Drilling system suitable for complex stratum and construction method

Abstract

The drilling system comprises a spiral drilling rod, the outer wall of the spiral drilling rod is provided with spiral blades, and a containing cavity is formed in the spiral drilling rod; a hard alloy cutter is arranged at the front end of the alloy cutter drill rod; the driving device is connected to the upper end of the alloy cutter drill rod; the torque sensor is arranged on the spiral drill rod; and the control device is electrically connected with the torque sensor and the driving device, and the control device judges the hardness of the stratum according to the real-time torque M monitored by the torque sensor and controls the driving device to drive the alloy cutter drill rod to stretch out or retract. The spiral drill rod has the beneficial effects that a telescopic alloy cutter drill rod sleeve type structure is arranged in the spiral drill rod, the control device is driven by torque sensing signals to automatically switch working modes, non-stop replacement of the drilling tool state is achieved according to stratum changes, the control device collects torque and rotating speed data in real time, and the control device is connected with the spiral drill rod. And the drilling speed is dynamically adjusted based on the real-time torque and rotating speed relation.

Description

Technical Field

[0001] This invention relates to the field of geological drilling technology, and in particular to a drilling system and construction method adapted to complex strata. Background Technology

[0002] In the construction of pile foundations, anchor bolts or anchor cables, complex strata with uneven hardness are often encountered, such as weathered strata with alternating layers of sandstone and mudstone, alternating layers of limestone and shale, alternating layers of volcanic rocks and sedimentary rocks, as well as granite weathering zones. In particular, high-voltage power transmission and transformation projects usually need to cross different geological regions and often encounter complex strata.

[0003] Different drilling bits are required for soft strata (such as soil) and hard strata (such as rock and weathered rock) with large differences in strength, in order to adapt to the different drilling process requirements of soft and hard strata, while preventing drill bit damage.

[0004] When drilling in strata with significant differences in hardness, existing technologies often require frequent manual replacement of different drill bits, resulting in low drilling efficiency and complex processes. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that, when drilling in strata with significant differences in hardness, the existing technology often requires frequent manual replacement of different drill bits, resulting in complex processes and low drilling efficiency.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a drilling system adapted to complex strata, which includes a spiral drill rod, with spiral blades on its outer wall and an axially arranged accommodating cavity inside; The alloy tool drill rod is axially telescopically disposed within the accommodating cavity, and its front end is provided with a carbide tool; A drive device, connected to the upper end of the alloy cutter drill rod, is used to drive it to extend or retract relative to the spiral drill rod; A torque sensor is mounted on the auger drill rod; The control device is electrically connected to the torque sensor and the drive device. The control device determines the hardness of the formation based on the real-time torque M monitored by the torque sensor, and controls the drive device to drive the alloy cutter drill rod to extend or retract, so as to achieve continuous hole forming without lifting the drill rod.

[0007] In a preferred embodiment of the drilling system adapted to complex formations described in this invention: when the alloy cutter drill rod extends, the carbide cutter at its front end protrudes from the bottom end of the spiral drill rod; when the alloy cutter drill rod retracts, the alloy cutter is completely hidden in the receiving cavity, and only the spiral blades cut the formation.

[0008] In a preferred embodiment of the drilling system adapted to complex formations described in this invention: the driving device is a hydraulic cylinder or a pneumatic cylinder, whose piston rod is coaxially and fixedly connected to the alloy cutter drill rod, and the stroke of the piston rod is not less than the designed extension length of the alloy cutter relative to the bottom end of the spiral drill rod.

[0009] In a preferred embodiment of the drilling system adapted to complex formations described in this invention: the control device is also connected to the rotation speed control unit of the drilling rig, the rotation speed control unit being located above the auger drill rod and including a drilling speed sensor, the control device being further configured to maintain the actual output power not exceeding a preset power threshold during drilling, and to dynamically adjust the rotation speed of the auger drill rod according to the real-time torque.

