Segmented hydraulic fracturing system and method for coal mine tunnel roof

Abstract

The invention provides a coal mine tunnel roof staged hydraulic fracturing system and method.The coal mine tunnel roof staged hydraulic fracturing system comprises a fracturing assembly and a regulating assembly, the fracturing assembly comprises a pressure pump set, a fracturing pipe column and a plugging fracturing piece which are connected in sequence, and part of the fracturing pipe column and the fracturing plugging piece are arranged in a fracturing drill hole; the regulation and control assembly comprises a first regulation and control part and a second regulation and control part, the first regulation and control part and the second regulation and control part are both arranged on the fracturing pipe column in a sealing and sleeving mode and located in the fracturing drill hole, a first pressure cavity is defined between the first regulation and control part and the second regulation and control part, and a second pressure cavity is defined between the second regulation and control part and the plugging fracturing part; and the first regulation and control part is used for regulating and controlling the pressure in the second pressure cavity. According to the segmented hydraulic fracturing system for the coal mine tunnel roof, the safety of the fracturing technology is improved, and the construction efficiency and the environmental protection performance are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic fracturing, and in particular to a coal mine roadway roof segmented hydraulic fracturing system and method. Background Art

[0002] Rock bursts, gas accumulation, and roof flooding are key challenges hindering safe and efficient coal mine production. In recent years, staged hydraulic fracturing has gained widespread application in coal mine disaster prevention and control due to its ability to actively weaken the hard roof and promote the development of fracture networks. This technology, through segmented isolation and step-by-step pressurization, creates a complex fracture network in the target rock formation, significantly reducing the overall strength of the roof and addressing problems such as overhanging roofs at tunnel ends and abnormal gas accumulation.

[0003] Existing staged fracturing techniques still face significant challenges in complex geological conditions. The risk of high-pressure gas leakage, in particular, has become a key bottleneck restricting the safe application of the technology. During fracturing operations, high-pressure fluids (typically containing gaseous media such as nitrogen and methane) can leak through various pathways, reducing fracturing efficiency and potentially causing catastrophic accidents such as explosions and poisoning. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a coal mine roadway roof segmented hydraulic fracturing system and method, which not only improves the safety of fracturing technology, but also enhances construction efficiency and environmental protection performance.

[0006] A coal mine roadway roof staged hydraulic fracturing system according to an embodiment of the present invention includes:

[0007] A fracturing assembly, comprising a pressure pump group, a fracturing string, and a fracturing plugging component connected in sequence, wherein a portion of the fracturing string and the fracturing plugging component are placed in a fracturing borehole, and the fracturing pump group is used to provide the fracturing plugging component with the pressure medium required for implementing the fracturing plugging technology;

[0008] A regulating component, the regulating component includes a first regulating control and a second regulating control, the first regulating control and the second regulating control are both sealed and sleeved on the fracturing string and located in the fracturing borehole, the first regulating control and the second regulating control are located on the side of the plugging fracturing component adjacent to the open end of the pressure borehole, and the first regulating control is arranged closer to the open end of the fracturing borehole than the second regulating control.

[0009] A first pressure chamber is defined between the first adjustment control and the second adjustment control, and the first adjustment control is used to adjust the pressure in the first pressure chamber. A second pressure chamber is defined between the second adjustment control and the sealing and fracturing component, and the first adjustment control is used to adjust the pressure in the second pressure chamber, and the pressure in the second pressure chamber is less than the pressure in the second pressure chamber.

[0010] The coal mine tunnel roof segmented hydraulic fracturing system of the present invention effectively prevents high-pressure gas leaks through precise pressure control and gas monitoring, reducing the risks of explosions and poisoning. Optimized pressure control and gas management also improve fracturing efficiency and reduce resource waste. Furthermore, the flexible design of the overall system's adjustment components allows for adaptability to varying geological and drilling conditions, enhancing operational suitability. By recovering useful gas and treating harmful gases, environmental pollution is reduced, meeting environmental protection requirements.

