Downhole Pulse Signal Generator and Transmission Method

Abstract

Provided is a downhole pulse signal generating device, including a non-magnetic drill collar. A connecting shaft is provided in the non-magnetic drill collar, and a generating unit and a driving unit are sequentially arranged on the connecting shaft. The generating unit includes a rotor, a modulation stator, and a modulation brake stator arranged in sequence. The rotor is configured to be able to rotate relative to the connecting shaft but not move, the modulation stator is configured to be fixed within the generating unit and not able to rotate or move relative to the connecting shaft, while the modulation brake stator is configured to be able to move relative to the connecting shaft but not rotate. The driving unit includes an excitation module arranged adjacent to the modulation brake stator, and a motor for driving the connecting shaft to rotate. The modulation brake stator is configured to move towards or away from the modulation stator under the action of the excitation module, thereby changing the flow area of the fluid flowing through the non-magnetic drill collar to generate a pulse signal. A corresponding downhole pulse signal transmission method is also provided.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling engineering in oil and gas exploration and development, and particularly relates to a downhole pulse signal generating device for generating mud pulse signals during the transmission of measurement data while drilling downhole. The present invention also relates to a downhole pulse signal transmission method. Background Art

[0002] With the continuous deepening of oil and gas exploration and development at home and abroad, the drilling operations of horizontal wells and highly deviated wells are increasing day by day, and the directional drilling technology is becoming increasingly important. Directional drilling refers to a drilling process method in which the wellbore trajectory is turned from the vertical direction to intersect with the target end point or drilled to the target formation along a specified path.

[0003] Measurement While Drilling (MWD) is one of the key technologies in directional drilling, which can provide downhole measurement information such as well inclination, azimuth, tool face, etc. to the ground in real time during the drilling process. Field engineers can optimize the drilling speed and wellbore trajectory based on this information.

[0004] Mud pulse transmission is the most widely used measurement while drilling method at present. Its principle is to form mud pressure pulses by modulating the downhole measurement data according to a certain coding modulation method and transmit them to the ground through the drilling fluid channel. The mud pressure pulses are formed by the downhole pulse generator generating a pressure difference by controlling the flow area and / or path of the mud. According to different signal generation methods, mud pulse transmission can be divided into three forms: positive pulse, negative pulse and continuous wave. High-speed mud pulse transmission usually adopts the continuous wave form, which has the advantages of high transmission rate, strong environmental adaptability, long service life, etc., and is the development direction in the field of measurement while drilling.

[0005] At present, high-speed mud pulse generators generally use motors to drive rotors for signal modulation, which will bring many problems in field applications. For example, by controlling the motor speed, the generation of binary numbers "0" and "1" can be achieved. However, when the motor speed often changes, the motor power will also fluctuate. If the instantaneous power is too high, it may shorten the motor life. In addition, when the motor speed is switched, there must be errors in the control system. When the errors gradually accumulate to a certain extent over time, it may cause coding errors.

[0006] CN201310744291.0 discloses a downhole high-speed mud pulse generation solution. The principle of this technical solution is to use a rotation-swing conversion mechanism to convert the rotational motion output by the power output unit into a lateral reciprocating motion, and then make the pendulum and the stator swing relative to each other. The beneficial effect of this technical solution is that it combines the dual advantages of a rotary valve and a swing valve, which not only reduces the requirements for motor control but also effectively avoids rotor blockage. However, its mechanical structure is relatively complex, and it has high requirements for the accuracy of the transformer during the rotation-swing conversion.

[0007] CN201510724458.6 discloses another downhole high-speed mud pulse generation solution. The principle of this technical solution is similar to that of the traditional positive pulse generator, that is, based on the reciprocating motion of the linear motor to directly drive the mushroom head, and then generate continuous wave positive pulses. The beneficial effect of this technical solution is to eliminate many mechanical failures of the traditional positive pulse generator and can improve the signal transmission rate to a certain extent. However, compared with the signal transmission rate of the rotary valve or oscillating valve type pulse generator, there is still a large gap.