[0010] In a preferred embodiment of the drilling system adapted to complex formations according to the present invention, the control device includes: The power calculation module is used to receive real-time torque. With rotational speed ω, calculate the actual power. ; The comparison and decision module is used to... With preset power threshold Compare, and > Output speed reduction command at time, in < Output speed-up command at the same time; The formation determination module is used to determine the real-time torque. With preset torque threshold , The comparison is used to determine the hardness of the formation and output the extension and retraction control command of the drive device.

[0011] The present invention also provides a drilling method adapted to complex strata, characterized by comprising the following steps: S1: Set drilling rig power threshold and torque threshold , ; S2: Drilling begins, and the torque sensor (4) monitors the drill rod torque in real time. And the drill rod rotation speed ω is obtained synchronously according to the drilling speed sensor (61); S3: The control device (5) calculates the actual power. =M×ω, and execute: like ≥ If the formation is determined to be a hard stratum, the control drive device (3) pushes the alloy cutter drill rod (2) to extend. like < If it is determined to be a soft formation, control drive device (3) retracts alloy cutter drill rod (2). S4: The control device (5) maintains and Consistency: When > When the speed ω is reduced, < Increase the speed ω, speed adjustment amount according to Calculation determined; S5: Repeat steps S2 to S4 until drilling is complete.

[0012] In a preferred embodiment of the drilling method for adapting to complex formations according to the present invention: the power threshold According to the rated power of the drilling rig System efficiency and safety factor Confirmed, satisfied , where 0.7≤ ≤0.9.

[0013] In a preferred embodiment of the drilling method for adapting to complex formations described in this invention: torque threshold , The settings are dynamically configured based on formation strength, drill bit diameter, and field test data. The torque that separates soft and hard formations. The torque at the boundary between hard and extremely hard formations, and > .

[0014] In a preferred embodiment of the drilling method for adapting to complex formations described in this invention: the rotation speed adjustment satisfies... ,in The adjusted target speed, To monitor the torque, a speed change rate limit is set during the adjustment process. To avoid mechanical impact.

[0015] In a preferred embodiment of the drilling method for adapting to complex formations described in this invention: when determining changes in the hardness of the formation, the control device must detect torque continuously n times. The extension and retraction of the alloy tool drill rod is triggered only when the corresponding threshold is exceeded, where n≥3, to prevent frequent switching and misjudgment at the formation interface.

[0016] The beneficial effects of this invention are as follows: the spiral drill rod has a sleeve-type structure with a built-in telescopic alloy tool drill rod, and the working mode is automatically switched by the torque sensor signal driving the control device. The functions of the two drilling tools are integrated into one, and the drilling tool status can be replaced without stopping according to the changes in the formation. The control device collects torque and speed data in real time and dynamically adjusts the drilling speed based on the real-time torque and speed relationship. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 A schematic diagram of the drilling rig's working state is shown when drilling in soft formations using a drilling system adapted to complex formations. Figure 2 A frontal cross-sectional view of a drilling rig is shown when drilling in soft formations using a drilling system adapted to complex formations. Figure 3 A top view of a drilling rig is shown when drilling in soft formations using a drilling system adapted to complex formations. Figure 4 A schematic diagram of the drilling rig's working state is shown when drilling in hard formations using a drilling system adapted to complex formations. Figure 5 A frontal cross-sectional view of a drilling rig is shown when drilling in hard formations using a drilling system adapted to complex formations. Figure 6 A schematic diagram of the alloy tool drill rod and alloy tool is shown. Figure 7 The control logic block diagram of the control device is shown. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0020] Reference Figures 1-6This embodiment provides a drilling system adapted to complex formations, including a spiral drill rod 1 with spiral blades 11 on its outer wall and an axially oriented accommodating cavity A inside. In this embodiment, the spiral drill rod 1 is a hollow cylindrical rod, serving as the main load-bearing structure of the entire drill bit. It transmits the drilling torque and axial pressure. The continuous spiral blades 11 wound around the outer wall of the spiral drill rod 1 mainly function to cut soft formations and simultaneously transport drill cuttings, realizing a single drilling mode for soft formations and ensuring continuous hole formation and efficient slag removal. The accommodating cavity A can accommodate the telescopic movement of the alloy tool drill rod 2 and constrain its circumferential degree of freedom.