[0011] In some embodiments, the regulating assembly further includes a pressurizing member, the first regulating member includes a first regulating body and a first filling portion, the first regulating body is sleeved on the fracturing string, the first filling portion is connected to the outer peripheral wall of the first regulating body and is arranged around the circumference of the first regulating body,

[0012] The second regulating control unit includes a second regulating body and a second filling part. The second regulating body is mounted on the fracturing pipe string. The second filling part is connected to the outer peripheral wall of the second regulating body and is arranged around the circumference of the second regulating body. The first filling part and the second filling part are both connected to the pressurizing part. The pressurizing part is used to introduce pressure medium into the first filling part and the second filling part so that the first filling part and the second filling part are sealed against the wall of the fracturing borehole.

[0013] In some embodiments, the regulating component also includes a gas extraction detection component and a gas injection component, both of which are connected to the second pressure chamber. The gas extraction detection component is used to extract the gas in the second pressure chamber and perform gas composition detection, and the gas injection component is used to introduce inert gas into the second pressure chamber.

[0014] In some embodiments, the air extraction detection component has an air extraction port, the air injection component has an air injection port, and the air extraction port is located above the air injection port.

[0015] In some embodiments, the first regulating component further includes a third filling portion, the third filling portion being connected to the inner circumferential wall of the first regulating body and being arranged around the circumference of the fracturing string.

[0016] The second regulating control unit also includes a fourth filling part, which is connected to the inner circumferential wall of the second regulating body and is arranged around the circumference of the fracturing string. The third filling part and the fourth filling part are both connected to the pressurizing part, and the pressurizing part is used to pass pressure medium into the third filling part and the fourth filling part so that the third filling part and the fourth filling part are sealed against the wall of the fracturing string.

[0017] In some embodiments, the regulating assembly further includes an annular flexible member, a first end of the annular flexible member being connected to the first regulating body, a second end of the annular flexible member being sealed against the outer peripheral wall of the fracturing pipe string, the annular flexible member being located on the side of the opening end of the first regulating body adjacent to the fracturing borehole, and the annular flexible member extending in a direction away from the opening end of the fracturing borehole.

[0018] In some embodiments, the volume of the first pressure chamber is less than or equal to the volume of the second pressure chamber.

[0019] The coal mine roadway roof segmented hydraulic fracturing method of an embodiment of the present invention is performed using the coal mine roadway roof segmented hydraulic fracturing system described in any one of the above embodiments, and is characterized by comprising the following steps:

[0020] S1. Install a fracturing assembly and a regulating assembly, and adjust the pressures in the first pressure chamber and the second pressure chamber respectively, so that the pressure in the second pressure chamber is lower than the pressure in the second pressure chamber;

[0021] S2. Introducing pressure medium into the plugging and fracturing components and performing fracturing operations;

[0022] S3, extracting gas from the second pressure chamber and detecting gas composition of the extracted gas, and monitoring pressure changes in the second pressure chamber;

[0023] S4: When the pressure change in the second pressure chamber exceeds a preset pressure value, while ensuring that the pressure in the first pressure chamber is greater than the pressure in the second pressure chamber, the rate of extracting gas from the second pressure chamber is increased and the gas composition is continuously detected;

[0024] S5. If the harmful gas content in the gas extracted from the second pressure chamber exceeds a preset content value, introducing an inert gas into the second pressure chamber;

[0025] S6. Repeat step S3 until the pressure change value in the second pressure chamber is within the range of the preset pressure value and the harmful gas content in the gas extracted from the second pressure chamber is within the range of the preset content value.

[0026] In some embodiments, in step S4, different components in the extracted gas are classified and processed, so that the classified gas can be recycled or discharged.

[0027] In some embodiments, in step S5 , the density of the introduced inert gas is greater than the density of the mixed gas in the second pressure chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the installation of a coal mine roadway roof segmented hydraulic fracturing system according to an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 An enlarged schematic diagram of point A is shown in FIG.

[0030] Reference numerals:

[0031] 100, fracturing borehole, 200, first pressure chamber, 300, second pressure chamber,

[0032] 1. Fracturing components, 11. Fracturing string, 12. Fracturing plugging parts,

[0033] 2. Control component, 21. First control component, 211. First control body, 212. First filling part, 213. Third filling part, 22. Second control component, 221. Second control body, 222. Second filling part, 223. Fourth filling part, 23. Air extraction detection part, 24. Air injection part, 25. Annular flexible part. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] The following describes a coal mine roadway roof staged hydraulic fracturing system according to an embodiment of the present invention with reference to the accompanying drawings.