[0008] CN201510079807.3 discloses yet another downhole high-speed mud pulse generation solution. The principle of this technical solution is to use two motors to drive two rotary encoding disks through magnetic drive respectively, and then change the mud pressure in the drill string to form a continuous wave signal. The beneficial effect of this technical solution is to achieve seamless continuous wave 2DPSK pressure wave fast transmission. However, due to the use of dual-motor drive, its power consumption is high, and the magnetic material is prone to demagnetization, resulting in abnormal torque transmission. Summary of the Invention

[0009] In view of at least some deficiencies in the prior art, the present invention provides a downhole pulse signal generating device. Compared with the conventional high-speed mud pulse generator that uses a motor to drive a rotor for signal modulation, the downhole pulse signal generating device of the present invention can achieve frequency shift keying modulation of the signal without changing the motor speed, overcoming the problems of unreliable and unstable generation of downhole continuous wave signals.

[0010] According to a first aspect of the present invention, there is provided a downhole pulse signal generating device, including a non-magnetic drill collar through which fluid flows. A longitudinally extending connecting shaft is provided in the non-magnetic drill collar, and a generating unit and a driving unit are sequentially arranged on the connecting shaft from top to bottom. The generating unit includes a rotor, a modulating stator, and a braking stator sequentially arranged from top to bottom. Among them, the rotor is configured to be able to rotate relative to the connecting shaft but not move, the modulating stator is configured to be fixed in the generating unit and cannot rotate or move relative to the connecting shaft, while the braking stator is configured to be able to move relative to the connecting shaft but not rotate. The driving unit includes an excitation module arranged adjacent to the braking stator, and a motor for driving the connecting shaft to rotate. Among them, the braking stator is configured to move towards or away from the modulating stator under the action of the excitation module, thereby changing the flow area of the fluid flowing through the non-magnetic drill collar to generate a pulse signal.

[0011] In a preferred embodiment, the rotor, the modulating stator, and the braking stator are all configured as disks, and diversion openings allowing fluid to pass through are provided on the disks, and the remaining parts of the disks are formed as current-limiting parts capable of blocking fluid passage.

[0012] In a preferred embodiment, the diversion openings of the modulation stator and the diversion openings (404) of the modulation rotor have the same size, but are offset from each other by a certain angle in the circumferential direction while maintaining partial overlap.

[0013] In a preferred embodiment, both the modulation stator and the modulation rotor include 4 blade-shaped diversion openings arranged uniformly in the circumferential direction, and the diversion openings of the modulation stator and the diversion openings of the modulation rotor are offset from each other by 45 degrees in the circumferential direction.

[0014] In a preferred embodiment, the rotor has a long and narrow diversion opening extending radially, and the long and narrow diversion opening is smaller than the diversion opening of the modulation stator.

[0015] In a preferred embodiment, a housing and a pressure-resistant cylinder are provided inside the non-magnetic drill collar, wherein the generating unit is arranged inside the housing, and the driving unit is arranged in the pressure-resistant cylinder.

[0016] In a preferred embodiment, an excitation driving module is provided downstream of the excitation module, and a motor driving module is provided downstream of the motor.

[0017] In a preferred embodiment, a control unit is further provided in the pressure-resistant cylinder for controlling the motor driving module and the magnetic driving module.

[0018] In a preferred embodiment, a measuring unit and a battery are further provided in the pressure-resistant cylinder, and the measuring unit transmits the measured downhole parameters to the control unit.

[0019] According to a second aspect of the present invention, there is provided a downhole pulse signal transmission method using the downhole pulse signal generating device as described above, including: encoding the measurement data acquired by the measurement unit by the control unit, and converting the encoded signal into a control signal for the excitation module; the control unit keeps the rotational speed of the motor unchanged, and controls the excitation module through the control signal, so as to drive the modulation rotor to move closer to or away from the modulation stator, generating a downhole mud pulse signal; modulating the encoded signal onto the downhole mud pulse signal, and transmitting it to the ground through the downhole mud.

[0020] According to the downhole pulse signal generating device of the present invention, the change of the downhole mud flow area is realized through the combination of the rotor, the modulation stator and the modulation rotor, thereby realizing signal modulation. Therefore, the downhole pulse signal generating device according to the present invention can keep the rotational speed of the motor constant during operation, and can realize frequency shift keying modulation of the signal without changing the rotational speed of the motor. In this case, the problems such as large power fluctuation and low control accuracy existing in the conventional high-speed mud pulse generator during the motor speed switching are overcome.

[0021] In addition, the downhole pulse signal generating device according to the present invention has a reasonable structure, is easy to process, and has strong adaptability, and can improve the reliability and stability of continuous wave signal generation in a complex downhole mud environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0023] Figure 1 Schematically shows the overall structure of the downhole pulse signal generating device according to the present invention.

[0024] Figure 2 Schematically shows Figure 1 the structure of the rotor in the downhole pulse signal generating device shown.

