Device and method for monitoring rotating speed of self-rotating jet drill bit

Abstract

The invention relates to the technical field of hydraulic drilling composite fracturing anti-reflection coal seams, and particularly discloses a device and method for monitoring the rotating speed of a self-rotating jet flow drill bit. The device comprises a water tank, a high-pressure pump, a self-rotating jet flow drill bit, a water shielding cover, a data processing terminal, a laser emission receiver and a reflective sticker. The water tank is connected with the high-pressure pump and the drill bit through pipelines, the water shield is fixed at the front end of the drill bit, the reflective sticker is adhered to the matte surface of a drill bit nozzle body, and the laser transceiver vertically irradiates the reflective sticker and is connected with the data processing terminal through a data line. The method comprises the steps of pretreating a drill bit and pasting a reflective sticker; assembling the system and calibrating the coaxiality of the light shield and the vertical incidence of laser; starting to increase the pressure at the step length of 1 MPa from the starting pressure p0, recording data after the rotating speed is stable, and obtaining a pressure-rotating speed change rule. According to the scheme, water mist is isolated through the water shielding cover, background interference is restrained through matte treatment, and non-contact high-precision monitoring of the rotating speed of the drill bit in the high-pressure water jet environment is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic drilling composite fracturing and permeability-enhancing coal seams, and relates to a device and method for monitoring the rotation speed of a self-rotating jet drill bit. Background Art

[0002] In the field of hydraulic drilling composite fracturing and permeability enhancement technology for coal seams, the use of continuous oil tubing to drive a self-rotating jet drill bit to drill and break the coal into holes is a key step in the subsequent implementation of hydraulic fracturing. Studies have shown that the coal breaking efficiency of a self-rotating jet drill bit increases first and then decreases with the change in the ratio of rotation speed to pressure, that is, there is an optimal speed range under a specific pressure. However, existing technologies have not yet solved the problem of real-time monitoring of the rotation speed of a self-rotating jet drill bit. Due to the lack of a reliable speed monitoring method, it is impossible to accurately obtain the dynamic change law of the drill bit's speed under a single pressure, making it difficult to stabilize the drill bit's operating state within the advantageous range with higher coal breaking efficiency through speed control means.

[0003] While some technologies currently attempt to monitor the rotational speed of rotating equipment, these solutions primarily rely on contact sensors or conventional optical measurement methods. In high-pressure water jet environments, contact sensors are susceptible to damage from the impact of the water flow, and their mounting structure can interfere with the drill bit's self-rotating motion. Conventional optical measurement methods, however, struggle to achieve stable and accurate speed capture even under high-speed rotation due to issues such as water mist and background interference. Existing technologies lack a non-contact speed monitoring solution designed for the specialized operating conditions of self-rotating jet drill bits. In particular, there is a lack of effective measures to suppress water mist interference and ensure stable optical signal transmission in high-pressure water jet environments. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a non-contact speed monitoring method that can adapt to complex working conditions underground, so as to obtain the speed data of the self-rotating jet drill bit under different pressures in real time, and provide technical support for optimizing the drill bit operating parameters and improving the coal seam breaking efficiency.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A device for monitoring the rotation speed of a self-rotating jet drill bit, comprising a water tank, a high-pressure pump, a self-rotating jet drill bit, a water shield, a data processing terminal, a laser transmitter and receiver, and reflective stickers;

[0007] The water outlet of the water tank is connected to the water inlet of the high-pressure pump through a pipeline, and the water outlet of the high-pressure pump is connected to the water inlet of the self-rotating jet drill through a high-pressure pipeline;

[0008] The water shield is fixedly arranged at the front end of the self-rotating jet drill bit, and a center hole is provided in the center thereof. The axis of the center hole coincides with the axis of the self-rotating jet drill bit, and the diameter of the center hole is 10 mm larger than the diameter of the drill bit;

[0009] The reflective sticker is attached to the nozzle body surface at the front end of the self-rotating jet drill bit;

[0010] The laser transmitter and receiver are fixedly installed, and the laser they emit is perpendicular to the surface of the reflective tape, and the distance between the laser transmitter and receiver and the reflective tape is 5 to 200 mm;

[0011] The laser transmitter and receiver are electrically connected to the data processing terminal via a data line, and are used to convert the reflected light signal into rotation speed data and transmit it to the data processing terminal.

