A continuous wave mud pulse generator

Abstract

The present invention discloses a continuous wave mud pulse generator, and proposes the following scheme, which includes a drill collar and a pulser assembly and a control unit installed on the drill collar. The pulser assembly includes a hydraulic stator, a hydraulic rotor, a drive assembly and a bearing assembly installed on the drill collar, and the drive assembly is fixedly connected to the drill collar; the present invention adopts a hollow motor design to meet the torque requirement of directly driving the hydraulic rotor to move. Since the hydraulic rotor is directly driven by the rotor of the hollow motor, the structure of the pulser can be greatly simplified and mechanical failures can be reduced. At the same time, the absence of an intermediate connecting device can also make the pulser design shorter, reserving more space for the design of other sensors of the downhole instrument. The torque transmission between the motor and the rotor is transmitted through the upper hollow bearing. Compared with the slender main shaft transmission torque of the traditional scheme, the hollow bearing is larger in size and higher in strength, avoiding the influence of the instrument performance due to the deformation of the main shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of pulse generators, and in particular to a continuous wave mud pulse generator. Background Art

[0002] With the deepening of oilfield development and advancements in drilling technology, directional, horizontal, and specialized wells are increasingly being used in drilling operations. To meet engineering and technical requirements such as accurately capturing formation information, precisely controlling directional well drilling trajectories, and effectively conducting reservoir evaluations, wireless measurement while drilling (MWD) is being widely used in directional well drilling operations. Wireless MWD technology is categorized into three different measurement systems based on the signal transmission pathway: mud pulse measurement, electromagnetic wave measurement, and acoustic wave measurement. Mud pulse transmission systems are currently the most widely used due to their stability, low cost, and long transmission distance. However, conventional mud pulse transmission systems currently have a low transmission rate, preventing all downhole measurement information from being transmitted to the surface in real time. This severely impacts technical decision-making at the drilling site, restricts drilling efficiency, and increases drilling risks and investment costs. The continuous wave mud pulse transmission system boasts a transmission rate over ten times that of conventional mud pulse transmission systems, enabling real-time transmission of large amounts of downhole information and effectively addressing the bottleneck of downhole information transmission speed. Drilling engineers can use real-time information to promptly evaluate downhole conditions, effectively avoid drilling risks, improve decision-making accuracy, significantly increase drilling efficiency, and create substantial economic benefits. With the development of technology, continuous wave mud pulse transmission technology will gradually become the mainstream technology for measurement while drilling in the future.

[0003] The core component of the continuous wave mud pulse transmission system is the continuous wave mud pulse generator, but the existing continuous wave mud pulse generator has many problems.

[0004] First, current pulsers are complex in design, typically requiring numerous precision components such as reducers, magnetic couplings, and drive shafts. All of these components require lubrication. Failure of any of these components can cause the pulser to malfunction, leading to severe interruptions in drilling operations and the need to trip the wellbore to replace the instrument. However, tripping the wellbore inevitably impacts drilling progress and significantly increases drilling costs. Furthermore, tripping the wellbore is the most risky process in well control, and tripping the wellbore due to instrument failure undoubtedly poses significant safety risks.

[0005] Second, the continuous-wave pulser's rotor is powered by a downhole permanent magnet motor. Since the motor must be housed within a compression-resistant cylinder approximately 48 mm in diameter, it must be very small, failing to meet the rotor's low-speed, high-torque requirements. Consequently, components such as a magnetic coupling, a speed reducer, and a coupling must be added between the rotor and the motor. This, combined with the tail control circuitry, inevitably results in an excessively long pulser. These practical issues not only impose excessively high motor performance requirements and create significant manufacturing difficulties, but also restrict the number of sensors that can be attached to the wireless measurement-while-drilling system. This limits the measurable information and makes it difficult to meet the increasingly complex drilling information requirements.

