Angle dependent valve release unit for shear valve pulser

Abstract

Systems and methods for generating pulses in a drilling fluid are provided. The system is configured to be positioned along a tubular string through which the drilling fluid flows. The system includes a housing supported along the tubular string. A valve stator is supported by the housing and has at least one flow path extending from an upstream end to a downstream end of the valve stator. A valve rotor is positioned adjacent the valve stator and is configured to selectively block the at least one flow path. An axial gap exists between the valve rotor and the valve stator. A motor is coupled to the valve rotor to rotate the valve rotor relative to the valve stator, and an axial release assembly having a rotating element is configured to adjust the axial gap between the valve rotor and the valve stator based on rotation of the rotating element.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Application Serial No. 63 / 033,532, filed on June 2, 2020, the entire disclosure of which is incorporated herein by reference. Background Technology Technical Field

[0003] This disclosure relates to drilling fluid telemetry systems, and more specifically to telemetry systems comprising an oscillating shear valve for regulating the pressure of drilling fluid circulating in a tubing string within a wellbore.

[0004] Description of Related Art

[0005] Drilling fluid telemetry systems (often called mud pulse systems) are particularly well-suited for telemetry (transmission) of information from the bottom of the borehole to the Earth's surface during underground operations (e.g., oil well drilling operations). Telemetry information typically includes, but is not limited to, parameters such as pressure, temperature, direction, and wellbore deviation. Other parameters include logging data such as resistivity, acoustic waves, density, porosity, induction, self-potential, and pressure gradients for various formations. This type of information can be critical to the efficiency of drilling operations.

[0006] Telemetry operations utilize mud pulse valves to generate pressure pulses within the fluid (i.e., drilling mud). Mud pulse valves must operate under extremely high static downhole pressures, high temperatures, high flow rates, and various erosive flows and fluid types. Under these conditions, the mud pulse valve must be able to generate pressure pulses ranging from approximately 100 psi to 300 psi.

[0007] Different types of valve systems can be used to generate downhole pressure pulses for telemetry. Opening and closing valves that bypass the tubing from the inside to the wellbore annulus generates negative pressure pulses, see, for example, U.S. Patent No. 4,953,595. Valves placed in the circulating mud flow and used in a controlled manner are generally referred to as positive pulse systems, see, for example, U.S. Patent No. 3,958,217. The entire contents of these patents are incorporated herein by reference.

[0008] There is a desire to increase the data transmission rate of mud pulse valves to accommodate the large volume of downhole data that needs to be transmitted to the surface. A major drawback of available mud pulse valves is their low data transmission rate. Increasing the data rate using available valve types results in unacceptably high power consumption, unacceptable pulse distortion, or may be physically impractical due to erosion, flushing, and abrasive wear. Due to their low activation / operating speeds, almost all existing mud pulse valves are only capable of generating discrete pulses. To effectively transmit frequency-shifted (FSK) or phase-shifted (PSK) encoded signals to the surface using a carrier wave, the actuation speed must be increased and fully controlled.

[0009] An example of a negative pulse valve is shown in U.S. Patent No. 4,351,037. The entire contents of this document are incorporated herein by reference. The present technology includes a downhole valve for discharging a portion of circulating fluid from the interior of a tubular string to an annular space between the tubular string and the borehole wall. Drilling fluid circulates down the interior of the tubular string, out through the drill bit, and up the annular space to the surface. By temporarily discharging a portion of the fluid flow from a side port, a transient pressure drop is created and is detectable at the surface to provide an indication of a downhole discharge. Downhole instrumentation is arranged to produce a signal or mechanical action upon the occurrence of a downhole detected event to create the discharge described above. The disclosed downhole valve is defined in part by a valve seat having an inlet and an outlet, and a valve stem movable in the linear path of the tubular string toward and away from the inlet end of the valve seat.

[0010] As will be appreciated by those skilled in the art, all negative pulse valves require a certain high differential pressure below the valve (i.e., downhole) to create a sufficient pressure drop when the valve is opened. Because of this high differential pressure, negative pulse valves are typically prone to washing. In general, it is not desirable to bypass flow above the drill bit into the annulus. Therefore, it is necessary to ensure that the valve can completely close the bypass. Each actuation, the valve impacts the valve seat. Because of this impact, negative pulse valves are more prone to mechanical and abrasive wear than positive pulse valves.

[0011] In contrast to negative pulse valves, positive pulse valves can but do not need to completely close the flow path to operate. Positive poppet type valves are not prone to wearing out the valve seat. The main force acting on positive poppet type valves is hydraulic pressure, as the valve opens or closes against the flow stream. To reduce actuation power, some positive poppet type valves are hydraulically driven, as described in U.S. Patent No. 3,958,217. The entire contents of this document are incorporated herein by reference. In such a configuration, the main valve is indirectly operated by a pilot valve. The low power consumption pilot valve closes the flow restriction, which activates the main valve to create the pressure drop. The power consumption of this valve is very small. The disadvantage of this valve is that the main valve is passively operated. At high actuation rates, the passive main valve cannot follow the actively operated pilot valve. As a result, the pulse signal generated downhole will become highly distorted, which is almost undetectable at the surface.

[0012] Alternative configurations include rotary disc valves configured to open and close flow passages perpendicular to the flow stream. The hydraulic forces acting on such valves are less than for poppet type valves. However, as the actuation speed increases, dynamic inertial forces are the dominant power consuming force. For example, U.S. Patent No. 3,764,968 describes a rotary valve configured to transmit frequency shift keyed (FSK) or phase shift keyed (PSK) encoded signals. The entire contents of this document are incorporated herein by reference. The valve uses a rotating disc and a non-rotating stator with multiple corresponding slots. The rotor is continuously driven by an electric motor. Depending on the motor speed, pressure pulses of a certain frequency are generated in the flow as the rotor intermittently interrupts the fluid flow. The motor speed needs to be changed to change the pressure pulse frequency to allow FSK or PSK type signals. There are several pulses per revolution of the rotor, corresponding to the number of slots in the rotor and stator. To change the phase or frequency, the rotor needs to increase or decrease speed. This can require the rotor to spin to overcome rotational inertia and achieve the new phase or frequency, requiring several pulse cycles to make the transition. For this continuously spinning device, amplitude encoding of the signal is not possible in nature. To change the frequency or phase, the large moment of inertia associated with the motor must be overcome, which requires a large amount of power. When continuously spinning at a certain speed, a turbine can be used or can include a gear to reduce the power consumption of the system. On the other hand, when the signal encoding is switched from one speed to another, both of these options significantly increase the inertia and power consumption of the system.

[0013] The above examples illustrate some of the key considerations in applying a fast acting valve to generate pressure pulses. Other considerations in using these systems in a drilling operation involve the extreme impact forces present in a moving pipe string, such as dynamic (vibration) energy. The result is excessive wear, fatigue, and failure of the operating components of the system. The particular difficulties encountered in a pipe string environment, including the need for long lasting systems to prevent premature failure and replacement of parts, require a robust and reliable valve system. SUMMARY

[0014] Systems and methods for generating pulses in a drilling fluid are provided herein. According to some embodiments, a pulser assembly is configured to be positioned along a tubular string through which the drilling fluid flows. The pulser assembly includes a housing configured to be supported along the tubular string, a valve stator supported by the housing, the valve stator having at least one flow path extending from an upstream end to a downstream end of the valve stator, a valve rotor positioned adjacent the valve stator, the valve rotor configured to selectively block the at least one flow path, wherein an axial gap exists between the valve rotor and the valve stator, a motor operably coupled to the valve rotor, wherein the motor is operable to rotate the valve rotor relative to the valve stator, and an axial release assembly including a rotating element configured to adjust the axial gap between the valve rotor and the valve stator based on rotation of the rotating element.

[0015] According to some embodiments, a method for generating pulses in a drilling fluid is provided. The method includes driving rotation of a valve rotor of a pulser assembly relative to a valve stator, wherein the pulser assembly includes a housing, wherein a motor is disposed within the housing and is configured to drive rotational movement of the valve rotor, and adjusting an axial gap between the valve rotor and the valve stator using an axial release assembly based on rotation of a rotating element, the axial release assembly including the rotating element.

[0016] The foregoing features and elements of the embodiments as set forth above can be combined in a variety of combinations, and are not limited to the specific embodiments described unless otherwise explicitly indicated. The foregoing features and elements of the embodiments as set forth above can be combined in a variety of combinations, and are not limited to the specific embodiments described unless otherwise explicitly indicated. The following description and drawings are illustrative of the embodiments and are not to be construed as limiting the inventive subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0017] The features, elements, and principles of the present application described above and illustrated in the drawings are presented by way of illustration only. The above description and drawings are not intended to limit the present application to such preferred embodiments. Rather, various modifications and variations can be made to the steps, features, and elements of the present application without departing from the spirit and scope of the application.

[0018] Figure 1 is a schematic diagram illustrating a rig involved in a drilling operation that can incorporate embodiments of the present disclosure;

[0019] Figure 2A is a schematic diagram of a pulser assembly that can incorporate embodiments of the present disclosure;

[0020] Figure 2B is a schematic diagram of a stator of the pulser assembly of Figure 2A

[0021] Figure 2C is a schematic diagram of a rotor of the pulser assembly of Figure 2A ​​

[0022] Figure 3A is a schematic of a pulser assembly that can incorporate embodiments of the present disclosure;

[0023] Figure 3B is a schematic of a portion of the pulser assembly of Figure 3A showing an open flow path of the pulser assembly;

[0024] Figure 4 is a sequence of orientations showing different valve clearances of a pulser assembly according to embodiments of the present disclosure;

[0025] Figure 5A is a schematic of an axial release assembly according to embodiments of the present disclosure;

[0026] Figure 5B shows a transition of the axial release assembly of Figure 5A during operation;

[0027] Figure 6A is a schematic of an axial release assembly according to embodiments of the present disclosure;

[0028] Figure 6B shows a transition of the axial release assembly of Figure 6A during operation;

[0029] Figure 7 is a schematic of an axial release assembly according to embodiments of the present disclosure;

[0030] Figure 8 is a schematic of an axial release assembly according to embodiments of the present disclosure;

[0031] Figure 9 is a schematic of a portion of an axial release assembly according to embodiments of the present disclosure;

[0032] Figure 10 is a schematic of an axial release assembly according to embodiments of the present disclosure;

[0033] Figure 11 is a schematic of a pulser assembly according to embodiments of the present disclosure;

[0034] Figure 12 is a schematic of a pulser assembly according to embodiments of the present disclosure;

[0035] Figure 13 is a schematic of a pulser assembly according to embodiments of the present disclosure;

[0036] Figure 14A is a pressure curve graph showing different pressure curves based on a separation clearance of a valve rotor relative to a valve stator;

[0037] Figure 14B Valve gap transitions of a system according to embodiments of the present disclosure are shown; and

[0038] Figure 14C is a plot of pressure versus time as generated by a system according to the present disclosure. DETAILED DESCRIPTION

[0039] The detailed description set forth below of one or more embodiments of the disclosed apparatus and method presented in this document is provided as an example and as a basis for the claims of this document.

[0040] Figure 1 is a schematic diagram showing a rig 100 involved in a drilling operation. Drilling fluid 102 (also known as drilling mud) is circulated by a pump 104, through a pipe string 106, down through a bottom hole assembly (BHA) 108, through a drill bit 110, and then back to the surface through an annulus 112 between the pipe string 106 and a borehole wall 114. The BHA 108 can include any of a number of sensor modules 116, 118, 120. The sensor modules 116, 118, 120 can include formation evaluation sensors, direction sensors, probes, pressure sensors, power generators (e.g., including a turbine), etc., as will be appreciated by those skilled in the art. Such sensors and modules are well known in the art and are not described further. The BHA 108 also includes a pulser assembly 122. The pulser assembly 122 is configured to induce pressure fluctuations in the mud flow of the drilling fluid 102. The pressure fluctuations or pulses propagate to the surface through the drilling fluid 102 in the pipe string 106 and / or through the drilling fluid 108 in the annulus 112 and are detected at the surface by a pulse sensor 124 and an associated control unit 126. As will be appreciated by those skilled in the art, the control unit 126 can be a general purpose or special purpose computer or other processing unit. The pulse sensor 124 is connected to a flow line 128 and can be a pressure transducer (pressure sensor) or a flow transducer, as will be appreciated by those skilled in the art.

