Well-ground combined tunneling strip horizontal well segmented fracturing rapid gas pre-drainage method

Abstract

The application discloses a kind of well-ground combined excavation strip horizontal well segmented fracturing rapid gas pre-extraction methods: step 1: along the working face excavation strip above construction coal seam roof horizontal well;Step 2: segmented hydraulic fracturing construction is carried out to horizontal well;Step 3: drainage valve and pressure gauge are installed at the toe end of horizontal well cylinder in the well;Step 4: after starting gas production, gas-water separator is installed at the toe end of horizontal well cylinder in the well roadway drainage valve;Step 5: simultaneously install negative pressure extraction system at the ground wellhead and the toe end of horizontal well cylinder in the well roadway;Step 6: multiple horizontal wells are constructed in the range of coal seam mining area along the working face excavation strip above, and gas extraction is realized.The method of the application changes the original excavation strip gas extraction method, uses a relatively safe ground construction method, and at the same time, can save the construction cost of underground floor rock roadway and floor through-hole.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas control technology, and relates to a method for rapid pre-extraction of gas through segmented fracturing of horizontal wells in a combined shaft-ground tunneling process. Background Technology

[0002] Coal plays a crucial role in my country's energy security, but the country's major coal-bearing basins are characterized by widespread, soft, and low-permeability coal seams. Statistics show that approximately 72% of coal seams have a permeability of less than 1.0 mD. These loosely packed coal seams, with their high gas pressure and low permeability, are highly susceptible to gas disasters, resulting in a persistently high proportion of mine gas-related deaths. Coal face tunnels are the primary location for these accidents. While bottom rock tunnels combined with cross-cutting boreholes are currently the most important technology for gas control in coal seam tunnels, overall gas extraction is difficult, management is complex, and control costs are high. Inadequate pre-extraction often leads to significant conflicts between mining and extraction, severely impacting efficient coal mining. With the development of surface gas extraction technology, coal mining enterprises have gradually recognized that surface drilling for pre-extraction of coal seam gas can facilitate the transformation from high-gas to low-gas mines. Surface engineering measures eliminate the need for additional tunnel development, allowing for pre-extraction in advance, and offering numerous advantages such as high safety and minimal time and space constraints. Article 35 of the "Coal Mine Safety Regulations (2022 Edition)" stipulates that "newly built mines with outburst-prone coal seams must undergo gas extraction before construction. Before the commencement of mine construction, surface drilling should be conducted to pre-extract gas from the outburst-prone coal seams in the first mining area, and the pre-extraction rate should reach more than 30%." Under the concept of "people-oriented and life-first," the state is increasingly strict in the safety management of such mines, and is vigorously promoting the principle of "extraction before construction, extraction before mining, and extraction of all gas that should be extracted" in high-gas mines. The use of surface methods for efficient gas control is a technical problem that urgently needs to be overcome in these areas, and it is also a development trend.

[0003] Therefore, it is urgent to research and design a rapid pre-gas extraction method that is easy to manage and safe. Summary of the Invention

[0004] The purpose of this invention is to provide a method for rapid pre-extraction of gas in a horizontal strip well through combined well-ground tunneling, in order to solve the problems of high difficulty, high cost and high risk in the gas control of strip wells in coal roadway tunneling in existing high-gas mines.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for rapid pre-gas extraction via staged fracturing in a horizontal strip well using a combined well-ground and surface tunneling approach includes the following steps:

[0007] Step 1: Construct a horizontal shaft above the coal seam roof along the excavation strip of the working face. The toe of the horizontal shaft is connected to the underground roadway.

[0008] Step 2: Perform segmented hydraulic fracturing on the horizontal well;

[0009] Step 3: Install drainage valves and pressure gauges at the toe of the horizontal shaft downhole, and carry out drainage operations according to the predetermined drainage system;

[0010] Step 4: After gas production begins, install a gas-water separator at the toe valve of the horizontal shaft in the underground roadway, and connect the exhaust port of the gas-water separator to the gas drainage system.

