Long distance drilling device for geological exploration and method thereof

Abstract

The application discloses a long-distance drilling device for geological exploration and a method thereof, and belongs to the technical field of geological exploration equipment. The long-distance drilling device comprises a driving system, a drill rod system and a drill bit system. The driving system is composed of a surface driving unit and a downhole driving unit. The drill rod system is a sectional drill rod with a hollow structure and is composed of a rigid main rod body and a flexible connecting section. The drill bit system comprises a drill bit and an intelligent guiding mechanism. The intelligent guiding mechanism comprises a piezoelectric deflection angle regulator, a while-drilling inclinometer, an electromagnetic induction guiding ring and a hydraulic servo adjusting assembly. The application dynamically distributes torque through magnetic coupling shaft couplings between a surface variable-frequency motor and a downhole turbine, realizes double-power coupling and efficiency increase, and realizes long-distance deep cumulative deflection of less than 0.8° through the cooperation of the piezoelectric deflection angle regulator and the hydraulic servo cylinder, the combination of laser guiding and electromagnetic induction rock stratum prediction, the satisfaction of the complex trajectory requirements of shale gas horizontal wells and the like, and the setting of a rigid-flexible self-adaptive drill rod system, thereby improving the service life of the drill rod.

Description

Technical Field

[0001] This invention relates to the field of geological exploration equipment, and in particular to a long-distance drilling device and method for geological exploration. Background Technology

[0002] In deep geological exploration (especially in ultra-deep formations above 3000 meters), traditional drilling equipment faces multiple technical bottlenecks: 1) Low power transmission efficiency: When a single surface power source transmits torque through a rigid drill pipe, the torque loss in deep hard rock layers (hardness > 7 Mohs) exceeds 40%, and traditional hydraulic compensation mechanisms cannot achieve intelligent dynamic power distribution, often resulting in the dilemma of "surface idling and downhole lack of power".

[0003] 2) Insufficient trajectory control accuracy: The drill pipe connection structure is prone to cumulative deviation under the stress of deep strata (the deviation is generally >3° at a depth of 1500 meters). The existing guidance system relies on a single inclination measurement method, which is slow to respond to complex rock interfaces (such as fault zones with dip angle >45°) and cannot achieve millimeter-level trajectory correction.

[0004] 3) Drill pipe reliability defects: Traditional steel drill pipes have poor wear resistance (hardness HV<1200), the threaded connection is easily jammed by rock cuttings (failure rate 35%), and there is a lack of real-time status monitoring, making it impossible to provide early warning of drill pipe deformation or seal failure risks.

[0005] Based on the above problems, a long-distance drilling device and method for geological exploration are proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a long-distance drilling device and method for geological exploration to solve the problems in the background art.

[0007] To achieve the above objectives, the present invention provides a long-distance drilling apparatus for geological exploration, comprising a drive system, a drill pipe system, and a drill bit system. The drive system consists of a surface drive unit and a downhole drive unit. The drill pipe system is configured as a hollow, segmented drill pipe, which consists of a rigid main body and a flexible connecting section. The drill bit system includes a drill bit and an intelligent guiding mechanism mounted on the drill bit. The intelligent guiding mechanism includes a piezoelectric deflection adjuster, a drilling homing instrument, an electromagnetic induction guide ring, and a hydraulic servo adjustment component. The drive system, drill pipe system, and drill bit system are all controlled by a central control system.

[0008] Preferably, the rigid main rod is made of carbon fiber reinforced titanium alloy composite material; the inner wall of the rigid main rod is provided with spiral prestressed reinforcing ribs, and the outer wall is provided with 45° spiral cleaning grooves; the flexible connecting section is connected to both ends of the rigid main rod through magnetic connectors; the flexible connecting section is set as a shape memory alloy spring structure, which can be bent when not energized, with a radius of curvature ≥5m, and solidifies into a rigid body after being heated to 60°C; strain sensors and temperature sensors are spirally laid on the inner wall of the rigid main rod; an tilt sensor is set at the center of the flexible connecting section.

[0009] Preferably, the drill bit has a pulse jet hole inside, which is connected to the inner hole of the rigid main body; a laser guide receiver is provided at the top of the drill bit, and an ultrasonic hardness sensor is provided at the front end of the drill bit.