[0036] like Figure 1 and Figure 2 As shown, the coal mine roadway roof segmented hydraulic fracturing system according to an embodiment of the present invention includes: a fracturing component 1 and a regulating component 2.

[0037] The fracturing assembly 1 includes a pressure pump group (not shown in the figure), a fracturing string 11 and a fracturing plugging component 12 connected in sequence. Part of the fracturing string 11 and the fracturing plugging component are placed in the fracturing borehole 100. The fracturing pump group is used to provide the pressure medium required for implementing the fracturing plugging technology to the fracturing plugging component 12.

[0038] Specifically, if Figure 1 and Figure 2As shown, the pressure pump assembly is located outside the fracturing borehole 100 to provide the subsequent pressure medium required for the plugging and fracturing component 12. The plugging and fracturing component 12 comprises a plug and a fracturing component. The pressure pump assembly injects pressure medium into the plug to create a closed space at the fracturing location, facilitating subsequent fracturing operations by the fracturing component. Specifically, the pressure pump assembly injects pressure medium (water / fracturing fluid) into the fracturing string 11, ultimately delivering it to the plugging and fracturing component 12 to achieve fracturing of the target rock formation.

[0039] The regulating component 2 includes a first regulating control 21 and a second regulating control 22. The first regulating control 21 and the second regulating control 22 are both sealed and sleeved on the fracturing pipe string 11 and located in the fracturing borehole 100. The first regulating control 21 and the second regulating control 22 are located on the side of the open end of the sealing fracturing component 12 adjacent to the pressure borehole, and the first regulating control 21 is arranged adjacent to the open end of the fracturing borehole 100 compared to the second regulating control 22. A first pressure chamber 200 is defined between the first regulating control 21 and the second regulating control 22. The first regulating control 21 is used to regulate the pressure in the first pressure chamber 200. A second pressure chamber 300 is defined between the second regulating control 22 and the sealing fracturing component 12. The first regulating control 21 is used to regulate the pressure in the second pressure chamber 300, and the pressure in the second pressure chamber 300 is less than the pressure in the second pressure chamber 300.

[0040] Specifically, if Figure 1 and Figure 2 As shown, the first adjustment control 21 is located on the left side of the second adjustment control 22, and the first adjustment control 21 and the second adjustment control 22 are both sealed and sleeved on the fracturing string 11, so that a plurality of closed cavities (i.e., the first pressure chamber 200 and the second pressure chamber 300) are formed between the fracturing area and the open end of the fracturing borehole 100. This not only provides more sealing nodes for the overall fracturing process, but also can prevent dangerous gases from leaking to the outside of the fracturing borehole 100 by utilizing the sealing performance of the first adjustment control 21 and the pressure difference between the first pressure chamber 200 and the second pressure chamber 300 when dangerous gas leaks at the sealing fracturing component 12 or the second adjustment control 22, thereby ensuring the safety of the construction environment.

[0041] When the pressures in the first pressure chamber 200 and the second pressure chamber 300 are adjusted using the first control unit 21 and the second control unit 22, respectively, high-pressure gas can be extracted or introduced using a gas extraction and ventilation device to adjust the pressure. Preferably, while extracting the gas, the content of hazardous gases in the extracted gas can also be monitored. When the content of hazardous gases (such as methane, hydrogen sulfide, carbon monoxide, etc.) in the extracted gas exceeds a safe value, a warning signal can be issued to alert underground construction workers, allowing them to quickly perform emergency operations based on actual working conditions to ensure construction safety.

[0042] It is understood that by configuring the control assembly 2, segmented pressure control can be achieved. The pressure difference between the first control unit 21 and the second control unit 22 can be adjusted separately, resulting in improved sealing performance during the fracturing process and more refined gas leakage monitoring and control, which facilitates fracturing and improves the safety of underground workers.

