An apparatus for enhancing fracturing of a well drilled into the ground and a method for determining fracturing conditions

Abstract

The application discloses a device for strengthening fracturing of a ground drilling well and a method for determining fracturing conditions, which comprises the following steps: firstly, after the ground drilling well passes through a coal seam, a bottom space of the drilling well is formed by continuous construction, and an air bag is arranged in the bottom space of the drilling well, which is used for avoiding that acid and alkali liquid enters the bottom space of the drilling well when fracturing, and after the fracturing is completed, the acid and alkali liquid is discharged into a lower rock layer under the bottom space of the drilling well; secondly, acid liquid and alkali liquid are alternately injected into the ground drilling well to perform fracturing impact; thirdly, the functions of dissolving and dissolving and corroding cementing material, mineral and blockage in the coal body by the acid liquid and the alkali liquid are used to improve fracturing effect; and fourthly, after the acid liquid is fractured, a positioning support ball is carried into a crack to perform support, and the positioning support ball can delay the closure of the crack and can move when the alkali liquid is fractured. After the fracturing is completed, the positioning support ball is distributed in the crack, the positions of the positioning support balls in the coal seam can be obtained by using a positioner detector, and then the development and cracking conditions of the crack after the fracturing can be obtained, so that the arrangement position of the next ground drilling well can be determined.

Description

An apparatus for enhancing surface drilling fracturing and a method for determining fracturing conditions. Technical Field

[0001] This invention relates to the field of coalbed methane extraction from surface drilling, specifically to an apparatus for enhancing surface drilling fracturing and a method for determining fracturing conditions. Background Technology

[0002] Coalbed methane is a clean energy source. According to statistics, my country's geological reserves of coalbed methane within a depth of 2000m are approximately 36.8 trillion cubic meters, ranking third in the world, and it has great development potential. However, the geological conditions of coalbed methane occurrence in my country are complex, and the permeability of coal seams is low, so coalbed methane extraction generally faces the problems of high extraction costs and low extraction efficiency.

[0003] To increase coalbed methane production from surface drilling, various enhancement techniques such as hydraulic fracturing, gas injection displacement, and multi-branch horizontal wells are employed. Among these, hydraulic fracturing is currently the most commonly used technique in coalbed methane extraction. However, existing hydraulic fracturing technologies create relatively few fractures within the coal seam, and these fractures tend to close easily. Furthermore, the open-cut nature of the fractures after fracturing is unclear, making it impossible to determine the extent of the hydraulic fracturing's impact and consequently affecting the design of subsequent surface drilling intervals. Therefore, improving the effectiveness of hydraulic fracturing and clarifying the open-cut nature of the fractures are areas requiring further research. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides an apparatus for enhancing surface drilling fracturing and a method for determining the fracturing status. Through the combined action of acid, alkali and positioning support ball, the permeability of the coal body is improved and the pressure is relieved, and the closure of the fracture network is delayed. At the same time, the fracturing status is determined by the positioning support ball.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a device for enhancing surface drilling fracturing, comprising a positioning support ball container, an injection pump, an acid tank, and an alkali tank;

[0006] The outlet of the positioning support ball container is connected to one port of a tee connector via a fifth pipe. The other two ports of the tee connector are connected to one end of a first pipe and one end of a second pipe, respectively. The other end of the second pipe is connected to the outlet of the injection pump. The first inlet of the injection pump is connected to the acid tank via a third pipe, and the second inlet of the injection pump is connected to the alkali tank via a fourth pipe. A first control valve is installed on the second pipe, a second control valve is installed on the third pipe, a third control valve is installed on the fourth pipe, and a fourth control valve is installed on the fifth pipe.

[0007] The positioning support ball container contains multiple positioning support balls, the acid tank contains acid, the alkali tank contains alkali, and the positioning support ball is equipped with a positioner.

