1. A gas injection displacement coal seam gas extraction-promoting coal seam gas drilling arrangement method is characterized by comprising the following steps:

s1: selecting a mode for implementing gas injection displacement according to the conditions of the coal seam and the actual situation on site;

s2: selecting a region for implementing gas injection and coal bed gas displacement, and drilling extraction holes and gas injection holes in the region;

s3: sealing the extraction hole and the gas injection hole;

s4: and connecting the gas injection hole to a high-pressure gas injection system, and connecting the extraction hole to an extraction system for implementing gas injection displacement.

2. The method according to claim 1, wherein in step S1, if a bottom drainage roadway exists in the coal mine, the gas injection displacement mode is a bottom drainage roadway displacement injection-drainage drilling fan-shaped arrangement mode, the bottom drainage roadway displacement injection-drainage drilling fan-shaped arrangement mode is a plurality of hole groups, each hole group includes the extraction gas injection hole and a plurality of the extraction gas injection holes, and the extraction holes are located between adjacent gas injection holes.

3. The gas injection displacement coal seam gas extraction-promoting drill hole arrangement method according to claim 2, wherein in the step S3, for a bottom suction roadway displacement injection and extraction drill hole fan-shaped arrangement mode, full-rock section hole sealing is performed on the extraction holes and the gas injection holes.

4. The gas injection displacement coal seam gas extraction-promoting drill hole arrangement method according to claim 1, wherein in the step S1, if a bottom extraction roadway does not exist in the coal mine and the thickness of the coal seam along the working face is less than 3.5m, a single-row parallel arrangement mode of coal seam injection and extraction drill holes is selected, the single-row parallel arrangement mode of coal seam injection and extraction drill holes is a plurality of hole groups, the plurality of hole groups are arranged at intervals along the direction of the working face along the groove, each hole group comprises a plurality of extraction holes and gas injection holes, the plurality of extraction holes are arranged at intervals along the direction of the working face along the groove, and the gas injection holes are arranged between adjacent extraction holes.

5. The gas injection displacement coal seam gas extraction-promoting drill hole arrangement method according to claim 1, wherein in the step S1, if a coal mine has no bottom drainage roadway and the thickness of the coal seam along the working face is greater than 3.5m, a coal seam injection-extraction drill hole double-row parallel arrangement mode is selected, the coal seam injection-extraction drill hole double-row parallel arrangement mode comprises a plurality of hole groups, the plurality of hole groups are arranged at intervals along the trend of the working face along the working face, and the plurality of hole groups comprise a plurality of extraction holes and gas injection holes.

The extraction holes comprise a plurality of first extraction holes and a plurality of second extraction holes, the first extraction holes and the second extraction holes are arranged in a double row mode, the first extraction holes are arranged along the direction of the working face crossheading at intervals, and the second extraction holes are arranged along the direction of the working face crossheading at intervals.

The extraction holes are located between the adjacent first extraction holes, or the extraction holes are located between the adjacent second extraction holes.

6. The gas injection displacement coal seam gas extraction-promoting drill hole arrangement method according to any one of claims 1-5, wherein in the step S3, the gas injection and extraction drill hole needs to ensure a sufficient hole sealing length to ensure the air tightness of the drill hole.

7. The gas injection displacement coal seam gas extraction-promoting drilling arrangement method according to any one of claims 1-5, wherein in the step S3, a steel pipe is additionally arranged at the orifice of the gas injection hole to facilitate connection with a gas injection pipeline, and the orifice of the gas injection hole is ensured to be safe during gas injection.

8. The gas injection displacement coal seam gas extraction promoting drill hole arrangement method according to any one of claims 1-5, wherein in the step S4, the extraction holes are converged through a pipeline, and the confluence pipeline is connected to the total extraction system.

9. The gas injection displacement coal seam gas extraction promoting drill hole arrangement method according to any one of claims 1-5, wherein the high pressure gas in the high pressure gas injection system is any one of air, nitrogen and carbon dioxide or any one of a mixture of at least two of the air, the nitrogen and the carbon dioxide.

