Pneumatic directional drilling device and method for horizontal section of horizontal well passing through goaf

Abstract

The invention discloses a pneumatic directional drilling device and method for a horizontal section of a horizontal well passing through a goaf, and belongs to the technical field of drilling equipment. The invention aims to provide a high-efficiency zero-pollution directional drilling device and method for a horizontal section of a horizontal well penetrating through a goaf. According to the technical scheme, the device comprises a drill bit, a pneumatic screw rod, a non-magnetic drill collar, a wireless while-drilling instrument, a heavy weight drill rod, a matched long connector and a drill rod, the drill bit is connected with one end of the pneumatic screw rod through threads, the other end of the pneumatic screw rod is connected with one end of the non-magnetic drill collar through a first directional connector after being provided with a one-way valve, and the wireless while-drilling instrument is installed in the non-magnetic drill collar. The other end of the non-magnetic drill collar is connected with one end of the heavy weight drill pipe through a second directional connector, and the other end of the heavy weight drill pipe is connected with the drill pipe through a matched length connector. The pneumatic screw comprises a transmission shaft assembly, a universal shaft assembly, a pneumatic motor assembly, an anti-falling assembly and a bypass valve assembly which are sequentially connected together. The device is used for drilling the horizontal section of the horizontal well in the goaf.

Description

Technical Field

[0001] The invention discloses a pneumatic directional drilling device and method for a horizontal section of a horizontal well passing through a goaf area, belonging to the technical field of drilling equipment. Background Art

[0002] Horizontal wells penetrating goafs are an effective means of developing underlying coalbed methane. However, due to the disturbance caused by goafs, the coal body suffers varying degrees of damage after stress redistribution in the underlying coal seam, resulting in complex geological conditions such as leakage or water gushing, unstable formations, etc. During the horizontal drilling process, there are problems such as uncontrollable rotary drilling trajectory of conventional hydraulic motors, shallow hole depth, serious leakage of conventional drilling fluids, frequent stuck drill accidents, low drilling efficiency, and severe reservoir pollution, which seriously restrict the efficient and clean development and utilization of underlying coalbed methane resources. Summary of the invention

[0003] In view of the deficiencies of the prior art, the object of the present invention is to provide a device and method for efficient "zero-pollution" directional drilling of a horizontal section of a horizontal well penetrating a goaf.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf, comprising: a drill bit, a pneumatic screw, a non-magnetic drill collar, a wireless drilling instrument, a weighted drill pipe, a matching length joint and a drill pipe, wherein the drill bit is connected to one end of the pneumatic screw through a thread, a one-way valve is installed at the other end of the pneumatic screw and then connected to one end of the non-magnetic drill collar through a first directional joint, the wireless drilling instrument is installed in the non-magnetic drill collar, the other end of the non-magnetic drill collar is connected to one end of the weighted drill pipe through a second directional joint, and the other end of the weighted drill pipe is connected to the drill pipe through a matching length joint;

[0005] The pneumatic screw includes a transmission shaft assembly, a universal shaft assembly, a pneumatic motor assembly, an anti-drop assembly and a bypass valve assembly which are connected in sequence. The transmission shaft assembly is connected to the drill bit through a thread, and the bypass valve assembly is connected to the non-magnetic drill collar through a first directional joint. The pneumatic motor assembly includes a stator and a rotor installed inside the stator, and a pneumatic speed limiting valve is installed on the upper end of the rotor.

[0006] The drill bit is a PDC drill bit, and a plurality of air holes are opened on the drill bit, a nozzle is installed in each air hole, and each air hole is connected with the air channel in the pneumatic screw.

[0007] Furthermore, the non-magnetic drill collar includes an upper non-magnetic drill rod, an insulating short joint and a lower non-magnetic drill rod. The upper non-magnetic drill rod is connected to the insulating short joint and then connected to one end of a wireless drilling instrument. The other end of the wireless drilling instrument is connected to the lower non-magnetic drill rod. The wireless drilling instrument includes a measuring short joint, a conversion joint, a battery pack and a wireless transmission part. The measuring short joint is connected to the battery pack through the conversion joint, the wireless transmission part is connected to the battery pack, and a sensor for measuring drilling trajectory parameters is arranged in the measuring short joint.

[0008] Furthermore, the cardan shaft assembly includes a cardan shaft and a housing, the housing is a single-bend outer tube with an angle, and a composite sheet gasket is welded on the housing, the cardan shaft is connected to the rotor through threads, and the housing is connected to the stator through threads.