[0008] Furthermore, the positioning support sphere has an internal spherical hollow structure, within which the locator is fixed. Multiple micropores are formed on the outer shell of the positioning support sphere, radially and evenly distributed around the sphere's center. The spherical hollow structure communicates with the outside world through these micropores. This structure not only supports the generated cracks, preventing them from automatically closing under ground stress, but also allows for subsequent positioning of crack opening.

[0009] Furthermore, the diameter of the positioning support ball is 3-5 mm, the diameter of the spherical hollow structure is 2 / 3 to 4 / 5 of the diameter of the positioning support ball, and the number of micropores on the outer shell of the positioning support ball is 6-9 per square centimeter.

[0010] Furthermore, a pressure gauge is installed on the second pipeline. The pressure gauge is used to monitor the pressure inside the surface well.

[0011] Furthermore, all components are coated with an acid- and alkali-resistant coating at the points where they come into contact with acid or alkali solutions during use. This design extends the service life of each component and reduces the frequency of maintenance.

[0012] The specific steps for using the aforementioned enhanced surface drilling fracturing device to perform fracturing and determine the fracturing status are as follows:

[0013] A. Construct a surface well for coalbed methane extraction according to design requirements. After the surface well penetrates the coal seam, continue drilling downwards for 1.1 to 1.2 times the coal seam thickness to form the bottom space of the well. Fix the separator inside the coalbed methane extraction pipe. One end of the gas injection pipe passes through the separator from one end of the coalbed methane extraction pipe to the other end and connects to the air bladder. One end of the liquid injection pipe passes through the separator from one end of the coalbed methane extraction pipe to the other end. Then, extend the other end of the coalbed methane extraction pipe into the surface well until it stops above the coal seam. At this time, the air bladder is in the bottom space of the well. Then fix the coalbed methane extraction pipe to the surface well and seal one end of the coalbed methane extraction pipe with a well sealing cap. The other end of the liquid injection pipe is connected to the other end of the first pipeline. The other end of the gas injection pipe is connected to the air compressor. The gas injection pipe is equipped with a fifth control valve and a pressure relief valve. An infrared rangefinder is installed on the separator, thus completing the installation of the device. Initially, all control valves are in the closed state, and the air bladder is in the uninflated state.

[0014] B. Open the fifth control valve and start the air compressor. Inject compressed air into the airbag through the air injection pipe. The airbag will begin to expand until it presses against the well wall at the bottom of the well. Then close the fifth control valve and stop the air compressor.

[0015] C. When co-injecting acid and positioning support ball, open the second control valve and the first control valve and start the injection pump. The injection pump injects the acid in the acid tank into the surface well through the third pipeline, the second pipeline, the tee joint, the first pipeline and the injection pipe. After 30-60 seconds of injection, open the fourth control valve. The positioning support ball is discharged from the positioning support ball container, passes through the fifth pipeline and the tee joint into the first pipeline, and is injected into the surface well along with the acid. Continuously observe the pressure gauge reading. When the pressure gauge reading starts to rise continuously, it indicates that the surface well is full of acid. Close the fourth control valve and the injection pump continues to pressurize, so that the acid pressure in the surface well reaches 40-50 MPa.

[0016] D. Continuously observe the pressure gauge readings. When the acid pressure on the pressure gauge suddenly drops, it indicates that under the corrosive dissolution of the high-pressure acid and the pressure, the fractures open along the weak surface of the coal body. Subsequently, the acid and the positioning support ball will enter the fractures. At this time, the positioning support ball fills and supports the fractures to prevent them from closing automatically under the action of ground stress. Then, close the second control valve and the first control valve and stop the injection pump. Let it stand for 24 to 36 hours. The acid in the surface well will continue to dissolve and erode the cementitious materials in the coal body, the minerals in the fractures, and the blockages, further increasing the permeability of the coal body.