[0011] Step 5: When the wellbore is no longer producing water in the later stage of drainage, a negative pressure extraction system can be installed at both the surface wellhead and the toe of the horizontal wellbore in the underground roadway.

[0012] Step 6: Following the methods in Steps 1 to 5, construct multiple horizontal wells above the working face tunneling strip within the coal seam mining area. Each horizontal well corresponds to one tunneling strip to achieve strip-type gas extraction; or, arrange multiple sets of horizontal wells along the working face strike to perform pre-extraction at the working face surface.

[0013] Furthermore, step 1 includes the following sub-steps:

[0014] Step 1.1: Optimize the design of the horizontal well drilling trajectory. The horizontal section of the horizontal well trajectory should be 0-10m above the top boundary of the coal seam, and the connection point with the underground roadway should be determined.

[0015] Step 1.2: Complete the first and second stages of drilling and cementing of the horizontal well;

[0016] Step 1.3: Complete the drilling of the third section of the horizontal well and connect it to the roadway.

[0017] Furthermore, in step 1.3, the drilling of the horizontal well in three sections adopts the tailpipe cementing method, and the specific steps are as follows:

[0018] 1.3.1: Geological steering drilling technology was adopted to complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well was located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, the direction of the trajectory guidance device was continuously determined. Drilling was stopped when the distance to the underground roadway was 10-60m.

[0019] Step 1.3.2: Run the casing for cementing. After cementing for more than 48 hours, conduct cementing quality testing.

[0020] Step 1.3.3: Continue drilling until the horizontal well is connected to the underground roadway. Then, lower the tailpipe hanger through the drill string to connect it to the roadway.

[0021] Furthermore, in step 1.3, the drilling of the third section of a horizontal well can also employ external packer cementing, with the specific steps as follows:

[0022] Step 1.3.1: Using geological steering drilling technology, complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well is located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, continuously determine the direction of the trajectory guidance device until it connects with the underground roadway.

[0023] Step 1.3.2: Lower the casing tool string, with an external packer connected to the end of the casing, and a perforated casing short section;

[0024] Step 1.3.3: Set the packer;

[0025] Step 1.3.4: Inject cement slurry for cementing, and after 48 hours of curing, conduct cementing quality testing.

[0026] Furthermore, step 2 includes the following sub-steps:

[0027] Step 2.1: Use the production capacity numerical simulation method to optimize and determine the number of fracturing stages in the horizontal section of the horizontal well;

[0028] Step 2.2: Taking into account cementing quality, casing coupling location, and distance between the horizontal well and the top boundary of the coal seam, the optimal perforation location for the horizontal well is determined; the safe distance between the perforation location and the bridge plug is not less than 10m.

[0029] Step 2.3: Perform segmented fracturing on the horizontal section of the horizontal well using either bridge plug perforation combined with segmented fracturing technology or coiled tubing with bottom seal dragged hydraulic jet segmented fracturing technology;

[0030] Furthermore, in step 2.3, the construction steps of the bridge plug perforation combined staged fracturing process are as follows:

[0031] Step 2.3.1: The first section uses tubing or coiled tubing to transport the perforating gun and bridge plug. After reaching the designed well depth, the bridge plug is set and pressure tested for 5-10 minutes. If the pressure does not decrease, the first section of bridge plug setting is complete.

[0032] Step 2.3.2: Perform the first perforation and lower the perforating gun to the ground;

[0033] Step 2.3.3: Pump fracturing fluid to carry out the first stage of fracturing construction; preferably, low-temperature temporary plugging technology can be used during the fracturing construction to increase the complexity of the fracture;

[0034] Step 2.3.4: The second stage uses a hydraulic pump to lower the bridge plug and perforation gun. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the second stage bridge plug setting is complete.

[0035] Step 2.3.5: Raise the perforating gun to complete the perforation operation, and lift the perforating gun to the ground;

[0036] Step 2.3.6: Pump fracturing fluid to carry out the second stage of fracturing operation;

[0037] Step 2.3.7: Repeat steps 2.3.5-2.3.6 to complete the fracturing construction of all subsequent fracturing sections;

[0038] Step 2.3.8: After the fracturing operation is completed, the well is flushed by drilling and plugging.

