A method for enhancing gas extraction by gas injection displacement in structurally developed coal seams

Abstract

The present invention relates to the technical field of mine gas control, and in particular to a method for gas injection displacement to strengthen gas extraction in a structurally developed coal seam, comprising: constructing a connecting borehole at a preset distance from the structure; sealing a gas injection pipe into the connecting borehole; constructing gas injection holes in the direction of the structure before and after the structure, and connecting the gas injection holes and the connecting borehole; sealing the gas injection holes; constructing gas extraction holes, and sealing the gas extraction holes into the gas injection holes; connecting the gas injection pipe at the gas injection hole orifice in parallel to the gas outlet of an underground air compressor, and promoting gas extraction by gas injection displacement in the coal seam. The gas injection holes at both ends of the structure are connected to ensure that the gas injected at one end of the gas injection hole can bypass the structure and flow into the gas injection hole behind the structure, thereby increasing the influence range of the gas injection hole, and utilizing the combined effect of directional drilling and connecting boreholes to ensure that the gas injection channel bypasses the structurally developed area, thereby realizing that the gas injection displacement technology can be applied in the structurally developed coal seam, improving the applicability of the gas injection displacement technology, and reducing the number of underground gas injection ports.

Description

Technical Field

[0001] The present application relates to the technical field of mine gas control, and in particular to a method for gas injection and displacement intensification of gas extraction in structurally developed coal seams. Background Art

[0002] Gas is a mixed gas with methane as the main component. It is the first of the five major disasters that affect the safe and efficient production of coal mines. It is also a clean energy with high calorific value and clean properties. Gas extraction is the most direct, effective and practical way to control gas, and it is also an effective way to obtain clean energy.

[0003] Gas injection displacement gas extraction technology not only increases the internal gas pressure of the coal body and improves the seepage velocity of mixed gas, but also reduces the effective partial pressure of gas and promotes the desorption of adsorbed gas. It has been applied in many mining areas in recent years. However, in some coal seams, there are structural developments such as faults, collapse columns or folds, which cause leakage of injected gas or conduction with extraction boreholes, making gas injection displacement technology extremely ineffective or even unusable under changed geological conditions.

[0004] In summary, there is an urgent need for a method of gas injection displacement to enhance gas extraction in tectonic coal seams to specifically address the problem of poor applicability of gas injection displacement technology in tectonic coal seams. Summary of the invention

[0005] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0006] To this end, the first purpose of this application is to propose a method for gas injection and displacement to enhance gas extraction in structurally developed coal seams, so as to solve the problems of existing technical means such as leakage of injected gas from structurally developed coal seams or connection between gas injection holes and extraction holes due to structure.

[0007] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a method for gas injection displacement and enhanced gas extraction in a structurally developed coal seam, comprising:

[0008] Construct connecting boreholes at a preset distance from the structure;

[0009] sealing the gas injection pipe into the connecting borehole;

[0010] Before and after the construction, gas injection holes are constructed in the construction direction respectively, and the gas injection holes are connected with the connection drilled holes;

[0011] sealing the gas injection holes;

[0012] constructing a gas extraction hole, and sealing the gas extraction hole into the gas injection hole;

[0013] The gas injection pipe at the gas injection hole is connected in parallel to the gas outlet of the underground air compressor to inject gas into the coal seam to promote gas extraction.

[0014] Preferably, constructing a connecting borehole at a preset distance from the structure includes: the opening position of the connecting borehole is a mining tunnel, the borehole azimuth is perpendicular to the mining tunnel, and the connecting borehole is generated by mechanical hole making or hydraulic punching hole making.

[0015] Preferably, the hole making length is greater than 2 m, the hole making radius is greater than 0.5 m, and the number of the holes is determined according to the number of the gas injection holes.

[0016] Preferably, sealing the gas injection pipe into the connecting borehole comprises:

[0017] The gas injection pipe is sealed into the connecting borehole using the pressure sealing method, in which the grouting liquid is expansive cement and the sealing length is greater than 30m.

[0018] Preferably, constructing gas injection holes in the construction direction before and after the construction, and connecting the gas injection holes with the connecting drilled holes comprises:

[0019] The gas injection holes are located in the lower 1 / 3 of the coal seam and are evenly distributed in the working face. The number of gas injection holes and the horizontal distance to the tunnel are the same before and after the structure. The gas injection holes are constructed and connected to each other within 50m from the structure.