[0017] E. Open the pressure relief valve and slowly release the air from the airbag. Continue this for a period of time until the airbag deflates, then close the pressure relief valve. At this time, the acid in the surface well flows into the bottom space of the well along the fractures and the gap between the airbag and the bottom space of the well, and gradually enters the rock fractures in the lower part of the bottom space of the well. Measure the level of the acid in the surface well using an infrared rangefinder. When the distance to the level measured by the infrared rangefinder is equal to the sum of the current coal seam thickness and the depth of the bottom space of the well, it indicates that most of the acid has been absorbed by the rock strata. At this time, open the fifth control valve and start the air compressor to inject air into the airbag again to expand it until the airbag is pressed tightly against the well wall of the bottom space of the well. Then close the fifth control valve and stop the air compressor.

[0018] F. Open the third and first control valves and start the injection pump. The injection pump injects the alkali solution in the alkali tank into the surface well through the fourth pipeline, the second pipeline, the tee joint, the first pipeline, and the injection pipe. Continuously observe the pressure gauge reading. When the pressure gauge reading starts to rise, it indicates that the surface well is full of alkali solution. Close the third control valve, and the injection pump continues to pressurize, so that the acid pressure in the surface well reaches 30-40 MPa. While keeping the power of the injection pump constant, if the pressure gauge pressure gradually decreases, it indicates that under the corrosive dissolution and impact of the high-pressure alkali solution, the existing fracture network has further expanded and developed. At the same time, the positioning support ball also moves further into the depth of the fracture with the alkali solution. When the pressure gauge reading decreases at a rate of 0.1-0.2 MPa / h, close the first control valve and stop the injection pump.

[0019] G. After standing for 6-12 hours, open the pressure relief valve and slowly release the air in the airbag. Continue for a period of time until the airbag deflates, then close the pressure relief valve. At this time, the alkaline solution in the surface well flows into the bottom space of the well along the fractures and the gap between the airbag and the bottom space of the well, and gradually enters the rock fractures in the lower part of the bottom space of the well. Measure the liquid level of the alkaline solution in the surface well with an infrared rangefinder. When the distance of the liquid level measured by the infrared rangefinder is equal to the sum of the current coal seam thickness and the depth of the bottom space of the well, it indicates that most of the alkaline solution has been absorbed by the rock strata, completing this acid-base fracturing coal body process.

[0020] H. The first pipeline of the enhanced surface drilling fracturing device is separated from the injection pipe, and the locator detector is turned on. Since the locator is installed inside the locator support ball, the position of each locator support ball can be determined, thereby determining the fracturing status and influence range of the fracture, and providing data guidance for the layout of the next surface drilling.

[0021] I. Connect the coalbed methane extraction pipe to the coalbed methane extraction pump station of the surface well to extract coalbed methane. During the continuous extraction process, when the concentration of coalbed methane extracted from the surface well is lower than 30%, stop the extraction work and repeat steps B to H to extract coalbed methane again until the extraction of coalbed methane from the surface well is completed.

[0022] Furthermore, the pH value of the acid solution is 3-5, and the pH value of the alkaline solution is 9-10.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. After drilling through the coal seam on the surface, the drilling continues to form a bottom space. Airbags are placed in the bottom space. When the airbags are inflated, they can fill the bottom space. This prevents acid or alkali from entering the bottom space when injected into the surface drilling for fracturing, which would otherwise cause the acid or alkali to flow out from the lower rock strata. After the acid or alkali fracturing is completed, the airbags are deflated to reduce their volume, allowing the acid or alkali to be discharged into the bottom space and eventually enter the lower rock strata. This ensures that the acid and alkali fracturing processes in the coal seam are relatively independent.