[0039] Furthermore, in step 2.3.1, the bridge plug should be inserted at a distance of 10-20m from the tailpipe hanger.

[0040] Furthermore, in step 2.3, the construction steps of the coiled tubing with bottom seal-driven hydraulic jet fracturing process are as follows:

[0041] 2.3.1: The bridge plug is set using a coiled tubing delivery method to seal the bottom of the horizontal well. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the bottom of the horizontal well is successfully sealed.

[0042] 2.3.2: Pull out the coiled tubing, install the bottom-seal drag-type hydraulic jet fracturing tool string, and connect it to the bottom of the coiled tubing; the spray gun uses a directional hydraulic jet tool;

[0043] 2.3.3: Run the coiled tubing to the bottom of the well, then gradually lift the coiled tubing, position it using the coupling locator, and push the coiled tubing down to set the bottom packer;

[0044] 2.3.4: Inject fracturing fluid into the coiled tubing for hydraulic blasting perforation, with a perforation flow rate of 0.2-1.0 m. 3 / min; After the perforation operation is completed, fracturing fluid is injected into the annulus between the coiled tubing and the casing to carry out fracturing operations;

[0045] 2.3.5: Raise the coiled tubing to release the packer, continue raising the coiled tubing to the second perforation section, set the packer, and repeat steps 2.3.3-2.3.4 to complete the fracturing operation of all fracturing sections;

[0046] 2.3.6: After the fracturing operation is completed, the coiled tubing and the segmented fracturing tool string are pulled out.

[0047] Furthermore, in step 2.3.1, the bridge plug should be inserted at a distance of 10-20m from the tailpipe hanger.

[0048] Furthermore, in step 3, drainage directional long boreholes are constructed in the underground roadway near the bottom of the coal seam as drainage holes. The boreholes are arranged parallel to the horizontal section of the horizontal well and are of similar length.

[0049] For coal seams with a small dip angle and downward dip, the drainage operation is completed by controlling the toe valve of the horizontal shaft in the roadway.

[0050] For coal seams that dip upwards, a pressurization device is installed at the surface wellhead to pressurize the medium into the horizontal well. The medium then drives the water in the wellbore to the valve at the toe of the horizontal wellbore in the roadway to complete the drainage operation.

[0051] Compared to existing technologies, this invention employs horizontal wells arranged within the coal roadway excavation zone for segmented fracturing of coal seams, which has the following beneficial effects:

[0052] (1) Using horizontal wells for staged fracturing on the surface results in large-scale fracturing, wide range of fracturing fractures, and guaranteed extraction effect;

[0053] (2) The underground negative pressure extraction system is used for extraction, which has a short extraction cycle and high extraction efficiency;

[0054] (3) No need to drill a vertical well, saving the cost of a vertical well in the existing roof horizontal well technology mode;

[0055] (4) Using underground roadways for drainage and gas extraction saves the cost of surface extraction equipment and has high drainage efficiency.

[0056] (5) In the later stage of gas production, the combined negative pressure extraction of the surface wellhead and underground roadway can be used to eliminate the problem of unidirectional pressure decay and uneven extraction range when extracting gas in long horizontal sections, thereby increasing the degree of gas extraction.

[0057] (6) Well repair operations (well washing) can make full use of the underground roadways, and no working machine is needed on the surface;

[0058] (7) It can replace underground gas control projects and save costs. Attached Figure Description

[0059] Figure 1 This is a cross-sectional schematic diagram of the working surface in the method of the present invention;

[0060] Figure 2 This is a top view of the working surface in the method of the present invention;

[0061] Figure 3 This is a schematic diagram of the tailpipe cementing method;

[0062] Figure 4 This is a schematic diagram of packer cementing methods;

[0063] Figure 5 This is a schematic diagram of drainage in downdipping formations;

[0064] Figure 6 This is a schematic diagram of the drainage of updipping strata;

[0065] Figure 7 This is a top view of the horizontal well area layout;