[0012] Optionally, the nozzle body surface of the self-rotating jet drill is matte-finished.

[0013] Optionally, an anti-blowout structure is provided at the pipe connection between the high-pressure pump and the self-rotating jet drill bit.

[0014] A method for monitoring the rotation speed of a self-rotating jet drill bit, using the above-mentioned device, comprises the following steps:

[0015] Step 1: Matte the nozzle body of the self-rotating jet drill and stick a reflective sticker on the surface of the nozzle body;

[0016] Step 2: Connect the water tank, high-pressure pump and self-rotating jet drill in sequence, and perform anti-blowout treatment on each pipe joint;

[0017] Step 3: Fix the water shield to ensure that the axis of its center hole coincides with the axis of the self-rotating jet drill bit;

[0018] Step 4: Fix the laser transmitter and receiver so that the laser they emit shines vertically on the reflective tape, and the distance between them is controlled within 5 to 200 mm.

[0019] Step 5: Connect the laser transmitter and receiver to the data processing terminal and set the acquisition frequency to 20Hz;

[0020] Step 6: Start the high-pressure pump and slowly increase the pressure. Record the pressure when the rotary jet drill bit starts to rotate as the starting pressure p0, and then turn off the high-pressure pump.

[0021] Step 7: Turn on the high-pressure pump and set the pressure pj = pi + 1 MPa (i = 0, 1, 2...; j = 1, 2, 3...). Record the speed through the data processing terminal. After the speed stabilizes, continue recording for 5 seconds and turn off the high-pressure pump.

[0022] Step 8: Repeat step 7 to obtain the change pattern of the drill bit speed under different pressures.

[0023] Optionally, the incremental step of the pressure pj in step 7 is 1 MPa.

[0024] Optionally, the laser transmitter and receiver in step 5 is set to a real-time data transmission mode.

[0025] The beneficial effects of the present invention are:

[0026] This solution solves the technical challenge of real-time monitoring of the rotational speed of a self-rotating jet drill bit through the collaborative design of non-contact optical monitoring and hydraulic systems. The specific effects are as follows:

[0027] High-precision dynamic monitoring

[0028] A laser transmitter and receiver vertically illuminates the reflective tape on the drill head's nozzle body. Combined with a 20Hz high-frequency data acquisition and processing terminal, the system accurately captures the instantaneous rotational speed of the drill head during high-speed rotation (error <±0.5%). The matte finish on the nozzle body effectively suppresses ambient light interference, and the directional reflective properties of the reflective tape ensure excellent signal-to-noise ratio in low-light environments. The 5-200mm laser ranging range balances near-field anti-fog interference with far-field installation flexibility.

[0029] Adaptability of high-pressure water jet working conditions

[0030] The water shield and its center hole design (10mm larger in diameter than the drill bit and coaxially fixed) are core innovations that break through the limitations of the downhole environment:

[0031] Water mist blocking: The water shield physically isolates the water mist generated by the high-pressure water jet to prevent the laser path from being scattered and interfered with;

[0032] Dynamic compatibility: 10mm gap ensures the free rotation of the drill bit while maintaining a minimal water mist escape channel;

[0033] Stable structure: Coaxial installation avoids mechanical collision caused by rotation eccentricity and ensures long-term monitoring stability.

[0034] Engineering safety and operational convenience

[0035] The pipeline anti-breakout structure can resist high-pressure water hammer impact (pressure can reach over 30MPa) to prevent the equipment from loosening during the monitoring process;

[0036] The pressure gradient control method (adjusting from the starting pressure p0 in 1 MPa steps) can systematically establish a pressure-speed mapping model to avoid transient fluctuation errors;

[0037] The entire process does not require modification of the drill body; only reflective stickers and a fixed water shield are required, reducing on-site deployment time.

[0038] Coal crushing efficiency optimization value

[0039] Based on the real-time acquired rotational speed variation patterns under different pressures, the coal crushing efficiency advantage range (such as the peak speed pressure point) can be accurately located.

[0040] In summary, this solution combines the innovative optical monitoring structure with the depth of hydraulic parameter control, providing reliable technical support for safe and efficient mining in coal mines.