[0041] Turning now to Figures 2A-2C , a schematic diagram of a pulser assembly 200 is shown. Figure 2A is a partial cross-sectional schematic diagram of the pulser assembly 200, Figure 2B is a schematic diagram of a stator 202 of the pulser assembly 200, and Figure 2C is a schematic diagram of a rotor 204 of the pulser assembly 200. The pulser assembly 200 can be installed or otherwise used in a downhole system, such as with respect to Figure 1shown and described. In this embodiment, the pulser assembly 200 is arranged as an oscillating shear valve assembly configured for mud pulse telemetry. As shown, the pulser assembly 200 is arranged in an inner bore of a tool housing 206. In some embodiments, the tool housing 206 can be a drill collar in a bottom hole assembly (e.g., as shown in Figure 1 The tool housing 206 can define an outer surface of the downhole tool and can be exposed to an annulus between the downhole tool 206 and a borehole wall or borehole casing. In other embodiments, the tool housing 206 can be a separate housing adapted to fit into a drill collar bore. Various other configurations are possible without departing from the scope of the present disclosure. In operation, e.g., while drilling, drilling fluid 208 will flow through the stator 202 and rotor 204 and through the annulus between the pulser housing 210 and the inner diameter or surface of the tool housing 206. According to some embodiments of the present disclosure, without limitation, the shear valve pulser can be configured to achieve data rates between 1 Hz and 60 Hz.

[0042] Figure 2A and Figure 2B The stator 202 is fixed relative to the tool housing 206 and the pulser housing 210 as shown in FIGS. 1-3. The stator 202 can define or include one or more longitudinal stator passages 212 (state flow passages). Figure 2A and Figure 2C The rotor 204 is shown as a disk having one or more slotted vanes 214 that define one or more rotor passages 216 (rotor flow passages) that are similarly sized and shaped to the one or more stator passages 212 in the stator 202 (but not as long axially as shown in Figure 2A Although shown as flow passages (defined by vanes), in some embodiments, holes or apertures can be formed in the stator and rotor, respectively. The rotor passages 216 are configured such that the rotor passages 216 will align with the stator passages 212 at certain angular positions to define straight or substantially straight (i.e., axial) flow paths. The rotor 204 is positioned immediately adjacent to the stator 202 and is configured to be rotationally oscillated or rotationally driven. The rotor 204 and stator 202 are separated in the axial direction by a gap (also referred to as a valve gap or axial gap). In some non-limiting embodiments, the valve gap can be in the range of a few millimeters (e.g., 0.5 mm to 2 mm). Angular displacement of the rotor 204 relative to the stator 202 will change the effective flow area of the axial flow paths defined by the flow passages 212, 216 and thus create pressure fluctuations in the circulated mud column. The tool housing includes a longitudinal axis H x that coincides with the rotational symmetry axis of the tool housing. The longitudinal axis A xcoincide with the axis of rotational symmetry of the pulser assembly 200 and / or the pulser housing 210. In some embodiments, the axis H x , A x may coincide, but in other embodiments, such alignment can not exist. In some embodiments, the pulser assembly 200 and / or the pulser housing 210 can be positioned eccentrically relative to the tool housing, and thus the axis H x , A x may not be aligned or coincident.

[0043] To achieve one pressure cycle, it is necessary to open and close the axial flow path by changing the angular positioning of the rotor blades 214 relative to the stator passages 212. This can be done by oscillatory movement of the rotor 204. The rotor blades 214 are rotated in a first direction until the flow area is completely or partially restricted. This partial or complete restriction (or occlusion) will create or generate a pressure increase in the fluid. The rotor blades 214 are then rotated in the opposite direction to again open the flow path. As the flow path opens, the pressure will decrease. The angular displacement required to generate a pressure pulse depends on the design of the rotor 202 and the stator 204. The greater the blockage of the flow path, the greater the resulting pressure fluctuation (pressure pulse). The narrower the flow path design of the pulser assembly 200, the less the amount of angular displacement required to create a pressure fluctuation. It is generally desirable for the amount of angular displacement to be relatively small (and thus a relatively narrow flow opening can be more desirable). However, narrow flow openings can have the disadvantage of being occluded by debris or foreign particles in the fluid flow, and thus a compromise must be made between a narrow opening for low displacement and a larger opening for allowing debris to pass therethrough.

[0044] The power required to accelerate the rotor 204 is proportional to the angular displacement. The smaller the angular displacement, the less actuation power is required to accelerate or decelerate the rotor 204. As an example, using an angular displacement of about 22.5° of the rotor 204 to create a pressure drop due to eight flow openings (rotor passages 216) on the rotor 204 and the stator 202 (stator passages 212) and maximizing the cross-section of the flow openings. Having such a relatively low angular displacement angle can ensure a relatively low actuation energy, even at high pulse frequencies. In some configurations, it can not be necessary to completely occlude the flow of fluid through the flow path to generate a pressure pulse. Thus, different amounts of occlusion or angular rotation can be used to generate different pulse amplitudes.

[0045] As Figure 2AAs shown, the rotor 204 is attached or operably coupled to a drive shaft 218. Thus, rotation of the drive shaft 218 can cause rotation or oscillation of the rotor 204. The drive shaft 218 is assembled through a seal 220 and through one or more bearings 222. The bearings 222 are configured to fix the drive shaft 218 in radial and axial position relative to the pulser housing 210. The drive shaft 218 is operably connected to a motor 224 (pulsing motor), where the drive shaft 218 is configured to be rotationally or oscillationally driven by the motor 224. The drive shaft 218 can be substantially parallel to an axis A of the pulser assembly 200 x The motor 224 can be, for example, an electric motor, such as a reversible brushless DC motor, a servo motor, or a stepper motor. The motor 224 can be configured to be electronically controlled, such as by circuitry in an electronics module 226. The electronics module 226 can enable precise operation of the rotor 204, such as in oscillatory movement in two rotational directions (e.g., clockwise or positive rotational direction and counterclockwise or negative rotational direction). Precise control of the rotor 204 position provides for specific shaping of pressure pulses generated by fluid flow (e.g., drilling mud) through the pulser assembly 200. The electronics module 226 can include a programmable processor that can be preprogrammed to transmit data with any of a number of encoding schemes, including but not limited to amplitude shift keying (ASK), frequency shift keying (FSK), or phase shift keying (PSK), or combinations of these techniques. A downhole power generator (not shown) can provide power to the motor 224 and the electronics module 226. The power generator can use turbine wheels to generate power from flow energy provided by the circulated drilling mud. In some embodiments, for example, power to drive the motor can be provided by a downhole battery.

[0046] In some embodiments, the tool housing 206 can include one or more pressure sensors 203 mounted at locations above (uphole / upstream) and below (downhole / downstream) the pulser assembly 200. Such pressure sensors can be configured with sensing surfaces exposed to fluid (drilling mud 208) flowing through the string bore. The pressure sensors can be powered by the electronics module 226 and can be configured to receive surface-transmitted pressure pulses. A processor and / or circuitry in the electronics module 226 can be programmed to change data encoding parameters based on the received surface-transmitted pulses. Encoding parameters can include the type of encoding scheme, baseline pulse amplitude, baseline frequency, or other parameters affecting data encoding. In some embodiments, the pressure sensors 203 can be used to monitor pressure fluctuations generated by the oscillating rotor 204. Depending on the monitored pressure fluctuations over time, encoding parameters can be adapted.

[0047] The pulser housing 210 can be filled with a suitable lubricant 228 to lubricate the bearing 222 and to pressure compensate the interior of the pulser housing 210 with downhole pressure of the drilling mud 208. The bearing 222 is a typical anti-friction bearing known in the art and is not further described. In some embodiments, and as shown, the seal 220 can be configured as a flexible bellows seal that directly couples the drive shaft 218 and the pulser housing 210. Thus, the seal 220 can seal (e.g., air-tightly) the pulser housing 210 that is filled with a lubricant 228 (e.g., oil). As the angular movement or angular rotation of the drive shaft 218 as driven by the motor 224 causes the flexible material of the seal 220 to twist, accommodating the angular motion while maintaining the lubricant 228 sealed within the pulser housing 210. In some embodiments, the flexible bellows material of the seal 220 can be an elastomeric material, a fiber-reinforced elastomeric material, or other suitable material as would be appreciated by one of skill in the art. Depending on the material of the seal 220, the arrangement of components, etc., it can be desirable to keep the angular rotation of the drive shaft 218 relatively small so that the material of the seal 220 will not be unduly stressed by the twisting motion. In other configurations, the seal 220 can be an elastomeric rotary shaft seal or a mechanical face seal as would be appreciated by one of skill in the art. That is, the seal 220 can take various configurations and arrangements to provide a sealed, lubricant-filled interior structure of the pulser assembly 200 without departing from the scope of the present disclosure.

[0048] In some embodiments, the motor 224 can be configured with a double ended shaft or a hollow shaft. In some such embodiments, one end of the motor shaft is attached to the drive shaft 218 of the pulser assembly 200 and the other end of the motor shaft is attached to a torsional spring 230. The torsional spring 230 can be anchored to an end cap 232. In such embodiments, the torsional spring 230, the drive shaft 218, and the rotor 216 are configured as a mechanical spring mass system. The torsional spring 230 is designed such that the natural frequency of the spring mass system is at or near the desired oscillatory pulse frequency of the pulser assembly 200. Methods for designing a resonant torsional spring mass system are well known in the mechanical arts and are not described herein. The advantage of a resonant system is that once the system is in resonance, the motor 224 only needs to provide power to overcome external forces and system damping, while the rotational inertia forces are balanced by the resonant system. As described in FIG. 2, the stator 202 and the rotor 204 can be located on the uphole side (e.g., closer to the surface) of the pulser assembly 200. The stator 202 can be arranged uphole relative to the rotor 204. Drilling mud circulated downhole by a surface mud pump first passes through the stator 202 and then through the rotor 204. In an alternative configuration, the stator 202 and the rotor 204 can be arranged downhole relative to the pulser motor 224. In some such embodiments, the stator 202 can be arranged downhole relative to the rotor 204. Thus, drilling mud passes through the rotor 204 before it passes through the stator 202. In both configurations, i.e., pulser motor uphole or downhole, stator / rotor (relative to valve uphole / downhole), the stator can alternatively be located between the rotor and the pulser motor. In some such configurations, the drive shaft connecting the rotor and the pulser motor can extend through the valve stator.

[0049] Turning now to Figures 3A-3B , a schematic view of a pulser assembly 300 is shown. Figure 3A The pulser assembly 300 is shown in a closed state, and Figure 3B The pulser assembly 300 is shown in an open state. The pulser assembly 300 includes a valve rotor 302 that is (rotationally) movable relative to a valve stator 304. The valve rotor 302 can be configured to selectively block one or more flow passages 306 of the valve stator 304. In Figures 3A-3BIn this particular embodiment, the flow direction X is to the right (downhole side) on the page, such that the valve stator 304 is disposed downstream of the valve rotor 302. The valve rotor 302 can be driven in an oscillatory manner (as compared to a full circle) by a motor 308. The motor 308 can be an electronic motor that drives a drive shaft 310, which is operably coupled to the valve rotor 302 and effects and drives the oscillatory motion of the valve rotor 302. The motor 308 and drive shaft 308 are contained within a pulser housing 312, which protects such components (and others) from the drilling fluid flowing along and through the pulser assembly 300, as described above. Operably coupled to the drive shaft 310 can be a torsion spring 314, which can be housed within the pulser housing 312.

[0050] As the motor 308 drives the drive shaft 310, and thus the valve rotor 302, one or more blocking elements (e.g., vanes) of the valve rotor 302 can oscillate into a blocking position to restrict or otherwise choke the flow through the flow passage 306 of the valve stator 304. When the blocking elements of the valve rotor 302 are aligned with portions of the valve stator 304, the flow passage 306 of the valve stator 304 can be fully open, as shown. Figure 3B Blocking the flow through the flow passage 306 of the valve stator 304 will cause or generate a pressure pulse within the fluid passing through the pulser assembly 300. In the open state Figure 3B ), drilling mud can pass through the pulser assembly 300 and through its flow passage 306. When the valve rotor 302 (i.e., its blocking elements) moves to choke the flow passage 306, fluid flow can be prevented. The valve rotor 302, as described above, is connected to the drive shaft 310, which is mounted radially and axially within the pulser housing 312. The drive shaft 310 is oscillated by a drive system (motor 308 and associated electronics), which converts an electrical code signal into a mud pulse signal for driving torque and thus oscillating the valve rotor 302.

[0051] The motor 308 can be an electric motor having a motor stator 316 and a motor rotor 318. The motor rotor 318 can be operably connected to the drive shaft 310 to drive rotational movement (e.g., oscillation) of the drive shaft 310. The motor stator 316 can be controlled to generate electrical pulses that drive the oscillation of the motor rotor 318, and as the motor rotor 318 oscillates, torque will be imparted to the drive shaft 310. The motor stator 316 can be securely mounted within the pulser housing 312. In this illustrative embodiment, the drive shaft 310 is connected to a rotational active spring element (i.e., torsion spring 314), as described above. The torsion spring 314 is configured to reset the orientation of the drive shaft 310 to define a zero position to guarantee a defined position between the valve rotor 302 and the valve stator 304 of the pulser assembly 300, typically a valve open position.