[0006] In summary, there is an urgent need to invent a simple, reliable and easy-to-maintain continuous wave mud pulse generator to meet the needs of current modern drilling projects. Summary of the Invention

[0007] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a continuous wave mud pulse generator device with simple structure, precise control and easy maintenance. The hydraulic rotor rotates to block the drilling fluid passing through the hydraulic stator to generate a mud pulse pressure signal. The hydraulic rotor is directly powered by the motor rotor through a hollow bearing. Accurate hydraulic rotor position control is achieved through different sensor layouts, greatly improving the continuous wave mud pulse generator with high modulation accuracy of the mud pulse signal.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A continuous wave mud pulse generator includes a drill collar and a pulser assembly and a control unit installed on the drill collar. The pulser assembly includes a hydraulic stator, a hydraulic rotor, a drive assembly and a bearing assembly installed on the drill collar. The drive assembly is fixedly connected to the drill collar, the drive assembly is installed on the outside of the bearing assembly, and drives the hydraulic rotor to rotate through the bearing assembly. The hydraulic stator is fixedly installed on the drill collar, a first drilling fluid channel is provided in the bearing assembly, and a second drilling fluid channel is provided in the drill collar. The first drilling fluid channel and the second drilling fluid channel constitute a drilling fluid channel. When the hydraulic rotor rotates under the drive of the drive assembly, the mud passes through the first drilling fluid channel and the second drilling fluid channel intermittently through the hydraulic rotor and the hydraulic stator to form pulses.

[0010] Preferably, the driving assembly directly drives the hydraulic rotor to rotate via the bearing assembly, so that the hydraulic rotor periodically blocks the valve port of the hydraulic stator, thereby generating a sinusoidally varying mud pulse signal in the drilling fluid channel.

[0011] Preferably, the bearing assembly includes a hollow bearing and a support bearing sleeved on the outside of the hollow bearing, the hollow bearing includes an upper hollow bearing and a lower hollow bearing, the support bearing is sleeved on the outside of the upper hollow bearing, and the first drilling fluid channel is formed by connecting the internal parts of the upper hollow bearing and the lower hollow bearing.

[0012] Preferably, the hydraulic stator is a disc provided with a plurality of fan-shaped stator valve ports, the lower part of the hydraulic stator is provided with a groove which cooperates with a positioning cross pin installed inside the drill collar, the hydraulic stator is provided with a circular concave surface on the side where the drilling fluid flows in, and the hydraulic stator is concave inward in the direction where the mud flows out to form a rotor accommodating cavity, the hydraulic rotor is an internally open structure, the surface of which is provided with a plurality of fan-shaped rotor valve ports, and the number of the rotor valve ports is consistent with the number of the stator valve ports, the rotor valve ports of the hydraulic rotor are coaxial with the stator valve ports of the hydraulic stator, and the inner arc radii of the rotor valve ports and the stator valve ports are equal, and the outer arc radius of the rotor valve ports is smaller than the outer arc radius of the stator valve ports, an adjustment gasket is provided at the lower part of the hydraulic stator, and the gap between the hydraulic rotor and the hydraulic stator is adjusted by adjusting the thickness of the gasket.

[0013] Preferably, the hydraulic rotor is provided with a fixing groove on the side where the mud flows out, and is connected to the upper hollow bearing through a thread on the inner wall of the fixing groove. The driving assembly includes a driving rotor, a driving stator, an upper support seat and a lower support seat. The upper support seat and the lower support seat constitute an outer shell. The upper hollow bearing is fixed to the upper support seat through a supporting bearing. The outer wall of the upper hollow bearing is fixed to the driving rotor through a retaining glue. The torque of the driving rotor is transmitted to the hydraulic rotor through the upper hollow bearing, so that the hydraulic rotor is driven to rotate periodically.

[0014] Preferably, the driving stator is fixed in a housing composed of an upper support seat and a lower support seat, the lower hollow bearing passes through the lower support seat and is connected to the drilling fluid channel of the drill collar, and a lower rotating seal is provided between the lower hollow bearing and the lower support seat for sealing, so as to prevent the drilling fluid from entering the interior of the driving component. When the driving rotor rotates, it drives the hollow bearing to rotate, thereby driving the hydraulic rotor to rotate, realizing that the hydraulic rotor is directly driven by the driving component. The rotation of the hydraulic rotor will periodically block the valve port of the hydraulic stator, thereby throttling the drilling fluid flowing through the inside of the drill collar, forming a periodic mud pulse signal.

