A precise cutting method for outburst energy units in thick coal belts in coal mine structural areas

Abstract

A precise cutting method for the outburst energy unit of the thick coal zone in the coal mine structural area. A parameter measurement borehole is constructed from the floor rock roadway to the coal seam away from the thickening zone near the fault, and the coal seam gas content unaffected by the fault is sampled and measured; multiple induced spraying boreholes are constructed from the floor rock roadway to the thickening zone near the fault. When the borehole is constructed to the coal-seeing point, the coal seam gas content is sampled and measured; several cross-cutting boreholes are constructed from the floor rock roadway to the middle of the induced spraying boreholes as wind-force reaming boreholes, and several supplementary drainage boreholes are interspersed and constructed between the induced spraying boreholes and the wind-force reaming boreholes; the induced spraying boreholes, the wind-force reaming boreholes and the supplementary drainage boreholes are sequentially blocked and connected to the drainage pipeline, and the gas pressure and gas content in the thickening zone near the fault are reduced through gas drainage. The invention safely eliminates the abnormal enrichment energy in the thickening zone of the coal seam near the fault, and realizes the efficient gas drainage and precise outburst elimination of the thick coal zone in the coal mine structural area.

Description

Technical Field

[0001] The present invention relates to the technical field of coal seam gas control, and particularly relates to a precise cutting method for an outburst energy unit in a thick coal zone in a coal mine structural area. Background Technique

[0002] In coal mines, thickening zones often appear near faults in structural coal seams, which are characterized by high in-situ stress, high gas pressure, and large gas content. There are potential risks of abnormal energy enrichment and outburst under the coupled and synergistic action of tectonic stress and gas pressure. Structural coal seams are mostly soft and low-permeability coal seams, and the gas drainage efficiency is low. For the gas control of the thickening zone near the fault in the coal seam, in the past, it was usually to construct intensive cross-cut boreholes for pre-drainage without discrimination for the whole coal seam or to implement cross-cut hydraulic measures (punching, slotting, fracturing, etc.) for pressure relief and permeability enhancement pre-drainage without discrimination, resulting in a large amount of engineering work and wasting a lot of time, manpower, and material resources. During the process of drilling for outburst elimination near the thickening zone near the fault, it is more likely to occur the phenomenon of hole spraying, resulting in gas overrun at the working site. In severe cases, the ejected coal will bury the drilling rig and block the roadway. The coal-water mixture formed by hydraulic measures in soft coal seams is easy to block the hole and jam the drill, and the scrapping of the borehole affects the construction progress. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above deficiencies, provide a precise cutting method for an outburst energy unit in a thick coal zone in a coal mine structural area, solve problems such as hole spraying, hole blocking and drill jamming, large amount of engineering work, and low efficiency during the process of drilling for outburst elimination, improve the coal seam permeability and gas drainage efficiency, and safely eliminate the abnormally enriched energy in the thickening zone near the fault in the coal seam.

[0004] The purpose of the present invention is achieved as follows:

[0005] A precise cutting method for an outburst energy unit in a thick coal zone in a coal mine structural area is to construct parameter measurement boreholes, induced spraying boreholes, air-force reaming boreholes, and supplementary drainage boreholes below the coal seam for outburst elimination and drainage of the thickening zone near the fault. The specific steps are as follows:

[0006] Step 1: Construct a parameter measurement borehole from the floor rock roadway to the coal seam away from the thickening zone near the fault, take samples to measure the coal seam gas content W1 not affected by the fault, and record the drill pipe torque T1 during the drilling process;

[0007] Step 2: Construct multiple induced spraying boreholes from the floor rock roadway to the thickening zone near the fault. When the borehole is constructed to the coal seam encounter point, take samples to measure the coal seam gas content W2, and record the drill pipe torque T2; then switch to high-pressure explosion-proof gas slag removal and rapid drilling to suddenly expose the coal body to ensure successful induced spraying, and form an induced spraying borehole pressure relief and permeability enhancement circle;

[0008] Step 3: Construct several cross - seam boreholes from the floor rock roadway towards the middle of the blow - out induction boreholes in Step 2 as air - powered reaming boreholes. Conduct air - powered reaming from the coal seam roof to the floor from top to bottom to form an air - powered reaming borehole pressure - relief and permeability - enhancement zone. The coal output per meter of reaming is determined according to the actual on - site situation;