[0052] In operation, the drilling mud flow can contain particulates (e.g., lost circulation material (LCM)) that can get stuck between the structures of the valve rotor and the valve stator (e.g., in the axial gap between the valve rotor and the valve stator). Typically, the gap between the valve rotor and the valve stator (valve gap) is a fixed separation distance, and if the particle size is too large, such particles can get stuck or jammed in the gap between the valve rotor and the valve stator. To avoid this, the gap or separation distance between the valve rotor and the valve stator can be configured to be larger. However, this larger axial gap can result in a smaller differential pressure across the valve rotor, and thus, a reduced efficiency of pressure pulse generation by the pulser assembly (e.g., reduced signal quality and / or reduced signal amplitude in the generated pulses). Thus, a balance can be necessary between maintaining a narrow gap for quality pulse generation and maintaining a large gap to prevent valve jamming. A typical gap between the valve rotor and the valve stator can be in the range of a few millimeters, such as, for example and without limitation, 1 mm to 2 mm (e.g., 1.5 mm).

[0053] In view of this, embodiments of the present disclosure are directed to a controlled axial gap that varies the gap based on an angular displacement angle of the valve rotor and, in some embodiments, a torque acting on the valve rotor. Thus, according to some embodiments, the valve rotor can be axially moved to increase or decrease the gap between the valve rotor and the valve stator based on the angular position or torque applied to a drive shaft that drives the motion of the valve rotor. Thus, in some embodiments of the present disclosure, the axial gap control is operably or functionally coupled with the torque and angular displacement angle of the oscillation of the pulser assembly system.

[0054] Figure 4 is a series of illustrations schematically showing an exemplary gap of a pulser assembly mounted on a downhole tool 400 according to embodiments of the present disclosure. The pulser assembly defines an axis A x and can be arranged in a flow direction of a fluid flowing through a downhole tool in which the pulser assembly is included. The axis A x is a longitudinal axis of the downhole tool 400. The pulser assembly includes a valve stator 402 and a valve rotor 404. The valve rotor 404 is connected to a drive shaft 406 configured to drive rotation and / or oscillation of the valve rotor 404 relative to the valve stator 402 to generate pressure pulses within a fluid passing through the downhole tool 400.

[0055] Figure 4The orientation (a) can indicate the default or initial spacing or separation between the valve stator 402 and the valve rotor 404, as indicated by the initial gap G0. The distance of the initial gap G0 can be set to achieve optimal pressure pulse generation. That is, the initial gap G0 can be used during normal operation to generate clean and clear pressure pulses. However, if foreign objects (e.g., debris, particles, etc.) become trapped in the space between the valve stator 402 and the valve rotor 404, increasing the gap can remove and eliminate any blockage. Therefore, embodiments of this disclosure achieve valve rotor 404 along axis A x Translate axially relative to valve stator 402 in the positive axial direction, such as Figure 4 As shown in orientation (b), the valve stator 402 remains axially stationary. In orientation (b), the distance between the valve rotor 404 and the valve stator 402 has been increased to an increased gap G1, where, in this illustration, gap G1 is in its fully extended position. Conversely, along axis A... x The negative axial direction may cause the pitch to decrease to the reduced gap G2 shown in orientation (c), where gap G2 is in a fully retracted position in the illustration. For example, at low flow rates, the reduced gap G2 can achieve a high pressure drop across the pulser assembly 400. However, at the reduced gap G2 shown in orientation (c), the likelihood of debris clogging the gap increases. Therefore, embodiments of this disclosure involve changing the gap between the valve stator and the valve rotor to ensure a strong or clear pulse signal while avoiding debris clogging the gap. In some embodiments, the valve stator 402 may be axially movable to increase or decrease the gap between the valve rotor 404 and the valve stator 402, while the valve rotor 404 remains axially stationary. Additionally, it should be understood that both components (e.g., the valve rotor 404 and the valve stator 402) may be movable to adjust the gap between the components.

[0056] Turn now Figures 5A-5B A schematic diagram of an axial release assembly 500 according to an embodiment of the present disclosure is shown. Figure 5A The axial release assembly 500 is shown in its fully retracted state, which can be its initial position. Figure 5B An axial release assembly 500 in its extended state is shown. The axial release assembly 500 includes a rotating element 502 and an axial moving element 504. The rotating element 502 can be operatively connected to and rotatably driven by the motor rotor or motor stator of the drive system of the pulser assembly. The axial moving element 504 is operatively connected to the rotating element 502 and configured such that rotational movement of the rotating element 502 causes axial movement of the axial moving element 504.

[0057] An axial movement element 504 is disposed within the pulser housing 506 of the pulser assembly. As used herein, axial movement is in the direction along the longitudinal axis of a downhole tool, such as a downhole tool housing or containing the pulser assembly, and rotational movement is movement about the longitudinal axis of the downhole tool. To ensure axial-only movement of the axial movement element 504, in this exemplary embodiment, the axial movement element 504 includes a key 508 (locking element) that can be arranged to slide or translate through a slot in the pulser housing 506. The keyway configuration ensures that the axial movement element 504 does not rotate within the pulser housing 506 during rotation of the associated rotary element 502. Other mechanisms besides keyways may be used without departing from the scope of this disclosure.

[0058] Axial movement element 504 is operatively connected to the drive shaft of the pulser assembly. Axial movement of axial movement element 504 is transmitted to the drive shaft to displace the drive shaft axially. Since the valve rotor is connected to the drive shaft, as described above, the valve rotor will translate axially as the drive shaft translates axially, thereby adjusting the clearance between the valve rotor and the valve stator. In some embodiments, axial movement element 504 may be connected to a bearing block of the drive shaft to allow the drive shaft to rotate relative to axial movement element 504.

[0059] According to an exemplary operation of the axial release assembly 500, the axial release assembly 500 is configured to release a section of the valve rotor and drive shaft in the axial direction (in... Figures 5A-5B The axial movement (indicated by direction x) varies with the oscillation of the drive system or motor. While the valve rotor is oscillating, the gap between the valve stator and the valve rotor changes via the axial release assembly 500. The axial release assembly 500 consists of a rotating element 502, which can oscillate or be driven by a torque transmission element of the drive system (i.e., driven by the motor stator or attached to the motor rotor). When the rotating element 502 moves from its initial position (… Figure 5A (The angular displacement angle is zero) Rotate to the specified angular displacement position. Figure 5B When the axial moving element 504 moves axially in the x-direction (i.e., axially away from the rotating element 502), it moves to the release position (e.g., the fully extended position of the axial release assembly), such as... Figure 5B As shown. The axial movement of the axial moving element 504 can be guided by one or more locking elements (e.g., key 508) located between the axial moving element 504 and the pulser housing 506. Therefore, rotation of the rotating element 502 is prevented from being transmitted to the axial moving element 504. When the rotating element 502 returns to or reverts to its initial position (e.g., in an oscillating manner), the axial moving element 504 moves backward to its initial position by axial movement in the negative x-direction (i.e., axially upward toward the rotating element 502, i.e., fully retracted). Figure 5A (as shown in the image).

[0060] In some embodiments, the axially moving element is axially and rotatably locked to the pulser housing, and the rotary moving element is rotatably and axially locked to the drive shaft. In such a configuration, the rotary element is axially and rotatably movable relative to the pulser housing, while there is no relative movement between the rotary element and the drive shaft. Axial movement generated by rotating the rotary element with the drive shaft is transmitted from the rotary element to the drive shaft. In some embodiments, the axial release assembly may not be fully extended (e.g., partially extended). Any extension of the axial release assembly between a fully retracted state and a fully extended state is possible (i.e., partial extension). The amount of extension depends on the angular displacement angle of the rotary element. To fully retract the axial release element, an angular displacement angle of less than 360° is required. Typically, rotation between 5° and 90° will allow the axial release assembly to fully extend. More specifically, the angular displacement angle of the rotary element may be between 10° and 45°. In another alternative embodiment, the angular displacement angle may be between 15° and 35°. In yet another embodiment, the angular displacement angle of the rotary element may be between 20° and 30°. In some embodiments, the axial displacement of the axial release assembly when fully extended can be from 0.1 mm to 10 mm. In another embodiment, the axial displacement (stroke or stroke length) of the axial release assembly when fully extended can be from 0.1 mm to 2 mm. In yet another embodiment, the axial displacement of the axial release assembly when fully extended can be from 0.4 mm to 1 mm.

[0061] Turning Figures 6A-6B An alternative configuration / operation of the axial release assembly 600 according to an embodiment of the present disclosure is shown. In this illustrative configuration, the axial release assembly 600 is designed such that its initial position is in an axially extended state. Figure 6A Therefore, the rotating element 602 moves from its initial position ( Figure 6A The rotation of the rotating element 604 causes an axial movement of the axial moving element 604 toward the rotating element 602 (i.e., in the negative x direction), such as... Figure 6B As shown. The direction of rotation can be positive (e.g., clockwise) or negative (e.g., counterclockwise). The rotating element can be connected to the rotating part of the motor or other drive system of the pulser assembly and can be rotatably driven therefrom. When the rotating element returns to its normal or initial position, the axial movement element 604 moves rearward in the positive x-direction, and thus increases the axial clearance. The extended state can be a fully extended state or any state between a fully retracted state and a fully extended state. The amount of extension is determined by the angular displacement angle of the rotating element 602.

[0062] exist Figures 5A-5BThe configuration of the axial release assembly 500 shown, the default or initial position is where the axial moving element 504 is closest to the rotating element 502. Thus, as the rotating element 502 rotates, the axial moving element 504 moves axially away from the rotating element 502. This means that the gap between the valve rotor and the valve stator increases as the rotating element 502 rotates, and decreases (or is minimal) when the rotating element 502 returns to the initial position. In contrast, in the axial release assembly 600 shown, Figures 6A-6B The configuration of the axial release assembly 600 shown, the default or initial position is where the axial moving element 604 is farthest from the rotating element 602. Thus, as the rotating element 602 rotates, the axial moving element 604 moves axially toward the rotating element 602. This means that the gap between the valve rotor and the valve stator decreases as the rotating element 602 rotates, and increases (or is maximal) when the rotating element 602 returns to the initial position.

[0063] Thus, it should be understood that the systems and assemblies described herein can be configured with various directional orientations. That is, the oscillation system can be driven in two opposite directions, positive (+) or negative (-) rotation about the x-axis correlates to positive or negative angular displacement angles of the rotating element. According to some embodiments, the axial release assembly can be symmetrical, as Figure 6B shown, or asymmetrical. In a symmetrical configuration, the axial moving element is configured to move in the same direction relative to the rotating element from the initial position (zero degree angular displacement) whether the rotation is positive (+) or negative (-). In an asymmetrical configuration, the axial moving element can move in different or opposite directions depending on whether the rotation of the rotating element from the initial position is positive (+) or negative (-). In an asymmetrical configuration, the initial or default position (default gap) can be a mid-distance gap or half-extended state, where positive rotation increases the gap distance from the default gap, and negative rotation decreases the gap distance from the default gap (e.g., Figure 4 ). In alternative embodiments, the initial position can be a fully-extended state, and negative (-) or positive (+) rotation causes the gap to decrease toward a fully-retracted state. Additionally, in some embodiments, the initial position can be a fully-retracted state, and positive (+) rotation or negative (-) rotation causes the gap to increase toward a fully-extended state.

[0064] Different mechanisms can be used to achieve the coupling of rotation (oscillation) and axial movement according to various embodiments of the present disclosure. That is, any rotation-to-axial movement conversion can be employed without departing from the scope of the present disclosure. The main feature of such systems is the coupling of angular position / orientation and / or torque to axial movement of the axial moving element (and thus axial movement of the valve rotor and control of the gap of the pulser assembly).

[0065] Turning now to Figure 7FIG. 7 shows a schematic view of an axial release assembly 700 according to embodiments of the present disclosure. The axial release assembly 700 comprises a rotating element 702 and an axially moving element 704. The rotating element 702 can be operably connected to a motor rotor or a motor stator of a drive system of a pulser assembly and can be rotatably driven thereby. The axially moving element 704 is operably connected to the rotating element 702 and is configured such that a rotational movement of the rotating element 702 causes an axial movement of the axially moving element 704. The axially moving element 704 is operably coupled or otherwise connected to a drive shaft and / or a valve rotor to effect an axial movement of the drive shaft and / or the valve rotor.