[0020] Preferably, the sealing of the gas injection holes comprises: using expansion cement to completely seal the drilled holes at one end of the gas injection holes before and after construction, and using a pressure sealing method to seal the gas injection pipe at the other end, and the sealing length is greater than 30m.

[0021] Preferably, constructing a gas extraction hole and sealing the gas extraction hole into the gas injection hole comprises: sealing the extraction pipe of the gas extraction hole into the gas injection hole by using a pressure sealing method, wherein the grouting liquid is expansive cement.

[0022] Preferably, the connecting borehole is constructed at a preset distance from the structure, and the preset distance is 20-50m.

[0023] Preferably, a throttle valve, a flow sensor and a pressure sensor are installed on the gas injection pipe between the two boreholes.

[0024] Preferably, the method of connecting the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor to inject gas into the coal seam to promote gas extraction includes:

[0025] Connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor, connect the extraction pipe to the extraction system, turn on the air compressor, inject gas with a pressure of more than 0.8MPa into the gas injection hole, and carry out coal seam gas injection to promote gas extraction.

[0026] The present application provides a method for gas injection and displacement intensified gas extraction in a structurally developed coal seam, which comprises the following steps: constructing a connecting borehole at a preset distance from the structure and sealing a gas injection pipe into the connecting borehole, constructing gas injection holes in the direction of the structure before and after the structure, and sealing the gas injection holes after connecting the gas injection holes to the connecting boreholes, starting to construct gas extraction holes and sealing the gas extraction holes into the gas injection holes, connecting the gas injection pipes at the gas injection hole openings in parallel to the gas outlet of an underground air compressor, and promoting gas extraction by gas injection displacement in the coal seam. Directional drilling technology is used to bypass the structurally developed area, so that the gas injection boreholes before and after the structural development can be connected, thereby reducing the number of underground gas injection openings and avoiding the laying of long underground pipelines.

[0027] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 A flow chart of a first specific embodiment of a method for enhanced gas extraction in a structurally developed coal seam by gas injection displacement provided by the present invention;

[0030] Figure 2 Schematic diagram of gas injection and displacement method for enhanced gas extraction in structurally developed coal seams;

[0031] Figure 3 A schematic diagram of the front and rear connection holes of the gas injection pipe connection structure;

[0032] Figure 4 Schematic diagram of the relative position of the gas injection hole and the fault;

[0033] Figure 5 This is a schematic diagram of gas injection through the gas injection hole;

[0034] Among them, there are the main tunnel of the panel area 1, the recovery tunnel 2, the directional drill hole 3, the hole 4, the connecting drill hole 5, the structure 6, the gas injection pipe 7, the directional drilling rig 8, the air compressor 9, the throttle valve 10, the flow sensor 11, the pressure sensor 12, and the extraction hole 13. DETAILED DESCRIPTION

[0035] The core of the present invention is to provide a method for gas injection displacement to enhance gas extraction in structurally developed coal seams, which uses directional drilling technology to bypass the structural development area, so that the gas injection boreholes before and after the structural development can be connected, the number of underground gas injection ports can be reduced, and the laying of long underground pipelines can be avoided.

[0036] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] Please refer to Figure 1 , Figure 1 This is a flow chart of a first specific embodiment of a method for gas injection displacement and enhanced gas extraction in a structurally developed coal seam provided by the present invention; the specific operation steps are as follows:

[0038] Step S101: constructing a connection borehole at a preset distance from the structure;

[0039] The opening position of the connecting borehole is the mining roadway, the borehole azimuth is perpendicular to the mining roadway, and the connecting borehole is formed by mechanical hole making or hydraulic punching hole making;

[0040] The hole making length is greater than 2m, the hole making radius is greater than 0.5m, and the number of the holes is determined according to the number of the gas injection holes;

[0041] The connecting borehole is constructed at a preset distance from the structure, and the preset distance is 20-50m.

[0042] Step S102: sealing the gas injection pipe into the connecting borehole;

[0043] The gas injection pipe is sealed into the connecting borehole using the pressure sealing method, in which the grouting liquid is expansive cement and the sealing length is greater than 30m.

[0044] Step S103: constructing gas injection holes in the construction direction before and after the construction, and connecting the gas injection holes with the connecting drilled holes;

[0045] The gas injection holes are located in the lower 1 / 3 of the coal seam and are evenly distributed in the working face. The number of gas injection holes and the horizontal distance to the tunnel are the same before and after the structure. The gas injection holes are constructed and connected to each other within 50m from the structure.