[0043] In other words, through the dual-pressure chamber gradient pressure difference design, two active sealing lines of defense are constructed to completely block the gas leakage path. If a micro-leak occurs in the sealing fracturing component 12, the high-pressure gas / liquid first enters the second pressure chamber 300. The pressure in the first pressure chamber 200 (high-pressure area) is always higher than that in the second pressure chamber 300, which can form a reverse pressure gradient. Once the pressure in the second pressure chamber 300 is abnormal (leakage signal), the first control unit 21 can quickly increase the pressure, reversely pressing the leaking fluid back into the deep borehole, physically blocking the leakage channel.

[0044] In this way, the pressures of the two pressure chambers are adjusted at the same time, and the pressure of the first pressure chamber 200 is dynamically maintained to be greater than the pressure of the second pressure chamber 300, thereby enhancing the sealing of the overall system and preventing leakage of dangerous gases. The setting of the adjustment component replaces the traditional passive seal and overcomes the defect of easy failure of a single seal.

[0045] In other words, the coal mine tunnel roof staged hydraulic fracturing system of the present invention effectively prevents high-pressure gas leaks and reduces the risks of explosions and poisoning through precise pressure control and gas monitoring. Optimized pressure control and gas management also improve fracturing efficiency and reduce resource waste. Furthermore, the flexible design of the overall system's adjustment components allows for adaptability to varying geological and drilling conditions, enhancing operational suitability. By recovering useful gas and treating harmful gases, environmental pollution is reduced, meeting environmental protection requirements.

[0046] In some embodiments, the regulating component 2 also includes a pressure piece, the first regulating part 21 includes a first regulating body 211 and a first filling part 212, the first regulating body 211 is mounted on the fracturing tubing string 11, the first filling part 212 is connected to the outer peripheral wall of the first regulating body 211 and is arranged around the circumference of the first regulating body 211, the second regulating part 22 includes a second regulating body 221 and a second filling part 222, the second regulating body 221 is mounted on the fracturing tubing string 11, the second filling part 222 is connected to the outer peripheral wall of the second regulating body 221 and is arranged around the circumference of the second regulating body 221, the first filling part 212 and the second filling part 222 are both connected to the pressure piece, and the pressure piece is used to introduce pressure medium into the first filling part 212 and the second filling part 222 so that the first filling part 212 and the second filling part 222 are sealed against the wall of the fracturing borehole 100.

[0047] It is understandable that if Figure 1 and Figure 2As shown, the pressurizing element can be connected to the first filling section 212 and the second filling section 222 via an injection and pressure pipeline to simultaneously inject a pressure medium (such as hydraulic oil or compressed gas) into the two filling sections. The first control body 211 is a rigid substrate that is sleeved onto the fracturing string 11. The first and second filling sections 212 and 222 surround the outer walls of the first and second control bodies 211 and 221, respectively. The first and second filling sections 212 and 222 can be inflatable sealed bladders (such as rubber sleeves).

[0048] That is, driven by the pressure element, the filling section radially expands until it completely fits the borehole wall, achieving full sealing even in the face of irregular borehole walls (such as complex geological conditions). Furthermore, the pressure element simultaneously injects pressure into both filling sections, causing the first and second control sections 22 to expand synchronously and form two parallel sealing barriers within the fracturing borehole 100. This prevents the failure of a single sealing layer while the other layer can still maintain a basic seal, thereby improving system reliability. Furthermore, the simultaneous injection ensures that the two filling sections apply uniform pressure to the borehole wall, and also prevents seal failure caused by localized stress concentration.

[0049] In some embodiments, the regulating component 2 also includes a gas extraction detection component 23 and a gas injection component 24. The gas extraction detection component 23 and the gas injection component 24 are both connected to the second pressure chamber 300. The gas extraction detection component 23 is used to extract the gas in the second pressure chamber 300 and perform gas composition detection. The gas injection component 24 is used to introduce inert gas into the second pressure chamber 300.

[0050] It is understandable that if Figure 1 and Figure 2 As shown, the gas extraction detection component 23 includes a connected gas storage part, a gas extraction detection part and a gas extraction pipe, the gas extraction end of the gas extraction pipe is placed in the second pressure chamber 300. The gas injection component 24 includes a gas storage tank and a gas injection pipe, the gas injection end of the gas injection pipe is placed in the second pressure chamber 300.