[0010] Preferably, the piezoelectric deflection adjuster consists of four sets of rectangular piezoelectric ceramic plates, which are attached to the root of the drive shaft of the drill bit; the hydraulic servo adjustment assembly is configured as four sets of hydraulic servo cylinders, which are circumferentially arranged at the connection between the drill bit and the segmented drill rod; the electromagnetic induction guide ring is installed on the segmented drill rod 1.5~2m behind the drill bit; and the drilling skewing instrument is installed on the drill bit.

[0011] Preferably, the surface drive unit includes a variable frequency motor and a planetary gearbox. The output shaft of the variable frequency motor is connected to the input end of the planetary gearbox via a rigid coupling. The hollow drive shaft of the planetary gearbox is connected to the wellhead sealing device.

[0012] Preferably, the downhole drive unit includes a turbine and a magnetic coupling. The turbine is nested at the front end of the segmented drill pipe, the outer casing is connected to the rigid main rod body above by threads, and the internal rotor shaft is connected to the drive shaft of the drill bit by splines. The magnetic coupling consists of a permanent magnet ring at the surface end and an induction ring at the bottom end. The permanent magnet ring is fixed to the end of the hollow drive shaft of the planetary gearbox, and the induction ring is fixed to the rotor shaft of the turbine.

[0013] Preferably, the central control system consists of a data acquisition module, an edge computing unit, and a remote terminal. The edge computing unit integrates a 12-core processor and a GPU, and the remote terminal is connected via a 5G network. The data acquisition module receives data from the tilt sensor, strain sensor, temperature sensor, and drilling survey instrument, and transmits it to the edge computing unit.

[0014] The present invention also provides a drilling method based on the above-mentioned long-distance drilling rig for geological exploration, comprising the following steps: S1. Drill assembly and lowering: On the drill rig, the single rigid main rod body and the flexible connecting section are quickly connected by a magnetic connector. The flexible section is energized to 60°C and cured into a rigid body. A torque wrench is used to test the connection strength and check the sealing pressure. Connect the drive shaft of the drill bit to the rotor shaft of the turbine at the front end of the drill pipe via spline, apply preload, and test the deflection accuracy of the piezoelectric regulator; lower the drill string, monitor the data of the inclination sensor of the flexible section in real time, and start the flexible section to cut off power when encountering resistance, restore flexibility to pass through the narrow-diameter formation, and re-energize and solidify after passing through. S2. The rock hardness is detected by an ultrasonic hardness sensor. After calculation, the edge computing unit determines whether to trigger the turbine to start and dynamically allocates power according to the hardness value. It also works with the drill bit pulse jet hole to achieve "rotational cutting + high pressure jet" composite rock breaking. S3. The logging-while-drilling instrument collects well inclination and azimuth data every 5 seconds. The laser guidance system emits a reference beam every 100 meters. The laser guidance receiver calculates the spatial coordinates and corrects the drill bit. The electromagnetic induction guide ring monitors the formation resistivity in real time. When a sudden change in resistivity is detected, a rock interface warning is sent 2 meters in advance. The edge calculation unit pre-adjusts the drill bit inclination angle by 0.5° to counteract the natural deflection force of the formation.

[0015] Preferably, in step S1, after every 10 drill pipe sections are connected, the overall straightness is calibrated using a ground straightening device, and the initial inclination angle data of each flexible section is recorded.

[0016] Preferably, in step S2, when the rock hardness is less than 7 Mohs and it is a soft rock layer, only the surface motor works, which is energy-saving and efficient; the downhole turbine rotates naturally with the drilling fluid, and the power distribution ratio is 100:0. When the rock hardness is >7 Mohs, indicating a hard rock layer, the downhole turbine is triggered to start. The torque distribution is dynamically adjusted through the magnetic coupler based on the hardness value. The downhole turbine compensates for the torque, avoiding overload of the surface motor and improving drilling efficiency in hard rock layers. The main drive motor speed is automatically adjusted according to the torque. The speed is 750~800rpm for soft rock layers and 1400~1500rpm for hard rock layers.