[0066] The rotating element 702 has a respective body 706 with at least one circularly arranged ramped surface 708 and an axial movement locking element 710. The ramped surface 708 comprises a first end 713a and a second end 713b. The ramped surface 708 is configured to effect a transition from a rotational movement (of the rotating element 702) to an axial movement (of the axially moving element 704). The ramped surface 708 is arranged on a side of the rotating element facing the axially moving element 704. The axial movement locking element 710 ensures that the rotating element 702 does not move axially during rotation or oscillation. The axial movement locking element 710 is configured to lock axial movement with respect to a housing (e.g., a pulser housing) in which the release assembly is located. In some embodiments, the axially moving element can be axially locked to the housing and the rotating element can be axially moveable with respect to the housing. The axial movement locking element 710 can be part of an axial movement locking assembly. In some embodiments, the axial movement locking assembly can comprise a circumferential recess in the housing 722 and / or the rotating element 702 and a key (e.g., a pin, a block, etc.) inserted into the recess or fixedly connected to one of the rotating element 702 and the housing 722.

[0067] The axially moving element 704 has a respective body 712 with at least one circularly arranged slot 714. The slot 714 of the axially moving element 704 is arranged on a side of the axially moving element 704 facing the rotating element 702. The slot is arranged on the same reference circle as the ramped surface 708 of the rotating element 702. That is, when the body 712 of the axially moving element 704 is arranged with respect to the body 706 of the rotating element 702, the slot 714 is aligned with the ramped surface 708 and defines a space therebetween.

[0068] One or more rolling bodies 716, such as balls, bearings, or the like, are inserted and disposed in the slots 714 and within the space between the slots 714 of the axial movement element 704 and the inclined surface 708 of the rotational element 702. The slots 714 are also referred to as rolling body slots or ball slots. The first end 713a of the inclined surface 708 can be the lowest point of the rolling bodies 716 on the inclined surface 708. The second end 713b of the inclined surface 708 can be the highest point of the rolling bodies 716 on the inclined surface 708. The rolling bodies 716 are secured within the space such that the rolling bodies 716 are free to rotate and move within the space along the inclined surface 708 and contact the body 712 of the axial movement element 704 within the slots 714. In some embodiments, the slots 714 can be substantially the same shape or profile as the rolling bodies 716 (e.g., have a concave portion with a spherical shape) to allow the rolling bodies 716 to rotate within the slots 714. According to some non-limiting embodiments, the rolling bodies 716 can have a diameter of 5 mm to 10 mm.

[0069] The rolling bodies 716 provide the engagement and coupling between the rotational element 702 and the axial movement element 704. As described above, the rolling bodies 716 are configured to roll along the respective inclined surfaces 708 of the rotational element 702. To ensure unobstructed contact between the rolling bodies 716 and the inclined surfaces 708 of the rotational element 702, the rotational element 702 and the axial movement element 704 have a common center axis of rotation 718. In some embodiments, a bearing block or a guide block can be disposed to guide rotation about the center axis 718 anywhere in the axial release assembly 700 or in the drive system of the pulser assembly. The axial movement element 704 is rotationally locked to a housing 722 by at least one locking element 720 (rotational locking element) that shares the center axis 718 as a center axis. The housing 722 can be a housing of the pulser assembly as shown and described above. As shown, the locking element 720 is a key that is engaged within a keyway, a recess, or a slot on an inner surface of the housing 722. It should be understood that other types of locking elements and configurations can be employed without departing from the scope of the present disclosure. The rotational locking element 720 can be part of a rotational locking assembly. In some embodiments, the rotational locking assembly can include an axial recess in the housing 722 and / or the axial movement element 704 and a key (e.g., a slide key, a spline, a slider / nut, etc.) that is inserted into the recess or securely connected to one of the axial movement element 704 and the housing. In alternative embodiments, the rotational locking assembly can include a splined spline.

[0070] The center axis 718 extends through the reference circle defined by the slot 714 and the ramped surface 708 and defines a center point (not shown) of the reference circle. The reference circle defined by the slot 714 and the reference circle defined by the ramped surface 708 have the same radius. The distance along the reference circle between the lowest point and the highest point on the ramped surface 708 defines a circular length 715 of the ramped surface 708. The ramped surface 708 projects to form a circular arc onto a plane that is perpendicular to the axis 718. The circular length of the ramped surface 708 can be defined by the circular arc measured in degrees. According to embodiments of the present disclosure, one ramped surface 708 has a circular length that is less than 360 degrees. That is, one ramped surface 708 covers only a portion of a full circle. In some embodiments, there can be ten ramped surfaces substantially equally spaced on the body 706 of the rotating element 702. Each ramped surface 708 can cover or span about a 10 degree to 36 degree angle. It should be appreciated that any number of ramped surfaces having any desired angular span can be employed without departing from the scope of the present disclosure.

[0071] Due to the ramping of the ramped surface 708, each ramped surface 708 represents a portion of a helical shape having a helical radius defined by the reference circle. Thus, if the ramped surface were to continue beyond the 360 degree angle, a helical shape would be formed. The ramped surface 708 can also be described as a trochoid or a guide. In a cross-section of the ramped surface 708, the shape of the ramped surface corresponds to the shape of the rolling body 716 (e.g., an arc of a circle). In other embodiments, for example, the cross-sectional shape of the ramped surface can be an arc of an ellipse. The ramped surface 708 has at least one radius in a radial direction with respect to the reference circle. The ramped surface 708 can have a constant slope along the circular length of the ramped surface 708.

[0072] In some embodiments, the slope of the ramped surface 708 along the circular length can not be constant but can vary with the circular length. In some embodiments, the slope of the ramped surface 708 determines the valve gap variation as a function of the rotational position of the valve rotor with respect to the valve stator of the pulser assembly. Varying the slope along the ramped surface 708 allows for a defined variation (e.g., a gear ratio) of the valve gap occurrence by the relative rotation (e.g., angular displacement) of the valve rotor and the valve stator. A constant slope would result in a linear relationship between the valve gap variation (mm) and the valve rotor rotation (degrees). A varying slope (e.g., a non-linear slope) would result in a non-linear relationship between the valve gap variation and the valve rotor rotation. It should be appreciated that all ramped surfaces on the rotating element have the same constant slope or have the same slope variation along the circular length of the ramped surface (i.e., each of the ramped surfaces is identical). According to embodiments of the present disclosure, the number of ramped surfaces 708 is equal to the number of rolling bodies 716.

[0073] In operation, as the rotating element 702 is rotated about the central axis 718, the rolling body 716 is caused to roll along the inclined surface 708, which is guided by the slot 714. The up and down movement of the rolling body 716 along the inclined surface 708 is transferred to the body 704 of the axial movement element 704. Thus, the axial movement element 704 is movable in a positive or negative axial direction along the central axis 718. Causing the rolling body 716 to move up along the inclined surface 708 causes extension of the axial release assembly 700. Causing the rolling body 716 to move down along the inclined surface 708 causes retraction of the axial release assembly. In alternative embodiments, the slot 714 can be arranged on the side of the rotating element 702 facing the axial movement element 704, and the inclined surface 708 can be arranged on the axial movement element 704 facing the rotating element 702.

[0074] Turning now to Figure 8 , a schematic illustration of an axial release assembly 800 according to embodiments of the present disclosure is shown. The axial release assembly 800 includes a rotating element 802 and an axial movement element 804. The rotating element 802 can be operably connected to and rotatably driven by a motor rotor or motor stator of a drive system of a pulser assembly. The rotating element 802 is configured to rotate relative to a housing, such as a pulser housing, that houses the axial release assembly 800. The axial movement element 804 is operably connected to the rotating element 802 and is configured such that rotational movement of the rotating element 802 causes axial movement of the axial movement element 804 relative to the pulser housing. The axial movement element 804 is operably coupled or otherwise connected to a drive shaft and / or valve rotor to effect axial movement of the drive shaft and / or valve rotor. The axial movement element 804 can not rotate with the drive shaft but can be rotationally stationary relative to the pulser housing. The drive shaft is configured to rotate relative to the axial movement element 804.

[0075] As Figure 8As shown, the axial release assembly 800 includes a rolling body 806 that is movable along an inclined surface 808 of the rotational element 802 and within a slot 810 of the axial movement element 804, as shown and described above. The inclined surface 808 includes a first end 813a and a second end 813b. The first end 813a can be the lowest point of the rolling body 806 on the inclined surface 808, and the second end 813b can be the highest point of the rolling body 806 in the inclined surface 808. The lowest point refers to the position of the rolling body 806 on the inclined surface 808 that relates to the retracted state of the axial release assembly 800. The highest point refers to the position of the rolling body 806 on the inclined surface 808 that relates to the extended state of the axial release assembly 800. The rotational element 802 is rotatable about a central axis 812, and the axial movement element 804 is movable along the central axis 812. According to some embodiments of the present disclosure, the slope of the inclined surface causes an axial displacement of the rolling body as it moves from the first end of the inclined surface to the second end of the inclined surface (e.g., the travel of the axial release assembly). The axial displacement can be between 0.1 mm to 5 mm. More particularly, the axial displacement can be between 0.2 mm to 3 mm. In alternative embodiments, the axial displacement can be between 0.2 mm to 0.7 mm. In yet another embodiment, the axial displacement can be between 0.4 mm and 0.6 mm.

[0076] In this configuration, the rotating element 802 includes a first end stop 814 and the axially moving element 804 includes a second end stop 816. The first end stop 814 includes a first end stop surface 814a and a second end stop surface 814b. The second end stop 816 includes a first end stop surface 816a and a second end stop surface 816b. The first end stop 814 and the second end stop 816 form an end stop pair configured to stop the circumferential movement of the rolling bodies 806 along the inclined surfaces 808 of the rotating body. For example, the end stop pair 814, 816 can prevent a given rolling body 806 from passing over the end of an inclined surface 806 and falling into / on the next / adjacent inclined surface 808. The end stop pair 814, 816 is configured to stop further rotation of the rotating element 802 relative to the axially moving element 804. When the first end stop surfaces 814a, 816a of the end stops 814, 816 are in contact, if the axially moving element 804 is rotatable and not fixed relative to the rotation by a rotation lock element or other rotational fixation means, rotation of the rotating element 802 about the central axis 812 can be prevented or directly transmitted to the axially moving element 804. In contrast, if the second surfaces 814b, 816b are in contact, positive rotation of the rotating element 802 about the central axis 812 can be stopped or transmitted to the axially moving element 804. In some embodiments, the end stops 814, 816 can be used to limit the axial displacement of the axially moving element 804 in the direction of the central axis 812.

[0077] When the first end stop surfaces 814a, 816a are in contact, the rolling body 806 is at the lowest point of the inclined surface 808 (e.g., the first end 813a), and the axial release assembly 800 is fully retracted. When the second end stop surfaces 814b, 816b are in contact, the rolling body 806 is at the highest point of the inclined surface 808 (e.g., the second end 813b), and the axial release assembly 800 is fully extended. The axial length of the end stops 814, 816 is at least as long as the length of travel (e.g., the difference between the fully extended state and the fully retracted state). In alternative embodiments, the inclined surface 808 can be inclined in the opposite rotational direction. Thus, when the first end stop surfaces 814a, 816a are in contact, the rolling body 806 will be at the highest point of the inclined surface 808, and the axial release assembly will be fully extended. Similarly, when the second end stop surfaces 814b, 816b are in contact, the rolling body 806 will be at the lowest point of the inclined surface 808, and the axial release assembly will be fully retracted. In the fully retracted state, the gap between the rotating element 802 and the axially moving element 804, and thus between the valve stator and the valve rotor (e.g., the valve gap), is at a minimum. In the fully extended state, the gap between the rotating element 802 and the axially moving element 804, and thus between the valve stator and the valve rotor, is at a maximum. In alternative embodiments, the end stop pairs 814 / 816 can be replaced by end stops on the first end 813a and the second end 813b on the inclined surface 808, respectively.

[0078] Turning now to Figure 9 , a schematic view of a portion of an axial release assembly 900 according to embodiments of the present disclosure is shown. Figure 9A configuration of a rotating element 902 that can be employed in various embodiments of the present disclosure is shown. The rotating element 902 can be connected to and rotatably driven by a motor rotor or motor stator of a drive system of a pulser assembly. As shown, the rotating element 902 includes an inclined surface 904 that includes a first end and a second end and a circular length from the first end to the second end. However, rather than being inclined in one direction, the inclined surface 904 includes a symmetrical configuration that includes the first and second ends in relation to two peaks 906a, 906b (a first peak or first highest point 906a and a second peak or second highest point 906b) and an inflection point 908 (e.g., a lowest point) located therebetween. Thus, the two peaks 906a, 906b form mirror image inclines about the inflection point 908. In some configurations, the inflection point 908 can be an initial position of the system (i.e., when no torque or rotation is applied to the rotating element 902). Thus, the rolling body 910 can increase along the incline in both positive and negative rotational directions of the rotating element 902. This allows the rolling body 910 to push the engaged axial movement element away from the rotating body 902 in both oscillation directions. When the rolling body 910 is at the inflection point 908, the engaged axial movement element will be positioned closest to the rotating element 902, and the axial release assembly 900 is fully retracted. Thus, the gap between the valve stator and valve rotor can be a minimum when the rolling body 910 is at the inflection point 908, and the gap between the valve stator and valve rotor can be a maximum when the rolling body 910 is at one of the peaks 906a, 906b.