Background

Along with the continuous extension of coal mine excavation towards deep level, the difficulty of gas treatment by means of conventional gas extraction and permeability-increasing technical measures taking coal bed modification as a premise is increased continuously, the treatment process needs to be greatly improved under the influence of occurrence conditions of the coal bed, and the problems of high technical difficulty, high cost investment and the like exist.

By using the oil reservoir displacement experience for reference, a method for displacing coal bed gas by gas injection is provided. However, in the related art, a complete set of technical standards and reference specifications for gas injection, displacement and coal bed gas extraction promotion are lacked, and especially a drilling hole arrangement method is yet to be verified.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

Therefore, the embodiment of the invention provides a gas injection displacement coal seam gas extraction promoting coal seam gas drilling arrangement method which aims at different coal seam occurrence conditions and extraction processes, is simple in process and wide in applicability.

The gas injection displacement coal seam gas extraction-promoting coal seam gas drilling hole arrangement method comprises the following steps: s1: selecting a mode for implementing gas injection displacement according to the conditions of the coal seam and the actual situation on site; s2: selecting a region for implementing gas injection and coal bed gas displacement, and drilling extraction holes and gas injection holes in the region; s3: sealing the extraction hole and the gas injection hole; s4: and connecting the gas injection hole to a high-pressure gas injection system, and connecting the extraction hole to an extraction system for implementing gas injection displacement.

According to the gas injection displacement coal seam gas extraction-promoting coal seam gas drilling arrangement method provided by the embodiment of the invention, according to the steps S1, S2, S3 and S4, the gas injection displacement coal seam gas extraction-promoting coal seam gas injection production drilling arrangement design and construction under different conditions can be guided, and technical reference and standard guidance are provided for large-scale application of a displacement process.

In some embodiments, in step S1, if a bottom suction lane exists in the coal mine, the gas injection displacement mode is a bottom suction lane displacement injection-extraction drilling fan-shaped arrangement mode, the bottom suction lane displacement injection-extraction drilling fan-shaped arrangement mode is a plurality of hole groups, each hole group includes the extraction hole and a plurality of gas injection holes, and the extraction holes are located between adjacent gas injection holes.

In some embodiments, in step S3, for the bottom suction roadway displacement injection-extraction drill hole sector arrangement, the extraction hole and the gas injection hole are subjected to full-section hole sealing.

In some embodiments, in step S1, if there is no bottom drainage roadway in the coal mine and the thickness of the coal seam in the working face crossheading is less than 3.5m, a single-row parallel arrangement manner of coal seam injection and drainage drill holes is selected, the single-row parallel arrangement manner of coal seam injection and drainage drill holes is a plurality of hole groups, the plurality of hole groups are arranged at intervals along the heading of the working face crossheading, each hole group includes a plurality of extraction holes and a plurality of gas injection holes, the plurality of extraction holes are arranged at intervals along the heading of the working face crossheading, and the gas injection holes are arranged between adjacent extraction holes.

In some embodiments, in step S1, if there is no draw-down lane in the coal mine and the thickness of the coal seam along the working face is greater than 3.5m, a double-row parallel arrangement of injection-draw drilling holes of the coal seam is selected. The double-row parallel arrangement mode of the coal seam injection and extraction drill hole comprises a plurality of hole groups, the hole groups are arranged along the direction of the working face crossheading at intervals, the hole groups comprise a plurality of extraction holes and gas injection holes, the extraction holes comprise a plurality of first extraction holes and a plurality of second extraction holes, the first extraction holes and the second extraction holes are arranged in a double-row mode, the first extraction holes are arranged along the direction of the working face crossheading at intervals, the second extraction holes are arranged in a multiple mode, the extraction holes are located between the adjacent first extraction holes, or the extraction holes are located between the adjacent second extraction holes.