[0017] Preferably, in step S3, the drill bit correction strategy is as follows: When the well inclination angle deviation θ≤0.5°, only the piezoelectric ceramic plate works, applying voltage in the opposite direction of the deviation and fine-tuning at a rate of 0.01° / ms until the error <0.05°; When the well inclination angle deviation θ>0.5°, the hydraulic servo cylinder is linked to adjust the drill bit speed synchronously, and the attitude correction is completed within 30 seconds.

[0018] Therefore, the long-distance drilling device and method for geological exploration of the present invention have the following beneficial effects: (1) The surface variable frequency motor and the downhole turbine dynamically distribute torque (0-100% adjustable) through a magnetic coupling, which improves the power transmission efficiency of hard rock formations by 60% and the mechanical drilling speed reaches 12m / h, solving the problem of insufficient torque in deep formations.

[0019] (2) The piezoelectric deflection adjuster (±0.1° accuracy) works in conjunction with the hydraulic servo cylinder, combined with laser guidance (±0.05° correction per 100 meters) and electromagnetic induction rock layer prediction (2m early warning), to achieve a cumulative deflection of <0.8° at a depth of 3000 meters, meeting the complex trajectory requirements of shale gas horizontal wells.

[0020] (3) The flexible connecting section (shape memory alloy spring) of the segmented drill pipe realizes the switching between rigid and flexible states. When powered on, it is solidified into a rigid body to ensure transmission stiffness. When powered off, it is restored to flexibility to absorb formation stress. With the help of distributed sensors (strain / temperature / inclination angle) for real-time monitoring, the life of the drill pipe is extended to 240 hours and the probability of connection seal failure is reduced to less than 5%.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a cross-sectional view of the drill pipe according to an embodiment of the present invention; Figure 3 This is a signal diagram of the central control system according to an embodiment of the present invention; Figure label: 1. Rigid main shaft; 2. Flexible connecting section; 3. Drill bit; 4. Piezoelectric ceramic plate; 5. Measurement while drilling (MSD); 6. Electromagnetic induction guide ring; 7. Strain sensor; 8. Temperature sensor; 9. Tilt sensor; 10. Ultrasonic hardness sensor; 11. Laser guidance receiver; 12. Hydraulic servo cylinder; 13. Variable frequency motor; 14. Planetary gearbox; 15. Permanent magnet ring; 16. Turbine; 17. Induction ring; 18. Data acquisition module; 19. Edge computing unit; 20. Remote terminal. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0025] Example like Figures 1-3 As shown, this invention provides a long-distance drilling rig for geological exploration, including a drive system, a drill pipe system, and a drill bit system. The drive system consists of a surface drive unit and a downhole drive unit. The drill pipe system is a hollow, segmented drill pipe, consisting of a rigid main body 1 and a flexible connecting section 2. Each segment consists of the rigid main body 1 and the flexible connecting section 2, which are connected by a magnetic connector to achieve intelligent conversion and reliable connection of the drill pipe's rigidity and flexibility. The drill bit system includes a drill bit 3 and an intelligent guiding mechanism mounted on the drill bit 3. The intelligent guiding mechanism includes a piezoelectric deflection adjuster, a drilling comprehension instrument 5, an electromagnetic induction guide ring 6, and a hydraulic servo adjustment component. The drive system, drill pipe system, and drill bit system are all controlled by a central control system.

[0026] The rigid main rod 1 is made of carbon fiber reinforced titanium alloy composite material. The inner wall of the rigid main rod 1 is equipped with spiral prestressed reinforcing ribs (100mm pitch, 3mm height) to improve torsional stiffness. The outer wall has 45° spiral cleaning grooves (6mm depth, 80mm pitch) running axially to guide rock cuttings. Strain sensors 7 (accuracy 0.01%) and temperature sensors 8 (±0.5℃) are spirally distributed on the inner wall. Flexible connecting sections 2 are located at both ends of the main rod (each 10cm long), using shape memory alloy springs (100mm diameter) coated with a nickel-titanium hafnium high-temperature alloy coating. They are bendable when not energized, with a curvature radius ≥5m, and solidify into a rigid body after being heated to 60℃. The magnetic connectors at both ends have built-in sealing rings made of polytetrafluoroethylene (PTFE), resistant to 70MPa. The coaxiality is automatically calibrated during drill rod docking, with a deviation <0.1mm. An inclination sensor 9 (±0.05°) is integrated at the center. An ultrasonic vibrator can also be installed on the drill pipe near the flexible connection section 2.

