Coal mining water and gas co-control system and construction method

Abstract

The present invention provides a coal mining water and gas co-control system, including at least one vertical borehole constructed from the ground to the aquifer adjacent to the first mining coal seam, and a horizontal grouting water plugging borehole in the aquifer connected to the vertical borehole, wherein the horizontal grouting water plugging borehole is at least one hole; and a first horizontal extraction borehole in the first mining coal seam connected to the vertical borehole; and a second horizontal extraction borehole in the overlying rock layer of the first mining coal seam connected to the vertical borehole. The advantages of the present invention are: by constructing a horizontal borehole through vertical ground drilling, coal mine gas control and water hazard control work are comprehensively completed, which is more efficient and more economical than constructing a gas control borehole and a groundwater control borehole separately.

Description

Technical Field

[0001] The present invention relates to the field of mineral resource development, and more specifically to a coal mining water and gas co-control system and a construction method. Background Art

[0002] In the process of underground coal resource mining, there are often threats from groundwater and gas. Before coal mining, drilling is often used to seal groundwater and extract gas respectively. The drilling is generally done on the ground or in underground tunnels. The use of vertical ground drilling for water blocking and gas extraction is safe, but the drilling work is large and the construction cost is high. However, drilling from underground tunnels has a small drilling work, but it is easy to cause blowout accidents, causing groundwater or gas to flow into the tunnels, and may even induce coal and gas outburst accidents, causing casualties and economic losses, and is highly dangerous. In addition, at present, gas extraction drilling is greatly affected by groundwater. The influx of groundwater into gas extraction drilling will reduce the effective airflow section of the extraction drilling, increase the extraction negative pressure loss, and thus reduce the efficiency of the gas extraction drilling or fail. Therefore, the existing coal mine groundwater and gas control technology is difficult to complete the water and gas control work in coal mining safely, economically and efficiently. Summary of the invention

[0003] The technical problem to be solved by the present invention is that under conditions of water and gas disasters, coal mining is highly dangerous, requires a large amount of work and has high construction costs. A water and gas co-control system and a construction method for coal mining are provided.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] A coal mining water and gas co-control system, comprising at least one vertical borehole constructed from the ground to an aquifer adjacent to a first-mined coal seam, and a horizontal grouting water plugging borehole in the aquifer connected to the vertical borehole, wherein the horizontal grouting water plugging borehole is at least one hole;

[0006] and a first horizontal extraction borehole in the first mining coal seam connected to the vertical borehole;

[0007] And a second horizontal extraction borehole connected to the vertical borehole located in the overlying rock strata of the first mining coal seam.

[0008] Preferably, it also includes: a third horizontal extraction borehole and a fourth horizontal extraction borehole which are sequentially opened in the coal seam above the first mining coal seam and the overlying rock stratum of the coal seam and are respectively connected to the vertical borehole.

[0009] Preferably, it also includes an auxiliary vertical extraction borehole; the bottom end of the auxiliary vertical extraction borehole is located in the coal seam.

[0010] A construction method for a coal mining water and gas co-control system comprises the following steps:

[0011] Grouting and water blocking construction steps: construct a vertical borehole from the ground to the aquifer adjacent to the first mining coal seam, then construct a horizontal grouting and water blocking borehole in the aquifer through directional drilling, inject water blocking materials into the horizontal grouting and water blocking borehole in the aquifer to block the groundwater in the aquifer;

[0012] The construction steps of gas extraction drilling are as follows: construct the first horizontal extraction drilling hole from the vertical drilling hole to the first mining coal seam, and construct the second horizontal extraction drilling hole from the vertical drilling hole to the overlying rock layer of the first mining coal seam;

[0013] The construction steps of gas pre-extraction and outburst elimination in the first mining coal seam are as follows: pre-extraction of gas in the first mining coal seam is carried out through horizontal extraction boreholes in the first mining coal seam to eliminate the outburst hazards in the first mining coal seam;

[0014] The construction steps for gas extraction from the first coal seam and pre-extraction of gas from the coal seam above it are: while mining the first coal seam, the gas released during the mining of the first coal seam is extracted through the second horizontal extraction borehole arranged in the overlying rock strata of the first coal seam. At the same time, the gas that flows into the overlying rock strata of the first coal seam due to the pressure relief caused by mining the first coal seam is extracted, that is, the upper coal seam is pre-extracted.