[0041] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0043] Figure 1 Schematic diagram of non-contact monitoring of the rotation speed of a self-rotating jet drill bit;

[0044] Figure 2 Schematic diagram of the relative positions of the water shield and the self-rotating jet drill bit.

[0045] Reference numerals: 1 water tank, 2 high-pressure pump, 3 self-rotating jet drill head, 3.1 nozzle body, 4 water shield, 4.1 center hole, 5 data processing terminal, 6 laser transmitter and receiver, 6.1 laser, 7 reflective tape. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0047] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0048] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0049] See also Figures 1 and 2 The implementation of this scheme needs to be carried out in conjunction with the attached drawings. The following details the device structure and operation process:

[0050] 1. Device Structure

[0051] 1. Hydraulic system

[0052] The water outlet of the water tank 1 is connected to the water inlet of the high-pressure pump 2 through a high-pressure pipeline;

[0053] The water outlet of the high-pressure pump 2 is connected to the water inlet of the rotary jet drill 3 through a pressure-resistant pipeline, and an anti-breakout structure is provided at the pipeline connection.

[0054] 2. Drill bit processing

[0055] The surface of the nozzle body 3.1 at the front end of the self-rotating jet drill 3 is matte-finished;

[0056] A reflective tape 7 is attached to the surface of the nozzle body 3.1, and the size of the reflective tape 7 matches the curvature of the nozzle body 3.1.

[0057] 3. Waterproof structure

[0058] The water shield 4 is fixed to the front end of the drill bit 3, and a center hole 4.1 is provided in the center thereof;

[0059] The diameter of the center hole 4.1 is 10 mm larger than the diameter of the drill bit 3, and the axis of the center hole 4.1 is strictly coincident with the axis of the drill bit 3 (coaxiality error ≤ 0.1 mm).

[0060] 4. Optical monitoring system

[0061] The laser transmitter and receiver 6 is fixed to the side of the water shield 4, and the emitted laser 6.1 vertically illuminates the surface of the reflective tape 7;

[0062] The distance between the laser transmitter and receiver 6 and the reflective tape 7 is controlled within 50 mm (preferably within the range of 5 to 200 mm);

[0063] The laser transmitter and receiver 6 is connected to the data processing terminal 5 via a data line, and the terminal 5 has a built-in rotation speed calculation module.

[0064] 2. Operation steps

[0065] 1. Preprocessing stage

[0066] Perform sandblasting on the nozzle body 3.1 of the drill bit 3 to achieve a matte finish and remove reflective impurities on the surface;

[0067] Stick the reflective tape 7 tightly to the center of the nozzle body 3.1.

[0068] 2. System Assembly

[0069] Connect the water tank 1 → high-pressure pump 2 → drill bit 3 in sequence, and use hydraulic clamps to reinforce the pipe interfaces;

[0070] Install the water shield 4 and use the positioning fixture to ensure that the center hole 4.1 is coaxial with the drill bit 3;

[0071] Adjust the position of the laser transmitter and receiver 6 so that the laser 6.1 is directed vertically toward the reflective tape 7, and the distance is calibrated to 50 mm.

[0072] 3. Parameter settings

[0073] Start the data processing terminal 5 and set the acquisition frequency of the laser transmitter and receiver 6 to 20 Hz;

[0074] Enable real-time data transfer mode.

[0075] Pressure-speed test

[0076] Turn on the high-pressure pump 2, increase the pressure at a rate of 0.5 MPa / s, and record the starting pressure p0 (for example: p0 = 8 MPa) at which the drill bit 3 starts to rotate; turn off the high-pressure pump 2 and reset the system;

[0077] Restart the high-pressure pump 2 and set the pressure pj = p0 + 1 MPa (j = 1, 2, 3 ...), for example, the first test pressure p1 = 9 MPa; record the speed through the data processing terminal 5, and continue recording for 5 seconds after the speed fluctuation rate is less than 2%;

[0078] Turn off the high-pressure pump 2 and repeat the above process until the pressure pn = 20 MPa.

[0079] 3. Key Implementation Details

[0080] 1. Anti-interference design

[0081] The water shield 4 isolates the water mist sprayed by the drill bit 3 from the laser path;

[0082] The 3.1 matte finish on the nozzle body reduces background scattered light and improves the visibility of the reflective tape 7 signal.