[0027] For a well depth of 3,000 meters, 200 drill pipe sections are connected end to end by magnetic connectors. Flexible sections are set up in groups of 10 sections (20 groups in total) to form a 3,000-meter drill string. The internal hollow channel (70mm in diameter) is used for gas-liquid flow and fiber optic transmission.

[0028] The crown of drill bit 3 is inlaid with 10 beads / cm 2 The drill bit 3 has PDC cutting teeth, and an ultrasonic hardness sensor 10 is installed on the PDC cutting teeth. The drive shaft of the drill bit 3 is a hollow cylindrical shaft with a spline at the front end and a rear end fixedly connected to the drill bit 3. The internal through hole communicates with the pulse jet hole of the drill bit 3. The drill bit 3 has multiple pulse jet holes (3mm in diameter) at its center, which communicate with the inner hole of the drill pipe and are connected to the surface high-pressure pump through them. A laser guide receiver 11 (50mm in diameter) is embedded at the top, aligned with the surface reference laser beam (accuracy ±0.05°). In addition, the drill bit 3 and the drill pipe are connected to the drilling fluid output device through holes located at their centers using conventional methods in the art.

[0029] The piezoelectric tilt adjuster consists of four sets of rectangular piezoelectric ceramic plates 4 (10mm×5mm×2mm), symmetrically attached to the root of the drill bit 3 drive shaft. Upon energization, it produces a micro-tilt of 0.01-0.1° (response time <5ms). The hydraulic servo adjustment assembly consists of four sets of hydraulic servo cylinders 12 (15mm diameter, 20mm stroke) circumferentially distributed at the connection between the drill bit 3 and the drill pipe (90° spacing). These are connected to the downhole hydraulic control unit via high-pressure oil pipes (4mm inner diameter). This setup follows standard geological exploration practices, enabling the drill bit 3 to achieve ±1.5° tilt adjustment. An electromagnetic induction guide ring 6 is installed on a segmented drill pipe 1.5~2m behind the drill bit 3. It senses changes in formation resistivity (resolution 0.1Ω·m) by emitting an alternating magnetic field, predicting rock interface 2m in advance. The measuring and surveying instrument 5 is integrated inside the drill bit 3. It uses a fiber optic gyroscope (drift rate 0.01° / h) and an accelerometer to collect well inclination angle and azimuth angle data every 5 seconds (accuracy ±0.1°).

[0030] The surface drive unit includes a variable frequency motor 13 and a planetary gearbox 14. The variable frequency motor 13 is horizontally mounted on the drilling platform base. The output shaft is connected to the input end of the planetary gearbox 14 through a rigid coupling. After a 1:8 reduction, the hollow drive shaft (carbon fiber reinforced titanium alloy, inner diameter 89mm) passes vertically downward through the wellhead sealing device and connects to the top of the drill pipe. The end is fixed with a permanent magnet ring 15.

[0031] The downhole drive unit includes a turbine 16 and a magnetic coupling. The turbine 16 is cylindrical and nested at the front end of the segmented drill pipe. The outer casing is connected to the rigid main body 1 at the front end of the drill pipe via threads, forming a rigid transmission chain of "drill pipe → turbine 16 → drive shaft → drill bit 3". The front end of the internal rotor shaft is provided with a spline, which mates with the drive shaft of the drill bit 3. The end of the rotor shaft is fixed with an induction ring 17, which forms a 5mm air gap with the surface permanent magnet ring 15 to achieve contactless torque transmission.

[0032] The magnetic coupling consists of a permanent magnet ring 15 at the surface end and an induction ring 17 at the downhole end. They achieve contactless torque transmission through a 5mm air gap. It can dynamically distribute torque between the surface and downhole (the ratio is adjustable from 0-100%), automatically increasing the downhole power proportion in hard rock formations to avoid excessive surface power loss. The drive shaft of drill bit 3 simultaneously receives torque from both the surface variable frequency motor 13 and the downhole turbine 16, forming a dual-power parallel drive.