[0015] Preferably, according to the extraction effect of the second horizontal extraction borehole on the upper coal seam, a third horizontal extraction borehole may be constructed in the upper coal seam or a fourth horizontal extraction borehole in the overlying stratum of the upper coal seam may be constructed to carry out further gas extraction work.

[0016] Preferably, if the coal seam has poor permeability, high-pressure water can be injected into the coal seam extraction borehole, and the coal seam can be hydraulically fractured to increase the permeability before gas pre-extraction work is carried out.

[0017] The advantages of the present invention are:

[0018] 1. Through the construction of vertical ground drilling and horizontal drilling, the coal mine gas control and water hazard control work can be completed comprehensively. Compared with the construction of gas control drilling and groundwater control drilling separately, it is more efficient and economical;

[0019] 2. Through the joint control of water and gas, it provides safety guarantee and construction conditions for the joint mining of coal and gas;

[0020] 3. While mining one coal seam, the gas pre-extraction of the adjacent coal seams can be realized, eliminating the hidden dangers of the adjacent coal seams, thereby realizing gas control for all coal seams in turn, making coal and gas mining more efficient and more economical;

[0021] 4. By blocking groundwater, the impact of groundwater on gas extraction drilling holes is eliminated, and the efficiency of gas extraction work is improved;

[0022] 5. Through gas extraction, the coal seam is depressurized, the gas pressure in the coal seam is reduced, thereby reducing the formation pressure. Combined with grouting water blocking measures, the hidden danger of groundwater intrusion into the underground working area of ​​the coal mine is eliminated;

[0023] 6. By constructing gas control drilling holes and water hazard control drilling holes from the ground, the ground construction site occupies a small area, the construction site and equipment layout are convenient and flexible, and the impact on the surrounding buildings and environment on the ground is relatively small;

[0024] 7. The present invention has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention. DETAILED DESCRIPTION

[0026] In order to have a further understanding and recognition of the structural features and the effects achieved by the present invention, a preferred embodiment and accompanying drawings are used for detailed description as follows:

[0027] like Figure 1 As shown, a coal mining water and gas co-control system includes at least one vertical borehole 2 constructed from the ground 1 to the aquifer 3 adjacent to the first mining coal seam 5, and a horizontal grouting water plugging borehole 4 in the aquifer 3 connected to the vertical borehole 2, wherein the horizontal grouting water plugging borehole 4 is at least one hole; and a first horizontal extraction borehole 6 in the first mining coal seam 5 connected to the vertical borehole 2; and a second horizontal extraction borehole 7 in the overlying stratum of the first mining coal seam 5 connected to the vertical borehole 2.

[0028] To ensure safety, a third horizontal extraction borehole 9 and a fourth horizontal extraction borehole 10 connected to the vertical borehole 2 may be opened in the coal seam 8 above the first mining coal seam 5 and the overlying rock stratum of the coal seam, respectively.

[0029] Furthermore, the extraction effect can be ensured by opening an auxiliary vertical extraction borehole 11; the bottom end of the auxiliary vertical extraction borehole 11 is located in the coal seam.

[0030] A construction method for a coal mining water and gas co-control system comprises the following steps:

[0031] Grouting water blocking construction steps: construct a vertical borehole 2 from the ground 1 to the aquifer 3 adjacent to the first mining coal seam 5, then construct a horizontal grouting water blocking borehole 4 in the aquifer 3 by directional drilling, and inject water blocking material into the horizontal grouting water blocking borehole 4 to block the groundwater in the aquifer;

[0032] Gas extraction drilling construction steps: constructing a first horizontal extraction drilling hole 6 from the vertical drilling hole 2 to the first mining coal seam 5, and constructing a second horizontal extraction drilling hole 7 from the vertical drilling hole 2 to the overlying rock layer of the first mining coal seam 5;

[0033] The construction steps of gas pre-extraction and outburst elimination in the first mining coal seam 5 are as follows: the gas stored in the first mining coal seam 5 is pre-extracted through the horizontal extraction borehole 6 in the first mining coal seam 5 to eliminate the outburst hazard of the first mining coal seam 5;

[0034] The construction steps of gas extraction from the first coal seam 5 and pre-extraction of gas from the coal seam above it are as follows: while mining the first coal seam 5, the gas released during the mining of the first coal seam 5 is extracted through the second horizontal extraction borehole 7 arranged in the rock stratum overlying the first coal seam 5. At the same time, the gas that flows into the rock stratum overlying the first coal seam 5 due to the pressure relief during mining of the first coal seam 5 is extracted, that is, the upper coal seam is pre-extracted.