[0079] In alternative embodiments, the inclined surface can be asymmetric with respect to the inflection point but can be asymmetric. The inclination of the inclined surface from the inflection point towards the first end can be different from the inclination of the inclined surface from the inflection point towards the second end. In another embodiment or in combination with this embodiment, the circular length of the inclined surface between the inflection point and the first end or first highest point can be different from the circular length between the inflection point and the second end or second highest point. Additionally, in some embodiments, the inclined surface can not have a slope on one side of the inflection point. In some embodiments, the axial release element can also function as a bearing element. Thus, the number of rolling bodies can be critical for such functionality. An asymmetric embodiment or configuration will only allow a small number of rolling bodies. Therefore, it can be beneficial to differentiate the symmetric movement from the initial position into two rotational directions by utilizing two axial movement elements. The bearing functionality of the axial release assembly allows to keep the friction low during the relative movement of the included parts (e.g. rotational element, axial movement elements, rolling bodies). The axial release assembly and all included parts are easier to manufacture compared to the spindle configuration used in other configurations. The axial release assembly as disclosed herein allows a non-linear relationship between the rotational movement and the axial movement. In the axial release assembly of the present disclosure, the axial force can be distributed among the rolling bodies (e.g. 10 rolling bodies each take 1 / 10 of the axial force acting on the rolling body). According to some embodiments of the present disclosure, and without limitation, the axial release assembly can be manufactured from metal (e.g. steel), ceramic, alloy, plastic / synthetic material, composite material, etc. Additionally, for example, in some embodiments, the inclined surface can be coated or hardened. Additionally, in some embodiments, different components of the axial release assembly can be manufactured by additive manufacturing.

[0080] For example, turning now to Figure 10 , a schematic view of a portion of an axial release assembly 1000 according to embodiments of the present disclosure is shown. Figure 10 A configuration of a rotational element 1002 that can be employed in various embodiments of the present disclosure is shown. The rotational element 1002 can be operably connected to a motor rotor or motor stator of a drive system of a pulser assembly and can be rotatably driven thereby. As shown, the rotational element 1002 includes an inclined surface 1004 on which, in this embodiment, primary rolling bodies 1006 can roll or move, as described above. The axial release assembly 1000 can be located in a housing (not shown) of the pulser assembly (e.g. a pulser housing). The rotational element 1002 is configured to move rotationally relative to the pulser housing while preventing axial movement (e.g. a locking element is used for rotational movement, as shown). The pulser assembly can include or define a longitudinal axis 1012, also referred to as a central axis, as described above. The longitudinal axis 1012 defines an axis of rotational symmetry of the axial release assembly 1000. Figure 7 The axial release assembly 1000 can include or define a longitudinal axis 1012, also referred to as a central axis, as described above. The longitudinal axis 1012 defines an axis of rotational symmetry of the axial release assembly 1000.

[0081] In this configuration, the axial release assembly 1000 includes two axial moving elements, where a first axial moving element 1008 is arranged adjacent to the rotating element 1002, and a second axial moving element 1010 is arranged adjacent to the first axial moving element 1008. The rotating element 1002 and the second axial moving element 1010 are arranged on opposite axial sides (e.g., along the axis 1012) relative to the first axial moving element 1008. Thus, the first axial moving element 1008 is positioned between the rotating element 1002 and the second axial moving element 1010. The first axial moving element 1008 is configured to move rotationally and axially relative to the pulser housing (e.g., without a locking element). The second axial moving element 1010 is configured to move axially relative to the pulser housing while preventing rotational movement relative to the pulser housing (e.g., using a locking element for rotational movement, as shown). Figure 7 The axial release assembly 1000 can provide bi-directional axial movement based on axial movement of the two axial moving elements (i.e., along the axis 1012). The axial release assembly includes a central passageway. The central passageway extends along the axis A x The central passageway passes through the rotating element, the first axial moving element, and the second axial moving element. The motor rotor or, alternatively, a drive shaft can extend through the central passageway connecting the valve rotor with the motor. As such, the axial release assembly can be configured to enclose the motor rotor or drive shaft.

[0082] In operation, the axial release assembly 1000 is configured such that an axial distance between the rotating element 1002 and the second axial moving element 1010 and / or the first axial moving element 1008 is increased / decreased by different axial moving elements 1008, 1010 as a result of positive (+) and / or negative (-) rotational direction of the rotating element 1002 about the central axis 1012. In some configurations, as shown, the first axial moving element 1008 and the rotating element 1002 define a first axial moving pair 1014, and the first axial moving element 1008 and the second axial moving element 1010 define a second axial moving pair 1016. The inclined surface 1004 in the rotating element 1002 is on an axial side (axis 1012) of the rotating element 1002 facing the first axial moving element 1008.

[0083] The rotating element 1002 has an end stop 1018 configured to impart positive (+) applied torque to the first axial movement element 1008. The torque can originate from a drive system or motor of the pulser assembly operably connected to the rotating element 1002, as described above. The rolling body 1006 is movable along the inclined surface 1004 and is disposed to move freely within a slot (not shown) in the first axial movement element 1008. The slot in the first axial movement element 1008 is on a side of the first axial movement element 1008 facing the rotating element 1002. The first axial movement element 1008 includes a corresponding end stop 1020 configured to engage with the end stop 1018 of the rotating element 1002. The end stop 1020 is on an axial side of the first axial movement element 1008 facing the rotating element 1002 and includes end stop surfaces 1020a, 1020b. The end stop 1018 is on an axial side of the rotating element 1002 facing the first axial movement element 1008 and includes end stop surfaces 1018a, 1018b. The end stops 1018, 1020 engage when the rotating element 1002 is rotated in the positive (+) rotational direction. As the rotating element 1002 is rotated, the end stop 1018 of the rotating element 1002 will contact and pass through the end stop 1020 of the first axial movement element 1008 to impart or transfer torque to the first axial movement element 1008, thereby causing the first axial movement element 1008 to rotate about the central axis 1012. That is, in this operation, the end stop surfaces 1018a, 1020b will contact for force transmission. Figure 10 A positive force transmission line 1021 is shown in the middle.

[0084] The first axial movement element 1008 comprises a respective inclined surface 1022 on which a rolling body 1024 is arranged. The inclined surface 1022 of the first axial movement element 1008 is on the axial side of the axial movement element 1008 facing the second axial movement element 1010. The rolling body 1024 is movable along the inclined surface 1022 and is arranged to move freely within a slot (not shown) of the second axial movement element 1010, as described above. The slot of the second axial movement element 1010 is arranged on the axial side of the second axial movement element 1010 facing the first axial movement element 1008. In the initial position, the rolling bodies 1006, 1024 are at the lowest points of the inclined surfaces 1004, 1022, respectively. The rolling body 1024 is movable along the inclined surface 1022 to move the inclined surface 1022 upwards when the first axial movement element 1008 is rotated by rotation of the rotation element 1002 and by torque transmission rotation through the end stop surfaces 1018a, 1020b. The rolling body 1024 moving along the inclined surface 1022 moves the second axial movement element 1010 axially away from the first axial movement element 1008 and the rotation element 1002. Thus, the second axial movement pair 1016 will extend. Rotation of the rotation element 1002 and the axial movement element 1008 stops when the end stops 1026 and 1028 make contact at the end stop surfaces 1026a, 1028b, and the rolling body 1024 reaches the highest point on the inclined surface 1022. In this state, the axial release assembly 1000 is fully extended, and the second axial movement pair 1016 is fully extended. As the end stops 1018, 1020 between the first axial movement pair 1014 are engaged and the end stops 1026, 1028 between the second axial movement pair 1016 are engaged, there can be no further relative rotation between the rotation element 1002, the first axial movement element 1008 and the second axial movement element 1010 in the positive (+) direction. Thus, the second axial movement element 1010 can be moved axially along the central axis 1012 by means of the rotation element 1002 and the interaction of its end stops 1018, 1020 when the first axial movement element 1008 is rotated. The end stop 1026 is on the axial side of the first axial movement element 1008 facing the second axial movement element 1010. The end stop 1028 is on the axial side of the second axial movement element 1010 facing the first axial movement element 1008.

[0085] Rotating the rotating element 1002 into the negative (-) rotational direction releases the contact between the end stop surfaces 1018a, 1020b of the end stops 1018, 1020. Due to the force exerted by the biasing member or the weight of the second axial movement element 1010 (e.g., gravity), the rolling body 1024 moves down the inclined surface 1022 and the second axial movement element 1010 moves axially back towards the first axial movement element 1008 and the rotating element 1002. The rolling body 1024 moving down the inclined surface 1022 rotates the first axial movement element 1008 in the negative (-) rotational direction after the rotating element 1002 is rotated in the negative (-) direction. When the rolling body 1024 reaches the lowest point of the inclined surface 1022 of the first axial movement element 1008, the end stops 1026, 1028 make contact at the end stop surfaces 1026b, 1028a. Thus, the axial release assembly 1000 returns to its initial position and fully retracts. The second axial movement pair 1016 fully retracts. When the rotating element 1002 is moved from the initial position into the negative (-) rotational direction, the rolling body 1006 between the rotating element 1002 and the first axial movement element 1008 moves up the inclined surface 1004 from the lowest point on the inclined surface 1004 of the first axial movement element 1008. The required torque (negative direction) is established via the negative force transmission lines 1023 through the end stop surfaces 1026b, 1028a of the first and second axial movement elements 1008, 1010, respectively. The first axial movement element 1008 moves axially away from the rotating element 1002 and so does the second axial movement element 1010. When the rolling body 1006 reaches the highest point on the inclined surface 1004, the end stops 1018, 1020 engage and the end stop surfaces 1018b, 1020a make contact. Thus, the axial release assembly 1000 fully extends. The first axial movement pair 1014 fully extends. Due to the engagement of the end stops 1018, 1020 between the first axial movement pair 1014 and the engagement of the end stops 1026, 1028 between the second axial movement pair 1016, there can be no further relative rotation in the negative (-) direction between the rotating element 1002, the first axial movement element 1008, and the second axial movement element 1010.

[0086] The rotating element 1002 is rotated in the positive (+) direction to release contact between the contact surfaces 1026b, 1028a. Due to gravity (e.g., the weight of the first axial movement element 1008 and the second axial movement element 1010) or force applied by a biasing member, the rolling body 1006 moves down the inclined surface 1004. When the end stop surfaces 1018a, 1020b come into contact, the first axial movement element 1008 moves axially rearward toward the rotating element 1002, and so does the second axial movement element 1010, until the rolling body 1006 reaches the lowest position on the inclined surface 1004. The axial release assembly 1000 returns to the initial position and fully retracts, with Figure 10 The depicted exemplary state of the axial release assembly. The first axial movement pair 1014 is fully retracted. In the initial position, the first axial movement pair 1014 and the second axial movement pair 1016 are fully retracted, with only one of the axial movement pairs 1014 and 1016 fully extended in the fully retracted position of the axial release assembly 1000.

[0087] Due to the rotational movement of the first axial movement element 1008, in this configuration, the first axial movement element 1008 can not be constrained in the rotational direction (e.g., thus, lacking a keyway configuration with respect to rotatable with the housing, as described above). However, the second axial movement element 1010 can not rotate, and thus, can include a key or other rotational stop that engages with the housing of the pulser assembly, as described above. The rotating element 1002, the first axial movement element 1008, and the second axial movement element 1010 share a single central axis 1012 (e.g., a rotational axis). The end stop surfaces 1018a, 1020b, 1018b, 1020a, 1028a, 1026b, 1028b, 1026a of the components are parallel to each other. The central axis 1012 can be perpendicular to the surface normal of the plane defined by the end stop surfaces 1018a, 1020b, 1018b, 1020a, 1028a, 1026b, 1028b, 1026a.

