upper axial compression column 17 and the lower axial compression column 16. The diameter of the central hole of the pressing column 16 and the upper axial pressing column 17 is determined by the outer diameter of the insulating sleeve 20 , and the diameter of the side hole is determined by the diameter of the air inlet pipe 10 and the air outlet pipe 11 . The side hole of the lower axial pressure column 16 is provided with an air intake pipe 10 connected with the vacuum pump device 6, the intake pipe 10 is provided with an air intake control valve 9, and the side hole of the upper axial pressure column 17 is provided with an air outlet pipe 11; The lower axial pressure column 16 and the upper axial pressure column 17 are respectively connected to the hydraulic control system 5 through hydraulic pipelines, and the hydraulic pipelines are connected to the hydraulic control valve 27 and the hydraulic control valve 28; the air intake pipe 10 is connected to the gas cylinder 7, and the air outlet pipe 11 is provided with a gas outlet control valve 22 and a gas flow meter 19 for measuring flow.

The above-mentioned integrated method for percolation of an integrated device for electric pulse fracturing and permeation enhancement and gas percolation includes the following steps:

a. Fix the coal sample 13 in the middle of the high pressure rubber sleeve 14, then put the high pressure rubber sleeve 14 with the coal sample 13 into the cavity 15, and set the upper axial compression column 17 and the lower axial compression column 16 on the coal sample respectively On the upper and lower end surfaces of 13, under the action of springs 1 25 and 2 sample 13;

b. Open the hydraulic control system 5, and apply the preset confining pressure and axial pressure to the coal sample 13 by adjusting the hydraulic control valve 27 and the hydraulic control valve 28, for example, the confining pressure is 10MPa, the axial pressure is 8MPa, and the hydraulic control system 5 is closed. control valve 27 and hydraulic control valve 28;

c. Charge the preset voltage 50kV into the high-voltage energy storage capacitor 2 through the high-voltage charging power supply 1, turn on the high-voltage discharge switch 3, and discharge the coal sample 13;

d. After repeating step c for many times to rupture the coal sample, turn off the high-voltage charging power supply 1 and the high-voltage discharge switch 3;

e. Use the sealing sleeve 21 to seal the connection between the wire and the lower axial pressure column 16 and the upper axial pressure column 17;

f. Open the inlet control valve 9, close the outlet control valve 22, and use the vacuum pump device 6 to evacuate the coal sample fixing device 4;

g. After vacuuming, close the intake control valve 9, unload the vacuum pump device 6, then connect the gas cylinder 7 into the intake pipe 10, open the gas cylinder 7, and set the intake pressure 1MPa by adjusting the intake control valve 9 , so that the adsorption of coal sample 13 is saturated for 3-5 days;

h, open the air outlet control valve 22, maintain the air inlet pressure 2MPa by adjusting the air inlet control valve 9, and measure the gas flow at the outlet end through the gas flow meter 19;

i. By changing the confining pressure, axial pressure, inlet gas pressure and the preset voltage of the high-voltage charging power supply 1 during the experiment, the crushing effect and gas permeability of coal samples after electric pulse breakdown were studied.

Claims (3)