[0015] Preferably, the upper hollow bearing is fixed to the outer shell through a support bearing to ensure that the upper hollow bearing can rotate smoothly under the drive of the driving rotor. An upper rotating seal is provided on the upper part of the support bearing, and the upper rotating seal is sleeved on the outer wall of the upper hollow bearing.

[0016] Preferably, the lower part of the lower hollow bearing is inlaid with a ring-shaped annular magnetic grating, and the annular magnetic grating is composed of a ring-shaped magnetic grating base, a positioning magnetic grating and a magnetic grating patch. The positioning magnetic grating is installed on the lower hollow bearing to measure the position of the lower hollow bearing, thereby realizing position control of the hydraulic rotor. The positioning magnetic grating is installed on the shoulder of the lower hollow bearing, and the rotation position of the hydraulic rotor is monitored in real time through the magnetic grating detection head.

[0017] Preferably, a control circuit board is installed in the groove of the outer wall of the drill collar, and the internal circuit of the drive assembly is connected to the control circuit board of the outer wall of the drill collar through the circuit wiring hole in the drill collar. The outer wall of the drill collar is installed with a circuit board cover for isolating the drilling fluid in the wellbore environmental control, thereby preventing the drilling fluid from entering the control circuit board. The lower support seat is embedded with a magnetic grating detection head for detecting the position of the hollow bearing, thereby controlling the position of the hydraulic rotor. The magnetic grating detection head is specifically a Hall sensor.

[0018] Preferably, the control unit includes a main control unit, a drive unit and a measuring unit. The measuring unit includes a current sensor for measuring the motor feedback current and a Hall sensor for measuring the position of the hydraulic rotor. The main control unit provides a set current value for the drive unit based on the position information fed back by the measuring unit and the current information fed back by the current sensor, controls the movement of the motor to realize the modulation of the continuous wave mud pulse signal and realize the forward and reverse rotation of the motor to unblock.

[0019] Compared with the prior art, the present invention provides a continuous wave mud pulse generator with the following features:

[0020] Beneficial effects:

[0021] 1. The continuous wave mud pulse generator adopts a hollow motor design, so the motor size is not limited by the inner diameter of the 48mm pressure tube. Larger rotor and stator coils can be designed, and the motor torque can be designed to be larger to meet the torque requirements of directly driving the hydraulic rotor. Since the hydraulic rotor is directly driven by the rotor of the hollow motor, there is no need for complex structural designs such as planetary reducers, magnetic couplings, and couplings in the middle. This can greatly simplify the structure of the pulser and reduce mechanical failures. At the same time, the lack of an intermediate connection device can also make the pulser shorter, leaving more space for the design of other sensors of the downhole instrument. The torque between the motor and the rotor is transmitted through the upper hollow bearing. Compared with the traditional solution of slender main shaft transmission torque, the hollow bearing is larger in size and higher in strength, avoiding the impact of main shaft deformation on instrument performance.

[0022] 2. The continuous wave mud pulse generator has a relatively simple structure. The main components for maintenance are only hollow bearings, motor stators, rotors and other components. After the overall installation is completed, they can be directly placed in the drill collar. Maintenance is simple, convenient and efficient. The gap between the drive stator and the drive rotor is easy to measure with an ordinary steel ruler. Adjusting the gap is also very convenient. You only need to remove the drive stator and add an adjustment gasket. The hollow bearing is larger in size and higher in strength, and can transmit greater torque. When sand gets stuck in the drive rotor, there is also greater force to maintain the rotation of the drive rotor, reducing the occurrence of sand jamming failure of the pulser. The drilling fluid passes through the motor through the hollow bearing, and the internal heat of the motor is promptly transferred out, which can effectively increase the heat dissipation effect of the motor. The shorter pulser design also requires a shorter drill collar, saving material costs.