[0033] The central control system consists of a data acquisition module 18, an edge computing unit 19, and a remote terminal 20. The data acquisition module 18 receives data in real time from the drill pipe inclination sensor 9, strain sensor 7, temperature sensor 8, as well as the drilling caliper 5 and electromagnetic induction guide ring 6, and transmits the data to the edge computing unit 19 on the ground surface through the drill pipe's built-in optical fiber (2mm diameter).

[0034] The edge computing unit 19 integrates a 12-core processor and a GPU, runs an LSTM neural network to predict drill pipe deformation, and dynamically adjusts the power distribution ratio, guidance parameters and chip removal strategy through a fuzzy PID algorithm. Control commands are sent to the downhole actuators (turbine 16, hydraulic servo cylinder 12, and surface pulse valve) via a 5G remote terminal 20.

[0035] The connections (lines, signals, etc.) between the above-described components are all implemented using conventional methods in the field, and are not specifically limited here, as long as the normal operation of each component can be achieved. The specific method for drilling a 3000-meter long-distance well using the above-described device is as follows: S1. Drill string assembly and lowering: 1) Segmented connection: On the drilling rig, 1.5m segmented drill pipes are assembled section by section and aligned using magnetic connectors. Flexible connecting section 2 is energized (24V DC power) and heated for 5 minutes to 60℃ to solidify into a rigid body, thus solidifying the shape memory alloy spring and forming a continuous drill string. 200 sections are required for a well depth of 3000 meters. A torque wrench is then used to test the connection strength (target 50kN·m), and an airtightness test is performed. Using 70MPa inflation, a pressure drop of less than 1% after 30 minutes is considered acceptable.

[0036] Every 10 drill pipe sections are connected, the overall straightness is calibrated using a ground straightening device (accuracy ±0.1°), and the initial values ​​of the tilt sensors 9 for each flexible section are recorded.

[0037] 2) Drill bit 3 installation: Insert the drive shaft spline of drill bit 3 into the rotor shaft of turbine 16, apply a preload of 5000 N·m to ensure reliable connection with the downhole drive unit, test the deflection accuracy of the piezoelectric regulator, input 50V voltage, check whether the change in the deflection angle of drill bit 3 reaches 0.05°±0.01°, and calibrate the laser guide receiver 11 to align with the surface reference beam.

[0038] 3) Component calibration: Strain sensor 7 and temperature sensor 8 are zero-point calibrated to ensure that the strain value of the drill pipe under no-load conditions is <0.01% and the temperature fluctuation is <±0.5℃. The ultrasonic hardness sensor 10 is integrated into the tooth gap of the drill bit 3PDC. It emits 50kHz ultrasonic waves to perform echo tests on standard rock samples and verify the hardness calculation accuracy (±0.5Mohs).

[0039] 4) Drilling parameter presets: The initial speed of the surface variable frequency motor 13 is set to 800 rpm, the planetary gearbox 14 has a reduction ratio of 1:8, and the output torque of the hollow drive shaft is 3000 N·m (no load).

[0040] The drilling fluid has a density of 1.5 g / cm³. 3 Displacement 30L / s, initial nitrogen injection 20m³ 3 / min (normal chip removal mode).

[0041] Install a wellhead sealing device to ensure that the hollow channel in the drill pipe is sealed and connected to the surface gas (nitrogen) and liquid (drilling fluid) channels, and conduct a pressure test at 70 MPa, with a leakage rate of <0.5%. The central control system was started, and the sensor data transmission delay was verified to be <10ms. The 19LSTM model and fuzzy PID algorithm of the edge computing unit were loaded.

[0042] 5) Decentralized control: The drill string is lowered at a speed of 0.5 m / s, and the dip angle data of the flexible section is monitored in real time. When encountering resistance (tension > 50 kN), the power supply to the flexible section is automatically cut off, and the flexibility is restored to pass through narrow-diameter strata (such as shale layers and clay rocks). After passing through, the power is restored and solidified.

[0043] S2, Dual-power coordinated drilling control: 1) Drilling in soft rock formations (hardness <7 Mohs): Only the surface variable frequency motor 13 operates at 800 rpm, while the downhole turbine 16 idles (driven by drilling fluid but not outputting torque), with a power distribution ratio of 100:0. The logging-while-drilling instrument 5 collects well inclination and azimuth angles every 5 seconds, and the central control system plots the wellbore trajectory in real time, with the deviation controlled within 0.2° / 100m.