[0021] Preferably, the alloy tool drill rod 2 is axially telescopically disposed within the accommodating cavity A, and its front end is provided with a carbide tool 21. The alloy tool drill rod 2 is a slender cylindrical rod with an outer diameter slightly smaller than the inner diameter of the accommodating cavity A. The alloy tool drill rod 2 serves as the mounting base for the carbide tool 21. In this embodiment, the alloy tool 21 is an ultra-hard material cutting edge inlaid / welded to the front end of the alloy tool drill rod 2. The specific method and material are not limited. The alloy tool 21 undertakes the main rock-breaking task in hard formations, realizing efficient drilling in hard rock and avoiding wear of the spiral blade 11 in hard formations.

[0022] Preferably, the drive device 3 is connected to the upper end of the alloy cutter drill rod 2 and is used to drive it to extend or retract relative to the spiral drill rod 1. In this embodiment, the drive device 3 is a linear actuator fixedly installed on the upper end of the drill rig power head or the spiral drill rod 1, which converts fluid pressure or electrical energy into mechanical thrust / pull force. The drive device 3 realizes the controllable, reversible, and positionable movement of the cutter extension and retraction and is an intelligent switching execution terminal.

[0023] Preferably, the torque sensor 4 is installed on the auger drill rod 1. In this embodiment, the torque sensor 4 is a strain gauge / magnetoelectric torque measuring device, which is fixedly installed on the auger drill rod 1, rather than on the stationary drilling rig frame, to sense the torsional torque borne by the drill rod in real time. The mechanical torque is converted into an electrical signal, providing quantitative data for determining the hardness of the formation. The torque signal is used for both formation determination and... ≥ ), and is also used for power calculation ( =M×ω), and is also used for speed regulation decisions ( ).

[0024] Preferably, the control device 5 is electrically connected to the torque sensor 4 and the drive device 3. The control device 5 determines the hardness of the formation based on the real-time torque M monitored by the torque sensor 4, and controls the drive device 3 to extend or retract the alloy cutter drill rod 2 to achieve continuous drilling without lifting the drill rod. The control device 5 receives the real-time torque signal from the torque sensor 4. ,based on The system executes the formation hardness / softness judgment logic, generates and outputs control commands for the drive device 3, converts physical sensing signals into mechanical execution actions, and realizes automatic switching of the drill bit's working mode.

[0025] Furthermore, when the alloy cutter drill rod 2 extends, the carbide cutter 21 at its front end protrudes from the bottom end of the auger drill rod 1; when the alloy cutter drill rod 21 retracts, the alloy cutter 21 is completely hidden in the receiving cavity A, and only the helical blade 11 cuts the formation. In this embodiment, in the extended state, the alloy cutter 21 protrudes from the bottom end of the auger drill rod 1 (the cutting height h ≥ 15 mm), which efficiently breaks rock in hard formations. In the retracted state, the alloy cutter 21 is completely hidden in the receiving cavity A (the bottom end of the cutter ≥ 5 mm from the port of receiving cavity A), and the helical blade 11 is the only rock-breaking tool at this time, cutting the formation across the entire cross section.

[0026] Reference Figures 1-6 As an optional embodiment, the drive device 3 is a hydraulic cylinder or a pneumatic cylinder, which is a linear actuator. Its piston rod 32 is coaxially and fixedly connected to the alloy tool drill rod 2, and directly transmits the driving force to the alloy tool drill rod 2, ensuring the shortest power transmission path and no transmission loss. The stroke of the piston rod 32 is not less than the designed extension length of the alloy tool 21 relative to the bottom end of the spiral drill rod 1, ensuring that the piston rod 32 can push the alloy tool 21 completely to the working position, without "half-extension" failure caused by insufficient stroke.