[0023] 3. The continuous wave mud pulse generator has an internally opened rotor with a simple structure and high strength compared to an externally opened rotor. It does not require special reinforced support wings for the rotor blades. The motor of a conventional continuous wave pulser is very small and the motor torque is not large, so it cannot drive an internally opened rotor with a large moment of inertia. In this case, the motor is large in size and has a large motor torque, which can drive an internally opened rotor. The internally opened rotor design can be used. Compared with the traditional externally opened rotor design, the drilling fluid can be effectively poured into the hollow bearing, making the drilling fluid channel at the hydraulic rotor and the hydraulic stator larger, reducing the local flow rate, and reducing the erosion of the mechanical parts by the drilling fluid. The surface of the outer wall of the hydraulic rotor of this structure that is in direct contact with the fluid is the hydraulic stator, rather than the inner wall of the drill collar in the traditional design, which can avoid the erosion of the inner wall of the drill collar by the drilling fluid, increase the downhole safety of the tool, and reduce the material cost of replacing the drill collar.

[0024] 4. The continuous wave mud pulse generator can have three different magnetic grating detection head layouts through the lower support base. The magnetic grating detection head is specifically a Hall sensor. The installation position of the Hall sensor and the magnet is designed. Through a small number of sensors and magnets, the precise positioning of the hydraulic rotor can be achieved.

[0025] 5. The control circuit board of the continuous wave mud pulse generator is installed on the outer wall of the drill collar, which makes the maintenance and inspection of the control circuit board more convenient. There is no need to disassemble the instrument connection or the pressure-resistant outer cylinder. It is convenient to inspect and maintain it by simply disassembling the circuit board cover on the outer wall of the drill collar, thus realizing the independent maintenance of the control circuit and the mechanical structure. Installing the control circuit board on the outer wall of the drill collar can also free up more design space, making the control circuit board design more flexible and further reducing the length of the entire pulser.

[0026] 6. When the rotational torque on the hydraulic rotor suddenly increases, the controller of this continuous wave mud pulse generator can determine the torque on the upper hollow bearing according to the current. If there is a possibility of foreign matter blocking the hydraulic rotor, causing excessive rotational torque, the control circuit can realize the self-unblocking function by controlling the motor to reverse. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall cross-sectional view of a continuous wave mud pulse generator proposed by the present invention;

[0028] Figure 2 This is an exploded view of a hollow motor according to an embodiment of the present invention;

[0029] Figure 3 A view of a hydraulic stator structure of the present invention;

[0030] Figure 4 A view of the hydraulic rotor structure of the present invention;

[0031] Figure 5 A view of a cross-sectional structure of a hydraulic rotor according to the present invention;

[0032] Figure 6 It is a top view of the annular magnetic grid of the present invention;

[0033] Figure 7 A view of a cross-sectional structure of a circular ring-shaped magnetic grating according to the present invention;

[0034] Figure 8 This is a block diagram of the magnetic grating detection circuit of the present invention;

[0035] Figure 9 This is a block diagram of the control circuit of the present invention;

[0036] Figure 10 FIG. 1 is a schematic diagram of one arrangement of the Hall effect sensor of the present invention.

[0037] In the figure: 1. Drill collar; 2. Hydraulic stator; 3. Positioning cross pin; 4. Hydraulic rotor; 5. Adjusting gasket; 6. Upper hollow bearing; 7. Upper rotating seal; 8. Support bearing; 9. Upper support seat; 10. Driving stator; 11. Driving rotor; 12. Lower support seat; 13. Annular magnetic grid; 1301. Magnetic grid base; 1302. Positioning magnetic grid; 1303. Magnetic grid patch; 14. Lower hollow bearing; 15. Magnetic grid detection head; 16. Lower rotating seal; 17. Control circuit board; 18. Circuit board cover; 19. Drilling fluid channel; 20. Circuit wiring hole. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0040] Reference Figure 1-10 A continuous wave mud pulse generator comprises a drill collar 1 and a pulser assembly and a control unit mounted on the drill collar 1, characterized in that the pulser assembly comprises a hydraulic stator 2, a hydraulic rotor 4, a drive assembly and a bearing assembly mounted on the drill collar 1, the drive assembly being fixedly connected to the drill collar 1, the drive assembly being mounted on the outside of the bearing assembly and driving the hydraulic rotor 4 to rotate through the bearing assembly, the hydraulic stator 2 being fixedly mounted on the drill collar 1, a first drilling fluid channel being provided in the bearing assembly, a second drilling fluid channel being provided inside the drill collar 1, the first drilling fluid channel and the second drilling fluid channel constituting a drilling fluid channel 19, and when the hydraulic rotor 4 rotates under the drive of the drive assembly, the mud passes through the first drilling fluid channel and the second drilling fluid channel intermittently through the hydraulic rotor 4 and the hydraulic stator 2 to form pulses.