[0046] Step S104: sealing the gas injection holes;

[0047] The gas injection holes before and after the construction are completely blocked at one end with expansion cement, and the gas injection pipe is sealed at the other end with pressure sealing method, and the sealing length is greater than 30m.

[0048] Step S105: constructing a gas extraction hole, and sealing the gas extraction hole into the gas injection hole;

[0049] The extraction pipe of the gas extraction hole is sealed into the gas injection hole by using a pressure sealing method, wherein the grouting liquid is expansive cement.

[0050] Step S106: Connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor to inject gas into the coal seam to promote gas extraction.

[0051] A throttle valve, a flow sensor and a pressure sensor are installed on the gas injection pipe.

[0052] Connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor, connect the extraction pipe to the extraction system, turn on the air compressor, inject gas with a pressure of more than 0.8MPa into the gas injection hole, and carry out coal seam gas injection to promote gas extraction.

[0053] The present embodiment provides a method for strengthening gas extraction by gas injection in a structurally developed coal seam. The method comprises the following steps: connecting drillers through construction, sealing a gas injection pipe into a connecting borehole by a "two blocking and one injection" method, constructing a gas injection hole, connecting the gas injection hole to the connecting borehole, sealing the gas injection pipe, starting to construct a gas extraction hole and sealing the gas extraction hole into the gas injection hole, connecting the gas injection pipe at the gas injection hole orifice in parallel to the gas outlet of an underground air compressor, and promoting gas extraction by gas injection in the coal seam. Directional drilling technology is used to bypass the structurally developed area, so that the gas injection boreholes before and after the structural development can be connected, thereby reducing the number of underground gas injection ports and avoiding the laying of long underground pipelines.

[0054] Based on the above embodiment, this embodiment describes a method for enhancing gas extraction in a structurally developed coal seam by gas injection displacement. Figure 2 As shown, the details are as follows:

[0055] Connection drilling construction: The connection drilling holes are constructed at a distance of 20m to 30m from the structure. The opening position of the connection drilling holes is the mining tunnel. The drilling azimuth is 90° perpendicular to the mining tunnel. The connection drilling holes are mechanically or hydraulically punched. The number of drilling holes is determined by the number of gas injection holes. The length of the hole is greater than 2m, and the radius of the hole is greater than 0.5m. The hole coordinates must be accurately recorded during the construction process to facilitate the later connection with the gas injection holes.

[0056] Sealing of connecting boreholes: The "two blocking and one injection" method is used to seal the gas injection pipe into the connecting borehole. The grouting liquid is expansive cement. The sealing length is generally not less than 30m. The gas injection pipe connects the connecting boreholes before and after the structure. A throttle valve, flow sensor, and pressure sensor are installed on the gas injection pipeline to monitor and adjust the flow and pressure of the gas injection holes in the rear section of the structure. Figure 3 As shown, an air injection pipe is connected to the borehole, and a throttle valve, a flow sensor and a pressure sensor are installed in the air injection pipe. The throttle valve is connected to the flow sensor, and the other end of the flow sensor is connected to the pressure sensor.

[0057] like Figure 4 As shown in the figure, gas injection hole construction: directional drilling rigs are used to construct gas injection holes in the direction of the structure before and after the structure. The gas injection holes are located in the lower 1 / 3 of the coal seam and are evenly distributed in the working face. The number of gas injection holes and the horizontal distance to the tunnel are the same before and after the structure. The gas injection holes are constructed to a distance of 50m from the structure and the docking mode is started. The corresponding holes are found according to the coordinates of the connecting holes to connect the gas injection holes with the connecting holes. The gas injection holes at both ends of the structure are connected to ensure that the gas injected at one end of the gas injection hole can bypass the structure and flow into the gas injection holes behind the structure, thereby increasing the influence range of the gas injection holes, reducing the number of gas injection ports, and thereby reducing the length of the laid pipeline.

[0058] Sealing of injection holes: Before and after the construction, one end of the injection hole is completely sealed with expansive cement, and the other end is sealed with the gas injection pipe using the "two blocking and one injection" method. The sealing length is generally not less than 30m.

[0059] Construction and sealing of extraction holes: Gas extraction holes are constructed in the mining tunnels. The gas extraction holes are located in the lower 1 / 3 of the coal seam. After the construction is completed, the extraction pipes are sealed into the gas injection holes using the "two blocking and one injection" method. The grouting liquid is expansive cement.