[0025] 2. By alternately injecting acid and alkali solutions into the surface well to induce fracturing, the dissolving and eroding properties of cementitious materials, minerals, and blockages within the coal seam are utilized to improve fracturing efficiency. Simultaneously, the acid carries positioning support balls into the fracture. After fracturing occurs, the support balls follow the acid into the fracture, supporting it and delaying its closure. Because the support balls have micropores, even if the fracture partially closes during subsequent extraction, the multiple micropores ensure unobstructed gas flow channels. Furthermore, as the fracture further develops after subsequent alkali injection, the support balls continue to move deeper into the fracture with the alkali. The key to their ability to flow with the acid and alkali solutions is their density, which is 0.95–1.05 times that of water. This facilitates the flow of the support balls to the deepest part of the fracture, achieving full-channel support throughout the fracture.

[0026] 3. After alternating fracturing impacts with acid and alkali solutions, the positioning support balls are already distributed within the fracture. Since each positioning support ball is equipped with a locator, the position of each positioning support ball within the coal seam can be determined through the locator detector. This allows for the determination of the fracture development and cracking status after this fracturing process (the fracture development and cracking status includes the fracture width and fracture range; the wider a certain segment of the fracture, the more positioning support balls are gathered in that segment, and the fracture range is determined by the distribution range of the positioning support balls). Based on this information, the location of the next surface well and its distance from the current surface well can be determined. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the layout of the device of the present invention;

[0028] Figure 2 is a schematic diagram of the distribution of the positioning support ball after it enters the crack in this invention;

[0029] Figure 3 is a schematic diagram of the positioning support ball of the present invention.

[0030] In the diagram: 1. Airbag; 2. Separator; 3. Infrared rangefinder; 4. Coal seam; 5. Surface well; 6. Coalbed methane extraction pipe; 7. Liquid injection pipe; 8. Gas injection pipe; 9. Drilling sealing cap; 10. First pipeline; 11. Second pipeline; 12. First control valve; 13. Liquid injection pump; 14. Third pipeline; 15. Second control valve; 16. Acid tank; 17. Fourth pipeline; 18. Third control valve; 19. Alkali tank; 20. Pressure gauge; 21. Positioning support ball container; 22. Fifth pipeline; 23. Fourth control valve; 24. T-joint; 25. Pressure relief valve; 26. Fifth control valve; 27. Air compressor; 28. Crack; 29. ​​Positioning support ball; 29-1. Outer shell; 29-2. Positioner; 29-3. Micropore. Detailed Implementation

[0031] The present invention will be further described below.

[0032] As shown in Figure 1, an enhanced surface drilling fracturing device includes a positioning support ball container 21, an injection pump 13, an acid tank 16, and an alkali tank 19.

[0033] The outlet of the positioning support ball container 21 is connected to one port of the tee connector 24 via the fifth pipe 22. The other two ports of the tee connector 24 are connected to one end of the first pipe 10 and one end of the second pipe 11, respectively. The other end of the second pipe 11 is connected to the outlet of the injection pump 13. The first inlet of the injection pump 13 is connected to the acid tank 16 via the third pipe 14, and the second inlet of the injection pump 13 is connected to the alkali tank 19 via the fourth pipe 17. The second pipe 11 is equipped with a first control valve 12, the third pipe 14 is equipped with a second control valve 15, the fourth pipe 17 is equipped with a third control valve 18, and the fifth pipe 22 is equipped with a fourth control valve 23. The second pipe 11 is equipped with a pressure gauge 20. Pressure gauge 20 is installed to monitor the pressure inside the surface drilling well; the positioning support ball container 21 contains multiple positioning support balls 29, the acid tank 16 contains acid, the alkali tank 19 contains alkali, and the positioning support balls 29 are equipped with positioners 29-2; all components are coated with acid and alkali corrosion resistant coatings at the locations that come into contact with acid or alkali during use. This arrangement can extend the service life of each component and reduce the frequency of maintenance.