[0041] In the present invention, the driving assembly directly drives the hydraulic rotor 4 to rotate through the bearing assembly, so that the hydraulic rotor 4 periodically blocks the valve port of the hydraulic stator 2, thereby generating a sinusoidal mud pulse signal in the drilling fluid channel 19. The bearing assembly includes a hollow bearing and a support bearing 8 sleeved on the outside of the hollow bearing. The hollow bearing includes an upper hollow bearing 6 and a lower hollow bearing 14. The support bearing 8 is sleeved on the outside of the upper hollow bearing 6. The first drilling fluid channel is composed of the upper hollow bearing 6 and the lower hollow bearing 14 being internally connected.

[0042] In the present invention, the hydraulic stator 2 is a disc provided with a plurality of fan-shaped stator valve ports. A groove is provided at the bottom of the hydraulic stator 2 to cooperate with a positioning cross pin 3 installed inside the drill collar 1. The hydraulic stator 2 is provided with a circular concave surface on the side of the drilling fluid flow, and the hydraulic stator 2 is concave in the direction of mud outflow to form a rotor accommodating cavity. The hydraulic rotor 4 is an internal opening structure, and a plurality of fan-shaped rotor valve ports are provided on the surface, and the number of rotor valve ports is consistent with the number of stator valve ports. The rotor valve port of the hydraulic rotor 4 is coaxial with the stator valve port of the hydraulic stator 2, and the inner arc radius of the rotor valve port is equal to that of the stator valve port, and the outer arc radius of the rotor valve port is smaller than that of the stator valve port. An adjusting gasket 5 is provided at the bottom of the hydraulic stator 2, and the gap between the hydraulic rotor 4 and the hydraulic stator 2 is adjusted by adjusting the thickness of the gasket 5. The thickness of the adjusting gasket 5 has multiple specifications of 0.25mm, 0.5mm, and 1mm to meet the adjustment requirements of different gap amounts.

[0043] In the present invention, the hydraulic rotor 4 is provided with a fixing groove on the side where the mud flows out, and is connected to the upper hollow bearing 6 through a thread on the inner wall of the fixing groove. The driving assembly includes a driving rotor 11, a driving stator 10, an upper support seat 9 and a lower support seat 12. The upper support seat 9 and the lower support seat 12 constitute an outer shell. The upper hollow bearing 6 is fixed on the upper support seat 9 through the support bearing 8. The outer wall of the upper hollow bearing 6 is fixed to the driving rotor 11 by a retaining glue. The torque of the driving rotor 11 is transmitted to the hydraulic rotor 4 through the upper hollow bearing 6, so that the hydraulic rotor 4 is driven to rotate periodically.

[0044] In the present invention, the driving stator 10 is fixed in a housing composed of an upper support seat 9 and a lower support seat 12. The lower hollow bearing 14 passes through the lower support seat 12 and is connected to the drilling fluid channel 19 of the drill collar 1. A lower rotating seal 16 is provided between the lower hollow bearing 14 and the lower support seat 12 for sealing, preventing the drilling fluid from entering the interior of the driving component. When the driving rotor 11 rotates, the hollow bearing is driven to rotate, thereby driving the hydraulic rotor 4 to rotate, realizing that the hydraulic rotor 4 is directly driven by the driving component. The rotation of the hydraulic rotor 4 will periodically block the valve port of the hydraulic stator 2, thereby throttling the drilling fluid flowing through the inside of the drill collar 1, forming a periodic mud pulse signal.

