CN102587889B - Experimental system for simulating solid-phase particles to plug coal (rock) cracks - Google Patents

Abstract

The invention discloses an experimental system for simulating solid-phase particle plugging of coal and rock fissures. The air inlet end of the secondary hole sealing device of the system is sequentially connected with an I control valve, a pressure regulating valve, a gas flow meter, a II control valve and an air flow meter. Compressor; the discharge end of the secondary sealing device is sequentially connected with the III control valve and the crack platform, and the secondary sealing device is located on the electronic scale. The invention has simple operation, scientific and accurate data collection, can directly observe the migration and plugging of particles in the cracks, and well simulates the process of particles plugging the cracks around the borehole, and simulates the process of particle plugging cracks through the experimental system The data of the electronic scale, gas flow meter and pressure regulating valve can determine the key process parameters of the secondary sealing technology, summarize the migration law of solid phase particles in the fracture through the experimental phenomenon, and analyze and explain it in combination with the experimental data. It is suitable for the experiment of simulating the plugging of cracks around boreholes by simulating particles in underground gas drainage engineering.

Description

Experimental system for simulating solid particles to plug coal and rock fissures

technical field

The present invention relates to an experimental system for simulating particle plugging cracks, especially an experimental system suitable for simulating particle plugging of cracks around boreholes in underground gas drainage projects.

Background technique

The Chinese patent specification discloses the "Secondary Sealing Method for Increasing Gas Drainage Concentration in Coal Seam Boreholes" (Patent No. 200810023609.5). This patented technology uses pneumatic conveying pressure to transport powder particles to the cracks around the borehole to block the gas leakage channel. It has been applied in more than 10 coal mines across the country, greatly improving the gas extraction concentration of underground coal seams. However, since the fractures in the downhole drilling area are inside the coal (rock) body, it is difficult to directly observe the migration, deposition and sealing process of particles in the fractures on site, which is not conducive to determining the key process parameters of the secondary sealing technology.

Contents of the invention

Technical problem: The purpose of this invention is to provide a simulation experiment system for solid-phase particles to seal coal and rock fissures, which can more intuitively monitor the migration and plugging characteristics of particles in the fissures during the secondary sealing process. In order to overcome the problem of using pneumatic conveying pressure, because the fractures in the downhole drilling area are inside the coal and rock mass, it is difficult to directly observe the migration, deposition and sealing process of particles in the fractures on site, which is not conducive to determining the secondary sealing technology. Defects in key process parameters.

Technical solution: An experimental system for simulating the sealing of coal and rock fissures by solid particles. The system includes an air compressor and a secondary sealing device. , gas flow meter, II control valve and air compressor, the discharge end of the secondary sealing device is connected with the III control valve and the crack platform in turn, and the secondary sealing device is placed on the electronic scale.

The lower part of the cracked platform is the platform base, the rubber gasket is located on the platform base, the transparent cover is located on the rubber gasket, and the transparent cover is connected to the platform base through fasteners; The opening on the platform base is a rectangular groove, the side and bottom of the rectangular groove are filled with composite materials, the rectangular groove is provided with main cracks and branch cracks, the main cracks are connected to each other through the branch cracks, the platform base is made of concrete, drilled The hole area is a semicircular groove with an upper opening, and a gas pressure sensor is installed on the side of the groove.

There are three main cracks and two branch cracks in the crack area, and the crack molds that form the main cracks and branch cracks are curved forming dies, straight-line forming dies, or variable-diameter forming dies. The composite material is made of water: gypsum: cement: sand: calcium carbonate = 2:2:1:7:0.5, and the weight ratio is used. Place a curved molding die in the middle of the rectangular groove, or a linear molding die, or a variable-diameter molding die, and form cracks of different shapes and widths by filling the composite material between the crack mold and the rectangular groove.

Beneficial effects: the invention has simple operation, scientific and accurate data collection, can directly observe the migration and plugging of particles in the cracks, and well simulates the process of plugging the cracks around the drill hole by particles, specifically reflected in:

1. By simulating the data of electronic scale, gas flow meter and pressure regulating valve in the process of particle sealing cracks by this experimental system, the key process parameters of secondary sealing technology can be determined, so as to better promote and apply this technology;

2. Through the observation surface, the transportation, deposition and plugging process of particles in boreholes and fractures can be observed. Cameras can also be used to record these experimental phenomena, and the migration laws of solid phase particles in fractures can be summarized through experimental phenomena, and combined with experiments Data analysis and interpretation;

3. The fractured platform is equipped with a drilled area and a fractured area, which can simulate the process of particles entering the cracks around the drilled hole through the drilled hole, which is consistent with the actual engineering;

4. Single cracks and complex crack networks of different types and widths can be formed by filling the composite material between the rectangular groove and the different crack molds that have been made.

Description of drawings

Figure 1 is a schematic structural view of an embodiment of the present invention.

Figure 2 is a schematic diagram of the fractured platform structure in Figure 1.

Figure 3 is a schematic diagram of the A--A section in Figure 2.

Figure 4 is a front view of the curved forming die of the present invention.

Figure 5 is a top view of the curved molding die of the present invention.

Figure 6 is a left view of the curved forming die of the present invention.

Figure 7 is a front view of the linear molding die of the present invention.

Figure 8 is a top view of the linear molding die of the present invention.

Figure 9 is a left side view of the linear molding die of the present invention.

Figure 10 is a front view of the forming die of the variable diameter shape of the present invention.