[0044] 2) Dual-power coordinated drilling in hard rock formations: When the ultrasonic hardness sensor 10 detects a rock hardness > 7 Mohs (calculated from ultrasonic echo data), the edge computing unit 19 triggers the downhole turbine 16 to start, dynamically allocating power according to the hardness value. At 7 Mohs, the surface / downhole torque ratio is 6:4, with a surface output torque of 1800 N·m and a downhole output torque of 1200 N·m. At 8 Mohs, adjust to 4:6, surface 1200 N·m + downhole 1800 N·m; At 9 Mohs, the total downhole power is set to 3000 N·m; 3) Synergistic effect of rock breaking and debris removal: The drill bit features a 30MPa pulsed water flow (5Hz) through its 3-pulse jet orifice, which, combined with the PDC cutting teeth, achieves a "cutting + impact" composite rock breaking, enabling a drilling speed of up to 12m / h in hard rock formations.

[0045] Gas-liquid two-phase flow start-up: Nitrogen flow rate 20m³ 3The cuttings mix with the drilling fluid at a speed of 1.8 m / s, forming a slug flow. The cuttings are then spiraled back up through the 45° spiral cleaning groove on the drill pipe.

[0046] S3, Fine-tuning of 3D trajectory: 1) Real-time inclinometer cycle: The logging-while-drilling instrument 5 uploads the well inclination angle (θ) and azimuth angle (θ) every 5 seconds. The laser guidance system emits a reference beam every 100 meters, and the receiving device on drill bit 3 calculates the spatial coordinate deviation (ΔX, ΔY, ΔZ≤10mm).

[0047] The electromagnetic induction guide ring 6 monitors the formation resistivity in real time and detects changes in formation resistivity 2m in advance. When a sudden change in resistivity is detected (such as the sandstone-limestone interface), a rock interface warning is sent 2m in advance. The central control system pre-adjusts the drill bit 3 inclination angle by 0.5° to counteract the natural directional force of the formation.

[0048] 2) Deviation correction strategy: Micro-deviation (0.05° < θ ≤ 0.5°): Only the piezoelectric ceramic sheet 4 is working. When a voltage of 50-100V is applied, it deflects in the opposite direction of the deviation at a rate of 0.01° / ms until the error is < 0.05°.

[0049] Large deviation (θ>0.5°): Link four sets of hydraulic servo cylinders 12, for example, the right cylinder extends by 0.1mm and the left cylinder retracts by 0.1mm, and the drill bit 3 speed is adjusted to 1000rpm simultaneously, and the three-dimensional correction (X / Y axis tilt angle and azimuth angle are calibrated simultaneously) is completed within 30 seconds.

[0050] This invention can also include a gas-liquid composite chip removal operation. In the conventional chip removal mode, nitrogen is injected into the surface air compressor at a flow rate of 20 m³ / h. 3 / min, pressure 1.2MPa, drilling fluid discharge 35L / s, cuttings removal efficiency stable at 85%.

[0051] Rock cuttings (particle size <3mm) move in a spiral motion under the guidance of the spiral cleaning trough. Combined with the air lift effect (nitrogen density < drilling fluid), the transport speed reaches 1.8m / s, and the cuttings removal efficiency is stable at over 85%.

[0052] When the pressure difference inside the drill pipe is >3MPa as monitored by strain sensor 7, the blockage emergency treatment mode is activated. If the pressure difference is 3~5MPa, start the pulse jet enhancement (frequency 10Hz) and impact the rock cuttings bed for 30 seconds.

[0053] If the pressure difference is >5MPa, suspend drilling and perform the following operations: ① Full-power injection of 15MPa high-pressure nitrogen (flow rate 30m³ / h) 3( / min), continuously airlifting for 1 minute to rapidly lift rock debris to the surface; ② Trigger the ultrasonic vibrator (40kHz) near the flexible section of the drill pipe to remove rock cuttings adhering to the thread groove for 10 seconds; ③ When resuming drilling, reduce the rotation speed to 1000 rpm, and gradually increase the parameters after the pressure stabilizes.

[0054] During the drilling process, intelligent monitoring and parameter optimization are carried out. When the strain sensor 7 detects that the deformation of a certain section of the drill pipe is greater than 0.3%, the central control system automatically marks the flexible section, displays a red warning on the operation interface, and prioritizes checking the connection sealing of the section during the next tripping operation.