[0025] Figure 3 Schematically shows Figure 1 the structure of the modulation stator in the downhole pulse signal generating device shown.

[0026] Figure 4 Schematically shows Figure 1 the structure of the modulation stator in the downhole pulse signal generating device shown.

[0027] Figure 5 Schematically shows the top view of the modulation combination obtained through Figure 1 the downhole pulse signal generating device shown.

[0028] Figure 6 Shows the mud pressure waveform diagram generated through Figure 1 the downhole pulse signal generating device shown.

[0029] In the drawings, the same components are denoted by the same reference numerals. The drawings are not drawn to actual scale. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be further described below with reference to the drawings. For ease of understanding, in the present application, the end close to the wellhead is defined as the upper end, the upstream end or similar terms, and the end far from the wellhead is defined as the lower end, the downstream end or similar terms; at the same time, the direction along the length direction of the downhole pulse signal generating device is called the longitudinal direction, the axial direction or similar terms, and the direction perpendicular thereto is called the transverse direction, the radial direction or similar terms.

[0031] Figure 1 Schematically shows the overall structure of the downhole pulse signal generating device 100 according to the present invention. As Figure 1As shown, the downhole pulse signal generating device 100 includes a non-magnetic drill collar 10. An outer shell 11 and a pressure-resistant cylinder 90 are arranged inside the non-magnetic drill collar 10 in sequence from top to bottom in the longitudinal direction. When used downhole, fluid (usually mud) flows through the non-magnetic drill collar 10. A connecting shaft 51 extending longitudinally is provided in the non-magnetic drill collar 10.

[0032] According to the present invention, a generating unit and a driving unit are sequentially arranged on the connecting shaft 51 from top to bottom. The generating unit is installed in the outer shell 11 and includes a rotor 20, a modulation stator 30, and a modulation rotor 40 that are sequentially arranged on the connecting shaft 51 from top to bottom. In the illustrated embodiment, the three components of the rotor 20, the modulation stator 30, and the modulation rotor 40 are all formed in a disc shape, and they are arranged at intervals along the connecting shaft 51.

[0033] According to the present invention, the rotor 20 is configured to be able to rotate relative to the connecting shaft 51 but not move relative to the connecting shaft 51. The modulation stator 30 is configured to be fixed within the outer shell 11, so that it cannot rotate or move relative to the connecting shaft 51. The modulation rotor 40 is configured to be able to move relative to the connecting shaft 51 but not rotate relative to the connecting shaft 51. The technical means that enable one component to rotate relative to another component without moving, to move relative to another component without rotating, and neither move nor rotate are well-known to those skilled in the field of structural design and will not be elaborated here.

[0034] Figure 2 shows a plan view of the rotor 20 in the generating unit of the downhole pulse signal generating device 100 according to the present invention. As Figure 2 shown, the rotor 20 is configured in the form of a disc and includes a central hole 201 through which the connecting shaft 51 passes. A first diversion port 203 is formed on the disc, and mud from the upstream can pass through the first diversion port 203 to flow in the downstream direction. In the illustrated embodiment, the first diversion port 203 is configured as a long and narrow opening extending in the radial direction. However, it can be understood that the first diversion port 203 can be configured according to the actual needs. In addition, the remaining part of the disc constitutes a first flow-limiting portion 202, which can block the passage of mud. Therefore, mud from the upstream can only pass through the first diversion port 203 to continue flowing in the downstream direction.

[0035] Figure 3 shows a plan view of the modulation stator 30 in the generating unit of the downhole pulse signal generating device 100 according to the present invention. As Figure 3As shown, the modulation stator 30 is also configured in the form of a disk and is fixed to the housing 11. The modulation stator 30 includes a central hole 301 through which the connecting shaft 51 passes, and a modulation stator shaft seat 302 for mounting the connecting shaft 51. The modulation stator shaft seat 302 and the connecting shaft 51 are in clearance connection and can rotate freely relative to each other. That is, when the connecting shaft 51 rotates, it does not drive the modulation stator shaft seat 302 to rotate. In fact, during the operation of the downhole pulse signal generating device 100, the modulation stator 30 always remains stationary.