[0066] Figure 8 This is a cross-sectional schematic diagram of another working surface in the method of the present invention. Detailed Implementation

[0067] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0068] The present invention provides a method for rapid pre-gas extraction via segmented fracturing in horizontal strip wells during combined well-ground tunneling. To ensure drilling safety, the horizontal section of the well can be arranged in the roof strata of the coal seam. This case takes this as an example, and specifically includes the following steps:

[0069] Step 1: Construct a horizontal shaft above the coal seam roof along the excavation strip of the working face. The toe of this horizontal shaft is connected to the underground roadway. Figure 1 , 2 As shown, the specific steps include the following:

[0070] Step 1.1: Optimize the design of the horizontal well drilling trajectory. The horizontal section of the horizontal well trajectory should be 0-10m above the top boundary of the coal seam, and the connection point with the underground roadway should be determined.

[0071] Step 1.2: Complete the first and second stages of drilling and cementing of the horizontal well;

[0072] Step 1.3: Complete the drilling of the third section of the horizontal well and connect it to the roadway; preferably, the drilling of the third section can be carried out using a tailpipe cementing method, such as... Figure 3 As shown, the specific steps are as follows:

[0073] Step 1.3.1: Using geological steering drilling technology, complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well is located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, continuously determine the direction of the trajectory guidance device. Stop drilling when the distance to the underground roadway is 10-60m.

[0074] Step 1.3.2: Run the casing for cementing. After cementing for more than 48 hours, conduct cementing quality testing.

[0075] Step 1.3.3: Continue drilling until the horizontal well is connected to the underground roadway. Then, lower the tailpipe hanger through the drill string to connect it to the roadway.

[0076] Preferably, three-section drilling can also employ external packer cementing, such as... Figure 4 As shown, the specific steps are as follows:

[0077] Step 1.3.1: Using geological steering drilling technology, complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well is located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, continuously determine the direction of the trajectory guidance device until it connects with the underground roadway.

[0078] Step 1.3.2: Lower the casing tool string, with an external packer connected to the end of the casing, and a perforated casing short section;

[0079] Step 1.3.3: Set the packer by dropping balls and pressing them on the ground; Step 1.3.4: Inject cement slurry to cement the well, and after 48 hours of curing, conduct a cementing quality test.

[0080] Step 2: Perform segmented hydraulic fracturing on the horizontal well. This includes the following sub-steps:

[0081] Step 2.1: Use the production capacity numerical simulation method to optimize and determine the number of fracturing stages in the horizontal section of the horizontal well;

[0082] Step 2.2: Taking into account cementing quality, casing coupling location, and distance between the horizontal well and the top boundary of the coal seam, the optimal perforation location for the horizontal well is determined; the safe distance between the perforation location and the bridge plug is not less than 10m.

[0083] Step 2.3: Perform segmented fracturing on the horizontal section of the horizontal well using either bridge plug perforation combined with segmented fracturing technology or coiled tubing with bottom seal dragged hydraulic jet segmented fracturing technology;

[0084] Specifically, the construction steps of the bridge plug perforation combined staged fracturing process are as follows:

[0085] Step 2.3.1: The first section uses tubing or coiled tubing to deliver the perforating gun and bridge plug. After reaching the designed well depth, the bridge plug is set and pressure tested for 5-10 minutes. If the pressure does not decrease, the first section of bridge plug setting is complete. The bridge plug should be lowered 10-20m away from the tailpipe hanger.

[0086] Step 2.3.2: Perform the first perforation and lower the perforating gun to the ground;

[0087] Step 2.3.3: Pump fracturing fluid to carry out the first stage of fracturing construction; preferably, low-temperature temporary plugging technology can be used during the fracturing construction to increase the complexity of the fracture;

[0088] Step 2.3.4: The second stage uses a hydraulic pump to lower the bridge plug and perforation gun. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the second stage bridge plug setting is complete.

