Rotary valve flow self-control type continuous wave mud pulse generator

Abstract

The utility model discloses a rotary valve flow self-control type continuous wave mud pulse generator which comprises a pulser pup joint, a turbine generator, a driving pup joint and an exploring tube pup joint. The pulser short section comprises an outer pipe shell, a motor shell, a motor, a motor speed reducer, a ball screw, a rotary encoder, a torque sensor and a rotary valve assembly composed of a stator and a rotor. The driving short-circuit energy-saving device realizes the adjustment of a gap of the rotary valve assembly and the generation of a pulse signal through the operation control of a motor; the exploring tube short section is used for measuring well drilling track parameters in an energy-saving manner and storing data, and sending an operation instruction to the driving short section according to a set program; the turbine generator provides a direct-current power supply for the system. The distance between the rotor and the stator of the rotary valve can be automatically adjusted according to time-varying factors such as pumping pressure, hole depth and flushing fluid density, so that the problem of pulse output waveform distortion caused by complex working conditions under long-time working is reduced, and the identifiability and demodulation performance of waveforms are improved.

Description

Technical Field

[0001] This utility model belongs to the field of underground tunnel drilling technology in coal mines, and relates to a continuous wave mud pulse generator in a wireless drilling measurement device, specifically to a rotary valve flow-controlled continuous wave mud pulse generator structure and its control method. Background Technology

[0002] In coal mining, directional drilling technology plays a crucial role, and measurement-while-drilling (MWD) technology, as its core component, is of paramount importance. Based on signal transmission methods, these technologies are broadly categorized into wired and wireless types. Wireless transmission, due to its ease of maintenance and operational flexibility, is gaining increasing attention. Currently, wireless transmission primarily utilizes three methods: electromagnetic waves, mud pulses, and acoustic waves. Among these, mud pulse transmission, with its long-distance transmission capability, strong resistance to formation interference, and simple structural design, has become a research hotspot.

[0003] In a continuous wave mud pulse system, a rotary valve generates a pressure wave signal through flow throttling. Specifically, a permanent magnet synchronous motor drives the rotary valve, causing the flow channel area between its rotor and stator to change according to a predetermined pattern, thereby generating a corresponding pressure wave signal. By adjusting the rotary valve clearance, the system can adapt to different operating conditions. For example, when the pump pressure is insufficient or the flushing fluid density is low, the pressure is increased by narrowing the clearance; conversely, when the pump pressure is too high, the hydraulic torque is effectively reduced by increasing the clearance, thereby minimizing the risk of blockage and erosion and extending the equipment's service life.

[0004] While existing research has yielded some results on the influence of flushing fluid on pulse waveform characteristics, most mud pulsers currently lack the ability to dynamically adjust the rotary valve clearance based on real-time operating conditions. This limitation can lead to pulse waveform instability in complex downhole environments, reducing system robustness and continuous operation performance. In the future, developing rotary valve devices with real-time monitoring and dynamic feedback adjustment capabilities will be a key direction for improving the stability and efficiency of mud pulse measurement-while-drilling systems. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a rotary valve flow-controlled continuous wave mud pulse generator. In existing technologies, multiple factors can affect the stability of the pulse signal during operation within the borehole. As the borehole depth increases, pressure loss also increases, affecting the transmission quality of the pulse signal. Simultaneously, pump pressure fluctuations can cause irregular pulse generation, further affecting the stability of the pulse waveform. In addition, the viscosity and gas content of the flushing fluid also affect signal transmission: higher viscosity slows mud flow, leading to increased signal attenuation; while high gas content causes air bubbles to interfere with the propagation of pressure pulses. This invention's generator can automatically adjust the distance between the rotary valve rotor and stator based on time-varying factors such as pump pressure, borehole depth, and flushing fluid density. This reduces pulse output waveform distortion caused by complex operating conditions during long-term operation, improving waveform recognizability and demodulation performance.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A rotary valve flow-controlled continuous wave mud pulse generator includes a pulse generator section, a turbine generator, a drive section, and a probe section connected in sequence.