[0009] Furthermore, the transmission shaft assembly includes an internal transmission main shaft and an external transmission shaft tube body, a transmission bearing group is arranged between the transmission main shaft and the transmission shaft tube body, one end of the transmission main shaft is connected to the universal shaft, and the other end is provided with an internal thread and connected to the drill bit.

[0010] Furthermore, the wireless drilling instrument is a shockproof electromagnetic wave type wireless drilling instrument.

[0011] Furthermore, the drill bit is a PDC drill bit.

[0012] A pneumatic directional drilling method for a horizontal section of a horizontal well passing through a goaf comprises the following steps:

[0013] S1. Select the drilling location according to geological conditions;

[0014] S2. Drilling is performed using the pneumatic directional drilling device for the horizontal section of a horizontal well passing through a goaf as described in claim 1, and a drilling method combining guided composite drilling and non-rotating directional drilling is adopted, with guided composite drilling as the main method and non-rotating directional drilling correction as the auxiliary method. During guided composite drilling, the drill rig drives the drill rod to rotate and drill, and at the same time, the air compressor or nitrogen generator supplies air to drive the pneumatic motor assembly in the pneumatic screw to operate normally, and the drill bit is driven by the composite rotation of the pneumatic motor assembly and the drill rod to break the rock;

[0015] S3. During the guided composite drilling process, the wireless downhole drilling instrument in the non-magnetic drill bit synchronously performs trajectory measurement and sends signals to record and verify the deviation between the current drilling trajectory and the designed trajectory. If the trajectory deviation is within the allowable range, the guided composite drilling is continued. If the trajectory deviation exceeds the allowable range, the guided composite drilling is stopped and switched to non-rotating directional drilling to correct the drilling trajectory. At this time, the drill rod does not rotate, and only the pneumatic motor assembly in the pneumatic screw driven by compressed air drives the drill bit to rotate and break the rock. The trajectory is corrected by adjusting the direction of the pneumatic motor assembly. During the non-rotating directional drilling process, the wireless downhole drilling instrument in the non-magnetic drill bit also synchronously performs trajectory measurement and sends signals until the drilling trajectory deviation returns to the allowable range.

[0016] S4, and then switch to guided composite drilling to continue drilling, and repeat this process until the drilling construction of the horizontal section of the horizontal well passing through the goaf is completed.

[0017] Furthermore, the gap between the pneumatic directional drilling device of the horizontal section of the horizontal well passing through the goaf and the well wall is the annular gap. During the directional composite drilling, the compressed gas from the air compressor or the nitrogen generator flows to the pneumatic screw through the channels in the drill pipe, the weighted drill pipe, and the non-magnetic drill collar. The gas driven by the pneumatic screw to do work passes through the nozzle on the drill bit and enters the flow field space at the bottom of the well in the form of a high-speed jet, cleans the bottom of the well, carries the cuttings into the annular gap, and is discharged under the stirring of the pneumatic screw and the drill pipe;

[0018] During the non-rotating directional drilling, after each 10m of non-rotating directional drilling is completed, the drill bit needs to rotate in situ to sweep the hole and remove slag to ensure that the hole is clean before continuing the non-rotating directional drilling.

[0019] Furthermore, during the drilling process, the drilling pressure is 20-50KN, the drill pipe speed is 30r / min, and the air volume is 30-50m 3 / min, wind pressure is 3MPa.

[0020] Compared with the prior art, the present invention has the following beneficial effects.

[0021] In order to solve the problems of uncontrollable rotary drilling trajectory, shallow hole depth, serious leakage of conventional drilling fluid, frequent stuck drill accidents, low drilling efficiency and serious reservoir pollution caused by conventional hydraulic motors, the present invention adopts a pneumatic motor, replaces "liquid" with "gas", and carries out adaptive design according to the characteristics of the pneumatic motor, thus solving the problems of "runaway" and braking of the pneumatic screw. In addition, when drilling with the drilling device of the present invention, the drilling trajectory can be measured by a wireless downhole instrument and corrected in time. The pneumatic motor does not have the problem of leakage of drilling fluid, will not cause pollution to coalbed methane, and can efficiently and cleanly develop and utilize the underlying coalbed methane resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0023] Figure 1 It is a structural schematic diagram of the drilling device in the present invention.

[0024] Figure 2 It is a schematic diagram of the structure of the pneumatic screw in the present invention.