[0045] In the present invention, the upper hollow bearing 6 is fixed to the outer shell through the support bearing 8 to ensure that the upper hollow bearing 6 can rotate smoothly under the drive of the driving rotor 11. The upper part of the support bearing 8 is provided with an upper rotating seal 7, and the upper rotating seal 7 is sleeved on the outer wall of the upper hollow bearing 6 to ensure that the upper hollow bearing 6 forms a seal while rotating, thereby preventing drilling fluid from entering the interior of the driving assembly.

[0046] In the present invention, a ring-shaped annular magnetic grating 13 is embedded in the lower part of the lower hollow bearing 14. The annular magnetic grating 13 consists of a ring-shaped magnetic grating base 1301, a positioning magnetic grating 1302 and a magnetic grating patch 1303. The positioning magnetic grating 1302 is installed on the lower hollow bearing 14 to measure the position of the lower hollow bearing 14, thereby realizing position control of the hydraulic rotor 4. The positioning magnetic grating 1302 is installed on the shoulder of the lower hollow bearing 14, and the rotation position of the hydraulic rotor 4 is monitored in real time through the magnetic grating detection head 15.

[0047] In the present invention, a control circuit board 17 is installed in the groove of the outer wall of the drill collar 1, and the internal circuit of the drive component is connected to the control circuit board 17 on the outer wall of the drill collar 1 through the circuit wiring hole 20 in the drill collar 1. The outer wall of the drill collar 1 is installed with a circuit board cover 18 for isolating the drilling fluid in the wellbore environmental control, thereby preventing the drilling fluid from entering the control circuit board 17. The lower support seat 12 is inlaid with a magnetic grating detection head 15 for detecting the position of the hollow bearing, thereby controlling the position of the hydraulic rotor 4. The magnetic grating detection head 15 is specifically a Hall sensor. The control circuit board 17 is installed in the groove of the outer wall of the drill collar 1 and is connected to the internal circuit of the drive component through the circuit wiring hole 20 inside the drill collar 1. There are three different sensor layouts between the lower support seat 12 and the magnetic grating detection head 15, which can realize precise position control of the hydraulic rotor 4.

[0048] The first layout method is to install a magnetic grid on the magnetic grid base 1301, and the magnetic grid base 1301 is pasted on the outer edge of the lower hollow bearing 14. Since the lower hollow bearing 14 is directly connected to the hydraulic rotor 4 through the driving rotor 11, the Hall sensor is installed on the lower support seat 12. There are four Hall sensors. The four Hall sensors correspond one to one to the opening position of the rotary valve of the hydraulic rotor 4. The magnetic grid position is detected by the Hall sensor, and the hydraulic rotor 4 is directly positioned to control the rotary valve position to modulate the mud pulse signal.

[0049] The second layout is to install 36 Hall sensors on the lower support seat 12, which are evenly distributed with reference to the rotary valve opening position. A Hall induction pulse will be triggered every 10°. By triggering different Hall sensors, the rotary valve position positioning is further refined, and the accuracy of mud pulse signal modulation of the rotary valve is further improved.

[0050] Due to the limited space of the lower support base 12, dozens of Hall sensors are installed in the same horizontal plane of the lower support base 12, which is relatively tight and difficult to route. Figure 10 As shown, three Hall sensors can be specifically used as a sensor group, and multiple sensor groups are arranged around the inner side of the lower support base 12. The three Hall sensors in the same sensor group are located in different planes, and the Hall sensors at corresponding positions in different sensor groups are located in the same plane.

[0051] The third layout is based on the second layout, reducing the number of Hall sensors to 12 and increasing the number of magnets to 3 with an interval of 10°. By adjusting the position of the magnets and the Hall sensors, the Hall sensors can generate a pulse signal when each magnet passes through the same Hall sensor. Therefore, by calculating the number of pulses continuously generated by the Hall sensor, the position of the lower hollow bearing 14 can be further determined, and the rotary valve position control accuracy can be controlled at 10°, which can further improve the mud pulse signal modulation accuracy.

[0052] In the present invention, the control unit includes a main control unit, a drive unit and a measuring unit. The measuring unit includes a current sensor for measuring the motor feedback current and a Hall sensor for measuring the position of the hydraulic rotor 4. The main control unit provides a set current value for the drive unit based on the position information fed back by the measuring unit and the current information fed back by the current sensor, controls the movement of the motor to realize the modulation of the continuous wave mud pulse signal and realize the forward and reverse rotation of the motor to unblock.