[0008] The pulse generator section includes an outer tube housing and a motor housing, motor, motor reducer, ball screw, rotary encoder, torque sensor, and a rotary valve assembly consisting of a stator and rotor arranged inside. The outer tube housing contains an axial channel. The motor housing is coaxially fixed inside the outer tube housing, housing the motor and motor reducer. The front end of the rotary encoder is connected to a communication cable for signal transmission, and the rear end is connected to the motor housing and the front of the motor. One end of the ball screw is coaxially connected to the output shaft of the motor via the motor reducer, and the other end passes through the central hole of the stator and connects to the rotor. The communication cable is connected to a torque sensor at the rear of the stator via the axial channel. The torque sensor can monitor the flushing fluid flow rate in real time and convert the measured data into a corresponding flow function, which is then transmitted to the drive section. The motor is a permanent magnet synchronous motor and serves as a power source, driving the dynamic matching of the flow channel holes between the rotor and stator to generate the required pressure wave signal. It can also drive the rotor to move axially to adjust the gap size of the rotary valve assembly.

[0009] The drive sub is used to adjust the gap of the rotary valve assembly and generate pulse signals through motor operation control; the probe sub is used to measure drilling trajectory parameters and store data, and at the same time send operation commands to the drive sub according to the set program to coordinate the operation of the entire system; the turbine generator provides DC power to the system.

[0010] This utility model also includes the following technical features:

[0011] Specifically, the stator is disc-shaped and is fixed to the outer tube housing through positioning holes and bolts.

[0012] Specifically, the stator has a central hole through which the rotor passes.

[0013] Specifically, the rotor includes an outer ring, a ball bearing, and an inner ring.

[0014] Specifically, the stator and rotor are each provided with multiple uniformly distributed flow channel holes to form a stable fluid passage; the channels remain fully open when not in operation.

[0015] Specifically, the stator has multiple fan-shaped flow channel through holes evenly distributed on it.

[0016] Specifically, the stator is provided with four flow channels evenly distributed at 90°, and a guide groove is provided at the inlet to optimize the liquid flow performance.

[0017] Compared with the prior art, this utility model has the following technical effects:

[0018] This invention dynamically adjusts the gap between the rotor and stator by driving a ball screw with a motor, thereby effectively reducing the impact of nonlinear interference caused by changes in flushing fluid flow and pressure fluctuations on system performance. This design ensures that the permanent magnet synchronous motor output shaft can accurately and quickly respond to control commands sent by the drive section, effectively suppressing distortion in the pulse generator output waveform, and simplifying the complexity of filtering and identification during orifice signal decoding.

[0019] This invention integrates a hydraulic torque sensor and a rotary encoder on a permanent magnet synchronous motor within the flow channel, enabling real-time acquisition of flushing fluid flow and motor position signals, thus constructing a closed-loop servo control system. This design not only ensures the system's rapid dynamic response capability but also effectively reduces the interference of hydraulic torque variations on motor control accuracy, improving the system's control performance under steady-state conditions. Simultaneously, it significantly enhances the equipment's adaptability to complex operating conditions, giving the system excellent anti-interference capabilities and operational stability, providing efficient and reliable technical support for drilling measurements in complex environments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0021] Figure 2 This is a schematic diagram of the specific structure of the pulse generator section of this utility model.

[0022] Figure 3 This is a servo control flowchart for the pulse generator of this utility model.

[0023] The meanings of the labels in the diagram are as follows:

[0024] 1. Pulse generator sub, 101. Rotary encoder, 102. Motor housing, 103. Motor reducer, 104. Ball screw, 105. Torque sensor, 106. Outer tube housing, 107. Stator, 108. Rotor; 2. Turbine generator, 3. Drive sub, 4. Probe sub. Detailed Implementation

[0025] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0026] Example 1:

[0027] This embodiment provides a rotary valve flow-controlled continuous wave mud pulse generator, such as... Figure 1 and Figure 2 It includes a pulse generator section 1, a turbine generator section 2, a drive section 3, and a probe section 4 connected in sequence.

[0028] The pulse generator section 1 includes an outer tube housing 106 and a rotary valve assembly consisting of a motor housing 102, a motor, a motor reducer 103, a ball screw 104, a rotary encoder 101, a torque sensor 105, a stator 107, and a rotor 108 arranged inside it. The outer tube housing 106 has a through axial channel. The motor housing 102 is coaxially fixed inside the outer tube housing 106. The motor housing 102 houses the motor and the motor reducer 103. Its front end is connected to the rotary encoder 101, and its rear end uses a ball screw to precisely adjust the gap between the rotor and the stator. The front end of the rotary encoder 101 is connected to a communication cable / insulated wire to transmit signals, and its rear end is connected to the motor housing 102 and the front of the motor and rigidly connected to the motor output. A ball screw 104 is coaxially connected at one end to the output shaft of the motor via a motor reducer 103, and at the other end passes through the central hole of the stator 107 and is connected to the rotor 108, realizing relative movement between the stator and the rotor, used to adjust the gap or generate pressure fluctuations; a communication cable is connected to a torque sensor 105 at the rear of the stator 107 via an axial channel. The torque sensor 105 can monitor the flushing fluid flow rate in real time and convert the measured data into a corresponding flow function, which is then transmitted to the drive section 3; the motor is a permanent magnet synchronous motor and serves as a power source to drive the flow channel through-hole between the rotor 108 and the stator 107 to dynamically match in order to generate the required pressure wave signal, and can also drive the rotor 108 to move axially to adjust the size of the rotary valve assembly gap;