[0034] As an improvement of the present invention, as shown in Figure 3, the positioning support ball 29 has a hollow spherical structure inside, and the locator 29-2 is fixed inside the hollow spherical structure. Multiple micro-holes 29-3 are formed on the outer shell 29-1 of the positioning support ball 29. The outer shell 29-1 is made of rubber, and the multiple micro-holes 29-3 are radially and evenly distributed around the center of the positioning support ball 29. The hollow spherical structure communicates with the outside world through each micro-hole 29-3. This structure not only supports the generated cracks to prevent them from automatically closing under the action of ground stress, but also can be used to locate subsequent crack opening. The diameter of the positioning support ball 29 is 3-5 mm, and the diameter of the hollow spherical structure is 2 / 3 to 4 / 5 of the diameter of the positioning support ball 29. The number of micropores 29-3 on the outer shell 29-1 of the positioning support ball 29 is 6-9 per square centimeter, and the pore diameter of the micropores 29-3 is 0.5 mm to 1 mm. The density of the positioning support ball 29 is 0.95 to 1.05 times the density of water. This makes it easier for the positioning support ball 29 to be inside the acid liquid when it flows with the acid liquid, and prevents it from interfering with transportation due to excessive or insufficient density.

[0035] The specific steps for using the aforementioned enhanced surface drilling fracturing device to perform fracturing and determine the fracturing status are as follows:

[0036] A. Construct a surface well 5 for coalbed methane extraction according to design requirements. After penetrating coal seam 4, the surface well 5 continues to descend for a distance of 1.1 to 1.2 times the coal seam thickness to form the bottom space of the well. Fix the separator 2 inside the coalbed methane extraction pipe 6, with a distance of 0.1 to 0.2 meters from the other end. One end of the gas injection pipe 8 passes through the separator 2 from one end of the coalbed methane extraction pipe 6 to the other end and is connected to the gas bag 1. One end of the liquid injection pipe 7 passes through the separator 2 from one end of the coalbed methane extraction pipe 6 to the other end. Then, extend the other end of the coalbed methane extraction pipe 6 into the surface well 5. The process continues until it stops above the coal seam 4. At this point, the airbag 1 is in the bottom space of the well. Then, the coalbed methane extraction pipe 6 is fixed to the surface well 5, and one end of the coalbed methane extraction pipe 6 is sealed with the well sealing cap 9. The other end of the injection pipe 7 is connected to the other end of the first pipeline 10, and the other end of the gas injection pipe 8 is connected to the air compressor 27. The gas injection pipe 8 is equipped with a fifth control valve 26 and a pressure relief valve 25, and an infrared rangefinder 3 is installed on the separator 2, thus completing the installation of the device. Initially, all control valves are in the closed state, and the airbag 1 is in the uninflated state.

[0037] B. Open the fifth control valve 26 and start the air compressor 27. Inject compressed air into the airbag 1 through the air injection pipe 8. The airbag 1 begins to expand until it presses against the well wall at the bottom of the well. Then close the fifth control valve 26 and stop the air compressor 27. The expanded airbag 1 can withstand a water pressure of 50-60 MPa.

[0038] C. When the acid and positioning support ball 29 are injected together, open the second control valve 15 and the first control valve 12 and start the injection pump 13. The injection pump 13 injects the acid in the acid tank 16 into the surface well 5 through the third pipeline 14, the second pipeline 11, the tee connector 24, the first pipeline 10 and the injection pipe 7. The pH value of the acid is 3 to 5. After 30 to 60 seconds of injection, open the fourth control valve 23. The positioning support ball 29 is discharged from the positioning support ball container 21, passes through the fifth pipeline 22 and the tee connector 24 into the first pipeline 10, and is injected into the surface well 5 along with the acid. Continuously observe the reading of the pressure gauge 20. When the reading of the pressure gauge 20 starts to rise continuously, it indicates that the acid in the surface well 5 is full. Close the fourth control valve 23 and the injection pump 13 continues to pressurize, so that the acid pressure in the surface well 5 reaches 40 to 50 MPa.