[0051] That is to say, the gas extraction detection part 23 enables the system to monitor the gas composition and pressure changes in the second pressure chamber 300 in real time, adjust the fracturing parameters in time, and ensure the safety of the fracturing process. By detecting the gas composition, the system operator can promptly detect and deal with harmful gases, such as methane, thereby reducing the risk of explosion and poisoning. The inert gas introduced by the gas injection part 24 can be used to control the pressure of the second pressure chamber 300 to ensure the stability and efficiency of the fracturing process. And by monitoring and adjusting the gas composition and pressure in the second pressure chamber 300, the system can promptly detect and deal with potential safety hazards and improve the safety of the overall operation. In addition, the use of the gas injection part 24 helps to optimize the gas management in the second pressure chamber 300. By introducing inert gas (such as nitrogen, etc.), the oxygen content can be reduced and the risk of oxidation reaction can be reduced.

[0052] The pressures in the first pressure chamber 200 and the second pressure chamber 300 can be monitored in real time and information transmitted and fed back using pressure monitoring equipment (such as a pressure gauge, etc.).

[0053] Preferably, the air extraction detection member 23 has an air extraction port, and the air injection member 24 has an air injection port, and the air extraction port is located above the air injection port. It can be understood that the air extraction port is located at the air extraction end of the air extraction pipe, and the air injection port is located at the air injection end of the air injection pipe.

[0054] Optionally, the inert gas (such as nitrogen) introduced into the second pressure chamber 300 will naturally sink to the bottom of the second pressure chamber 300 due to its density being greater than that of air. Furthermore, since the gas injection port is located below the gas extraction port, as the inert gas is continuously injected, the accumulated nitrogen pushes the air upward, forming an inerting gradient from bottom to top. Prioritizing inerting the area with the highest risk of leakage (the side adjacent to the sealing fracturing component 12) also avoids "gas mass short-circuiting." That is, if the gas injection port is at the top of the second pressure chamber 300 and nitrogen is introduced at the bottom of the second pressure chamber 300, the inert gas can be prevented from flowing directly to the gas extraction port, thereby wasting resources.

[0055] The positioning of the exhaust and injection ports enables more efficient gas exchange and improves the efficiency of detecting and adjusting gas composition. Positioning the injection port below the exhaust port not only facilitates uniform gas distribution within the second pressure chamber 300, avoiding localized excess or excess gas concentrations and ensuring uniformity and stability during the fracturing process, but also allows for better control of the gas pressure and composition within the second pressure chamber 300, thereby reducing safety risks such as leakage and explosion.

[0056] In some embodiments, the first adjustment control unit 21 also includes a third filling part 213, which is connected to the inner circumferential wall of the first adjustment body 211 and is arranged around the circumference of the fracturing string 11. The second adjustment control unit 22 also includes a fourth filling part 223, which is connected to the inner circumferential wall of the second adjustment body 221 and is arranged around the circumference of the fracturing string 11. The third filling part 213 and the fourth filling part 223 are both connected to a pressure member, which is used to introduce pressure medium into the third filling part 213 and the fourth filling part 223 so that the third filling part 213 and the fourth filling part 223 are sealed against the wall of the fracturing string 11.

[0057] It is understandable that if Figure 1 and Figure 2As shown, the third and fourth filling sections 213, 223 are similar to the first and second filling sections 212, 222. Specifically, the provision of the third and fourth filling sections 213, 223 further enhances the sealing effect between the fracturing string 11 and the wall of the fracturing borehole 100, effectively preventing leakage of high-pressure fluid. Independent control of the third and fourth filling sections 213, 223 enables more refined regulation of the fracturing process and optimizes the formation of the fracture network. This enhanced sealing performance also improves the overall safety of the system and reduces safety risks associated with leakage.

[0058] In some embodiments, the regulating component 2 also includes an annular flexible member 25, the first end of the annular flexible member 25 is connected to the first regulating body 211, the second end of the annular flexible member 25 is sealed against the outer peripheral wall of the fracturing pipe string 11, and the annular flexible member 25 is located on the side of the opening end of the first regulating body 211 adjacent to the fracturing borehole 100, and the annular flexible member 25 extends in a direction away from the opening end of the fracturing borehole 100.