[0025] Figure 3 It is a schematic diagram of the structure of the non-magnetic drill collar in the present invention.

[0026] In the figure: 1 is a drill bit, 2 is a pneumatic screw, 3 is a one-way valve, 4 is a first directional joint, 5 is a wireless drilling instrument, 6 is a non-magnetic drill collar, 7 is a second directional joint, 8 is a weighted drill pipe, 9 is a matching length joint, 10 is a drill pipe, 11 is an annular space gap, 12 is a bypass valve assembly, 13 is a pneumatic motor assembly, 14 is a universal shaft assembly, 15 is a drive shaft assembly, 16 is a valve body, 17 is a valve core, 18 is a valve sleeve, 19 is an anti-drop connecting rod, 20 is a pneumatic speed limiting valve, 21 is a universal shaft, 22 is a housing, 23 is a drive shaft tube body, 24 is a drive bearing group, 25 is a drive main shaft, 26 is a stator, 27 is a rotor, 28 is an upper non-magnetic drill pipe, 29 is an insulating short section, 30 is a lower non-magnetic drill pipe, 31 is a measuring short section, 32 is a conversion joint, 33 is a battery pack, 34 is a wireless transmission part, and 35 is a sensor. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides the following embodiments.

[0029] like Figure 1 As shown, the present invention provides a pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf, comprising: a drill bit 1, a pneumatic screw 2, a one-way valve 3, a non-magnetic drill collar 6, a wireless while-drilling instrument 5, a weighted drill pipe 8 and a drill pipe 10, wherein the drill bit 1 is connected to one end of the pneumatic screw 2 through a thread, the other end of the pneumatic screw 2 is installed with a one-way valve 3 and then connected to one end of the non-magnetic drill collar 6 through a first directional joint 4, the wireless while-drilling instrument 5 is installed in the non-magnetic drill collar 6, the other end of the non-magnetic drill collar 6 is connected to one end of the weighted drill pipe 8 through a second directional joint 7, and the other end of the weighted drill pipe 8 is connected to the drill pipe 10 through a matching length joint 9;

[0030] like Figure 2 As shown, the pneumatic screw 2 includes a transmission shaft assembly 15, a universal shaft assembly 14, a pneumatic motor assembly 13, an anti-drop assembly and a bypass valve assembly 12 which are connected in sequence. The transmission shaft assembly 15 is connected to the drill bit 1 through a thread. The bypass valve assembly 12 is connected to the non-magnetic drill collar 6 through a first directional joint 4 after installing a one-way valve 3. The pneumatic motor assembly 13 includes a stator 26 and a rotor 27 installed inside the stator 26. A pneumatic speed limiting valve 20 is installed on the upper end of the rotor 27.

[0031] The drill bit 1 is a PDC drill bit, and is provided with a plurality of air holes, each of which is provided with a nozzle, and each of which is connected to a gas channel in the pneumatic screw 2 .

[0032] like Figure 3 As shown, the non-magnetic drill collar 6 includes an upper non-magnetic drill rod 28, an insulating short section 29 and a lower non-magnetic drill rod 30. The upper non-magnetic drill rod 28 is connected to the insulating short section 29 and then connected to one end of the wireless drilling instrument 5. The other end of the wireless drilling instrument 5 is connected to the lower non-magnetic drill rod 30. The wireless drilling instrument 5 includes a measuring short section 31, a conversion joint 32, a battery pack 33 and a wireless transmission part 34. The measuring short section 31 is connected to the battery pack 33 through the conversion joint 32. The wireless transmission part 34 is connected to the battery pack 33. A sensor 35 for measuring drilling trajectory parameters is arranged in the measuring short section 31.

[0033] The cardan shaft assembly 14 includes a cardan shaft 21 and a housing 22. The housing 22 is a single-bend outer tube with an angle, and a composite sheet gasket is welded on the housing 22. The cardan shaft 21 is connected to the rotor 27 through threads, and the housing 22 is connected to the stator 26 through threads.

[0034] The transmission shaft assembly 15 includes a transmission main shaft 25 located inside and a transmission shaft tube body 23 located outside. A transmission bearing group 24 is arranged between the transmission main shaft 25 and the transmission shaft tube body 23. One end of the transmission main shaft 25 is connected to the universal shaft 21, and the other end is provided with an internal thread and connected to the drill bit 1.

[0035] The wireless drilling instrument 5 is a shockproof electromagnetic wave type wireless drilling instrument.

[0036] The drill bit 1 is a PDC drill bit.