[0039] D. Continuously observe the reading of pressure gauge 20. When the acid pressure in pressure gauge 20 suddenly drops, it indicates that under the corrosive dissolution of high-pressure acid and the action of pressure, fracture 28 has cracked along the weak surface of the coal body. Then, acid and positioning support ball 29 will enter the fracture 28, as shown in Figure 2. At this time, the positioning support ball 29 fills and supports the fracture 28 to prevent the fracture 28 from closing automatically under the action of ground stress. Then close the second control valve 15 and the first control valve 12 and stop the injection pump 13. Let it stand for 24 to 36 hours. The acid in the surface well 5 continues to dissolve and erode the cement in the coal body, the minerals in the fracture 28 and the blockages, further increasing the permeability of the coal body.

[0040] E. Open the pressure relief valve 25 and slowly release the air in the airbag 1. Continue for a period of time until the airbag 1 deflates, then close the pressure relief valve 25. At this time, the acid in the surface well 5 flows into the bottom space of the well along the fracture 28 and the gap between the airbag 1 and the bottom space of the well, and gradually enters the rock fractures in the lower part of the bottom space of the well. The surface level of the acid in the surface well 5 is measured by the infrared rangefinder 3. When the distance of the liquid level measured by the infrared rangefinder 3 is equal to the sum of the current coal seam thickness and the bottom space depth of the well, it indicates that most of the acid has been absorbed by the rock strata. At this time, open the fifth control valve 26 and start the air compressor 27 to inject air into the airbag 1 again to make it expand until the airbag 1 is pressed tightly against the well wall of the bottom space of the well. Then close the fifth control valve 26 and stop the air compressor 27.

[0041] F. Open the third control valve 18 and the first control valve 12, and start the injection pump 13. The injection pump 13 injects the alkali solution in the alkali tank 19 into the surface well 5 through the fourth pipeline 17, the second pipeline 11, the tee connector 24, the first pipeline 10, and the injection pipe 7. The pH value of the alkali solution is 9-10. Continuously observe the reading of the pressure gauge 20. When the reading of the pressure gauge 20 begins to rise, it indicates that the alkali solution in the surface well 5 is full. Close the third control valve 18, and the injection pump 13 continues to pressurize. The acid pressure inside the surface well 5 is brought to 30-40 MPa. If the pressure on the pressure gauge 20 gradually decreases while keeping the power of the injection pump 13 constant, it indicates that the fracture network that has been formed has further expanded and developed under the corrosive dissolution and impact of the high-pressure alkaline solution. At the same time, the positioning support ball 29 also moves further into the depth of the fracture 28 along with the alkaline solution. When the reading of the pressure gauge 20 decreases at a rate of 0.1-0.2 MPa / h, the first control valve 12 is closed and the injection pump 13 is stopped.

[0042] G. After standing for 6-12 hours, open the pressure relief valve 25 and slowly release the air in the airbag 1. Continue for a period of time until the airbag 1 deflates, then close the pressure relief valve 25. At this time, the alkaline solution in the surface well 5 flows into the bottom space of the well along the fracture 28 and the gap between the airbag 1 and the bottom space of the well, and gradually enters the rock fractures in the lower part of the bottom space of the well. The liquid level of the alkaline solution in the surface well 5 is measured by the infrared rangefinder 3. When the liquid level distance measured by the infrared rangefinder 3 is equal to the sum of the current coal seam thickness and the bottom space depth of the well, it indicates that most of the alkaline solution has been absorbed by the rock strata, and the acid-base fracturing coal body process is completed.

[0043] H. The first pipeline 10 of the enhanced surface drilling fracturing device is separated from the injection pipe 7, and the locator detector is turned on. Since the locator 29-2 is installed inside the locator support ball 29, the position of each locator support ball 29 can be determined, thereby determining the cracking condition and influence range of the fracture 28, and providing data guidance for the arrangement position of the next surface drilling 5.