[0059] It is understandable that if Figure 1 and Figure 2 As shown, the cross-sectional profile of the annular flexible member 25 is inclined, and the end of the annular flexible member 25 that abuts against the fracturing string 11 is arranged farther away from the opening end of the fracturing borehole 100 than the other end, so that when the annular flexible member 25 leaks in the first pressure chamber 200, it can still ensure sealed contact with the outer wall of the fracturing string 11 under the action of the pressure in the first pressure chamber 200, further reducing the risk of leakage.

[0060] It should be noted that the annular flexible member 25 can be made of rubber material.

[0061] In some embodiments, the volume of the first pressure chamber 200 is less than or equal to the volume of the second pressure chamber 300 .

[0062] It is understood that the volume of the first pressure chamber 200 is smaller than that of the second pressure chamber 300, which can be used for more precise pressure control. For example, when rapid response and pressure adjustment are required during the fracturing process, the first pressure chamber 200 can reach the required pressure more quickly. The second pressure chamber 300 has a larger volume, which can provide more space to accommodate high-pressure fluid (hazardous gas) in the event of a leak in the fracturing area, or utilize the larger volume to stabilize and maintain pressure.

[0063] Furthermore, the volume design of the two pressure chambers allows the system to implement graded pressure management, that is, using different pressure chambers at different pressure stages to improve fracturing efficiency and safety. Thus, when the fracturing plug 12 fails or a leak occurs, high-pressure gas flows into the second pressure chamber 300. Because the second pressure chamber 300 has a certain volume, the pressure within it rises slowly. The system monitors the pressure changes within the second pressure chamber 300 and feeds the detection signal back to the first control unit 21, allowing pressure to be injected into the smaller first pressure chamber 200. This achieves graded pressure management, shortening the time the leaking gas is blocked by back pressure, thereby eliminating the risk of spillage.

[0064] The following describes a method for staged hydraulic fracturing of a coal mine roadway roof according to an embodiment of the present invention.

[0065] The coal mine roadway roof segmented hydraulic fracturing method according to an embodiment of the present invention is performed using the coal mine roadway roof segmented hydraulic fracturing system according to any one of the above embodiments, and is characterized in that it includes the following steps:

[0066] S1. Install the fracturing assembly 1 and the control assembly 2, and adjust the pressures in the first and second pressure chambers 200 and 300, respectively, so that the pressure in the second pressure chamber 300 is lower than the pressure in the second pressure chamber 300. It is understood that the fracturing string 11 and the fracturing plug 12 are installed in the fracturing borehole 100. Connect the first and second control components 21 and 22 to the fracturing string 11, ensuring that they are located on the side of the fracturing plug 12 adjacent to the open end of the fracturing borehole 100. Use a pressurizing component to introduce pressure medium into the third and fourth filling sections 213 and 223, ensuring that they seal against the walls of the fracturing string 11. Use the first and second control components 21 and 22 to adjust the pressures in the first and second pressure chambers 200 and 300, ensuring that the pressure in the second pressure chamber 300 is lower than the pressure in the first pressure chamber 200. This ensures that pressure can be effectively controlled and adjusted during the fracturing process, improving fracturing efficiency and safety.

[0067] S2. Introduce pressure medium into the plugging and fracturing components 12, and initiate fracturing operations. It is understood that the pressure medium is introduced into the plugging and fracturing components 12 using a pressure pump assembly. Under the action of the pressure medium, the plugging and fracturing components 12 begin to operate and initiate fracturing operations. The introduction of pressure medium can actively weaken the hard roof, promote the development of the fracture network, and address problems such as overhanging roofs at the tunnel ends and abnormal gas accumulation.

[0068] S3. Extract the gas in the second pressure chamber 300 and detect the gas composition of the extracted gas, and monitor the pressure changes in the second pressure chamber 300. It is understandable that the gas extraction detection member 23 is used to extract the gas sample in the second pressure chamber 300, and the gas composition detection equipment (such as multiple single gas detectors or gas integrated detectors) is used to detect the composition of the gas sample. The pressure change in the second pressure chamber 300 is monitored using a pressure gauge. Therefore, through gas composition detection and pressure change monitoring, harmful gases can be discovered and handled in a timely manner, reducing the risk of explosion and poisoning.