[0037] The drill rod 10 is a spiral drill rod or a triangular drill rod.

[0038] During the drilling process of the pneumatic directional drilling device for the horizontal section of a horizontal well passing through a goaf area of ​​the present invention, the gap between the device and the well wall is an annular gap 11.

[0039] In the present invention, a nozzle is installed in the air hole on the drill bit 1 to effectively control the back pressure and avoid the pneumatic screw 2 from "stalling". At the same time, a pneumatic speed limiting valve 20 is installed in the pneumatic screw 2 to ensure that the pneumatic screw 2 will not seriously stall or brake when the drilling pressure is large, and sufficient working torque can be output to improve the rock breaking ability. The pneumatic speed limiting valve 20 is installed on the upper end of the rotor 27, and the automatic control causes bypass diversion to suppress the increase in the speed of the pneumatic screw 2, so that the gas screw drilling tool itself has the function of automatically controlling and adjusting the speed, and ensuring the stability of the speed.

[0040] In the present invention, the one-way valve 3 is used to prevent excessive pipeline pressure and air backflow, the wireless drilling instrument 5 is installed in the non-magnetic drill collar 6 to monitor the wellbore trajectory, one end of the weighted drill pipe 8 is connected to the non-magnetic drill collar 6 through the second directional joint 7, ensuring the effective transmission of drilling pressure; the flexible drilling tool combination of the φ89mm drill pipe 10 applies drilling pressure and is connected to the weighted drill pipe 8 through the matching length joint 9.

[0041] In the present invention, the bypass valve assembly 12 includes a valve body 16 , a valve core 17 , a valve sleeve 18 and a spring. When the drill bit 1 is not working, the compressed gas in the drill string will flow to the annular space 11 through the bypass valve assembly 12 .

[0042] In the present invention, the anti-drop assembly includes an anti-drop connecting rod 19, which can prevent objects from falling into the well when the shell of the pneumatic screw 2 below the anti-drop assembly is broken or disengaged due to abnormal reasons.

[0043] In the present invention, in the pneumatic motor assembly 13, the stator 26 is a steel pipe with a rubber bushing vulcanized on the inner wall, the inner hole of the rubber bushing is a cavity with a spiral surface, and the transmission shaft of the motor adopts a self-lubricating structure. During operation, oil mist is introduced into the compressed air to assist lubrication and cooling, thereby reducing the heating and wear of the bearings, thereby increasing the service life of the motor. The upper joint of the motor is designed with an internal thread to connect with the upper drilling tool, and the upper joint and the outer tube body of the stator are connected by a threaded connection.

[0044] A pneumatic directional drilling method for a horizontal section of a horizontal well passing through a goaf comprises the following steps:

[0045] S1. Select the drilling location according to geological conditions;

[0046] S2. Drilling is performed using the pneumatic directional drilling device for the horizontal section of a horizontal well passing through a goaf as described in claim 1, and a drilling method combining guided composite drilling and non-rotating directional drilling is adopted, with guided composite drilling as the main method and non-rotating directional drilling correction as the auxiliary method. During guided composite drilling, the drill rig drives the drill rod 10 to rotate and drill, and at the same time, the air compressor or nitrogen generator supplies air to drive the pneumatic motor assembly 13 in the pneumatic screw 2 to operate normally, and the drill bit 1 is driven by the composite rotation of the pneumatic motor assembly 13 and the drill rod 10 to break the rock;

[0047] S3, during the guided composite drilling process, the wireless drilling instrument 5 in the non-magnetic drill jack 6 synchronously performs trajectory measurement and sends signals to record and verify the deviation between the current drilling trajectory and the designed trajectory. If the trajectory deviation is within the allowable range, the guided composite drilling is continued. If the trajectory deviation exceeds the allowable range, the guided composite drilling is stopped and switched to non-rotating directional drilling to correct the drilling trajectory. At this time, the drill rod 10 does not rotate, and only the pneumatic motor assembly 13 in the pneumatic screw 2 driven by compressed air drives the drill bit 1 to rotate and break the rock. The trajectory is corrected by adjusting the direction of the pneumatic motor assembly 13. During the non-rotating directional drilling process, the wireless drilling instrument 5 in the non-magnetic drill jack 6 also synchronously performs trajectory measurement and sends signals until the drilling trajectory deviation returns to the allowable range;

[0048] S4, and then switch to guided composite drilling to continue drilling, and repeat this process until the drilling construction of the horizontal section of the horizontal well passing through the goaf is completed.