[0044] I. Connect the coalbed methane extraction pipe 6 to the coalbed methane extraction pump station of the surface well 5 to extract coalbed methane. During the continuous extraction process, when the concentration of coalbed methane extracted from the surface well 5 is lower than 30%, stop the extraction work and repeat steps B to H to extract coalbed methane again until the extraction of coalbed methane from the surface well 5 is completed.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for enhancing surface drilling fracturing equipment to perform fracturing and determine fracturing conditions, characterized in that, The enhanced surface drilling fracturing device includes a positioning support ball container, an injection pump, an acid tank, and an alkali tank. The outlet of the positioning support ball container is connected to one port of a tee connector via a fifth pipeline. The other two ports of the tee connector are connected to one end of a first pipeline and one end of a second pipeline, respectively. The other end of the second pipeline is connected to the outlet of the injection pump. The first inlet of the injection pump is connected to the acid tank via a third pipeline, and the second inlet of the injection pump is connected to the alkali tank via a fourth pipeline. A first control valve and a pressure gauge are installed on the second pipeline, a second control valve on the third pipeline, a third control valve on the fourth pipeline, and a fourth control valve on the fifth pipeline. The positioning support ball container contains... Multiple positioning support balls are placed inside. The acid tank contains acid, and the alkali tank contains alkali. Positioning support balls are equipped with positioning devices. The specific steps are as follows: A. Construct a surface well for coalbed methane extraction according to design requirements. After the surface well penetrates the coal seam, continue drilling downwards for 1.1 to 1.2 times the coal seam thickness to form the bottom space of the well. Fix the separator inside the coalbed methane extraction pipe. One end of the gas injection pipe passes through the separator from one end of the coalbed methane extraction pipe to the other end and connects to the gas bladder. One end of the liquid injection pipe passes through the separator from one end of the coalbed methane extraction pipe to the other end. Then, extend the other end of the coalbed methane extraction pipe into the surface well until it stops above the coal seam. At this point, the gas bladder is located within the bottom space of the well. Then, the coalbed methane extraction pipe is fixed to the surface well, and one end of the extraction pipe is sealed with a well sealing cap. The other end of the injection pipe is connected to the other end of the first pipeline, and the other end of the gas injection pipe is connected to the air compressor. The gas injection pipe is equipped with a fifth control valve and a pressure relief valve, and an infrared rangefinder is installed on the separator, thus completing the installation of the device. Initially, all control valves are closed, and the air bladder is uninflated. B. Open the fifth control valve and start the air compressor. Compressed air is injected into the air bladder through the injection pipe. The air bladder begins to expand until it presses tightly against the well wall at the bottom of the well. Then, close the fifth control valve and stop the air compressor. C. Begin When injecting acid and positioning support ball together, open the second control valve and the first control valve and start the injection pump. The injection pump injects the acid in the acid tank into the surface well through the third pipeline, the second pipeline, the tee joint, the first pipeline and the injection pipe. After 30-60 seconds of injection, open the fourth control valve. The positioning support ball is discharged from the positioning support ball container, passes through the fifth pipeline and the tee joint into the first pipeline, and is injected into the surface well along with the acid. Continuously observe the pressure gauge reading. When the pressure gauge reading starts to rise continuously, it indicates that the surface well is full of acid. Close the fourth control valve and the injection pump continues to pressurize, so that the acid pressure in the surface well reaches 40-50 MPa.D. Continuously observe the pressure gauge readings. When the acid pressure on the pressure gauge suddenly drops, it indicates that under the corrosive dissolution and pressure of the high-pressure acid, the fractures have opened along the weak surfaces of the coal body. Subsequently, the acid and positioning support balls will enter the fractures. At this time, the positioning support balls fill and support the fractures to prevent them from automatically closing under the action of ground stress. Then, close the second and first control valves and stop the injection pump. Let it stand for 24–36 hours. The acid in the surface well will continue to dissolve and erode the cementitious materials in the coal body, the