[0035] According to the extraction effect of the second horizontal extraction borehole 7 on the upper coal seam, a third horizontal extraction borehole 9 may be constructed in the upper coal seam 8 or a fourth horizontal extraction borehole 10 in the overlying stratum of the upper coal seam may be selected to carry out further gas extraction work.

[0036] If the permeability of the coal seam is poor, high-pressure water can be injected into the coal seam extraction borehole, and the coal seam can be hydraulically fractured to increase the permeability before gas pre-extraction work can be carried out.

[0037] The size of the water plugging and gas extraction area can be determined according to the needs. One vertical borehole and several horizontal extraction boreholes connected to it can be selected to complete the water plugging and gas extraction work alone, or multiple vertical boreholes and several horizontal boreholes connected to them can be used to complete the water plugging and gas extraction work;

[0038] According to the gas extraction effect of the horizontal drilling, it is possible to select to construct auxiliary vertical extraction drilling holes 11 from the ground to the coal seam to extract coal seam gas, thereby further improving the coal seam outburst elimination and gas extraction effects;

[0039] The construction sequence of grouting water blocking and coal and gas co-mining can be flexibly arranged according to the geological conditions of the construction site. After completing the water blocking work, gas extraction work can be carried out on each coal seam in turn.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A coal mining water and gas co-control system, characterized by: The invention comprises at least one vertical borehole (2) constructed from the ground (1) to an aquifer (3) adjacent to a first-mined coal seam (5), and a horizontal grouting water-blocking borehole (4) in the aquifer (3) connected to the vertical borehole (2), wherein the horizontal grouting water-blocking borehole (4) is at least one hole; and a first horizontal extraction borehole (6) in the first-mined coal seam (5) connected to the vertical borehole (2); and a second horizontal extraction borehole (7) in the overlying stratum of the first-mined coal seam (5) connected to the vertical borehole (2); and a third horizontal extraction borehole (9) and a fourth horizontal extraction borehole (10) are sequentially opened in the coal seam above the first-mined coal seam (5) and the overlying stratum of the coal seam, respectively connected to the vertical borehole (2).

2. A coal mining water and gas co-control system according to claim 1, characterized in that: It also includes an auxiliary vertical extraction borehole (11); the bottom end of the auxiliary vertical extraction borehole (11) is located in the coal seam.

3. A method for the co-control of water and gas in coal mining, characterized by: The co-governance system applied to any one of claims 1 to 2 comprises the following steps: Grouting water blocking construction steps: constructing a vertical borehole (2) from the ground (1) to an aquifer (3) adjacent to the first mining coal seam (5), then constructing a horizontal grouting water blocking borehole (4) in the aquifer (3) by directional drilling, and injecting water blocking material into the horizontal grouting water blocking borehole (4) to block groundwater in the aquifer; The gas extraction drilling construction steps are as follows: constructing a first horizontal extraction drilling hole (6) from the vertical drilling hole (2) toward the first mining coal seam (5), and constructing a second horizontal extraction drilling hole (7) from the vertical drilling hole (2) toward the overlying rock layer of the first mining coal seam (5); The construction steps of pre-extraction and outburst elimination of gas in the first mining coal seam (5) are as follows: pre-extraction of gas stored in the first mining coal seam (5) is performed through the first horizontal extraction borehole (6) of the first mining coal seam (5) to eliminate the outburst hazard of the first mining coal seam (5); The construction steps of gas extraction from the first coal seam (5) and pre-extraction of gas from the coal seam above it are as follows: while mining the first coal seam (5), the gas released during the mining of the first coal seam (5) is extracted through a second horizontal extraction borehole (7) arranged in the overlying strata of the first coal seam (5). At the same time, the gas that flows into the overlying strata of the first coal seam (5) due to the pressure relief during mining of the first coal seam (5) is extracted from the coal seam above it, i.e., pre-extraction of the upper coal seam is performed.

4. A method for co-controlling coal mining water and gas according to claim 3, characterized in that: According to the extraction effect of the second horizontal extraction borehole (7) on the upper coal seam, a third horizontal extraction borehole (9) can be constructed in the upper coal seam or a fourth horizontal extraction borehole (10) in the overlying stratum of the upper coal seam can be selected to carry out further gas extraction work.

5. A method for co-controlling coal mining water and gas according to claim 3, characterized in that: If the permeability of the coal seam is poor, high-pressure water is injected into the coal seam extraction borehole to perform hydraulic fracturing on the coal seam to increase the permeability, and then gas pre-extraction work is carried out.

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