[0049] The gap between the pneumatic directional drilling device and the well wall in the horizontal section of the horizontal well passing through the goaf is the annular gap 11. During the directional composite drilling, the compressed gas from the air compressor or the nitrogen generator flows to the pneumatic screw 2 through the channels in the drill pipe 10, the weighted drill pipe 8, and the non-magnetic drill collar 6. The gas driven by the pneumatic screw 2 to do work passes through the nozzle on the drill bit 1 and enters the flow field space at the bottom of the well in the form of a high-speed jet, cleans the bottom of the well, carries the cuttings into the annular gap, and is discharged under the stirring of the pneumatic screw 2 and the drill pipe 10;

[0050] During the non-rotating directional drilling, after each 10 m of non-rotating directional drilling is completed, the drill bit 1 needs to rotate in situ to clean the hole and remove slag to ensure that the hole is clean before continuing the non-rotating directional drilling.

[0051] During drilling, the drilling pressure is 20-50KN, the drill pipe speed is 30r / min, and the air volume is 30-50m 3 / min, wind pressure is 3MPa.

[0052] In order to ensure the quality of the well wall, reduce friction and avoid complicated situations in the well, during the drilling process of the horizontal section of the horizontal well, especially the non-rotation directional correction section, a short trip should be carried out every time a certain distance is drilled, such as about 30m, and the drill tool should be moved in time to prevent sticking and cuttings deposition, and the technical measures for drilling the target layer should be strictly implemented. When encountering resistance during drilling, the pump should be opened in time to avoid sudden lifting and releasing. Short trips should be carried out according to the underground conditions, and the well should be fully washed before the trip.

[0053] The pneumatic directional drilling device and method for the horizontal section of a horizontal well passing through a goaf area of ​​the present invention is adopted, the drill bit diameter is 171.4mm, the drilling pressure is 20-50KN, the drill rod speed is 30r / min, and the air volume is 30-50m 3 / min, wind pressure 3Mpa, effective horizontal section footage of 266m, pure drilling time 14h, mechanical efficiency 19m / h. The drilling efficiency is higher than that of conventional mud drilling, which has obvious advantages.

[0054] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf, comprising: A drill bit (1), a pneumatic screw (2), a one-way valve (3), a non-magnetic drill collar (6), a wireless drilling instrument (5), a weighted drill rod (8) and a drill rod (10), characterized in that: the drill bit (1) is connected to one end of the pneumatic screw (2) through a thread, the other end of the pneumatic screw (2) is installed with a one-way valve (3) and then connected to one end of the non-magnetic drill collar (6) through a first directional joint (4), the wireless drilling instrument (5) is installed in the non-magnetic drill collar (6), the other end of the non-magnetic drill collar (6) is connected to one end of the weighted drill rod (8) through a second directional joint (7), and the other end of the weighted drill rod (8) is connected to the drill rod (10) through a matching length joint (9); The pneumatic screw (2) comprises a transmission shaft assembly (15), a universal shaft assembly (14), a pneumatic motor assembly (13), an anti-drop assembly and a bypass valve assembly (12) which are connected in sequence. The transmission shaft assembly (15) is connected to the drill bit (1) through a thread. The bypass valve assembly (12) is connected to the non-magnetic drill collar (6) through a first directional joint (4) after a one-way valve (3) is installed. The pneumatic motor assembly (13) comprises a stator (26) and a rotor (27) installed inside the stator (26). A pneumatic speed limiting valve (20) is installed on the upper end of the rotor (27). The drill bit (1) is a PDC drill bit and is provided with a plurality of air holes, each of which is equipped with a nozzle, and each of which is connected to a gas channel in a pneumatic screw (2).

2. The pneumatic directional drilling device for the horizontal section of a horizontal well passing through a goaf according to claim 1, characterized in that: The non-magnetic drill collar (6) comprises an upper non-magnetic drill rod (28), an insulating short joint (29) and a lower non-magnetic drill rod (30); the upper non-magnetic drill rod (28) is connected to the insulating short joint (29) and then connected to one end of a wireless drilling instrument (5); the other end of the wireless drilling instrument (5) is connected to the lower non-magnetic drill rod (30); the wireless drilling instrument (5) comprises a measuring short joint (31), a conversion joint (32), a battery pack (33) and a wireless transmission part (34); the measuring short joint (31) is connected to the battery pack (33) via the conversion joint (32); the wireless transmission part (34) is connected to the battery pack (33); a sensor (35) for measuring drilling trajectory parameters is arranged in the measuring short joint (31).