Figure 11 is a top view of the forming die of the variable diameter shape of the present invention.

Fig. 12 is the left side view of the forming die of variable diameter of the present invention.

In the figure: 1. Air compressor, 2. Secondary sealing device, 3. I control valve, 4. Pressure regulating valve, 5. Gas flow meter, 6. II control valve, 7. III control valve, 8. Crack Platform, 8-1. Platform base, 8-2. Rubber gasket, 8-3. Transparent cover, 8-4. Fasteners, 8-5. Drilling area, 8-6. Crack area, 8- 7. Main crack, 8-8. Branch crack, 8-9. Rectangular groove, 8-10. Composite material, 8-11. Gas pressure sensor, 9. Electronic scale, 10. Bending mold, 11. Straight forming die, 12. variable diameter forming die.

Detailed ways

In Fig. 1, the inlet end of the secondary sealing device 2 is connected with I control valve 3, pressure regulating valve 4, gas flow meter 5, II control valve 6 and air compressor 1 in sequence; The discharge end is connected with the III control valve 7 and the crack platform 8 in sequence, and the secondary sealing device 2 is located on the electronic scale 9 .

In Fig. 2 and Fig. 3, below the crack platform 8 is the platform base 8-1, the rubber gasket 8-2 is located on the platform base 8-1, the transparent cover 8-3 is located on the rubber gasket 8-2, and the transparent cover Plate 8-3 is attached to platform base 8-1 by fasteners 8-4. The fissure platform 8 is provided with a drilling area 8-5 and a fissure area 8-6. The platform base 8-1 of the fissure area 8-6 is provided with a main fissure 8-7 and a branch fissure 8-8. Between the main fissure 8-7 The main cracks 8-7 and the branch cracks 8-8 are rectangular grooves 8-9 with upper openings, and the sides and bottom of the rectangular grooves 8-9 are filled with composite materials 8-10. The platform base 8-1 is made of concrete, and the drilling area 8-5 is a semicircular groove with an upper opening, and a gas pressure sensor 8-11 is installed on the edge of the groove.

In the middle of the crack area 8-6 rectangular groove 8-9, place a curved forming die 10 coated with lubricating oil, or a linear forming die 11, or a variable-diameter forming die 12, and fill the composite material 8-10 To the forming die 10 of curved shape, or the forming die 11 of linear shape, or around the forming die 12 of variable-diameter shape, compact and ensure that the height of the upper surface of composite material 8-10 is consistent with rubber gasket 8-2, to ensure Sealing effect, after drying for 5~6 hours, pull out the curved forming mold 10, or the straight forming mold 11, or the variable diameter forming mold 12, thereby forming main cracks 8-7 or Branch fissures 8-8. If the main crack 8-7 or the branch crack 8-8 does not allow particles to enter, it can be blocked with a composite material 8-10; after the main crack 8-7 and the branch crack 8-8 are formed, the rectangular groove 8-9 and Evenly apply a layer of sealant on the outer upper surface of the drilling area 8-5, close the transparent cover plate 8-3 to the rubber gasket 8-2, and finally fix the fastener 8-4 to realize the sealing of the entire crack platform 8.

When in use, close the I control valve 3, II control valve 6 and III control valve 7, add 15~20Kg of solid-phase particle powder into the secondary sealing device 2, and make the readings of the electronic scale 9 and the gas flow meter 5 return to zero , open the air compressor 1 and control valve Ⅱ and control valve 6, adjust the pressure regulating valve 4 to control the pressure of the pressure regulating valve 4 at 0.2~0.3MPa, open the control valve Ⅲ and control valve Ⅰ successively, and the secondary sealing device 2 starts Convey powder. Record the readings of gas flowmeter 5, electronic scale 9 and pressure regulating valve 4 every 5s, and when the readings of electronic scale 9 and gas flowmeter 5 no longer change, close control valve Ⅰ, control valve Ⅱ, 6 and Ⅲ Control valve 7 and air compressor 1, and the experiment ends.

Claims (3)

1. An experimental system for simulating solid-phase particle plugging of coal and rock fissures. The system includes an air compressor and a secondary sealing device. The air inlet of the secondary sealing device is connected with I control valve, pressure regulating valve, Gas flow meter, II control valve and air compressor; the discharge end of the secondary sealing device is connected with the III control valve and the crack platform in turn, and the secondary sealing device is located on the electronic scale, and the characteristics are as follows: Below the cracked platform is the platform base, the rubber gasket is located on the platform base, the transparent cover is located on the rubber gasket, the transparent cover is connected to the platform base through fasteners; the cracked platform is provided with a drilling area and a cracked area, and the cracked area The opening on the platform base is a rectangular groove, and the side of the rectangular groove is filled with composite materials. There are main cracks and branch cracks in the rectangular groove. The main cracks are connected to each other through the branch cracks. The platform base is made of concrete. The drilling area It is a semicircular groove with an upper opening, and a gas pressure sensor is arranged on the side of the groove. 2. The experimental system for simulating solid phase particle plugging of coal and rock fissures according to claim 1, wherein the composite material is mixed by water: gypsum: cement: sand: calcium carbonate=2:2:1:7:0.5 Formed by weight ratio. 3. The experimental system for simulating solid-phase particle plugging of coal and rock fissures according to claim 1, characterized in that: the fissure dies forming the main fissures and branch fissures are curved forming dies, or linear forming dies, or Diameter-shaped forming die.