[0060] like Figure 5 As shown, gas injection and displacement promote gas extraction: connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor, connect the extraction pipe to the extraction system, turn on the air compressor, inject gas with a pressure of more than 0.8MPa into the gas injection hole, and carry out coal seam gas injection and displacement to promote gas extraction.

[0061] The embodiment of the present invention provides a method for gas injection displacement to enhance gas extraction in a structurally developed coal seam. A connecting borehole is constructed at a preset distance from the structure and an injection pipe is sealed into the connecting borehole. During the construction process, the coordinates of the holes must be accurately recorded to facilitate the connection with the injection holes in the later stage. Gas injection holes are constructed in the direction of the structure before and after the structure, and the injection holes are sealed after the injection holes are connected to the connecting boreholes. A throttle valve, a flow sensor, and a pressure sensor are installed on the injection pipe to monitor and adjust the flow and pressure of the injection holes in the rear section of the structure. The construction of the gas extraction hole is started and the gas extraction hole is sealed into the injection hole. The injection pipe at the orifice of the injection hole is connected in parallel to the gas outlet of the underground air compressor to promote gas extraction in the coal seam by gas injection displacement. The corresponding hole is found according to the coordinates of the connecting hole to connect the injection hole to the connection hole. The injection holes at both ends of the structure are connected to ensure that the gas injected at one end of the injection hole can bypass the structure and flow into the injection hole behind the structure, thereby increasing the influence range of the injection hole, reducing the number of injection ports, and thus reducing the length of the pipeline. Directional drilling technology is used to bypass the structural development area, so that the gas injection boreholes before and after the structural development can be connected, the number of underground gas injection ports can be reduced, and the laying of long underground pipelines can be avoided.

[0062] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0063] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0064] The present application is expected to provide an implementation scheme for users to selectively block the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0065] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0066] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0068] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0069] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0070] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0071] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0072] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for enhancing gas extraction by gas injection in a structurally developed coal seam, characterized in that: include: Construct connecting boreholes at a preset distance from the structure; sealing the gas injection pipe into the connecting borehole; Before and after the construction, gas injection holes are constructed in the construction direction respectively, and the gas injection holes are connected with the connection drilled holes; sealing the gas injection holes; constructing a gas extraction hole, and sealing the gas extraction hole into the gas injection hole; Connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor to inject gas into the coal seam to promote gas extraction; The construction of the connecting borehole at a preset distance from the structure includes: the opening position of the connecting borehole is a mining roadway, the borehole azimuth is perpendicular to the mining roadway, and the connecting borehole is formed by mechanical hole making or hydraulic punching hole making; The hole making length is greater than 2m, the hole making radius is greater than 0.5m, and the number of the holes is determined according to the number of the gas injection holes; The method of constructing gas injection holes in the construction direction before and after the construction, and connecting the gas injection holes with the connecting drill holes comprises: The gas injection holes are located in the lower 1 / 3 of the coal seam and are evenly distributed in the working face. The number of gas injection holes and the horizontal distance to the tunnel are the same before and after the structure. The gas injection holes are constructed and connected to each other within 50m from the structure.

2. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 1, characterized in that: The step of sealing the gas injection pipe into the connecting borehole comprises: The gas injection pipe is sealed into the connecting borehole using the pressure sealing method, in which the grouting liquid is expansive cement and the sealing length is greater than 30m.

3. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 1, characterized in that: The sealing of the gas injection hole comprises: using expansion cement to completely seal the drilled hole at one end of the gas injection hole before and after construction, and using a pressure sealing method to seal the gas injection pipe at the other end, and the sealing length is greater than 30m.

4. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 1, characterized in that: The construction of the gas extraction hole and sealing the gas extraction hole into the gas injection hole comprises: using a pressure sealing method to seal the extraction pipe of the gas extraction hole into the gas injection hole, wherein the grouting liquid is expansive cement.

5. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 1, characterized in that: The connecting borehole is constructed at a preset distance from the structure, and the preset distance is 20-50m.

6. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 3, characterized in that: A throttle valve, a flow sensor and a pressure sensor are installed on the gas injection pipe between the two boreholes.

7. The method for enhanced gas extraction by gas injection displacement in a structurally developed coal seam according to claim 1, characterized in that: The method of connecting the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor to inject gas into the coal seam to promote gas extraction includes: Connect the gas injection pipe at the gas injection hole in parallel to the gas outlet of the underground air compressor, connect the extraction pipe to the extraction system, turn on the air compressor, inject gas with a pressure of more than 0.8MPa into the gas injection hole, and carry out coal seam gas injection to promote gas extraction.

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