[0027] Reference Figures 1-6 As an optional embodiment, the control device 5 is also connected to the drilling rig's speed control unit 6. The speed control unit 6 is located above the auger drill rod 1. The speed control unit 6 is used to receive speed commands from the control device 5 and adjust the output speed of the power head. The speed control unit 6 realizes closed-loop speed control and is the execution terminal for constant power regulation. The speed control unit 6 is a hydraulic motor speed control valve or frequency converter built into the drilling rig and is installed in the drilling rig's power head or main control cabinet. The control device 5 communicates with the speed control unit 6 through a CAN bus or hardwired connection, sending it a target speed command to realize real-time adjustment of the speed of the auger drill rod 1. The speed control unit 6 includes a drilling speed sensor 61, providing a second variable to realize dual-parameter monitoring. The control device 5 is further configured to maintain the actual output power not exceeding a preset power threshold during drilling and dynamically adjust the speed of the auger drill rod 1 according to the real-time torque. During operation, in hard formations ( Increase): Control device 5 automatically reduces the speed ,satisfy To prevent motor overload while maintaining maximum rock-breaking capacity, soft strata ( (Reduce): Control device 5 automatically increases the speed Make full use of the remaining power to increase the mechanical drilling speed, and ensure that the drilling rig always operates at its rated power. Nearby, the equipment utilization rate is >95%, which is 20% to 40% more efficient than constant speed control.

[0028] Preferably, the control device 5 includes a power calculation module 51 for receiving real-time torque. With rotational speed ω, calculate the actual power. Simultaneously, it receives torque from torque sensor 4. and the rotational speed of the drilling speed sensor 61 To construct the complete parameter set required for power calculation, in this embodiment... and Sampling synchronization (time difference Δt < 10ms) ensures The calculation is distortion-free; the comparison decision module 52 is used to... With preset power threshold Compare, and > Output speed reduction command at time, in < The system outputs a speed-up command, which receives the output from the power calculation module 51. and the system's preset power threshold ; Formation determination module 53, used to determine real-time torque With preset torque threshold , The comparison is used to determine the hardness of the formation and output the extension and retraction control command of the drive device 3, directly receiving the torque sensor 4. Value, and preset torque threshold , (torque threshold) , (Based on geological tests), the power calculation module 51 uses a floating-point unit (FPU) and completes a calculation every 100ms. =M×ω calculation, comparison decision module 52 built-in PID controller, when and When the deviation exceeds ±5%, the PWM signal with adjustable duty cycle is output to the speed control unit 6. The adjustment rate is 10 rpm every 500ms. The formation judgment module 53 adopts a state machine model and triggers the expansion command only when the same formation condition is met in 3 consecutive samplings (1s interval). The switching delay is set to 2 seconds.

[0029] Reference Figures 1 to 7 As an optional embodiment, a drilling method adapted to complex formations includes the following steps: S1: Set drilling rig power threshold and torque threshold , Drilling rig power threshold Boundary constraint parameters define the upper limit of the drilling rig's rated power, serving as a safety benchmark for constant power control, and the torque threshold. , The quantitative criteria for classifying soft and hard strata are the triggering conditions for switching drill bits; S2: Drilling begins; torque sensor 4 monitors drill pipe torque in real time. The drill pipe rotation speed ω is synchronously obtained from the drill speed sensor 61, and the drill pipe torque is collected in real time by the torque sensor 4. The drilling speed sensor 61 provides the first variable for calculating formation hardness and power, and collects the drill pipe rotation speed in real time. It provides a second variable for power calculation and a speed regulation object; S3: Control device 5 calculates actual power =M×ω, and execute: like ≥ If the formation is determined to be hard, the control drive device 3 will push the alloy cutter drill rod 2 to extend. like < If the formation is determined to be soft, the control drive device 3 retracts the alloy tool drill rod 2. The drive device 3 receives the control command and drives the alloy tool drill rod 2 to complete the extension and retraction physical action. S4: Control device 5 maintains and Consistency: When > When the speed ω is reduced, < Increase the speed ω, speed adjustment amount according to Once the calculation is complete, control device 5 performs calculations, comparisons, judgments, and outputs commands. The strict timing sequence of "first determine the formation → then calculate the power → then output the command" in S3 forms a nested loop with "continuous maintenance" in S4. S5: Repeat steps S2 to S4 until drilling is complete.