[0036] A second diversion opening 304 is formed in the disk of the modulation stator 30. Thus, the mud flowing downstream through the rotor 20 can pass through the second diversion opening 304 and continue to flow downstream. Preferably, a plurality of second diversion openings 304 can be provided, and they are arranged at equal intervals in the circumferential direction. In the illustrated embodiment, a total of four blade-shaped second diversion openings 304 are provided, and adjacent second diversion openings 304 are spaced 90 degrees apart. Each blade-shaped second diversion opening 304 is configured to have a width that gradually decreases from the inside to the outside in the radial direction. However, it can be understood that according to the actual needs, the second diversion opening 304 can also have other numbers, positions, shapes or arrangements. The remaining part of the disk of the modulation stator 30 constitutes a second flow-limiting portion 303, which can block the passage of mud. Therefore, the mud from the upstream can only pass through the second diversion opening 304 to flow downstream.

[0037] Figure 4 A plan view of the modulation stator 40 in the generating unit of the downhole pulse signal generating device 100 according to the present invention is shown. As Figure 4 shown, the modulation stator 40 is also configured in the form of a disk, including a central hole 402 through which the connecting shaft 51 passes, and a modulation stator shaft seat 401 for mounting the connecting shaft 51. The connection between the modulation stator shaft seat 401 and the connecting shaft 51 allows the modulation stator 40 to move relative to the connecting shaft 51 but not rotate, such as a spline connection.

[0038] A third diversion opening 404 is formed in the disk of the modulation stator 40. Thus, the mud flowing downstream through the modulation stator 30 can pass through the third diversion opening 404 and continue to flow downstream. Preferably, a plurality of third diversion openings 404 can be provided, and they are arranged at equal intervals in the circumferential direction. In the illustrated embodiment, a total of four blade-shaped third diversion openings 404 are provided, and adjacent third diversion openings 404 are spaced 90 degrees apart. Each blade-shaped third diversion opening 404 is configured to have a width that gradually decreases from the inside to the outside in the radial direction. The remaining part of the disk of the modulation stator 40 constitutes a third flow-limiting portion 403, which can block the passage of mud. Therefore, the mud from the upstream can only pass through the third diversion opening 404 to flow downstream.

[0039] It should be noted that according to the present invention, when installed on the connecting shaft 51, the modulation stator 30 and the modulation stator 40 are arranged such that their second diversion ports 304 and third diversion ports 404 are circumferentially offset by an angle. Thus, the second diversion port 304 and the third diversion port 404 only partially overlap in the circumferential direction. In the illustrated embodiment, the second diversion port 304 and the third diversion port 404 are offset by 45 degrees in the circumferential direction. The function of this arrangement will be described in detail below.

[0040] As Figure 1 shown, the connecting shaft 51 extends longitudinally within the non-magnetic drill collar 10 and extends downstream from the housing 11. The drive unit is mounted on the region of the connecting shaft 51 outside the housing 11. According to the present invention, within the non-magnetic drill collar 10, a pressure-resistant cylinder 90 is further provided downstream of the housing 11. The connecting shaft 51 extends into the pressure-resistant cylinder 90, so the drive unit is also within the pressure-resistant cylinder 90. The drive unit includes a motor 50 provided at the downstream end of the connecting shaft 51. The motor 50 is connected to the rotor 11 and is used to drive the rotor 11 to rotate at a high speed.

[0041] In addition, according to the present invention, an excitation module 110 and an excitation drive module 111 are further provided on the connecting shaft 51 between the motor 50 and the housing 11. The excitation module 110 is arranged at a position in the pressure-resistant cylinder 90 adjacent to the housing 11, that is, immediately adjacent to the modulation stator 40. The excitation drive module 111 is used to drive the excitation module 110 to be energized or de-energized. Thus, the excitation module 110 can alternately generate a magnetic field, thereby driving the modulation stator 40 to move up and down along the connecting shaft 11.

[0042] A motor drive module 60, a control unit 70, a measurement unit 80, and a battery 85 are also provided in the pressure-resistant cylinder 90. The control unit 70 is connected to both the motor drive module 60 and the excitation drive module 111 and is used to issue instructions to control the motor drive module 60 and the excitation drive module 111 to drive the motor 50 and the excitation module 110 to work respectively. The measurement unit 80 is used to measure various downhole parameters, including well inclination, azimuth, tool face, etc., and send these measured parameters to the control unit 70. The battery 85 is used to provide power for various components in the downhole pulse signal generating device 100. The structures and functions of the excitation module 110, the excitation drive module 111, the motor 50, the motor drive module 60, the control unit 70, the measurement unit 80, and the battery 85 are well known to those skilled in the art and will not be elaborated here.