[0009] Step 4: Intersperse and construct several supplementary drainage boreholes between the blow - out induction boreholes and the air - powered reaming boreholes constructed in Steps 2 and 3. When the borehole reaches the coal - seeing point, switch to high - pressure explosion - proof gas slag discharge to reduce the phenomena of borehole blockage and sticking;

[0010] Step 5: Seal the blow - out induction boreholes, air - powered reaming boreholes, and supplementary drainage boreholes in sequence and connect the drainage pipelines to reduce the gas pressure and gas content in the thickening zone near the fault through gas drainage;

[0011] Step 6: If the coal seam gas content W2 measured in Step 2 is greater than the coal seam gas content W1 measured by the parameter - determination borehole in Step 1, and the drill - pipe torque T2 in Step 2 is greater than the drill - pipe torque T1 in Step 1, then repeat Steps 2 to 5 until all abnormal enrichment energies in the thickening zone near the fault are eliminated.

[0012] Further, the borehole layout of multiple blow - out induction boreholes in Step 2 is arranged in a rectangular array, and a blow - out induction borehole is also arranged at the center of each rectangle.

[0013] Further, the air - powered reaming boreholes are evenly distributed between multiple blow - out induction boreholes, and the distance between adjacent two air - powered reaming boreholes is the same.

[0014] Further, the supplementary drainage boreholes are evenly distributed between the blow - out induction boreholes and the air - powered reaming boreholes, and the distance between adjacent two supplementary drainage boreholes is the same.

[0015] Further, a safety blow - out guiding device is provided at the orifice of the blow - out induction borehole.

[0016] Further, a protection distance is reserved for the blow - out induction borehole, that is, the distance of the rock - hole section between the floor rock roadway and the coal - seeing point is greater than 10 m.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] The present invention utilizes a blowout induction borehole, a wind-force hole enlargement borehole, and a supplementary drainage borehole to accurately eliminate the outburst danger in the thickening zone near the fault. By measuring the gas parameters during the implementation process, the specific range of the thickening zone near the detected fault can be determined. The blowout induction borehole is used to controllably induce blowout holes in the thickening zone near the coal seam fault, reducing the possibility of blowout holes in the coal body around the blowout induction borehole. At the same time, during the construction process of the borehole in the coal seam section, high-pressure explosion-proof gas is used to discharge the slag, which can effectively avoid the phenomena of borehole blockage and sticking of the drill bit. The present invention realizes the simultaneous outburst elimination, detection, and efficient pressure relief and permeability enhancement drainage in the thickening zone of the coal seam near the fault, reducing a large amount of time, manpower, and material costs. The method of the present invention is simple and has good effects, and has wide practicability in the technical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the cross-cut borehole construction of Embodiment 1 of the present invention.

[0020] Figure 2 It is a schematic diagram of the borehole layout of Embodiment 1 of the present invention.

[0021] Figure 3 It is a schematic diagram of the borehole layout of Embodiment 2 of the present invention.

[0022] Wherein:

[0023] The thickening zone 1 near the fault, the coal seam 2, the parameter measurement borehole 3, the floor rock roadway 4, the wind-force hole enlargement borehole 5, the blowout induction borehole 6, the pressure relief and permeability enhancement circle 7 of the wind-force hole enlargement borehole, the supplementary drainage borehole 8, the pressure relief and permeability enhancement circle 9 of the blowout induction borehole, and the coal seam penetration point 10. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To better understand the technical solution of the present invention, the following will be described in detail with reference to the relevant drawings. It should be understood that the following specific embodiments are not intended to limit the specific implementation modes of the technical solution of the present invention, and they are only the implementation modes that can be adopted by the technical solution of the present invention. It should be noted first that the description of the positional relationship of each component herein, such as component A is located above component B, is based on the relative positions of the components in the drawings and is not intended to limit the actual positional relationship of the components.

[0025] Embodiment 1:

[0026] Refer to Figure 1 - Figure 2 , Figure 1 A schematic diagram of the cross-cut borehole construction of Embodiment 1 is drawn. As shown in the figure, a precise cutting method for the outburst energy unit in the thick coal zone of the coal mine structure area in this Embodiment 1 includes the following contents:

[0027] It includes constructing a parameter measurement borehole 3, a blowout induction borehole 6, a wind-force hole enlargement borehole 5, and a supplementary drainage borehole 8 to eliminate outburst and drain in the thickening zone of the structural coal seam near the fault. The specific steps are as follows:

[0028] Step 1: Construct a parameter measurement borehole 3 from the floor rock roadway 4 to the coal seam 2 away from the thickening zone 1 near the fault, sample and measure the coal seam gas content W1 not affected by the fault, and record the drill pipe torque T1 during the drilling process;

[0029] Step 2: Construct five induced spraying boreholes 6 from the floor rock roadway 4 to the thickening zone 1 near the fault. When the borehole is constructed to the coal seam intersection point 10, sample and measure the coal seam gas content W2, and record the drill pipe torque T2; then switch to high-pressure explosion-proof gas slag removal and rapid drilling to suddenly expose the coal body to ensure successful induced spraying and form an induced spraying borehole pressure relief and permeability enhancement zone 9;

[0030] Step 3: Construct several cross-layer boreholes as air-force reaming boreholes 5 from the floor rock roadway 4 to the middle of the induced spraying boreholes 6 in Step 2, and conduct air-force reaming from the coal seam roof to the floor from top to bottom to form an air-force reaming borehole pressure relief and permeability enhancement zone 7, and the coal output per meter of reaming is determined according to the actual situation on site;

[0031] Step 4: Intersperse and construct several supplementary extraction boreholes 8 between the induced spraying boreholes 6 and the air-force reaming boreholes 5 constructed in Step 2 and Step 3. When the borehole is constructed to the coal seam intersection point 10, switch to high-pressure explosion-proof gas slag removal to reduce the phenomenon of borehole blockage and drill pipe jamming;

[0032] Step 5: Seal the induced spraying boreholes 6, the air-force reaming boreholes 5, and the supplementary extraction boreholes 8 in sequence and connect the extraction pipeline, and reduce the gas pressure and gas content in the thickening zone 1 near the fault through gas extraction;

[0033] Step 6: If the parameters (coal seam gas content W and drill pipe torque T) measured in Step 2 are greater than the parameters measured by the parameter measurement borehole 3 in Step 1, repeat Step 2 to Step 5 until all abnormal enrichment energies in the thickening zone 1 near the fault are eliminated.

[0034] In this Example 1, the coal seam gas content W is measured in accordance with the national standard "Underground Direct Measurement Method for Coal Seam Gas Content".

[0035] In this Example 1, the arrangement of the five induced spraying boreholes 6 constructed in Step 2 is as follows: Four of the induced spraying boreholes 6 are arranged at the four corners of a square, and the fifth induced spraying borehole 6 is arranged at the diagonal center of the square formed by these four induced spraying boreholes 6; One air-force reaming borehole 5 is arranged at the center of each of the four side lines of the square formed by these four induced spraying boreholes 6, and one supplementary extraction borehole 8 is arranged at the center of the connection line between each of the four induced spraying boreholes 6 at the four corners of the square and the fifth induced spraying borehole 6 at the diagonal center, that is, the supplementary extraction borehole 8 is arranged at the overlapping center of two adjacent air-force reaming borehole pressure relief and permeability enhancement zones 7.

[0036] In this Embodiment 1, the distance between the blowout induction boreholes 6 is determined according to the specific conditions of the coal seam 2; a safety blowout guiding device is provided at the orifice of the blowout induction borehole 6; sufficient protection distance should be reserved for the blowout induction borehole 6, that is, the distance of the rock hole section between the floor rock roadway 4 and the coal-seeing point 10 should be greater than 10 m, and it can be appropriately increased when the lithology is poor.

[0037] Embodiment 2:

[0038] Refer to Figure 3 , Figure 3 A schematic diagram of the borehole layout of Embodiment 2 is drawn. As shown in the figure, a precise cutting method for the outburst energy unit of the thick coal zone in the coal mine structural area of this Embodiment 2 is different from that of Embodiment 1 in that, in this Embodiment 2, the positions of the wind-reaming boreholes 5 and the supplementary drainage boreholes 8 are swapped with those of the wind-reaming boreholes 5 and the supplementary drainage boreholes 8 in Embodiment 1, that is, the arrangement of the five blowout induction boreholes 6 constructed in Step 2 is as follows: Four of the blowout induction boreholes 6 are arranged at the four corners of a square, and the fifth blowout induction borehole 6 is arranged at the diagonal center of the square formed by these four blowout induction boreholes 6; One supplementary drainage borehole 8 is arranged at the center of each of the four side lines of the square formed by these four blowout induction boreholes 6; One wind-reaming borehole 5 is arranged at the center of the connection line between each of the four blowout induction boreholes 6 at the four corners of the square and the fifth blowout induction borehole 6 at the diagonal center.