In some embodiments, in step S3, the injection and extraction drill holes need to ensure a sufficient hole sealing length to ensure the air tightness of the drill holes.

In some embodiments, in step S3, a steel pipe is added to the gas injection hole to facilitate connection with the gas injection pipeline, and to ensure the safety of the gas injection hole during gas injection.

In some embodiments, in step S4, the extraction holes are merged by a pipeline, and a manifold is connected to the total extraction system.

In some embodiments, the high pressure gas in the high pressure gas injection system is any one of air, nitrogen and carbon dioxide or any mixture of at least two of the air, the nitrogen and the carbon dioxide.

Drawings

FIG. 1 is a flow chart of a gas injection displacement enhanced coal seam gas drilling arrangement method according to an embodiment of the invention.

Fig. 2 is a partial schematic view of a fan-shaped arrangement mode of a bottom drainage roadway displacement injection-drainage borehole of the gas injection-displacement coal seam gas-drainage-promoting borehole arrangement method according to the embodiment of the invention.

Fig. 3 is a sectional schematic view of a drilling final hole of a bottom drainage roadway displacement injection-drainage drilling fan-shaped arrangement mode of the gas injection-displacement coal seam gas-drainage-promoting drilling arrangement method according to the embodiment of the invention.

Fig. 4 is a partial schematic view of a coal seam injection-drainage borehole single-row parallel arrangement mode of the gas injection-displacement coal seam gas-drainage-promoting borehole arrangement method according to the embodiment of the invention.

Fig. 5 is a partial schematic view of a double-row parallel arrangement manner of coal seam injection-drainage drill holes in the gas injection displacement coal seam gas-drainage-promoting drill hole arrangement method according to the embodiment of the invention.

Reference numerals:

a bottom suction lane 1; a working surface gate 2; extracting holes 3; a first extraction hole 31; a second extraction hole 32; and a gas injection hole 4.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The following describes a gas injection displacement coal seam gas extraction promoting drilling hole arrangement method according to an embodiment of the invention with reference to the accompanying drawings.

As shown in fig. 1 to 5, the gas injection displacement coal seam gas extraction-promoting coal seam gas drilling arrangement method according to the embodiment of the invention comprises the following steps:

s1: and selecting a mode for implementing gas injection displacement according to coal seam occurrence conditions and field actual conditions. Specifically, different gas injection displacement modes are selected according to whether the bottom suction roadway 1 exists in the mine or not or the thickness of the coal seam exists in the mine.

S2: selecting a region for implementing gas injection displacement to promote coal seam gas extraction, and drilling extraction holes 3 and gas injection holes 4 in the region. Specifically, the implementation area may be a designated area or an area with a large gas content, and the extraction hole 3 and the gas injection hole 4 are drilled in the area, where the gas injection hole 4 is used for injecting high-pressure gas, and the displaced gas is extracted through the extraction hole 3.

S3: and sealing the extraction hole 3 and the gas injection hole 4. Therefore, the sealing of the gas injection hole 4 and the gas extraction hole 3 is guaranteed.

S4: and connecting the gas injection hole 4 to a high-pressure gas injection system, and connecting the extraction hole 3 to an extraction system for implementing gas injection displacement. Therefore, the high-pressure gas injection system injects high-pressure gas into the coal seam through the gas injection hole 4, and the extraction system extracts the displaced gas mixture through the extraction hole 3.

According to the gas injection displacement coal seam gas drilling arrangement method, through the steps S1, S2, S3 and S4, gas in the coal seam can be displaced and extracted, and technical references and specification guidance are provided for large-scale application of a displacement process.

In some embodiments, in step S1, if the coal mine has a bottom suction lane 1, the gas injection displacement mode is a bottom suction lane displacement injection-extraction drilling fan-shaped arrangement mode, the bottom suction lane displacement injection-extraction drilling fan-shaped arrangement mode is a plurality of hole groups, each hole group includes an extraction hole 3 and a plurality of gas injection holes 4, and the extraction holes 3 are located between adjacent gas injection holes 4.