[0030] Preferably, power threshold According to the rated power of the drilling rig System efficiency and safety factor Confirmed, satisfied , where 0.7≤ ≤0.9, in this embodiment the drilling rig's rated power is 100kW, and the system efficiency is... The estimated value is 0.9, with a safety factor of [missing information]. If we take 0.85, then... This setting ensures that the equipment always operates at full load within its safe operating capacity, with upper and lower torque thresholds. , The value is determined based on various factors, including on-site geological conditions, equipment status, and necessary physical and mechanical tests. It is not a simple constant value; it is used for formation determination and drill bit switching, and to improve system efficiency. Bench tests were conducted to determine the comprehensive corrections for hydraulic pump volumetric efficiency, motor mechanical efficiency, and transmission chain efficiency for fully hydraulic drilling rigs. The value of η is 0.85~0.90; for electric drilling rigs, the value of η is 0.92~0.95, and the safety factor is... Based on geological conditions: homogeneous soft soil k=0.85-0.9, interbedded soft and hard soil k=0.8~0.85, fractured rock strata =0.7~0.8, power threshold The calculation is automatically completed by the control device 5 during initialization.

[0031] Preferably, torque threshold , The settings are dynamically configured based on formation strength, drill bit diameter, and field test data. The torque that separates soft and hard formations. The torque at the boundary between hard and extremely hard formations, and > Formation strength is positively correlated with torque; the torque generated by hard to extremely hard formations is necessarily higher than the boundary torque between soft and hard formations. > It is an objective reflection of the mechanical properties of the strata; if there is no... ,only Single threshold, in soft and hard interlayer Will The nearby oscillations cause the cutting tools to switch several times per minute, resulting in significant mechanical impact and shortening the lifespan of the seals.

[0032] Preferably, the speed adjustment meets the requirements. ,in The adjusted target speed, The torque sensor 4 measures the instantaneous value at the current time t to monitor the torque, reflecting the current cutting resistance of the formation. A speed change rate limit is set during the adjustment process. To avoid mechanical impact It is the range of change in rotational speed per unit time, and is a core control indicator for preventing mechanical shock. It represents the upper limit of the rate of change, the maximum permissible speed regulation slope, reflecting the matching between the mechanical system's inertia and dynamic response capabilities. The speed control output variable is the desired speed for the next cycle calculated by control device 5, and it is the command value sent to speed control unit 6, such as... Mutation (e.g., encountering a rock). It can change drastically in an instant, causing the actual power to... Severe oscillations may trigger system protection or borehole instability, while the effect of constraints, such as rate-of-change limitations, makes... Smooth transition, It approaches smoothly within 1 to 2 seconds. This ensures both constant power output and stable drilling.

[0033] Preferably, when determining changes in the hardness of the formation, the control device 5 must detect torque continuously for n times. The extension and retraction of the alloy tool drill rod 2 is triggered only when the corresponding threshold is exceeded, where n≥3, in order to prevent misjudgment and frequent switching at the formation interface.

[0034] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A borehole system adapted to complex formations, characterized by: Comprising, a spiral drill rod (1) having spiral blades (11) on its outer wall and a receiving cavity (A) in its interior along the axial direction; an alloy cutter drill rod (2) axially telescopically arranged in the receiving cavity (A) and having a hard alloy cutter (21) at its front end; a driving device (3) connected to the upper end of the alloy cutter drill rod (2) for driving it to extend or retract relative to the spiral drill rod (1); a torque sensor (4) mounted on the spiral drill rod (1); a control device (5) electrically connected to the torque sensor (4) and the driving device (3), which judges the hardness of the stratum according to the real-time torque M monitored by the torque sensor (4) and controls the driving device (3) to drive the alloy cutter drill rod (2) to extend or retract, thereby realizing continuous hole forming without separate lifting and drilling.