[0083] 2. Data accuracy assurance

[0084] Laser 6.1 vertical incidence to avoid cosine error;

[0085] The 20Hz sampling rate covers the maximum speed of drill bit 3 (≤600rpm);

[0086] 5 seconds of stable recording to eliminate startup transient noise.

[0087] 3. Safety measures

[0088] The anti-breakaway structure can withstand a pressure of ≥30MPa;

[0089] The 10 mm gap of the center hole 4.1 of the water shield 4 prevents the drill bit 3 from swinging and colliding.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A device for monitoring the rotation speed of a self-rotating jet drill bit, characterized in that: include: A water tank (1), a high-pressure pump (2), a self-rotating jet drill (3), a water shield (4), a data processing terminal (5), a laser transmitter and receiver (6), and a reflective tape (7); The water outlet of the water tank (1) is connected to the water inlet of the high-pressure pump (2) through a pipeline, and the water outlet of the high-pressure pump (2) is connected to the water inlet of the self-rotating jet drill (3) through a high-pressure pipeline; The water shield (4) is fixedly arranged at the front end of the self-rotating jet drill bit (3); The reflective sticker (7) is attached to the surface of the nozzle body (3.1) at the front end of the self-rotating jet drill (3); The laser transmitter and receiver (6) is fixedly arranged, and the laser light (6.1) emitted by the laser transmitter and receiver is perpendicular to the surface of the reflective tape (7); The laser transmitter and receiver (6) is electrically connected to the data processing terminal (5) via a data line, and is used to convert the reflected light signal into rotation speed data and transmit the data to the data processing terminal (5).

2. The device according to claim 1, characterized in that: A central hole (4.1) is provided at the center of the water shield (4).

3. The device according to claim 2, characterized in that: The axis of the central hole (4.1) coincides with the axis of the self-rotating jet drill bit (3).

4. The device according to claim 1, characterized in that: The diameter of the central hole (4.1) is 10 mm larger than the diameter of the drill bit.

5. The device according to claim 1, characterized in that: The surface of the nozzle body (3.1) of the self-rotating jet drill (3) is matte-finished.

6. The device according to claim 1, characterized in that: The distance between the laser transmitter and receiver (6) and the reflective sticker (7) is 5 to 200 mm.

7. The device according to claim 1, characterized in that: An anti-slip structure is provided at the pipe connection between the high-pressure pump (2) and the self-rotating jet drill bit (3).

8. A method for monitoring the rotation speed of a self-rotating jet drill bit, using the device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Matting the nozzle body (3.1) of the self-rotating jet drill (3) and pasting a reflective sticker (7) on the surface of the nozzle body (3.1); Step 2: Connect the water tank (1), high-pressure pump (2) and self-rotating jet drill (3) in sequence, and perform anti-stripping treatment on each pipe joint; Step 3: Fix the water shield (4) to ensure that the axis of its center hole (4.1) coincides with the axis of the self-rotating jet drill (3); Step 4: Fix the laser transmitter and receiver (6) so that the laser (6.1) it emits is perpendicular to the reflective tape (7), and the distance between the two is controlled to be 5 to 200 mm; Step 5: Connect the laser transmitter and receiver (6) to the data processing terminal (5) and set the acquisition frequency to 20 Hz; Step 6: Start the high-pressure pump (2) and slowly increase the pressure, record the pressure when the rotary jet drill bit (3) starts to rotate as the starting pressure p0, and then turn off the high-pressure pump (2); Step 7: Turn on the high-pressure pump (2), set the pressure pj = pi + 1 MPa (i = 0, 1, 2 ...; j = 1, 2, 3 ...), record the speed through the data processing terminal (5), and continue recording for 5 seconds after the speed stabilizes, and then turn off the high-pressure pump (2); Step 8: Repeat step 7 to obtain the change pattern of the drill bit speed under different pressures.

9. The method according to claim 8, characterized in that: In step 7, the incremental step of the pressure pj is 1 MPa.

10. The method according to claim 8, characterized in that: In step 5, the laser transmitter and receiver (6) is set to a real-time data transmission mode.

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