Specifically, as shown in fig. 2-3, the fan-shaped arrangement manner of the bottom suction roadway displacement injection and suction drill holes is a plurality of hole groups, each hole group includes one gas injection hole 4 and two extraction holes 3, and the gas injection hole 4 is located between the two extraction holes 3. Because the fan-shaped arrangement mode of the bottom suction roadway displacement injection and suction drill holes can cover the whole area of the selected drill holes, the gas injection displacement gas extraction promoting efficiency is improved.

In some embodiments, in step S3, for the bottom suction roadway displacement injection-suction drilling fan-shaped arrangement, the extraction holes 3 and the gas injection holes 4 ensure the sealing of the whole rock section. The bottom pumping roadway 1 is a floor roadway and is positioned on a rock stratum below a coal seam. Therefore, when the extraction hole 3 and the gas injection hole 4 are sealed, the whole-rock-section sealing needs to be guaranteed, the air tightness of the drilled hole during gas injection and pumping promotion is guaranteed, and the gas pumping promotion efficiency is improved.

In some embodiments, in step S1, if the coal mine does not have the bottom drainage roadway 1 and the thickness of the coal seam in the working face gateway 2 is less than 3.5m, a single-row parallel arrangement manner of coal seam injection and drainage drill holes is selected, the single-row parallel arrangement manner of coal seam injection and drainage drill holes is a plurality of hole groups, the plurality of hole groups are arranged at intervals along the direction (the left and right direction shown in fig. 4) of the working face gateway 2, each hole group includes a plurality of extraction holes 3 and gas injection holes 4, the plurality of extraction holes 3 are arranged at intervals along the direction of the working face gateway 2, and the gas injection holes 4 are arranged between adjacent extraction holes 3.

Specifically, as shown in fig. 4, the drilling construction is selected on the working face crossheading 2, the drilling and trepanning layer is selected in the middle of the coal seam, a plurality of hole groups are arranged at intervals along the coal seam direction, each hole group comprises one gas injection hole 4 and two extraction holes 3, the gas injection hole 4 is located between the two extraction holes 3, and the two extraction holes 3 and the gas injection hole 4 are arranged at intervals along the direction of the working face crossheading 2. The coal seam drilling arrangement adopts a parallel design, so that one gas injection hole 4 serves two extraction holes 3, and the gas injection displacement efficiency is improved.

It can be understood that the distance between the gas injection hole 4 and the extraction hole 3 and the drilling parameters in the coal seam injection and extraction drill hole single-row parallel arrangement mode are not limited and can be adjusted according to actual conditions.

In some embodiments, in step S1, if the coal mine has no bottom drainage roadway 1 and the thickness of the coal seam in the working face gateway 2 is greater than 3.5m, a double-row parallel arrangement of injection-drainage drilling holes of the coal seam is selected. The double-row parallel arrangement mode of the coal seam injection and extraction drill holes comprises a plurality of hole groups, the plurality of hole groups are arranged at intervals along the direction of the working face crossheading 2, the plurality of hole groups comprise a plurality of extraction holes 3 and gas injection holes 4, the extraction holes 3 comprise a plurality of first extraction holes 31 and a plurality of second extraction holes 32, the plurality of first extraction holes 31 and the plurality of second extraction holes 32 are arranged in a double-row mode, the plurality of first extraction holes 31 are arranged at intervals along the direction (the left and right direction shown in figure 5) of the working face crossheading 2, the plurality of second extraction holes 32 are arranged at intervals along the direction of the working face crossheading 2, and the gas injection holes 4 are located between any one of the adjacent first extraction holes 31 and the adjacent second extraction holes 32.