[0069] S4: When the pressure change in the second pressure chamber 300 exceeds the preset pressure value, while ensuring that the pressure in the first pressure chamber 200 is greater than the pressure in the second pressure chamber 300, the rate of gas extraction from the second pressure chamber 300 is increased and the gas composition is continuously monitored. It is understood that when the pressure change in the second pressure chamber 300 exceeds the preset pressure value, the pressure in the corresponding chamber is adjusted by extracting and injecting gas to ensure that the pressure in the first pressure chamber 200 is greater than the pressure in the second pressure chamber 300. While increasing the rate of gas extraction from the second pressure chamber 300, the efficiency of gas composition monitoring is improved, ensuring the timely detection and treatment of harmful gases, and timely adjusting the pressure and gas composition, thereby improving fracturing efficiency and safety.

[0070] S5. If the harmful gas content in the gas extracted from the second pressure chamber 300 exceeds a preset content value, inert gas is introduced into the second pressure chamber 300. It is understood that introducing inert gas into the second pressure chamber 300 not only replaces the air in the second pressure chamber 300 with the inert gas, but also reduces the concentration of harmful gases, thereby improving fracturing safety.

[0071] S6. Repeat step S3 until the pressure change value in the second pressure chamber 300 is within the range of the preset pressure value and the harmful gas content in the gas extracted from the second pressure chamber 300 is within the range of the preset content value.

[0072] It is understandable that

[0073] In some embodiments, in step S4, different components in the extracted gas are classified and processed, so that the classified gas can be recycled or discharged.

[0074] It is understandable that the extracted gas can be separated using gas separation equipment, and gases of different components can be classified and processed. According to the characteristics of the gas components, recyclable gases are recycled and processed, while non-recyclable or toxic and harmful gases are safely discharged. That is, the extracted gas is separated using gas separation equipment to separate gases of different components. Recyclable gases (such as nitrogen, methane, etc.) are transported to recycling equipment for collection and processing for reuse. Non-recyclable or toxic and harmful gases are safely discharged through discharge equipment to ensure that they do not pollute the environment.

[0075] Therefore, by recycling renewable gas components, we can reduce resource waste, lower production costs, improve the economic benefits of fracturing operations, and increase coal mine profits. By classifying and treating harmful gases and discharging them, we can reduce environmental pollution, lower the risk of accidents, and ensure the safety of coal mine production.

[0076] In some embodiments, in step S5, the density of the introduced inert gas is greater than the density of the mixed gas within the second pressure chamber 300. It is understood that due to the higher density of the inert gas, a relatively stable bottom layer is formed within the second pressure chamber 300 after introduction, which helps to push the harmful gases to the upper layer, making them more easily extracted and processed by the gas extraction detection element 23. By forming a stable bottom layer, the harmful gases within the second pressure chamber 300 can be more effectively discharged, thereby improving the discharge efficiency.

[0077] Furthermore, the higher inert gas density helps reduce the risk of high-pressure fluid leaking through potentially tiny leak paths. By effectively controlling the concentration of hazardous gases, the risk of explosion and poisoning can be significantly reduced, improving the safety of fracturing operations.

[0078] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. 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, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0080] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0081] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0082] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean 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 invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0083] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A coal mine roadway roof segmented hydraulic fracturing system, characterized in that: include: A fracturing assembly, comprising a pressure pump group, a fracturing string, and a fracturing plugging component connected in sequence, wherein a portion of the fracturing string and the fracturing plugging component are placed in a fracturing borehole, and the fracturing pump group is used to provide the fracturing plugging component with the pressure medium required for implementing the fracturing plugging technology; A regulating component, the regulating component includes a first regulating control and a second regulating control, the first regulating control and the second regulating control are both sealed and sleeved on the fracturing string and located in the fracturing borehole, the first regulating control and the second regulating control are located on the side of the plugging fracturing component adjacent to the open end of the pressure borehole, and the first regulating control is arranged closer to the open end of the fracturing borehole than the second regulating control. A first pressure chamber is defined between the first adjustment control and the second adjustment control, and the first adjustment control is used to adjust the pressure in the first pressure chamber. A second pressure chamber is defined between the second adjustment control and the sealing and fracturing component, and the first adjustment control is used to adjust the pressure in the second pressure chamber, and the pressure in the second pressure chamber is less than the pressure in the second pressure chamber.