[0055] Edge computing unit 19 trains an LSTM model every 10 minutes based on historical data (torque, rotational speed, footage, lithology) to predict the optimal parameters for the next formation, for example: Before entering the hard rock layer, the downhole power ratio is automatically increased to 70% and the pulse jet pressure is increased to 35MPa. The fuzzy PID controller dynamically adjusts the surface motor speed according to the real-time torque fluctuation (±5%) (adjustment step size 5rpm) to ensure maximum power transmission efficiency.

[0056] Temperature sensor 8 monitors the drilling fluid temperature rise in real time. When the temperature exceeds 150°C, it triggers the surface heat exchanger to control the drilling fluid temperature below 80°C (cooling rate 5°C / min).

[0057] S4. After drilling is completed, the drill string is retrieved: 1) Drilling is carried out section by section. The flexible connecting section 2 is de-energized to restore its flexibility, making it easier to pass through the narrow-diameter well section; 2) Check the wear condition of the magnetic connector seal ring (maximum allowable wear is 0.2mm), and replace any worn parts.

[0058] 3) Disassemble drill bit 3, check the wear of the PDC cutting teeth (maximum allowable wear 0.5mm), and use 5MPa high-pressure water to flush and clean the blockage in the pulse jet hole; Turbine 16 was returned to the factory for inspection to check the wear of the ceramic bearing (radial runout ≤0.05mm), and magnetic coupling induction ring 17 was demagnetized (residual magnetism ≥80% is acceptable).

[0059] 4) The central control system exports data for the entire well section, including drill pipe strain curves, drill bit torque fluctuations, and lithology identification results, which are used for subsequent formation modeling and drilling parameter optimization. Generate a well completion report, recording key indicators such as deviation at a depth of 3000 meters, mechanical drilling rate, and cuttings removal efficiency.

[0060] Therefore, the present invention provides a long-distance drilling device and method for geological exploration. By dynamically distributing torque between a surface variable frequency motor and a downhole turbine through a magnetic coupling, dual-power coupling efficiency is achieved. A piezoelectric deflection adjuster works in conjunction with a hydraulic servo cylinder, combined with laser guidance and electromagnetic induction rock layer prediction, to achieve a cumulative depth deviation of <0.8° over long distances, meeting the complex trajectory requirements of shale gas horizontal wells, and a rigid-flexible adaptive drill pipe system is set up to improve drill pipe life.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A long-distance drilling rig for geological exploration, characterized in that: The system includes a drive system, a drill pipe system, and a drill bit system. The drive system consists of a surface drive unit and a downhole drive unit. The drill pipe system is a hollow, segmented drill pipe, which consists of a rigid main body and flexible connecting sections. The drill bit system includes a drill bit and an intelligent guidance mechanism mounted on the drill bit. The intelligent guidance mechanism includes a piezoelectric deflection adjuster, a drilling rig, an electromagnetic induction guide ring, and a hydraulic servo adjustment component. The drive system, drill pipe system, and drill bit system are all controlled by a central control system.

2. The long-distance drilling rig for geological exploration according to claim 1, characterized in that: The rigid main rod is made of carbon fiber reinforced titanium alloy composite material; the inner wall of the rigid main rod is provided with spiral prestressed reinforcing ribs, and the outer wall is provided with 45° spiral cleaning grooves; the flexible connecting section is connected to both ends of the rigid main rod through magnetic connectors; the flexible connecting section is set as a shape memory alloy spring structure, which can be bent when not energized, with a radius of curvature ≥5m, and solidifies into a rigid body after being heated to 60°C; strain sensors and temperature sensors are spirally laid on the inner wall of the rigid main rod; an angle sensor is set at the center of the flexible connecting section.

3. The long-distance drilling rig for geological exploration according to claim 1, characterized in that: The drill bit has a pulse jet hole inside, which is connected to the inner hole of the rigid main body; a laser guide receiver is provided on the top of the drill bit.