[0053] Working principle: The drilling fluid flows directly through the pulser assembly through the hollow upper hollow bearing 6 and the lower hollow bearing 14. The rotor of the motor directly drives the hydraulic rotor 4 to rotate through the upper hollow bearing 6. The hydraulic rotor 4 periodically blocks the valve port of the hydraulic stator 2, thereby generating a sinusoidal mud pulse signal in the drilling fluid channel 19. A positioning magnetic grid 1302 is installed on the shoulder of the lower hollow bearing 14. The position of the hollow bearing can be detected by the magnetic grid detection head 15 embedded in the lower support seat 12 of the motor, thereby controlling the position of the hydraulic rotor 4. The control circuit board 17 of the motor is installed in the slot on the outer wall of the drill collar 1 and is connected to the internal circuit of the motor through the circuit wiring hole 20 inside the drill collar 1;

[0054] When the annular magnetic grating 13 arranged on the lower hollow bearing 14 passes over the magnetic grating detection head 15 installed on the lower support base 12 of the motor, it will trigger the magnetic grating detection head 15 to output a pulse, thereby determining the position of the hydraulic rotor 4;

[0055] The control unit includes a main control unit, a drive unit and a measuring unit. The measuring unit includes a current sensor for measuring the motor feedback current and a magnetic grating detection head 15 for measuring the position of the hydraulic rotor 4. According to the position information feedback from the measuring unit and the current information feedback from the current sensor, the main control unit provides a set current value for the drive unit to control the movement of the motor to realize the modulation of the continuous wave mud pulse signal and realize the forward and reverse rotation of the motor to unblock.

[0056] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A continuous wave mud pulse generator, comprising a drill collar (1) and a pulser assembly and a control unit mounted on the drill collar (1), characterized in that: The pulser assembly comprises a hydraulic stator (2), a hydraulic rotor (4), a driving assembly and a bearing assembly mounted on a drill collar (1); the driving assembly is fixedly connected to the drill collar (1); the driving assembly is mounted outside the bearing assembly and drives the hydraulic rotor (4) to rotate through the bearing assembly; the hydraulic stator (2) is fixedly mounted on the drill collar (1); a first drilling fluid channel is provided in the bearing assembly; a second drilling fluid channel is provided inside the drill collar (1); the first drilling fluid channel and the second drilling fluid channel constitute a drilling fluid channel (19); when the hydraulic rotor (4) rotates under the drive of the driving assembly, mud passes through the first drilling fluid channel and the second drilling fluid channel intermittently through the hydraulic rotor (4) and the hydraulic stator (2), forming a pulse; The bearing assembly comprises a hollow bearing and a support bearing (8) sleeved on the outside of the hollow bearing, the hollow bearing comprises an upper hollow bearing (6) and a lower hollow bearing (14), the support bearing (8) is sleeved on the outside of the upper hollow bearing (6), and the first drilling fluid channel is formed by connecting the interiors of the upper hollow bearing (6) and the lower hollow bearing (14); The hydraulic rotor (4) is provided with a fixing groove on the side where the mud flows out, and is connected to the upper hollow bearing (6) through a thread on the inner wall of the fixing groove. The driving assembly comprises a driving rotor (11), a driving stator (10), an upper support seat (9) and a lower support seat (12). The upper support seat (9) and the lower support seat (12) constitute an outer shell. The upper hollow bearing (6) is fixed to the upper support seat (9) through a supporting bearing (8). The outer wall of the upper hollow bearing (6) is fixed to the driving rotor (11) through a retaining glue. The torque of the driving rotor (11) is transmitted to the hydraulic rotor (4) through the upper hollow bearing (6), so that the hydraulic rotor (4) is driven to rotate periodically. The driving stator (10) is fixed in a housing composed of an upper support seat (9) and a lower support seat (12), and the lower hollow bearing (14) passes through the lower support seat (12) and is connected to the drilling fluid channel (19) of the drill collar (1).