[0088] In some embodiments, the end stop surfaces can be angled relative to the central axis 1012. The surface normal of the end stop surfaces can have an angle relative to the central axis 1012 that is different from 90°. In some such embodiments, the angled end stop surfaces can provide effective torque transfer from one end stop to an adjacent end stop. The angle of the angled end stop surfaces can correspond to the slope of the inclined surface on the corresponding element (e.g., a rotating element or an axially moving element) such that the force on the end stop element is perpendicular to the end stop surface. Such angled end stop surfaces on the end stop can be on the end stop side that transmits torque (e.g., torque transmission lines 1021, 1023). In some alternative embodiments, both sides of the end stop can include angled end stop surfaces. Referring again to Figure 10 , the base 1029 of the end stop (i.e., the connection to the axially moving element or the rotating element) can not have sharp edges or corners (as shown), but can include a rounded, faceted, or curved transition (e.g., one or more radii) of the bulk material from the end stop to the associated component / element. Figure 10 The axial release assembly 1000 in FIG. 10 includes one rotating element and two axially moving elements. However, in other embodiments of the present disclosure, the axial release assembly can have more than two axially moving elements (e.g., 3, 4, 5, 6, or more) and / or more than two axially moving pairs (e.g., 3, 4, or more). In other embodiments, the axial release assembly of the present disclosure can have more than one rotating element (e.g., 2 or more). In some embodiments, the axial release assembly can not include an axial release assembly housing. The axial movement of portions of the axial release assembly 1000 can be limited by components of the pulser assembly in which the axial release assembly can be located (e.g., such as locking elements or biasing members). The lateral movement of portions of the axial release assembly (e.g., the rotating element, the first and second axially moving elements, the rolling body, etc.) relative to each other can be limited by the shape of the slot and the shape of the inclined surface 1004, 1022. The rolling body 1024 placed in the slot and on the inclined surface is configured to limit the lateral movement of the portions of the axial release assembly relative to each other. In alternative embodiments, the movement (e.g., axial and lateral movement) of different portions of the axial release assembly relative to each other can be limited by a cage (e.g., a housing) or similarly acting features, structures, or mechanisms.

[0089] Turning now to Figure 11 , a schematic diagram of a pulser assembly 1100 according to the present disclosure is shown. The pulser assembly 1100 includes a valve rotor 1102 that is (rotationally) movable relative to a valve stator 1104. The valve rotor 1102 can be configured to selectively block one or more flow passages of the valve stator 1104, as described above. In Figure 11In this configuration, the valve stator 1104 is arranged upstream of the valve rotor 1102. The valve rotor 1102 can be driven by a motor 1106 in an oscillating manner (compared to full rotation). The motor 1106 can be an electric motor that drives a drive shaft 1108 operatively coupled to the valve rotor 1102 and drives the oscillating motion of the valve rotor 1102. The motor 1106 and drive shaft 1108 are contained within a pulser housing 1112, which protects such components (and other components) from the effects of drilling fluid along and through the pulser assembly 1100, as described above. A torsion spring can be operatively coupled to the drive shaft 1108, which can be housed within the pulser housing 1112, as shown and as described above. As shown, the motor 1106 includes a motor stator 1114 and a motor rotor 1116, wherein the motor rotor 1116 is operatively coupled to the drive shaft 1108. The pulser assembly 1100 can be included in a downhole tool. Such downhole tools include a tool housing (not shown) that may contain a pulser assembly 1100. The tool housing and the pulser assembly may share the same central axis H. x A x Central axis A x H x These can be the rotational symmetry axes of the tool housing and the pulser housing 1112, respectively. Between the pulser housing 1112 and the tool housing can be an annular space allowing drilling fluid to flow around the pulser assembly 1100. In some embodiments, the central axis H... x A x They don't have to overlap.

[0090] Arranged between the motor 1106 and the rotor 1102 is an axial release assembly 1118. The axial release assembly 1118 may be similar to... Figure 10 The axial release assembly shown and described has a rotating element 1120, a first axial moving element 1122, and a second axial moving element 1124. The rotating element 1120 is coupled to the motor 1106 via a bearing 1126 (e.g., a radial bearing). The bearing 1126 enables the motor stator 1114 of the motor 1106 to be mounted within the pulser housing 1112.

[0091] As described above, the motor stator 1114 is mounted in the pulser housing 1112 by bearings 1126. If the motor stator 1114 rotates, the rotation is transmitted to the axial release assembly 1118, which produces axial movement, as described above. The axial movement of the axial release assembly 1118 will cause the drive shaft mount 1128 (e.g., a radial bearing) to move in the axial direction (i.e., downstream toward the valve rotor 1102). The axial movement of the drive shaft mount 1128 will cause the drive shaft 1108 to move axially. Thus, the axial movement of the drive shaft 1108 will cause the valve rotor 1102 to move axially. As such, the axial valve gap between the valve stator 1104 and the valve rotor 1102 can be adjusted or otherwise controlled. To achieve the axial movement of the drive shaft 1108, the motor rotor 1116 and the drive shaft 1108 can be freely coupled axially by a slipper 1130, thereby axially decoupling the motor rotor 1116 and the drive shaft 1108. The slipper 1130 allows torque to be transmitted from the motor rotor 1116 to the drive shaft 1108 while allowing axial movement between the motor rotor 1116 and the drive shaft 1108. In this illustrative embodiment, the axial movement of the drive shaft 1108 can be constrained or biased by a biasing member 1132 (e.g., a drive shaft spring).

[0092] According to embodiments of the disclosure, the biasing member 1132 can bias movement of the drive shaft 1108 in the axial direction to increase the valve gap or can bias movement of the drive shaft 1108 in the axial direction to decrease the valve gap. The drive shaft 1108 extends through the valve stator 1104. A radial bearing (not shown) between the drive shaft 1108 and the valve stator 1104 can facilitate relative rotation between the drive shaft 1108 and the valve stator 1104. A drive shaft seal 1131 between the valve stator 1104 and the drive shaft 1108 can seal an interior space within the pulser housing 1112 from drilling mud entering from a downstream end of the pulser assembly 1100. On an upstream end of the pulser assembly 1100, another seal (not shown) can seal a space inside the pulser housing 1112 from drilling mud entering from the upstream end of the pulser assembly 1100. The seal on the upstream end can be included in a flow diverter (not shown) that redirects drilling mud flowing through an inner bore of a tubular drill or BHA to pass through the pulser assembly 1100 through an annular space between the pulser housing 1112 and a tool housing. In some embodiments, the flow diverter can secure the uphole end of the pulser assembly to the tool housing to prevent radial and axial movement of the pulser assembly relative to the tool housing.

[0093] If a torque is applied to the drive system (e.g., motor 1106), the torque can be transmitted to the drive shaft 1108 and the axial release assembly 1118. The torque can be applied to the motor stator 1114 of the motor 1106 as the particles in the drilling mud block the valve and the rotation of the motor rotor 1116. The motion behavior can depend on the stiffness of the drive shaft spring 1132 and the transmission ratio (e.g., slope of the inclined surface, axial movement per angular displacement angle (mm / angle)) of the axial release assembly 1118, a torsion spring (not shown) operably connected to the motor rotor 1116 and / or the drive shaft 1108, the load (torque) on the valve rotor, and the position of the valve end stop 1134 that constrains the rotational movement of the drive shaft 1108. If a torque is applied to the motor stator 1114 that is rotatably freely mounted in the pulser housing 1112, the motor stator can rotate in the positive (+) rotational direction relative to the pulser housing 1112 and transmit the rotation in the positive (+) rotational direction through the bearing 1126 to the rotating element 1120. The rotating element 1120 rotates from an initial position to the positive (+) rotational direction. As described with respect to Figure 10 The positive (+) rotational direction of the rotating element 1120 extends the second axial release assembly 1118 and moves the second axial movement element 1124 axially (e.g., in the positive (+x) direction) relative to the pulser housing 1112. The axial movement of the second axial movement element 1124 is transmitted through the drive shaft mount 1128 to the drive shaft 1108. The drive shaft 1108 moves axially in the downstream direction (+x) and the valve gap between the valve rotor 1102 and the valve stator 1104 increases by a distance that depends in part or entirely on the angular displacement angle of the rotating element 1120 relative to the pulser housing 1112 (maximum axial extension of the axial release assembly). The valve gap increases and the oscillating particles blocking the valve rotor 1102 are released and flushed away by the flowing drilling mud (not shown). If a torque is applied to the motor stator 1114 in the negative (-) rotational direction, the motor stator 1114 rotates in the negative (-) rotational direction relative to the pulser housing 1112 and transmits the rotation in the negative (-) rotational direction through the bearing 1126 to the rotating element 1120. The rotation of the rotating element 1120 in the negative (-) rotational direction extends the first axial movement element 1122 and moves the second axial movement element 1124 axially (+x) relative to the pulser housing. The valve gap increases and the oscillating particles blocking the valve rotor 1102 are released and flushed away by the flowing drilling mud. In this embodiment, the second axial movement element 1124 can be rotationally locked with the pulser housing 1112.

[0094] Therefore, an oscillation system (e.g., pulser assembly 1100) is realized that achieves both rotational oscillation (via motor 1106) and axial movement (via axial release assembly 1118). Coupling of oscillation with torque on the system (e.g., drive shaft and / or motor stator) is provided. This configuration can be used to prevent blockage of the valve rotor-stator assembly, as increasing the torque increases the gap between valve stator 1104 and valve rotor 1102. As the gap increases, trapped particles or other debris can be released from between stator 1104 and valve rotor 1102. The amount of torque coupled with the axial movement of motor stator 1114 and drive shaft 1108, and with the increase in valve gap, can be adjusted by parameters of bias element 1132 (e.g., drive shaft spring constant). The sensitivity of the valve gap change to the increase in torque on motor stator 1114 can be adjusted by adjusting bias element 1132.

[0095] In some implementations, the system can be configured to increase the clearance between the valve rotor and the valve stator based on predefined torque or angular limits. For example, in steering... Figure 12 A schematic diagram of a pulser assembly 1200 according to this disclosure is shown. The pulser assembly 1200 includes a valve rotor 1202 that is (rotatably) movable relative to a valve stator 1204. The valve rotor 1202 can be configured to selectively block one or more flow passages in the valve stator 1204, as described above. Figure 12 In this configuration, the valve stator 1204 is arranged upstream of the valve rotor 1202. The valve rotor 1202 can be driven oscillatingly by a motor 1206. The motor 1206 can be an electric motor that drives a drive shaft 1208 operatively coupled to the valve rotor 1202 to achieve and drive the oscillating motion of the valve rotor 1202. The drive shaft 1208 can be connected to the pulser housing 1212 via a bearing 1209 (e.g., a radial bearing). The motor 1206 and the drive shaft 1208 are contained within the pulser housing 1212, which protects such components (and other components) from the effects of drilling fluid along and through the pulser assembly 1200, as described above. In this embodiment, a clutch assembly 1210 can be operatively coupled to the drive shaft 1208, and this clutch assembly can be housed within the housing 1212. As shown in the figure, motor 1206 includes a motor stator 1214 and a motor rotor 1216, wherein the motor rotor 1216 is operatively coupled to a drive shaft 1208. An axial release assembly 1218 is arranged to allow axial movement of the valve rotor 1202 relative to the valve stator 1204, as shown and as described above. In this embodiment, the axial release assembly 1218 is configured similar to... Figure 10 and Figure 11The axial release assembly shown, but other configurations of the axial release assembly can be employed without departing from the scope of the present disclosure. The motor stator 1214 can be substantially fixedly connected to the housing 1212, and the clutch assembly 1210 can be configured to selectively disengage the fixed connection between the motor stator 1214 and the housing 1212.

[0096] In Figure 12 In the configuration shown, the axial release assembly 1218 is linked with (i.e., through the motor stator 1214) a torque control unit 1220 that includes the clutch assembly 1210. This configuration enables a separation of functions of the pulser assembly 1200. That is, the operation for generating pressure pulses can be decoupled or disengaged from the function for releasing the valve (i.e., increasing the gap between the valve rotor 1202 and the valve stator 1204). The torque control unit 1220 can be adjusted or set to a predefined torque value to activate and / or operate the clutch assembly 1210. When the operating torque is below the predefined torque value, the axial release assembly 1218 is disengaged and cannot cause axial movement of the valve rotor 1202. However, when the operating torque exceeds the predefined torque value, the clutch assembly 1210 can engage, thereby disengaging the motor stator 1214 from the housing 1212 and engaging the motor stator 1214 with the axial release assembly 1218. Thus, in this case, the operating torque can be transmitted to both the drive shaft 1208 and the axial release assembly 1218.