2. The coal mine roadway roof staged hydraulic fracturing system according to claim 1, characterized in that: The regulating assembly further includes a pressurizing member, the first regulating member includes a first regulating body and a first filling portion, the first regulating body is sleeved on the fracturing string, the first filling portion is connected to the outer peripheral wall of the first regulating body and is arranged around the circumference of the first regulating body, The second regulating control unit includes a second regulating body and a second filling part. The second regulating body is mounted on the fracturing pipe string. The second filling part is connected to the outer peripheral wall of the second regulating body and is arranged around the circumference of the second regulating body. The first filling part and the second filling part are both connected to the pressurizing part. The pressurizing part is used to introduce pressure medium into the first filling part and the second filling part so that the first filling part and the second filling part are sealed against the wall of the fracturing borehole.

3. The coal mine roadway roof staged hydraulic fracturing system according to claim 2, characterized in that: The regulating component also includes a gas extraction detection part and a gas injection part, both of which are connected to the second pressure chamber. The gas extraction detection part is used to extract the gas in the second pressure chamber and perform gas composition detection, and the gas injection part is used to introduce inert gas into the second pressure chamber.

4. The coal mine roadway roof staged hydraulic fracturing system according to claim 3, characterized in that: The air extraction detection component has an air extraction port, the air injection component has an air injection port, and the air extraction port is located above the air injection port.

5. The coal mine roadway roof staged hydraulic fracturing system according to claim 4, characterized in that: The first control unit further includes a third filling portion, which is connected to the inner peripheral wall of the first control body and arranged around the circumference of the fracturing string. The second regulating control unit also includes a fourth filling part, which is connected to the inner circumferential wall of the second regulating body and is arranged around the circumference of the fracturing string. The third filling part and the fourth filling part are both connected to the pressurizing part, and the pressurizing part is used to pass pressure medium into the third filling part and the fourth filling part so that the third filling part and the fourth filling part are sealed against the wall of the fracturing string.

6. The coal mine roadway roof staged hydraulic fracturing system according to claim 5, characterized in that: The regulating assembly also includes an annular flexible member, a first end of the annular flexible member is connected to the first regulating body, a second end of the annular flexible member is sealed against the outer peripheral wall of the fracturing pipe string, the annular flexible member is located on the side of the opening end of the first regulating body adjacent to the fracturing borehole, and the annular flexible member extends in a direction away from the opening end of the fracturing borehole.

7. The coal mine roadway roof staged hydraulic fracturing system according to claim 6, characterized in that: The volume of the first pressure chamber is smaller than or equal to the volume of the second pressure chamber.

8. A method for hydraulic fracturing of a coal mine roadway roof, wherein the method is performed using the hydraulic fracturing system for the coal mine roadway roof according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Install a fracturing assembly and a regulating assembly, and adjust the pressures in the first pressure chamber and the second pressure chamber respectively, so that the pressure in the second pressure chamber is lower than the pressure in the second pressure chamber; S2. Introducing pressure medium into the plugging and fracturing components and performing fracturing operations; S3, extracting gas from the second pressure chamber and detecting gas composition of the extracted gas, and monitoring pressure changes in the second pressure chamber; S4: When the pressure change in the second pressure chamber exceeds a preset pressure value, while ensuring that the pressure in the first pressure chamber is greater than the pressure in the second pressure chamber, the rate of extracting gas from the second pressure chamber is increased and the gas composition is continuously detected; S5. If the harmful gas content in the gas extracted from the second pressure chamber exceeds a preset content value, introducing an inert gas into the second pressure chamber; S6. Repeat step S3 until the pressure change value in the second pressure chamber is within the range of the preset pressure value and the harmful gas content in the gas extracted from the second pressure chamber is within the range of the preset content value.

9. The coal mine roadway roof staged hydraulic fracturing method according to claim 8, characterized in that: In step S4, different components in the extracted gas are classified and processed, so that the classified gas can be recycled or discharged.

10. The coal mine tunnel roof staged hydraulic fracturing method according to claim 9, characterized in that: In step S5 , the density of the inert gas introduced is greater than the density of the mixed gas in the second pressure chamber.

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