[0043] In the operation of the downhole pulse signal generating device 100 according to the present invention, the control unit 70 issues an instruction to control the motor drive module 60, and further drives and controls the motor 50 to operate. The motor 50 drives the rotor 20 to rotate. In this way, the mud from the upstream will flow downward through the first diversion port 203 in the rotor 20. Since the rotor 20 rotates at a high speed and the modulation stator 30 remains stationary, the mud will flow downstream through the only first diversion port 203 and continue to flow downstream through each second diversion port 304 on the modulation stator 30 in turn. In the illustrated embodiment, since the modulation stator 30 has four second diversion ports 304, when the rotor 20 rotates one week, the flow-through area of the modulation stator 30 will change periodically four times.

[0044] Meanwhile, the control unit 70 also issues an instruction to control the excitation drive module 111, and further drives and controls the excitation module 110 to operate. This control and drive are alternating, resulting in the excitation module 110 being alternately powered on and off. In this way, the modulation stator 40 moves up and down along the connecting shaft 51 under the action of the force generated by the excitation module 110, so as to move closer to or away from the modulation stator 30. However, as described above, the modulation stator 40 does not rotate with the connecting shaft 51.

[0045] In this case, when the modulation stator 40 approaches the modulation stator 30, the current-limiting surfaces and diversion surfaces of the two will overlap. As Figure 5 shown, after the modulation stator 40 and the modulation stator 30 overlap, a new combined current-limiting portion 503 and a new combined diversion port 504 are formed. Since the modulation stator 40 and the modulation stator 30 only partially overlap with each other in the circumferential direction, in the illustrated embodiment, eight combined diversion ports 504 are formed. In this way, when the rotor 20 rotates one week, the combined flow-through area of the modulation stator 40 and the modulation stator 30 will change periodically eight times. Therefore, when the modulation stator 40 and the modulation stator 30 overlap, the number of times of change of the flow-through area twice that of a single modulation stator 30 can be achieved. This greatly enhances the periodic change of the flow-through area.

[0046] When the modulation stator 40 moves away from the modulation stator 30, since the modulation stator 40 does not rotate with the connecting shaft 51, the modulation stator 40 basically loses its modulation function. At this time, only the second current-limiting portion 303 and the second diversion port 304 of the modulation stator 30 can modulate the fluid pressure. In this case, when the rotor 20 rotates one week, the overall flow-through area of the modulation stator 30 and the modulation stator 4 still only changes periodically four times.

[0047] Therefore, according to the present invention, the rotor 20 and the modulating stator 30 are positioned adjacent to each other, and the current-limiting portions and the diversion openings of the two overlap. As the rotor 20 rotates at a high speed, the flow area of the formed fluid changes periodically. As the flow area of the fluid changes periodically, it will cause a periodic change in the mud pressure wave in the wellbore. In addition, since the modulating stator 40 reciprocates closer to or farther from the modulating stator 30, the combined diversion opening formed by the modulating stator 40 and the modulating stator 30 also changes, resulting in a further periodic change in the flow area of the formed fluid. This further periodic change in the flow area enhances the periodic change in the mud pressure wave in the wellbore, as Figure 6 shown.

[0048] According to the present invention, the frequency of this change can be easily determined by the rotational speed of the motor 50, the diversion channel structure of the modulating stator 30, and the diversion channel structure of the modulating stator 40.

[0049] The downhole pulse signal generating device according to the present invention realizes the change of the downhole mud flow area through the combination of the rotor, the modulating stator, and the modulating stator, thereby realizing signal modulation. Therefore, the downhole pulse signal generating device according to the present invention can keep the rotational speed of the motor constant during operation, and can achieve frequency shift keying modulation of the signal without changing the rotational speed of the motor. In this case, the problems such as large power fluctuation and low control accuracy existing in the conventional high-speed mud pulse generator during the motor speed switching are overcome.

[0050] In addition, the downhole pulse signal generating device according to the present invention has a reasonable structure, is easy to process, and has strong adaptability, and can improve the reliability and stability of the continuous wave signal generation in the complex downhole mud environment.

[0051] According to another aspect of the present invention, there is also provided a downhole pulse signal transmission method using the above-mentioned downhole pulse signal generating device 100.