[0089] Step 2.3.5: Raise the perforating gun to complete the perforation operation, and lift the perforating gun to the ground;

[0090] Step 2.3.6: Pump fracturing fluid to carry out the second stage of fracturing operation;

[0091] Step 2.3.7: Repeat steps 2.3.5-2.3.6 to complete the fracturing construction of all subsequent fracturing sections.

[0092] Step 2.3.8: After the fracturing operation is completed, the well is flushed by drilling and plugging.

[0093] Specifically, the construction steps of the coiled tubing with bottom seal-driven hydraulic jet fracturing process are as follows:

[0094] 2.3.1: The bridge plug is set using coiled tubing to seal the bottom of the horizontal well. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the bottom of the horizontal well is successfully sealed. The bridge plug should be placed 10-20m away from the tailpipe hanger.

[0095] 2.3.2: Remove the coiled tubing, install the bottom-seal drag-type hydraulic jet fracturing tool string, and connect it to the bottom of the coiled tubing; the spray gun uses a directional hydraulic jet tool.

[0096] 2.3.3: Run the coiled tubing to the bottom of the well, then gradually lift the coiled tubing, position it using the coupling locator, and push the coiled tubing down to set the bottom packer;

[0097] 2.3.4: Inject fracturing fluid into the coiled tubing for hydraulic blasting perforation, with a perforation flow rate of 0.2-1.0 m. 3 / min; After the perforation operation is completed, fracturing fluid is injected into the annulus between the coiled tubing and the casing to carry out fracturing operations;

[0098] 2.3.5: Raise the coiled tubing to release the packer, continue raising the coiled tubing to the second perforation section, set the packer, and repeat steps 2.3.3-2.3.4 to complete the fracturing operation of all fracturing sections;

[0099] 2.3.6: After the fracturing operation is completed, the coiled tubing and the segmented fracturing tool string are pulled out.

[0100] Step 3: Install a drain valve and pressure gauge at the toe of the downhole horizontal shaft, and carry out drainage operations according to the predetermined drainage system.

[0101] Specifically, to facilitate the flowback of fracturing fluid, long directional boreholes can be drilled in the underground roadway near the coal seam floor as drainage holes, such as... Figure 1 The boreholes are arranged parallel to the horizontal sections of the horizontal wells, with similar lengths, and traverse the fracturing fracture zone to drain water from the fracturing area.

[0102] For coal seams with a small dip angle and those that dip downwards, such as Figure 5The drainage operation can be completed by controlling the drainage valve at the toe of the horizontal shaft in the roadway.

[0103] For coal seams that dip upwards, such as Figure 6 If controlling only the toe valve of the horizontal shaft in the roadway is not enough to completely drain the water from the horizontal shaft, a booster device can be installed at the surface wellhead to pressurize the medium into the horizontal shaft. The medium will then drive the water in the shaft to the toe valve of the horizontal shaft in the roadway, thereby improving the efficiency of underground drainage.

[0104] Step 4: After gas production begins, install a gas-water separator at the toe valve of the horizontal shaft in the underground roadway, and connect the exhaust port of the gas-water separator to the gas extraction system.

[0105] Step 5: When the wellbore is no longer producing water in the later stage of drainage, a negative pressure extraction system can be installed at both the surface wellhead and the toe of the horizontal wellbore in the underground roadway to achieve uniform and maximum extraction in the long horizontal section.

[0106] Step 6: Following the methods in Steps 1 to 5, construct multiple horizontal wells above the working face excavation strip within the coal seam mining area. Each horizontal well corresponds to one excavation strip, achieving efficient strip-type gas extraction. Figure 7 As shown. Multiple sets of horizontal wells can also be arranged along the working face to carry out efficient pre-drainage of the working face surface.

[0107] It should be noted that this plan only uses a roadway in a coal seam as an example. When the roadway is in the bottom or top strata of the coal seam, a connecting hole can be drilled using a downhole drilling rig, and the hole can be enlarged at the bottom to connect with a horizontal well. Figure 8 As shown.