[0097] As noted, the torque control unit 1220 includes a clutch assembly 1210, which can be a torque-dependent clutch assembly. The clutch assembly 1210 is connected with the motor stator 1214 through a link element 1222. The link element 1222 can be rotationally connected to the pulser housing 1212 through a bearing 1223 (e.g., a radial bearing). To ensure the motor stator 1214 returns to the home position, one or more bi-directional springs 1224, 1226 are incorporated into the torque control unit 1220 following a release cycle (i.e., clutch activation and axial extension) at a defined angular position relative to the drive shaft 1208. The bi-directional springs 1224, 1226 can be connected with the link element 1222, the motor stator 1214, or other elements of the motor 1206. If the motor stator 1214 rotates, one of the bi-directional springs 1224, 1226 will compress toward a spring end stop element 1228, which in turn is part of or connected to the housing 1212. The bi-directional springs 1224, 1226 are configured to generate a counter or opposing force that pushes the motor stator 1214 back to the home position (i.e., when the operating torque does not exceed a predefined torque value). According to some embodiments of the present disclosure, the predefined torque value can be between 5 Nm and 20 Nm. In some embodiments, the predefined torque value can be between 8 Nm and 15 Nm. In yet other embodiments, the predefined torque value can be between 9 Nm and 11 Nm.

[0098] The torque dependent clutch assembly 1210 can comprise a ball disc 1230 with one or more recesses to hold a ball 1232, for example. The ball disc 1230 can be firmly connected to the motor stator 1214 and / or the link element 1222. A ball carrier 1234 is arranged with holes to enable the ball 1232 to slide through the holes of the ball carrier 1234 to a disc 1236. The disc 1236 has a spring force applied to it. The spring force applied to the disc 1236 of the clutch assembly 1210 can be provided by a plate spring 1238. The plate spring 1238 can be a pre-compression spring pre-compressed by a nut 1240 carried by or threadedly attached to the ball carrier 1234. The nut 1240 and / or the ball carrier 1234 can be supported by a ball carrier support 1235. The ball carrier support 1235 can be firmly connected to the pulser housing 1212. In the locked position, the ball 1232 is pressed into the recess in the ball disc 1230. However, if the operating torque increases to a value that exceeds a predefined torque value, the ball 1232 will exert a force in axial direction that exceeds the spring force of the plate spring 1238, the ball 1232 will slide through or past the holes in the ball carrier 1234. With the ball 1232 disengaged from the ball carrier 1234, the ball disc 1230 can freely rotate. In some embodiments, to ensure that the operation occurs in a certain position / angle, the recesses in the ball disc 1230 can be designed such that one ball 1232 can only move into one recess of the ball disc 1230 per rotational direction. In some embodiments, the clutch assembly 1210 can be located uphole relative to the motor 1206. In other embodiments, the clutch assembly 1210 can be located downhole relative to the motor 1206.

[0099] In addition to providing a torque dependent axial movement mechanism (or as an alternative thereto), embodiments of the present disclosure can be angle dependent. For example, the steering Figure 13 A schematic diagram of a pulser assembly 1300 according to the present disclosure is shown. The pulser assembly 1300 comprises a valve rotor 1302 that is (rotationally) movable relative to a valve stator 1304. The valve rotor 1302 can be configured to selectively block one or more flow passages of the valve stator 1304. In Figure 13In the configuration shown and described, the valve stator 1304 is disposed upstream of the valve rotor 1302. The valve rotor 1302 can be driven in an oscillating manner by a motor 1306. The motor 1306 can be an electric motor that drives a drive shaft 1308 that is operably coupled to the valve rotor 1302 and effects and drives oscillating motion of the valve rotor 1302. The motor 1306 and drive shaft 1308 are contained within a pulser housing 1310 that protects such components (and other components) from drilling fluid flowing along and through the pulser assembly 1300. In this embodiment, an axial release assembly 1312 is disposed within the pulser housing 1310 and is configured to effect adjustment of the gap between the valve rotor 1302 and the valve stator 1304, as described above. In this illustrative configuration, the axial release assembly 1312 is disposed in a bi-directional configuration that is similar to that described with respect to Figures 10-11 the bi-directional configuration shown and described.

[0100] The axial release assembly 1312 is operably coupled to the drive shaft 1308 to cause axial movement of the drive shaft 1308 and the valve rotor 1302. As shown, the motor 1306 includes a motor stator 1314 and a motor rotor 1316, with the motor rotor 1316 being operably coupled to the drive shaft 1308. In this embodiment, as described above, the axial release assembly 1312 is configured similar to Figure 10 and Figure 11 the axial release assembly shown, although other configurations of the axial release assembly can be employed without departing from the scope of the present disclosure.

[0101] The axial release assembly 1312 is connected with the drive shaft 1308 to provide angularly related movement of the valve rotor 1302 in the negative axial direction (-x) (i.e., toward the valve stator 1304, and thus, decreasing the valve gap therebetween). In the initial position of the valve opening (i.e., when the valve rotor 1302 is not blocking or obstructing the valve stator 1304), there is an axial valve gap between the valve rotor 1302 and the valve stator 1304. As the drive shaft 1308 rotates, the valve rotor 1302 closes or obstructs the flow passages of the valve stator 1304. In synchronization with this rotation, the bi-directional axial release assembly 1312 is configured to produce axial movement in the negative axial direction (i.e., the valve rotor 1302 will move toward the valve stator 1304). Thus, and as a result of this, as the degree of closure of the valve increases, the axial valve gap between the valve rotor 1302 and the valve stator 1304 decreases (i.e., as the valve rotor 1302 increases the obstruction of the flow path of the valve stator 1304). Thus, in this embodiment, the initial valve gap between the valve rotor 1302 and the valve stator 1304 can be set to a sufficiently large valve gap to prevent debris or other particles from plugging or obstructing. A small valve gap can be used to produce sufficient pressure drop when the valve rotor 1302 is near the angular end position (i.e., full range of drive oscillation, the flow passages of the valve stator are partially or completely closed). If debris plugging occurs when the valve rotor 1302 is at full range, a relatively small angular rotation of the valve rotor 1302 back toward the initial position will automatically increase the axial valve gap between the valve rotor 1302 and the valve stator 1304, and thus, will release any trapped debris or particles.

[0102] In this illustrative configuration, the bi-directional axial release assembly 1312 includes a rotating element 1318, a first axial movement element 1320, and a second axial movement element 1322 (e.g., similar to the Figures 10-11 shown and described). However, in this embodiment, the second axial movement element 1322 is fixedly connected to the pulser housing 1310. The first axial movement element 1320 and the second axial movement element 1322 have slots that receive the rolling bodies, as described above. The rotating element 1318 is rotationally connected with the drive shaft 1308 (e.g., by a key connection 1324). In the axial direction, the rotating element 1318 (and thus the axial release assembly 1312) is supported by a shoulder 1326 of the drive shaft 1308. If the drive shaft 1308 rotates, the rotating element 1318 interacts with the first axial movement element 1320 of the axial release assembly 1312, and causes movement of the rotating element 1318 in the negative axial direction (-x) as a result of the movement of the rolling bodies on the inclined surfaces of the rotating element 1318 and the first axial movement element 1320, as described above. In some embodiments, and as Figure 13As shown, the motor 1306 can be held in a fixed axial position by coupling the slide 1328 between the drive shaft 1308 and the motor rotor 1316. The slide 1328 is comprised of two parts 1328a, 1328b. The first part 1328a of the slide 1328 is connected to the motor rotor 1316 (e.g., motor rotor slide part), and the second part 1328b of the slide 1328 is connected to the drive shaft 1308 (e.g., drive shaft slide part).

[0103] In some embodiments, to ensure that the axial release assembly 1312 stays together in all positions and operations, a flexible holding member 1330 (e.g., spring) can be employed (axially) between the pulser housing 1310 and the rotating element 1318 of the axial release assembly 1312. With respect to Figure 13 The described concepts can work well with so-called close-to-close pulser. Close-to-close pulser is also known as normally open pulser. An example of such close-to-close pulser is described in U.S. Patent Application No. 17 / 126,984, filed December 18, 2020, entitled “Oscillating Shear Valve for Mud Pulse Telemetry and Operation Thereof,” which is commonly owned, and the contents of which are incorporated herein in their entirety.

[0104] In the close-to-close pulser configuration, and continuing to refer to Figure 13 The valve rotor 1302 oscillates between two closed positions (i.e., stator passages are closed or blocked by rotor vanes). The reversal points in the oscillating movement of the valve rotor 1302 are at the closed positions. The open position of the valve is reached during the transition between the two closed positions. The closed positions correspond to the extended position of the axial release assembly 1312, and the valve gap is reduced or is at a minimum. The open position corresponds to the initial position of the axial release assembly 1312, and the valve gap is increased or is at a maximum. In an alternative embodiment, the closed positions correspond to the retracted position of the axial release assembly, and the open position corresponds to the extended position of the axial release assembly. Figure 13 The illustrated system can be modified to serve an open-to-open pulser. In the open-to-open pulser, again referring to Figure 13, the valve rotor 1302 oscillates between two open positions. The reversal points in the oscillating movement of the valve rotor are at the open positions. The closed position of the valve is reached during the transition between the two open positions. In yet another embodiment, the initial position can be a half-closed valve position (e.g., the stator channels are half obstructed by the rotor blades). From the initial half-closed position, the valve rotor rotates in the positive (+) rotational direction to the closed position. From the closed position, the valve rotor rotates in the negative (-) rotational direction to the initial position (half-closed position). The valve rotor continues to rotate in the negative (-) rotational direction to the valve open position. At the valve closed position, the valve gap should be a minimum value.

[0105] At the initial position and at the open position, the valve gap should be a maximum value. To achieve such a gap variation with the oscillating valve rotor 1302, the inclined surface on the rotating element 1318 or the inclined surface on the first axial movement element 1320 can be flat without a slope. The inclined surface on the rotating element or the first axial movement element can be not inclined but a flat surface. The inclined surface on the other one of the rotating element and the first axial movement element can have a slope and can not be flat.

[0106] In some embodiments, instead of coupling the rotation of the rotating element with the rotational movement of the motor stator or motor rotor (or drive shaft) in the pulser assembly, the rotation required for the extended axial release assembly can be provided by a gap release motor. The gap release motor can be coupled to the rotating element of the axial release assembly and configured to drive the rotation of the rotating element. That is, the motor rotor or motor stator of the gap release motor can be operatively coupled to the rotating element. In some embodiments, the gap release motor can be an electric motor. The gap release motor can be controlled by a processor or other controller. The processor can be coupled to a torque sensor. The torque sensor is configured to measure the torque on the motor rotor or motor stator of the pulser motor. Depending on the torque measured by the torque sensor, the gap release motor is configured to start the rotation of the rotating element to change the valve gap (e.g., increase, decrease). In alternative embodiments, the processor can monitor the power consumption of the pulser motor and can be configured to rotate the rotating element depending on the power consumption and / or current consumption of the pulser motor. Both (i) the torque on the motor rotor or motor stator of the pulser motor and (ii) the power or current consumption of the pulser motor are related to the torque acting on the valve rotor in the pulser assembly. Thus, the rotation provided to the rotating element by the gap release motor depends on the torque on the valve rotor.

[0107] Angle-dependent systems (e.g., as with respect to Figure 13The described method can be used to regulate the pressure drop across the pulser assembly. Typically, a defined characteristic curve exists between the pressure drop and the angular position of the valve rotor relative to the valve stator (e.g., the amount of opening in the flow path through the valve stator). However, the shape of this curve depends in part on the axial valve clearance between the valve rotor and the valve stator. Because embodiments of this disclosure allow for adjustment of the axial valve clearance during operation, additional control over the pressure drop is achieved. That is, by adjusting the axial valve clearance based on rotation, the pressure drop can be freely adjusted within a static curve for two different valve clearance sizes (e.g., small valve clearance, large valve clearance) (i.e., a controlled adjustable valve clearance).

[0108] This is Figures 14A-14B This is illustrated illustratively. Figure 14A On graph 1400, curves 1402 for the large valve clearance and 1404 for the small valve clearance are shown at a specific flow rate (l / min). As shown, for both curves 1402 and 1404, the pressure drop increases when the valve is closed (i.e., the valve rotor blocks more flow paths through the valve stator). However, for each of curves 1402 and 1404, the curve is primarily dependent on the angular displacement angle (e.g., angular position) of the valve rotor and / or drive shaft. In contrast, variable pressure drop, as indicated by curve 1406, can be achieved by implementing an axial release assembly within the pulser assembly, as shown and as described above, representing a shaped valve clearance adjusted based on angular position. Figure 14B The corresponding valve clearance size is shown in the figure. Here, the pressure drop also depends on the valve clearance.