4. The long-distance drilling rig for geological exploration according to claim 1, characterized in that: The piezoelectric deflection adjuster consists of four sets of rectangular piezoelectric ceramic plates, which are attached to the root of the drive shaft of the drill bit; the hydraulic servo adjustment assembly is configured as four sets of hydraulic servo cylinders, which are circumferentially arranged at the connection between the drill bit and the segmented drill rod; the electromagnetic induction guide ring is installed on the segmented drill rod 1.5~2m behind the drill bit; and the drilling skewing instrument is installed on the drill bit.

5. A long-distance drilling rig for geological exploration according to claim 1, characterized in that: The surface drive unit includes a variable frequency motor and a planetary gearbox. The output shaft of the variable frequency motor is connected to the input end of the planetary gearbox via a rigid coupling. The hollow drive shaft of the planetary gearbox is connected to the wellhead sealing device.

6. The long-distance drilling rig for geological exploration according to claim 1, characterized in that: The downhole drive unit includes a turbine and a magnetic coupling. The turbine is nested at the front end of the segmented drill pipe. The outer shell is connected to the rigid main rod body above by threads, and the internal rotor shaft is connected to the drive shaft of the drill bit by splines. The magnetic coupling consists of a permanent magnet ring at the surface end and an induction ring at the bottom end. The permanent magnet ring is fixed to the end of the hollow drive shaft of the planetary gearbox, and the induction ring is fixed to the rotor shaft of the turbine.

7. A long-distance drilling rig for geological exploration according to claim 1, characterized in that: The central control system consists of a data acquisition module, an edge computing unit, and a remote terminal. The edge computing unit integrates a 12-core processor and a GPU, and the remote terminal is connected via a 5G network. The data acquisition module receives data from the tilt sensor, strain sensor, temperature sensor, and drilling survey instrument, and transmits it to the edge computing unit.

8. A drilling method based on the long-distance drilling rig for geological exploration as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Drill assembly and lowering: On the drill rig, the single rigid main rod body and the flexible connecting section are quickly connected by a magnetic connector. The flexible section is energized to 60°C and cured into a rigid body. A torque wrench is used to test the connection strength and check the sealing pressure. Connect the drive shaft of the drill bit to the rotor shaft of the turbine at the front end of the drill pipe via spline, apply preload, and test the deflection accuracy of the piezoelectric regulator; lower the drill string, monitor the data of the inclination sensor of the flexible section in real time, and start the flexible section to cut off power when encountering resistance, restore flexibility to pass through the narrow-diameter formation, and re-energize and solidify after passing through. S2. The rock hardness is detected by an ultrasonic hardness sensor. After calculation, the edge computing unit determines whether to trigger the turbine to start and dynamically allocates power according to the hardness value. It also works with the drill bit pulse jet hole to achieve "rotational cutting + high pressure jet" composite rock breaking. S3. The logging-while-drilling instrument collects well inclination and azimuth data every 5 seconds. The laser guidance system emits a reference beam every 100 meters. The laser guidance receiver calculates the spatial coordinates and corrects the drill bit. The electromagnetic induction guide ring monitors the formation resistivity in real time. When a sudden change in resistivity is detected, a rock interface warning is sent 2 meters in advance. The edge calculation unit pre-adjusts the drill bit inclination angle by 0.5° to counteract the natural deflection force of the formation.

9. The drilling method for a long-distance drilling rig for geological exploration according to claim 8, characterized in that: In S2, when the rock hardness is less than 7 Mohs and it is a soft rock layer, only the surface motor works, and the downhole turbine rotates naturally with the drilling fluid, with a power distribution ratio of 100:

0. When the rock hardness is >7 Mohs, indicating a hard rock layer, the downhole turbine is triggered to start, and the torque distribution is dynamically adjusted through the magnetic coupler according to the hardness value. The main drive motor speed is automatically adjusted according to the torque. The speed is 750~800rpm for soft rock layers and 1400~1500rpm for hard rock layers.

10. The drilling method for a long-distance drilling rig for geological exploration according to claim 8, characterized in that: In S3, the drill bit correction strategy is as follows: When the well inclination angle deviation θ≤0.5°, only the piezoelectric ceramic plate works, applying voltage in the opposite direction of the deviation and fine-tuning at a rate of 0.01° / ms until the error <0.05°; When the well inclination angle deviation θ>0.5°, the hydraulic servo cylinder is linked to adjust the drill bit speed synchronously, and the attitude correction is completed within 30 seconds.

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