[0108] This invention utilizes segmented fracturing and extraction via horizontal wells to create a fracture network within the coal seam excavation zone. The surface wellhead fracturing scale is large, ranging from 8 to 14 meters. 3 / min, while the downhole fracturing scale is only 1-2m 3 The fracturing speed is [ / min], resulting in a long surface extension of the fractures and a large extraction range, which is beneficial for coal seam gas extraction. Extraction is carried out using roadways connected to horizontal wells, eliminating the need for conventional vertical shaft drilling and the installation of extraction equipment. Furthermore, due to the hydraulic pressure within the horizontal wellbore, extraction only requires controlling the opening of the extraction valve, making it easy to implement. Later, it can be connected to an underground negative pressure extraction system to reduce reservoir pressure by 4-35 kPa, further promoting coal seam gas desorption. Simultaneously, negative pressure extraction equipment is installed at the surface wellhead to achieve uniform extraction of the entire coal seam. This invention changes the original method of strip gas extraction during tunneling, adopting a safer surface construction method while saving on the construction costs of underground floor rock roadways and floor penetration holes.

Claims

1. A method for rapid pre-drainage of gas in a strip horizontal well using combined well-ground tunneling, characterized in that, Specifically, the steps include the following: Step 1: Construct a horizontal shaft for the coal seam roof above the tunneling strip of the working face, with the toe end of the horizontal shaft connected to the underground roadway; Step 2: Perform segmented hydraulic fracturing on the horizontal well; Step 3: Install drainage valves and pressure gauges at the toe of the horizontal shaft downhole, and carry out drainage operations according to the predetermined drainage system; Step 4: After gas production begins, install a gas-water separator at the toe valve of the horizontal shaft in the underground roadway, and connect the exhaust port of the gas-water separator to the gas drainage system. Step 5: When the wellbore is no longer producing water in the later stage of drainage, a negative pressure extraction system is installed at both the surface wellhead and the toe of the horizontal wellbore in the underground roadway. Step 6: Following the methods in Steps 1 to 5, construct multiple horizontal wells above the working face tunneling strip within the coal seam mining area. Each horizontal well corresponds to one tunneling strip to achieve strip-type gas extraction; or, arrange multiple sets of horizontal wells along the working face strike to perform pre-extraction at the working face surface.

2. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 1, characterized in that: Step 1 includes the following sub-steps: Step 1.1: Optimize the design of the horizontal well drilling trajectory. The horizontal section of the horizontal well trajectory should be 0-10m above the top boundary of the coal seam, and the connection point with the underground roadway should be determined. Step 1.2: Complete the first and second stages of drilling and cementing of the horizontal well; Step 1.3: Complete the drilling of the third section of the horizontal well and connect it to the roadway.

3. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 2, characterized in that: In step 1.3, the drilling of the third section of the horizontal well adopts the tailpipe cementing method, and the specific steps are as follows: 1.3.1: Geological steering drilling technology was adopted to complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well was located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, the direction of the trajectory guidance device was continuously determined. Drilling was stopped when the distance to the underground roadway was 10-60m. Step 1.3.2: Run the casing for cementing. After cementing for more than 48 hours, conduct cementing quality testing. Step 1.3.3: Continue drilling until the horizontal well is connected to the underground roadway. Then, lower the tailpipe hanger through the drill string to connect it to the roadway.

4. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 2, characterized in that, In step 1.3, the drilling of the third section of the horizontal well adopts the external packer cementing method. The specific steps are as follows: Step 1.3.1: Using geological steering drilling technology, complete the three-stage drilling of the horizontal well. The horizontal section of the horizontal well is located in the roof strata within the range of 0-10m above the coal seam. During the drilling process, continuously determine the direction of the trajectory guidance device until it connects with the underground roadway. Step 1.3.2: Lower the casing tool string, with an external packer connected to the end of the casing, and a perforated casing short section; Step 1.3.3: Set the packer; Step 1.3.4: Inject cement slurry for cementing, and after 48 hours of curing, conduct cementing quality testing.

5. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 2, characterized in that... Step 2 includes the following sub-steps: Step 2.1: Use the production capacity numerical simulation method to optimize and determine the number of fracturing stages in the horizontal section of the horizontal well; Step 2.2: Taking into account cementing quality, casing coupling location, and distance between the horizontal well and the top boundary of the coal seam, determine the perforation locations for the horizontal well sections; the safe distance between the perforation location and the bridge plug shall not be less than 10m; Step 2.3: Use the bridge plug perforation combined fracturing process or the coiled tubing with bottom seal to drive the hydraulic jet fracturing process to perform segmented fracturing on the horizontal section of the horizontal well.

6. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 5, characterized in that, In step 2.3, the construction steps of the bridge plug perforation combined staged fracturing process are as follows: Step 2.3.1: The first section uses tubing or coiled tubing to transport the perforating gun and bridge plug. After reaching the designed well depth, the bridge plug is set and pressure tested for 5-10 minutes. If the pressure does not decrease, the first section of bridge plug setting is complete. Step 2.3.2: Perform the first perforation and lower the perforating gun to the ground; Step 2.3.3: Pump fracturing fluid to carry out the first stage of fracturing construction; low-temperature temporary plugging technology is used during the fracturing construction to increase the complexity of the fracture; Step 2.3.4: The second stage uses a hydraulic pump to lower the bridge plug and perforation gun. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the second stage bridge plug setting is complete. Step 2.3.5: Raise the perforating gun to complete the perforation operation, and lift the perforating gun to the ground; Step 2.3.6: Pump fracturing fluid to carry out the second stage of fracturing operation; Step 2.3.7: Repeat steps 2.3.5-2.3.6 to complete the fracturing construction of all subsequent fracturing sections; Step 2.3.8: After the fracturing operation is completed, the well is flushed by drilling and plugging.

7. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 6, characterized in that, In step 2.3.1, the bridge plug should be inserted at a distance of 10-20m from the tailpipe hanger.

8. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 5, characterized in that, In step 2.3, the construction steps of the coiled tubing with bottom seal-driven hydraulic jet fracturing process are as follows: 2.3.1: The bridge plug is set using a coiled tubing delivery method to seal the bottom of the horizontal well. After the bridge plug reaches the designed well depth, a pressure test is performed for 5-10 minutes. If the pressure does not decrease, the bottom of the horizontal well is successfully sealed. 2.3.2: Pull out the coiled tubing, install the bottom-seal drag-type hydraulic jet fracturing tool string, and connect it to the bottom of the coiled tubing; the spray gun uses a directional hydraulic jet tool; 2.3.3: Run the coiled tubing to the bottom of the well, then gradually lift the coiled tubing, position it using the coupling locator, and push the coiled tubing down to set the bottom packer; 2.3.4: Inject fracturing fluid into the coiled tubing for hydraulic blasting perforation, with a perforation flow rate of 0.2-1.0 m. 3 / min; After the perforation operation is completed, fracturing fluid is injected into the annulus between the coiled tubing and the casing to carry out fracturing operations; 2.3.5: Raise the coiled tubing to release the packer, continue raising the coiled tubing to the second perforation section, set the packer, and repeat steps 2.3.3-2.3.4 to complete the fracturing operation of all fracturing sections; 2.3.6: After the fracturing operation is completed, the coiled tubing and the segmented fracturing tool string are pulled out.

9. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 8, characterized in that, In step 2.3.1, the bridge plug should be inserted at a distance of 10-20m from the tailpipe hanger.

10. The method for rapid pre-drainage of gas in a horizontal strip well using combined well-ground tunneling as described in claim 5, characterized in that, In step 3, drainage directional long boreholes are constructed in the underground roadway near the bottom of the coal seam as drainage holes. The boreholes are arranged parallel to the horizontal section of the horizontal well and are of similar length. For coal seams with a small dip angle and downward dip, the drainage operation is completed by controlling the toe valve of the horizontal shaft in the roadway. For coal seams that dip upwards, a pressurization device is installed at the surface wellhead to pressurize the medium into the horizontal well. The medium then drives the water in the wellbore to the valve at the toe of the horizontal wellbore in the roadway to complete the drainage operation.

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