3. A pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf according to claim 1 or 2, characterized in that: The cardan shaft assembly (14) comprises a cardan shaft (21) and a housing (22); the housing (22) is a single-bend outer tube with an angle, and a composite sheet gasket is welded on the housing (22); the cardan shaft (21) is connected to the rotor (27) via a thread, and the housing (22) is connected to the stator (26) via a thread.

4. A pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf according to claim 1 or 2, characterized in that: The transmission shaft assembly (15) comprises a transmission main shaft (25) located inside and a transmission shaft tube body (23) located outside, a transmission bearing group (24) is arranged between the transmission main shaft (25) and the transmission shaft tube body (23), one end of the transmission main shaft (25) is connected to the universal shaft (21), and the other end is provided with an internal thread and connected to the drill bit (1).

5. A pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf according to claim 1 or 2, characterized in that: The wireless drilling instrument (5) is a shockproof electromagnetic wave type wireless drilling instrument.

6. A pneumatic directional drilling device for a horizontal section of a horizontal well passing through a goaf according to claim 1 or 2, characterized in that: The drill bit (1) is a PDC drill bit.

7. A method for pneumatic directional drilling of a horizontal section of a horizontal well through a goaf, characterized in that The following steps are involved: S1. Select the drilling location according to geological conditions; S2. Drilling is performed using the pneumatic directional drilling device for the horizontal section of a horizontal well passing through a goaf as described in claim 1, and a drilling method combining guided composite drilling and non-rotating directional drilling is adopted, with guided composite drilling as the main method and non-rotating directional drilling correction as the auxiliary method. During guided composite drilling, the drill rig drives the drill rod (10) to rotate and drill, and at the same time, the air compressor or nitrogen generator supplies air to drive the pneumatic motor assembly (13) in the pneumatic screw (2) to operate normally, and the drill bit (1) is driven by the composite rotation of the pneumatic motor assembly (13) and the drill rod (10) to break rocks; S3, during the guided composite drilling process, the wireless drilling instrument (5) in the non-magnetic drill shank (6) synchronously performs trajectory measurement and sends signals to record and verify the deviation between the current drilling trajectory and the designed trajectory. If the trajectory deviation is within the allowable range, the guided composite drilling is continued. If the trajectory deviation exceeds the allowable range, the guided composite drilling is stopped and switched to non-rotating directional drilling to correct the drilling trajectory. At this time, the drill rod (10) does not rotate, and only the pneumatic motor assembly (13) in the pneumatic screw (2) driven by compressed air drives the drill bit (1) to rotate and break the rock. The trajectory is corrected by adjusting the direction of the pneumatic motor assembly (13). During the non-rotating directional drilling process, the wireless drilling instrument (5) in the non-magnetic drill shank (6) also synchronously performs trajectory measurement and sends signals until the drilling trajectory deviation returns to the allowable range. S4, and then switch to guided composite drilling to continue drilling, and repeat this process until the drilling construction of the horizontal section of the horizontal well passing through the goaf is completed.

8. The method for pneumatic directional drilling of a horizontal section of a horizontal well passing through a goaf according to claim 7, characterized in that: The gap between the pneumatic directional drilling device and the well wall in the horizontal section of the horizontal well passing through the goaf is an annular gap (11). During the directional composite drilling, the compressed gas from the air compressor or the nitrogen generator flows to the pneumatic screw (2) through the drill pipe (10), the weighted drill pipe (8), and the channel in the non-magnetic drill collar (6). The gas driven by the pneumatic screw (2) to do work passes through the nozzle on the drill bit (1) and enters the flow field space at the bottom of the well in the form of a high-speed jet, cleans the bottom of the well, carries rock cuttings into the annular gap, and discharges the rock cuttings under the stirring of the pneumatic screw (2) and the drill pipe (10); During the non-rotating directional drilling, after each 10 m of non-rotating directional drilling is completed, the drill bit (1) needs to rotate in situ to clean the hole and remove slag to ensure that the hole is clean before continuing the non-rotating directional drilling.

9. A method for pneumatic directional drilling of a horizontal section of a horizontal well passing through a goaf according to claim 7 or 8, characterized in that: During drilling, the drilling pressure is 20-50KN, the rotation speed of the drill rod (10) is 30r / min, and the air volume is 30-50m 3 / min, wind pressure is 3MPa.

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