[0029] The drive sub 3 is used to adjust the clearance of the rotary valve assembly and generate pulse signals through motor operation control. When the drive sub receives a clearance adjustment signal, the motor drives the output shaft to rotate, and the ball screw converts the rotational motion into linear motion, driving the rotor to move axially to adjust the clearance. When a pulse signal is received, the motor rotates in both directions, causing the rotor and stator to generate circumferential relative displacement, changing the flow area, thereby generating a periodic pressure wave signal, which is transmitted to the orifice. The drive sub integrates motor control and drive circuitry, enabling precise control of speed, direction, and start / stop.

[0030] The probe section 4 is used to measure drilling trajectory parameters and store data. At the same time, it sends operation commands to the drive section 3 according to the set program to coordinate the operation of the entire system. The probe section includes a sensor assembly and a main control module, which are used to collect drilling parameters and send control signals to generate pulse signals, respectively.

[0031] Turbine generator 2 provides DC power to the system.

[0032] The rotary valve assembly is designed with a disc-shaped structure. Specifically, the stator 107 is disc-shaped and is fixed to the outer casing 106 by three 120° evenly distributed positioning holes and bolts. The stator 107 has a central hole for the rotor 108 to pass through. The rotor 108 includes an outer ring, ball bearings, and an inner ring.

[0033] The stator 107 and rotor 108 are respectively provided with multiple uniformly distributed flow channel holes to form a stable fluid passage; the channels are kept fully open when not in operation.

[0034] Multiple fan-shaped flow channel holes are evenly distributed on the stator 107; specifically, the stator 107 is provided with four flow channels evenly distributed at 90°, and a guide groove is provided at the inlet to optimize the liquid flow performance.

[0035] The system uses a permanent magnet synchronous motor as its core power unit. Its input signals include the motor angular position signal calculated based on real-time flow and the drilling data transmitted from the probe section. The output includes pulse signals generated by adjusting the rotary valve assembly clearance or driving the rotor to swing. By dynamically adjusting the rotary valve clearance, the device effectively reduces the impact of hydraulic torque fluctuations on the pressure waveform, significantly improving the stability of signal transmission and the robustness of the system.

[0036] To further optimize system performance, improvements were made to the circuit conversion module, motor housing, and control strategy: ① The circuit conversion module forms multiple fan-shaped flow channels through the connection of the outer and inner rings. The communication cable passes through the wire hole on the side wall of the housing and connects to the guide ring and torque sensing module to achieve efficient signal transmission. ② The motor housing is fixed inside the housing and houses a permanent magnet synchronous motor. Its front end is connected to a rotary encoder, and the rear end uses a ball screw to precisely adjust the gap between the rotor and stator. ③ In terms of control strategy, the device combines real-time flow measurement and dynamic closed-loop control technology to achieve multi-condition adaptability. First, the built-in hydraulic torque sensor monitors the flushing fluid flow rate in real time and transmits the data to the drive sub for analysis. When the flow rate changes, the drive sub adjusts the motor's operating state through closed-loop control, dynamically optimizing the gap between the rotor and stator to ensure the stability of the hydraulic system. Under stable flow conditions, the probe sub encodes the drilling data into motor position commands, controlling the rotary valve to periodically adjust the flow channel area to generate pressure wave signals for data transmission. In addition, when changes in flushing fluid characteristics or drilling depth cause flow deviations, the device adjusts the rotor axial position via a ball screw to precisely control the flow channel clearance, thereby adapting to complex working conditions.

[0037] This device, through optimized structural design and servo control strategy, not only improves the stability of mud pulse signals but also enhances operational reliability in complex downhole environments, providing a new solution for measurement-while-drilling technology in the coal mining field.