2. A continuous wave mud pulse generator according to claim 1, characterized in that: The driving assembly directly drives the hydraulic rotor (4) to rotate via the bearing assembly, so that the hydraulic rotor (4) periodically blocks the valve port of the hydraulic stator (2), thereby generating a sinusoidally varying mud pulse signal in the drilling fluid channel (19).

3. The continuous wave mud pulse generator according to claim 1, characterized in that: The hydraulic stator (2) is a disk provided with a plurality of fan-shaped stator valve ports. The lower part of the hydraulic stator (2) is provided with a groove which cooperates with a positioning transverse pin (3) installed inside the drill collar (1). The hydraulic stator (2) is provided with a circular concave surface on the side where the drilling fluid flows in. The direction in which the mud flows out of the hydraulic stator (2) is concave to form a rotor accommodating cavity. The hydraulic rotor (4) is an inner opening structure. The surface is provided with a plurality of fan-shaped rotor valve ports, and the number of the rotor valve ports is consistent with the number of the stator valve ports. The rotor valve port of the hydraulic rotor (4) is coaxial with the stator valve port of the hydraulic stator (2), and the inner arc radius of the rotor valve port and the stator valve port is equal. The outer arc radius of the rotor valve port is smaller than the outer arc radius of the stator valve port. The lower part of the hydraulic stator (2) is provided with an adjusting gasket (5). The gap between the hydraulic rotor (4) and the hydraulic stator (2) is adjusted by adjusting the thickness of the gasket (5).

4. A continuous wave mud pulse generator according to claim 1, characterized in that: A lower rotating seal (16) for sealing is provided between the lower hollow bearing (14) and the lower support seat (12) to prevent drilling fluid from entering the interior of the drive assembly.

5. A continuous wave mud pulse generator according to claim 4, characterized in that: The upper hollow bearing (6) is fixed to the housing via a support bearing (8), ensuring that the upper hollow bearing (6) can rotate smoothly under the drive of the driving rotor (11); an upper rotating seal (7) is provided on the upper part of the support bearing (8), and the upper rotating seal (7) is sleeved on the outer wall of the upper hollow bearing (6).

6. A continuous wave mud pulse generator according to claim 5, characterized in that: The lower part of the lower hollow bearing (14) is inlaid with a ring-shaped annular magnetic grid (13), and the annular magnetic grid (13) is composed of an annular magnetic grid base (1301), a positioning magnetic grid (1302) and a magnetic grid patch (1303). The positioning magnetic grid (1302) is installed on the lower hollow bearing (14) and is used to measure the position of the lower hollow bearing (14), thereby realizing position control of the hydraulic rotor (4). The positioning magnetic grid (1302) is installed on the shoulder of the lower hollow bearing (14) and monitors the rotation position of the hydraulic rotor (4) in real time through a magnetic grid detection head (15).

7. A continuous wave mud pulse generator according to claim 6, characterized in that: A control circuit board (17) is installed in the slot on the outer wall of the drill collar (1), and the internal circuit of the drive component is connected to the control circuit board (17) on the outer wall of the drill collar (1) through the circuit wiring hole (20) in the drill collar (1). The outer wall of the drill collar (1) is installed with a circuit board cover (18) for isolating the drilling fluid in the wellbore environmental control, thereby preventing the drilling fluid from entering the control circuit board (17). A magnetic grating detection head (15) for detecting the position of the hollow bearing is embedded on the lower support seat (12), thereby controlling the position of the hydraulic rotor (4), and the magnetic grating detection head (15) is specifically a Hall sensor.

8. A continuous wave mud pulse generator according to any one of claims 1 to 7, characterized in that: The control unit comprises a main control unit, a drive unit and a measuring unit. The measuring unit comprises a current sensor for measuring the feedback current of the motor and a Hall sensor for measuring the position of the hydraulic rotor (4). The main control unit provides a set current value for the drive unit based on the position information fed back by the measuring unit and the current information fed back by the current sensor, controls the movement of the motor to achieve modulation of the continuous wave mud pulse signal and realize forward and reverse rotation of the motor to remove blockage.

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