[0039] Compared with the existing scheme of constructing dense boreholes without difference from the coal seam, for the precise cutting method of the outburst energy unit of the thick coal zone in the coal mine structural area of the present invention, after application, the borehole engineering quantity of the outburst energy unit of the thick coal zone in the structural area can be reduced by 40 - 60%, and the gas control period can be shortened by 45 - 65%, thus saving a great deal of manpower and resources to a large extent, improving the operation efficiency, and saving the operation cost.

[0040] The above are only specific application examples of the present invention and do not constitute any limitation to the protection scope of the present invention. Any technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of the protection of the rights of the present invention.

Claims

1. A precise cutting method for the outburst energy unit of the thick coal zone in the coal mine structural area, characterized in that: Construct parameter measurement boreholes (3), induced spraying boreholes (6), air-powered reaming boreholes (5) and supplementary drainage boreholes (8) below the coal seam (2) to eliminate outburst and drain gas from the thickening zone (1) near the fault. The specific steps are as follows: Step 1: Construct a parameter measurement borehole (3) from the floor rock roadway (4) to the coal seam (2) away from the thickening zone (1) near the fault, take samples to measure the coal seam gas content W1 not affected by the fault, and record the drill pipe torque T1 during drilling; Step 2: Construct multiple induced spraying boreholes (6) from the floor rock roadway (4) to the thickening zone (1) near the fault. When the borehole reaches the coal-seam encounter point (10), take samples to measure the coal seam gas content W2 and record the drill pipe torque T2; then switch to high-pressure explosion-proof gas slag removal for rapid drilling to suddenly expose the coal body, ensure successful induced spraying, and form an induced spraying borehole pressure relief and permeability enhancement zone (9); Step 3: Construct several cross-measurement boreholes as air-powered reaming boreholes (5) from the floor rock roadway (4) to the middle of the induced spraying boreholes (6) in Step 2, and conduct air-powered reaming from the coal seam roof to the floor from top to bottom to form an air-powered reaming borehole pressure relief and permeability enhancement zone (7); Step 4: Intersperse and construct several supplementary drainage boreholes (8) between the induced spraying boreholes (6) and air-powered reaming boreholes (5) constructed in Steps 2 and 3. When the borehole reaches the coal-seam encounter point (10), switch to high-pressure explosion-proof gas slag removal to reduce the phenomenon of borehole blockage and sticking; Step 5: Seal the induced spraying boreholes (6), air-powered reaming boreholes (5) and supplementary drainage boreholes (8) in sequence and connect the drainage pipeline, and reduce the gas pressure and gas content of the thickening zone (1) near the fault through gas drainage; Step 6: If the coal seam gas content W2 measured in Step 2 is greater than the coal seam gas content W1 measured by the parameter measurement borehole (3) in Step 1, and the drill pipe torque T2 in Step 2 is greater than the drill pipe torque T1 in Step 1, then repeat Steps 2 to 5 until all abnormal enrichment energies in the thickening zone (1) near the fault are eliminated.

2. The precise cutting method for the outburst energy unit of the thick coal zone in the coal mine structural area according to claim 1, characterized in that: The borehole layout of the multiple induced spraying boreholes (6) in Step 2 is arranged in a rectangular array, and an induced spraying borehole (6) is also arranged at the center of each rectangle.

3. The precise cutting method of the outburst energy unit in the thick coal zone of the coal mine structure area according to claim 1, characterized in that: The air-powered reaming boreholes (5) are evenly distributed among the multiple induced spraying boreholes (6), and the distance between adjacent two air-powered reaming boreholes (5) is the same.

4. The precise cutting method of the outburst energy unit in the thick coal zone of the coal mine structural area according to claim 1, characterized in that: The supplementary drainage boreholes (8) are evenly distributed between the induced spraying boreholes (6) and air-powered reaming boreholes (5), and the distance between adjacent two supplementary drainage boreholes (8) is the same.

5. The precise cutting method of the outburst energy unit of the thick coal zone in the coal mine structural area according to claim 1, characterized in that: A safety guiding spraying device is provided at the orifice of the induced spraying borehole (6).

6. The precise cutting method for the outburst energy unit of the thick coal zone in the coal mine structural area according to claim 1, characterized in that: A protection distance is reserved for the induced spraying borehole (6), that is, the distance of the rock hole section between the floor rock roadway (4) and the coal-seam encounter point (10) is greater than 10m.

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