[0038] Example 2:

[0039] This embodiment provides a servo control method for a rotary valve flow-controlled continuous wave mud pulse generator, such as... Figure 3 As shown, it includes:

[0040] First, a torque sensor installed inside the outer casing monitors the flushing fluid flow rate in real time and converts the measured data into a corresponding flow function, which is then transmitted to the drive section for processing. The motor control circuit calculates the optimal clearance between the rotary valve stator and rotor based on this flow function to meet the requirements of the current operating conditions.

[0041] When the flushing fluid flow rate changes, the control circuit dynamically adjusts based on the received hydraulic torque signal using a closed-loop control algorithm. By comparing the result with a preset calibration value, the required control command is determined and sent to the permanent magnet synchronous motor. The motor drives the output shaft to rotate according to the command, and the ball screw converts the rotational motion into axial displacement, thereby adjusting the clearance of the rotary valve rotor. This ensures the system responds quickly to changes in flow rate and maintains operational stability.

[0042] With the flushing fluid flow rate maintained at a stable level, the probe section is responsible for collecting drilling parameters and performing data calculations during the drilling process. Subsequently, the control circuit encodes the collected data based on a mud pulse coding algorithm to generate the target position command for the motor. Simultaneously, the rotary encoder tracks the current position of the motor in real time and feeds it back to the control circuit. By comparing and calculating the deviation, a correction command is generated and sent to the motor drive circuit. The motor drives the output shaft and the rotary valve rotor to oscillate circumferentially according to the control signal. By adjusting the opening of the rotary valve flow channel, periodic hydraulic pressure waves are formed, transmitting information containing data to the wellhead in the form of pressure waves. The host computer receives the pressure waves, decodes and analyzes them, and achieves accurate data transmission and processing.

[0043] Through the above control strategies, this system can dynamically adjust the valve gap according to the operating conditions, respond to changes in flow rate in real time, ensure the stability and reliability of the hydraulic pressure wave signal, and improve the efficiency and accuracy of data transmission.

[0044] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0045] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

[0046] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A rotary valve flow-controlled continuous wave mud pulse generator, characterized in that, It includes a pulse generator section (1), a turbine generator (2), a drive section (3), and a probe section (4) connected in sequence; The pulse generator section (1) includes an outer tube housing (106) and a rotary valve assembly consisting of a motor housing (102), a motor, a motor reducer (103), a ball screw (104), a rotary encoder (101), a torque sensor (105), a stator (107), and a rotor (108) arranged inside it; the outer tube housing (106) has an axial channel; the motor housing (102) is coaxially fixed inside the outer tube housing (106), and the motor and motor reducer (103) are built into the motor housing (102); the front end of the rotary encoder (101) is connected to a communication cable to transmit signals, and the rear end is connected to the motor housing (102) and the front of the motor; the ball screw (104) is... 4) One end is coaxially connected to the output shaft of the motor via a motor reducer (103), and the other end passes through the center hole of the stator (107) and is connected to the rotor (108); the communication cable is connected to the torque sensor (105) at the rear of the stator (107) via an axial channel. The torque sensor (105) can monitor the flushing fluid flow rate in real time and convert the measured data into the corresponding flow function and transmit it to the drive section (3); the motor is a permanent magnet synchronous motor and serves as a power source to drive the flow channel through hole between the rotor (108) and the stator (107) to dynamically match to generate the required pressure wave signal. It can also drive the rotor (108) to move axially to adjust the size of the rotary valve assembly gap. The drive section (3) is used to adjust the gap of the rotary valve assembly and generate pulse signals through motor operation control; the probe section (4) is used to measure drilling trajectory parameters and store data, and at the same time send operation instructions to the drive section (3) according to the set program to coordinate the operation of the entire system; the turbine generator (2) provides DC power to the system.

2. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The stator (107) is disc-shaped and is fixed to the outer tube housing (106) through positioning holes and bolts.

3. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The stator (107) has a central hole through which the rotor (108) passes.

4. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The rotor (108) includes an outer ring, a ball bearing, and an inner ring.

5. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The stator (107) and rotor (108) are respectively provided with multiple uniformly distributed flow channel holes to form a stable fluid passage; the channels are kept fully open when not in operation.

6. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The stator (107) has a plurality of fan-shaped flow channel through holes evenly distributed on it.

7. The rotary valve flow-controlled continuous wave mud pulse generator as described in claim 1, characterized in that, The stator (107) is provided with four 90° evenly distributed flow channels, and a guide groove is provided at the inlet to optimize the liquid flow performance.

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