minerals in the fractures, and the blockages, further increasing the permeability of the coal body. E. Open the pressure relief valve and slowly release the air from the airbag. Continue for a period of time until the airbag deflates, then close the pressure relief valve. At this time, the acid in the surface well will flow along the fractures and... The acid flows into the bottom space of the well through the gap between the airbag and the bottom space, and gradually enters the rock fissures below the bottom space. The surface level of the acid is measured using an infrared rangefinder. When the distance measured by the infrared rangefinder equals the sum of the current coal seam thickness and the depth of the bottom space, it indicates that most of the acid has been absorbed by the rock formation. At this point, the fifth control valve is opened and the air compressor is started to inflate the airbag again until it presses tightly against the well wall of the bottom space. Then, the fifth control valve is closed and the air compressor stops working. Next, the third and first control valves are opened and the injection pump is started. The injection pump injects the alkali solution from the alkali tank into the surface through the fourth pipeline, the second pipeline, the tee joint, the first pipeline, and the injection pipe. Inside the well; continuously observe the pressure gauge reading. When the pressure gauge reading begins to rise, it indicates that the surface well is full of alkali solution. Close the third control valve, and continue pressurizing the injection pump to bring the acid pressure inside the surface well to 30-40 MPa. While maintaining the injection pump power, if the pressure gauge pressure gradually decreases, it indicates that the existing fracture network has further expanded and developed under the corrosive, dissolving, and impacting effects of the high-pressure alkali solution. Simultaneously, the positioning support ball also moves further into the depths of the fractures along with the alkali solution. When the pressure gauge reading decreases at a rate of 0.1-0.2 MPa / h, close the first control valve and stop the injection pump. G. After standing for 6-12 hours, open the pressure relief valve to slowly release the air from the airbag. Continue this process until the airbag deflates before closing the valve. Close the pressure relief valve; at this time, the alkaline solution in the surface well flows into the bottom space of the well along the fractures and the gap between the airbag and the bottom space of the well, and gradually enters the rock fractures in the lower part of the bottom space of the well. The liquid level of the alkaline solution in the surface well is measured by an infrared rangefinder. When the liquid level distance measured by the infrared rangefinder is equal to the sum of the current coal seam thickness and the bottom space depth of the well, it indicates that most of the alkaline solution has been absorbed by the rock strata, and the acid-alkali fracturing process of the coal body is completed; H. Separate the first pipeline and the injection pipe of the enhanced surface drilling fracturing device, and open the locator detector. Since the locator is installed inside the locator support ball, the position of each locator support ball can be determined, thereby determining the fracturing situation and the range of influence of the fracture, and providing data guidance for the layout of the next surface well; I. Connect the coalbed methane extraction pipe to the coalbed methane extraction pump station of the surface well for coalbed methane extraction. During continuous extraction, when the concentration of coalbed methane extracted from the surface well is below 30%, the extraction work is stopped, and steps B to G are repeated to extract coalbed methane again until the extraction of coalbed methane from the surface well is completed.

2. The method according to claim 1, characterized in that, The positioning support ball has a hollow spherical structure inside, and the positioner is fixed inside the hollow spherical structure. Multiple micro-holes are opened on the outer shell of the positioning support ball. The multiple micro-holes are evenly distributed radially around the center of the positioning support ball. The hollow spherical structure is connected to the outside world through each micro-hole.

3. The method according to claim 1, characterized in that, The diameter of the positioning support ball is 3-5 mm, the diameter of the hollow spherical structure is 2 / 3 to 4 / 5 of the diameter of the positioning support ball, and the number of micropores on the outer shell of the positioning support ball is 6-9 per square centimeter.

4. The method according to claim 1, characterized in that, All parts that come into contact with acid or alkali solutions during use are coated with an acid and alkali corrosion resistant coating.

5. The method according to claim 1, characterized in that, The acid solution has a pH of 3 to 5, and the alkaline solution has a pH of 9 to 10.

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