Specifically, as shown in fig. 5, the drilling construction is located in the working face crossheading 2, the height of a drilled hole is determined according to the roadway height and the drilling machine capacity, a plurality of hole groups are arranged at intervals along the direction of the working face crossheading 2, the plurality of hole groups include four extraction holes 3 and one gas injection hole 4, the four extraction holes 3 include two first extraction holes 31 and two second extraction holes 32, the two first extraction holes 31 and the two second extraction holes 32 are arranged in double rows, the two first extraction holes 31 are arranged at intervals along the direction of the working face crossheading 2, the two second extraction holes 32 are arranged at intervals along the direction of the working face crossheading 2, the gas injection hole 4 is located between the two first extraction holes 31, and the gas injection hole 4 and the two first extraction holes 31 are arranged at intervals along the direction of the working face crossheading 2. Therefore, double rows of gas injection holes 4 and extraction holes 3 which are staggered up and down are arranged on the working face crossheading 2, four extraction holes 3 are radiated around one gas injection hole 4, the distance between each extraction hole 3 and each gas injection hole 4 in the group is guaranteed to be equal by changing the drilling inclination angle parameter, and the gas injection displacement efficiency is improved.

It is worth explaining that the gas injection displacement coal seam gas extraction promoting drill hole arrangement method of the embodiment of the invention obtains that the fan-shaped arrangement mode of the bottom drainage roadway displacement injection and extraction drill hole, the single-row parallel arrangement mode of the coal seam injection and extraction drill hole and the double-row parallel arrangement mode of the coal seam injection and extraction drill hole are feasible through the field verification of the inventor through the practical application of the inventor, and compared with the gas extraction in the related technology, the method for displacing the coal seam gas has the advantages of low investment cost, small technical difficulty and high gas extraction efficiency.

It can be understood that the distance between the gas injection hole 4 and the extraction hole 3 and the drilling parameters in the double-row parallel arrangement mode of the coal seam injection and extraction drill hole in the embodiment of the invention are not limited, and can be adjusted according to actual conditions. In the adjacent hole groups, the gas injection hole 4 of one hole group is positioned between the two first extraction holes 31, and the gas injection hole 4 of the other hole group is positioned between the two second extraction holes 32, so that the blank zone influenced by gas injection displacement is reduced, and the gas yield of the coal seam promoted by displacement is increased.

In some embodiments, in step S3, the injection and extraction drill holes need to ensure a sufficient hole sealing length to ensure the air tightness of the drill holes. As the coal body has crack growth in the process of tunneling and anchoring the underground tunnel, in order to ensure that the crack area of the coal tunnel along the wall surface towards the direction of the coal body is sealed and the sealing performance of the drill hole is improved, the injection-extraction drill hole needs to ensure the hole sealing distance with a certain length.

In some embodiments, in step S3, a steel pipe is added to the orifice of the gas injection hole 4 to facilitate connection with an external gas injection pipeline, and to ensure the safety of the orifice when the gas injection hole 4 injects gas. Since high-pressure gas is injected into the gas injection hole 4, the orifice pressure of the gas injection hole 4 becomes excessively high. Therefore, the pressure-resistant steel pipe is arranged at the orifice of the gas injection hole 4, and the pressure-resistant performance of the orifice of the gas injection hole 4 is improved.

In some embodiments, in step S4, the extraction holes 3 are confluent via a pipeline, and the confluence pipe is connected to the extraction system. Therefore, the communication between the extraction hole 3 and an extraction system is realized, and the method is used for extracting the displaced gas out of the coal bed.

In some embodiments, the high pressure gas in the high pressure gas injection system is any one of air, nitrogen and carbon dioxide or any mixture of at least two of air, nitrogen and carbon dioxide. Specifically, the high-pressure gas may be air, nitrogen, carbon dioxide (or liquid CO)₂) And mixing the three in different proportions, or mixing nitrogen and carbon dioxide in different proportions. Thereby, at the same time, consisting ofThe nitrogen and the carbon dioxide have inertia, and the spontaneous combustion of the coal bed can be further prevented and controlled while the gas is displaced by injecting the coal bed.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.