1. An integrated device for electric pulse cracking, anti-reflection and gas seepage, comprising a high-voltage charging power supply (1), a high-voltage energy storage capacitor (2), a high-voltage discharge switch (3), a coal sample fixing device (4), a hydraulic control The system (5), the vacuum pump device (6), the gas cylinder (7), the pressure gauge (8) and the intake control valve (9), the gas cylinder (7) is connected with a pressure gauge (8) and an intake control valve Valve (9); characterized in that: the output end of the high-voltage charging power supply (1) is connected to the positive pole of the high-voltage energy storage capacitor (2), and the output end of the high-voltage energy storage capacitor (2) is connected to the high-voltage discharge switch (3) is connected to the input end, the output end of the high-voltage discharge switch (3) is connected to the coal sample fixing device (4), and the output end of the coal sample fixing device (4) is connected to the high-voltage energy storage capacitor (2). ) is connected to the negative pole of the ); the coal sample fixing device (4) is respectively connected with the hydraulic control system (5), the vacuum pump device (6) and the gas cylinder (7); the coal sample fixing device (4) includes a support table ( 18) A cavity (15) arranged on the support table (18), a high-pressure rubber sleeve (14) is arranged in the cavity (15), and the outer circular surface of the high-pressure rubber sleeve (14) is connected to the inside of the cavity (15). There is a gap filled with hydraulic oil (12) between the circular surfaces. The bottom of the cavity (15) is provided with an oil inlet pipe for injecting hydraulic oil into the gap. The oil inlet pipe is connected to the hydraulic control system (5). The high-pressure rubber sleeve (14) A coal sample (13) is arranged in the middle, an upper axial compression column (17) is arranged on the upper end surface of the coal sample (13), and a lower axial compression column (16) is arranged on the lower end surface of the coal sample (13), The lower axial compression column (16) and the upper axial compression column (17) each have a central hole and a side hole, and the central hole of the upper axial compression column (17) is embedded with a spring one (25) which is pushed against the coal. The needle-shaped positive electrode (23) on the sample, and the needle-shaped negative electrode (24) pressed against the coal sample by the second spring (26) is embedded in the central hole of the lower axial compression column (16); the needle-shaped positive electrode ( 23) and the needle-shaped negative electrode (24) are covered with an insulating sleeve (20), and the insulating sleeve (20) is embedded in the upper axial compression column (17) and the lower axial compression column (16); the lower shaft The side hole of the pressure column (16) is provided with an air intake pipe (10) connected with the vacuum pump device (6). An air outlet pipe (11) is arranged in the hole; the lower axial pressure column (16) and the upper axial pressure column (17) are respectively connected with the hydraulic control system (5) through the hydraulic pipeline, and the hydraulic pipeline is connected with the hydraulic control valve one (27) and hydraulic control valve two (28); the air inlet pipe (10) is connected to the gas cylinder (7), and the gas outlet pipe (11) is provided with a gas outlet control valve (22) and a gas flow meter (19) for measuring flow. 2. The electric pulse cracking, anti-reflection and gas seepage integrated device according to claim 1, characterized in that: the diameter of the central hole of the lower axial compression column (16) and the upper axial compression column (17) It is determined by the outer diameter of the insulating sleeve (20), and the diameter of the side hole is determined by the diameters of the air inlet pipe (10) and the air outlet pipe (11). 3. the seepage integrated method of a kind of electric pulse cracking and anti-reflection and gas seepage integrated device according to claim 1 or 2, comprising the following steps: a. Fix the coal sample (13) in the middle of the high-pressure rubber sleeve (14), then put the high-pressure rubber sleeve (14) containing the coal sample (13) into the cavity (15), and press the upper shaft to press the column (17) ) and the lower axial pressure column (16) are respectively arranged on the upper and lower end faces of the coal sample (13), and under the action of the spring one (25) and the second spring (26), they are arranged on the upper axial pressure column (17) and the lower axis The needle-shaped positive electrode (23) and the needle-shaped negative electrode (24) in the central hole of the pressing column (16) are adjacent to the coal sample (13); b. Open the hydraulic control system (5), apply the preset confining pressure and axial pressure to the coal sample (13) by adjusting the hydraulic control valve one (27) and the hydraulic control valve two (28), and then close the hydraulic control system (5). ), hydraulic control valve one (27) and hydraulic control valve two (28); c. Charge the preset voltage into the high-voltage energy storage capacitor (2) through the high-voltage charging power supply (1), turn on the high-voltage discharge switch (3), and discharge the coal sample (13); d. After repeating step c for several times to rupture the coal sample, turn off the high-voltage charging power supply (1) and the high-voltage discharge switch (3); e. Use the sealing sleeve (21) to seal the connection between the wire and the lower axial pressure column (16) and the upper axial pressure column (17); f. Open the air inlet control valve (9), close the air outlet control valve (22), and use the vacuum pump device (6) to evacuate the coal sample fixing device (4); g. After vacuuming, close the intake control valve (9), remove the vacuum pump device (6), then connect the gas cylinder (7) to the intake pipe (10), open the gas cylinder (7), and adjust the intake The gas control valve (9) sets the inlet pressure to 1MPa, so that the coal sample (13) is adsorbed and saturated for 3-5 days; h. Open the gas outlet control valve (22), maintain the inlet pressure at 2MPa by adjusting the inlet gas control valve (9), and measure the gas flow at the gas outlet through the gas flow meter (19); i. By changing the confining pressure, axial pressure, inlet gas pressure and the preset voltage of the high-voltage charging power supply (1) during the experiment, the crushing effect and gas permeability of coal samples after electric pulse breakdown were studied.

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