2. The borehole system adapted for complex formations of claim 1, wherein: When the alloy cutter drill rod (2) extends, the hard alloy cutter (21) at its front end protrudes from the bottom end of the spiral drill rod (1); when the alloy cutter drill rod (2) retracts, the alloy cutter (21) is completely hidden in the receiving cavity (A) and only the spiral blades (11) cut the stratum.

3. The borehole system adapted for complex formations of claim 1, wherein: The driving device (3) is a hydraulic cylinder or a pneumatic cylinder, the piston rod (32) of which is coaxially fixedly connected with the alloy cutter drill rod (2), and the stroke of the piston rod (32) is not less than the designed extension length of the alloy cutter (21) relative to the bottom end of the spiral drill rod (1).

4. The borehole system adapted for complex formations of claim 1, wherein: The control device (5) is also connected with a rotary speed control unit (6) of the drilling rig, which is located above the spiral drill rod (1) and includes a drilling speed sensor (61), and the control device (5) is further configured to maintain the actual output power not exceeding a preset power threshold during drilling and dynamically adjust the rotary speed of the spiral drill rod (1) according to the real-time torque.

5. The borehole system adapted for complex formations of claim 4, wherein: The control device (5) includes: a power calculation module (51) for receiving the real-time torque and the rotational speed ω and calculating the actual power ; A comparison decision module (52) is used to compare the preset power threshold with the current power value, and output a speed-down instruction when > the current power value is greater than the preset power threshold, and output a speed-up instruction when < the current power value is less than the preset power threshold. The formation judging module (53) is configured to compare the real-time torque with a preset torque threshold , to judge the hardness of the formation and output the extension control instruction of the driving device (3).

6. A method of drilling a borehole in a complex formation using a drilling system as claimed in any one of claims 1 to 5, characterised in that, The method comprises the following steps: S1 : Set drill power threshold and torque threshold , ; S2: start drilling, the torque sensor (4) monitors the drilling pipe torque in real time and the drilling speed sensor (61) synchronously obtains the drilling pipe rotating speed ω; S3: The control device (5) calculates the actual power = M x ω, and performs: If ≥ , it is determined that the ground is hard, and the driving device (3) is controlled to push the alloy cutter drill pipe (2) to extend out. If < , it is determined that the ground is soft, and the driving device (3) is controlled to retract the alloy cutter drill pipe (2). S4: said control device (5) maintains conformity with : when > the rotation speed ω is reduced, when < the rotation speed ω is increased, the amount of speed regulation is calculated and determined in accordance with ; S5: repeating steps S2-S4 until the drilling is completed.

7. The method of claim 6, wherein: the power threshold in accordance with the rated power of the drilling rig , the system efficiency and the safety factor is determined, which satisfies where 0.7 ≤ ≤ 0.

9.

8. The method of claim 6, wherein: torque threshold , The threshold torque is dynamically set according to the formation strength, bit diameter and field test data, wherein is the soft-hard formation boundary torque, is the hard-extremely hard formation boundary torque, and .​ 9. The method of claim 6, wherein: The rotational speed adjustment meets wherein is the adjusted target rotational speed, is the current monitored torque, and a rotational speed change rate limit is set during the adjustment to avoid mechanical shocks.

10. A method of drilling a borehole to accommodate complex formations according to any one of claims 6 to 9, wherein: The control device (5) needs to meet the condition that the torque is monitored continuously n times when determining the change of formation hardness The telescopic action of the alloy cutter drill rod (2) is triggered only when the corresponding threshold is crossed, wherein n≥3, so as to prevent frequent switching and misjudgment at the formation interface.

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