[0052] In this method, first, the measurement data obtained by the measurement unit 80 is encoded, and the control unit 70 converts the encoded signal into a control signal for the excitation drive module 111. Then, the control unit 70 issues an instruction to the motor drive module 60 to keep the rotational speed of the motor 50 unchanged, whereby the motor 50 drives the rotor 20 to rotate at a high speed. At the same time, the control unit 70 controls the excitation module 110 through the above control signal, thereby driving the modulating stator 40 to move closer to or farther from the modulating stator 30, so as to change the flow area of the entire generating unit. Finally, the encoded signal is modulated onto the downhole mud pressure wave and transmitted to the ground through the downhole mud.

[0053] The above is only the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or variations within the disclosure scope of the present invention, and such changes or variations should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. Downhole pulse signal generating device (100), including a non-magnetic drill collar (10) through which fluid flows, a longitudinally extending connecting shaft (51) is provided in the non-magnetic drill collar (10), and a generating unit and a driving unit are sequentially arranged on the connecting shaft (51) from top to bottom. Wherein: The generating unit includes a rotor (20), a modulation stator (30), and a modulation rotor (40) sequentially arranged from top to bottom. Among them, the rotor (20) is configured to be able to rotate relative to the connecting shaft (51) but not move, the modulation stator (30) is configured to be fixed in the generating unit and cannot rotate or move relative to the connecting shaft (51), and the modulation rotor (40) is configured to be able to move relative to the connecting shaft (51) but not rotate. The driving unit includes an excitation module (110) arranged adjacent to the modulation rotor (40), and a motor (50) for driving the connecting shaft (51) to rotate. Among them, the modulation rotor (40) is configured to move towards or away from the modulation stator (30) under the action of the excitation module (110), so as to change the flow area of the fluid flowing through the non-magnetic drill collar (10) to generate a pulse signal. The rotor (20), the modulation stator (30), and the modulation rotor (40) are all configured as discs. A first diversion port (203), a second diversion port (304), and a third diversion port (404) allowing fluid to pass through are provided on the disc. The remaining parts of the disc are formed into a first flow-limiting portion (202), a second flow-limiting portion (303), and a third flow-limiting portion (403) capable of blocking fluid passage. The second diversion port (304) of the modulation stator (30) and the third diversion port (404) of the modulation rotor (40) have the same size, but are offset from each other by a certain angle in the circumferential direction and maintain partial overlap. The modulation stator (30) and the modulation rotor (40) respectively include 4 blade-shaped second diversion ports (304) and third diversion ports (404) evenly arranged in the circumferential direction. The second diversion port (304) of the modulation stator (30) and the third diversion port (404) of the modulation rotor (40) are offset from each other by 45 degrees in the circumferential direction, so that the flow area undergoes four periodic changes when the modulation stator (30) and the modulation rotor (40) move away from each other and the motor (50) drives the rotor (20) to rotate one week, and undergoes eight periodic changes when the modulation stator (30) and the modulation rotor (40) overlap and the motor (50) drives the rotor to rotate one week.

2. The downhole pulse signal generating device (100) according to claim 1, Characterized in that, The rotor (20) has a long and narrow first diversion port (203) extending radially, and the long and narrow first diversion port (203) is smaller than the second diversion port (304) of the modulation stator (30).

3. The downhole pulse signal generating device (100) according to claim 1 or 2, Characterized in that, An outer shell (11) and a pressure-resistant cylinder (90) are arranged inside the non-magnetic drill collar (10), wherein the generating unit is arranged inside the outer shell (11), and the driving unit is arranged inside the pressure-resistant cylinder (90).

4. The downhole pulse signal generating device (100) according to claim 3, characterized in that, an excitation driving module (111) is arranged downstream of the excitation module (110), and a motor driving module (60) is arranged downstream of the motor (50).

5. The downhole pulse signal generating device (100) according to claim 4, characterized in that, a control unit (70) is further arranged inside the pressure-resistant cylinder (90) for controlling the motor driving module (60) and the excitation driving module (111).

6. The downhole pulse signal generating device (100) according to claim 5, characterized in that, a measuring unit (80) and a battery (85) are further arranged inside the pressure-resistant cylinder (90), and the measuring unit (80) transmits the measured downhole parameters to the control unit (70).

7. A downhole pulse signal transmission method using the downhole pulse signal generating device according to any one of claims 1 to 6, comprising: encoding the measurement data acquired by the measurement unit by the control unit and converting the encoded signal into a control signal for the excitation module; the control unit keeps the rotation speed of the motor unchanged and controls the excitation module through the control signal, so as to drive the modulation rotor to move closer to or away from the modulation stator, generating a downhole mud pulse signal; modulating the encoded signal onto the downhole mud pulse signal and transmitting it to the ground through the downhole mud.

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