[0109] The quality of the pressure wave transmitted downhole depends on the shape of the transition curve over time between two pressure levels, such as... Figure 14C As shown. Figure 14C Two transitions are illustrated, namely, transition 1 and transition 2. For example, a sinusoidal shape can improve signal quality. Typically, the transition curves of a system with a fixed valve gap are adjusted by the time-dependent shape of the drive cycle. This is further affected by the system's inertia, static torque, and hysteresis and acceleration characteristics. However, as described herein, using valve gap size adjustment as an additional degree of freedom can harmonize the characteristics of the drive system (e.g., a motor) with the valve rotor and valve stator system and can be used to improve signal quality.

[0110] Although the embodiments described herein have been described with reference to specific accompanying drawings, it should be understood that various changes may be made and equivalents may be substituted for elements therein without departing from the scope of this disclosure. Furthermore, many modifications will be made to adapt particular apparatus, situations, or materials to the teachings of this disclosure without departing from the scope of this disclosure. Therefore, it is contemplated that this disclosure is not limited to the specific embodiments disclosed, but rather will include all embodiments falling within the scope of the following description of the appended claims or possible embodiments.

[0111] Embodiment 1 : A pulser assembly configured to be positioned along a tubular string through which a drilling fluid flows, the pulser assembly comprising: a housing configured to be supported along the tubular string; a valve stator supported by the housing, the valve stator having at least one flow path extending from an upstream end to a downstream end of the valve stator; a valve rotor positioned adjacent the valve stator, the valve rotor configured to selectively block the at least one flow path, wherein an axial gap exists between the valve rotor and the valve stator; a motor operably coupled to the valve rotor, wherein the motor is operable to rotate the valve rotor relative to the valve stator; and an axial release assembly comprising a rotating element configured to adjust the axial gap between the valve rotor and the valve stator based on rotation of the rotating element.

[0112] Embodiment 2: The pulser assembly according to any preceding embodiment, wherein the axial release assembly further comprises: an axially moving element, wherein rotation of the rotating element relative to the housing causes axial movement of the axially moving element.

[0113] Embodiment 3: The pulser assembly according to any preceding embodiment, further comprising a biasing element configured to bias the axial movement of the axially moving element.

[0114] Embodiment 4: The pulser assembly according to any preceding embodiment, wherein the axial release assembly further comprises at least one rolling body disposed between the rotating element and the axially moving element.

[0115] Embodiment 5: The pulser assembly according to any preceding embodiment, wherein: one of the rotating element and the axially moving element comprises at least one inclined surface, and the other of the rotating element and the axially moving element comprises at least one slot, and the at least one rolling body is disposed within the at least one slot and is configured to freely roll within the at least one slot along the at least one inclined surface.

[0116] Embodiment 6: The pulser assembly according to any preceding embodiment, wherein the at least one inclined surface comprises a symmetrical configuration comprising two peaks and an inflection point located between the two peaks.

[0117] Embodiment 7: The pulser assembly according to any preceding embodiment, wherein the rotating element comprises a first end stop and the axially moving element comprises a second end stop, wherein the first end stop and the second end stop are configured to limit an amount of rotation of the rotating element relative to the axially moving element.

[0118] Embodiment 8: The pulser assembly of any preceding embodiment, wherein one of the rotating element and the axially moving element is axially constrained relative to the housing, and the other of the rotating element and the axially moving element is rotationally constrained relative to the housing.

[0119] Embodiment 9: The pulser assembly of any preceding embodiment, wherein the motor comprises a motor stator and a motor rotor.

[0120] Embodiment 10: The pulser assembly of any preceding embodiment, wherein the rotating element is coupled to the motor stator.

[0121] Embodiment 11: The pulser assembly of any preceding embodiment, wherein the rotating element is coupled to the motor rotor.

[0122] Embodiment 12: The pulser assembly of any preceding embodiment, further comprising a drive shaft operably connecting the motor to the valve rotor, wherein the axial release assembly is configured to adjust an axial position of the drive shaft to adjust an axial gap between the valve rotor and the valve stator.

[0123] Embodiment 13: The pulser assembly of any preceding embodiment, wherein the drive shaft is axially freely coupled to motor rotor by a slide.

[0124] Embodiment 14: The pulser assembly of any preceding embodiment, further comprising a clutch assembly configured to selectively operate the axial release assembly based on a torque applied to the valve rotor.

[0125] Embodiment 15: The pulser assembly of any preceding embodiment, wherein the axial release assembly is configured such that (i) rotation of the rotating element from an initial position in a first rotational direction and rotation of the rotating element from the initial position in a second rotational direction opposite the first rotational direction causes the axial gap to increase, or (ii) rotation of the rotating element from an initial position in a first rotational direction and rotation of the rotating element from the initial position in a second rotational direction opposite the first rotational direction causes the axial gap to decrease.

[0126] Embodiment 16: The pulser assembly of any preceding embodiment, wherein the axial release assembly comprises: a rotating element; a first axially moving element operably coupled to the rotating element; and a second axially moving element operably coupled to the first axially moving element; wherein rotation of the rotating element causes axial movement of at least one of the first axially moving element and the second axially moving element.

[0127] Embodiment 17: The pulser assembly of any preceding embodiment, wherein the axial release assembly is configured such that rotation of the rotating element from an initial position in a first rotational direction causes the first axial movement element to move axially relative to the rotating element, and rotation of the rotating element from the initial position in a second rotational direction opposite the first rotational direction causes the second axial movement element to move axially relative to the rotating element.

[0128] Embodiment 18: The pulser assembly of any preceding embodiment, further comprising a gap release motor configured to drive the rotation of the rotating element in dependence on a torque acting on the valve rotor.

[0129] Embodiment 19: A method for generating pulses in a drilling fluid, the method comprising: driving rotation of a valve rotor of a pulser assembly relative to a valve stator, wherein the pulser assembly comprises a housing, wherein a motor is arranged within the housing and configured to drive rotational movement of the valve rotor; and adjusting an axial gap between the valve rotor and the valve stator based on rotation of a rotating element using an axial release assembly comprising the rotating element.

[0130] Embodiment 20: The method of any preceding embodiment, wherein adjusting the axial gap comprises at least one of: increasing the axial gap during rotation of the rotating element from an initial position in a first rotational direction and increasing the axial gap during rotation of the rotating element from the initial position in a second rotational direction opposite the first rotational direction, and decreasing the axial gap during rotation of the rotating element from an initial position in a first rotational direction and decreasing the axial gap during rotation of the rotating element from the initial position in a second rotational direction opposite the first rotational direction.

[0131] The systems and methods described herein provide various advantages. For example, as compared to prior art systems and methods, the embodiments provided herein enable improved and more efficient data transmission through mud pulse telemetry. For example, more distinct and more easily reconstructable signals can be generated through the use of angularly dependent axial release assemblies. Additionally, advantageously, due to the axial movement of the valve rotor relative to the valve stator, debris and other particulates can be moved away or prevented from becoming stuck within the pulser assembly. Such axial movement can be correlated or coupled to the rotational angle of the valve rotor or to a torque within the system, such as a torque exerted to a motor stator of the pulser assembly. That is, torque dependent axial release assemblies are provided herein that provide advantages over various other pulser assemblies.

[0132] According to various embodiments of the present disclosure, an axial relief mechanism is implemented as part of a shear valve pulser. The axial relief mechanism enables an increase in the space (e.g., axial space or axial gap) between the valve rotor and the valve stator to allow material (e.g., particles) to flow therethrough. This increased gap or space can reduce or eliminate plugging or obstruction of fluid flow through the pulser assembly. According to some embodiments, the oscillation and axial movement are mechanically coupled through the axial relief mechanism / assembly, enabling a particular torque (or angle) to trigger axial movement of the valve rotor relative to the valve stator, and thus, an increase in the gap between the valve rotor and the valve stator (e.g., to dislodge stuck particles or other obstructions).

[0133] The axial gap provided by the axial relief assembly described herein can be continuously operable such that the axial gap changes with oscillation (i.e., direct and continuous coupling of the axial gap with the rotational movement). This configuration can enable tuning of the pulser assembly to different flow rates. For example, if there is low flow, a small initial gap is typically needed to create a pressure pulse, as otherwise there would be low pressure drop at low flow and only created if the valve is almost or fully closed. However, by coupling the gap distance with the rotational angle of the valve rotor, a large initial gap can be employed for low flow (and the valve is fully closed at high angle, creating a small gap), to only to a certain extent for low flow (small angle creates a large gap).

[0134] Advantageously, the embodiments described herein enable axial movement of the valve rotor relative to the valve stator to increase the separation gap and thus allow increased flow to dislodge or prevent obstruction of the pulser assembly. The axial gap can be reduced after the obstruction is relieved to ensure the necessary pressure drop across the pulser assembly and enable clean and distinct pressure pulses to be created by the pulser assembly. The direct mechanical connection between the rotational oscillation and the axial movement is provided by the axial relief assembly described herein. Thus, a passive relief (i.e., increase in gap) to a particular torque that can occur when an obstruction occurs can be achieved.

[0135] Additionally, according to some embodiments, a bi-directional release system (i.e., bi-directional rotation / oscillation) is also described, where the mechanism can both actively increase and actively decrease the axial gap between the valve rotor and the valve stator. According to some embodiments, a tension spring (e.g., leaf spring) can be used to pre-set the torque that triggers activation of the axial release assembly described herein. The tension spring can be configured to ensure that the valve rotor returns to the initial position after releasing the debris (i.e., after performing the increase gap operation). In some embodiments, such as torque related systems, the pre-set or pre-defined torque value can be set or controlled by the spring in the clutch mechanism. Thus, the clutch can be used to activate / deactivate based on the pre-set torque (provided by the clutch). In some such embodiments, the clutch can be firmly connected with the pulser housing until the pre-set torque is achieved, and then the clutch engages / activates to trigger the axial movement provided by the axial release mechanism.

[0136] In some embodiments, a keyway configuration can be used to ensure that the axial movement element of the axial release assembly does not rotate during operation, but rather only moves or translates axially. In contrast, the rotational element of the axial release assembly described herein can be axially secured, but freely rotatingly moves (e.g., in an oscillating manner). Additionally, advantageously, the axial gap control can add an additional level of control for the pressure differential across the pulser assembly (e.g., a smaller gap provides a higher pressure drop across the pulser assembly).

[0137] To support the teachings herein, various analytical components, including digital and / or analog systems, may be used. For example, controllers, computer processing systems, and / or geological guidance systems as provided herein and / or used with the embodiments described herein may include digital and / or analog systems. These systems may have components such as processors, storage media, memories, inputs, outputs, communication links (e.g., wired, wireless, optical, or others), user interfaces, software programs, signal processors (e.g., digital or analog), and other such components (e.g., resistors, capacitors, inductors, etc.) for providing operation and analysis of the apparatus and methods disclosed herein in any of several manners well known in the art. It may be understood that these teachings may be implemented, but not necessarily, in conjunction with a set of computer-executable instructions stored on a non-transitory computer-readable medium, including memory (e.g., ROM, RAM), optical media (e.g., CD-ROM), or magnetic media (e.g., disk, hard disk drive), or any other type of media, which, when executed, cause a computer to perform the methods and / or processes described herein. In addition to the functions described in this disclosure, these instructions may also provide equipment operation, control, data collection, analysis, and other functions that system designers, owners, users, or other such persons deem relevant. Processed data (such as the results of the implemented methods) may be transmitted as signals via a processor output interface to a signal receiving device. The signal receiving device may be a display monitor or printer used to present the results to the user. Alternatively or otherwise, the signal receiving device may be a memory or storage medium. It should be understood that storing the results in memory or storage medium allows the memory or storage medium to be converted from a previous state (i.e., without results) to a new state (i.e., containing results). Furthermore, in some embodiments, if the results exceed a threshold, an alarm signal may be emitted from the processor to the user interface.

[0138] In addition, various other components may be included, and they may be required to provide aspects of the teachings herein. For example, sensors, transmitters, receivers, transceivers, antennas, controllers, optical units, electrical units, and / or electromechanical units may be included to support the aspects discussed herein or to support other functions beyond this disclosure.

[0139] Elements of embodiments have been introduced by the articles "a" or "an." The articles are intended to mean that there are one or more of the elements. The terms "including" and "having" are intended to be inclusive and are meant to indicate that there can be additional elements other than the listed elements. The conjunction "or" when used with a list of two or more items, is intended to mean any of the items in the list or a combination of items in the list. The term "configured" relates to one or more structural limitations of an apparatus that are required for the apparatus to perform a function or operation that the apparatus is configured to perform. The terms "first" and "second" do not denote any particular order but are used to distinguish different elements.

[0140] Many variations of the steps (or operations) described herein can be made without departing from the scope of the disclosure. For example, the steps can be performed in different orders, or steps can be added, deleted, or modified. All such variations are considered to be part of the disclosure.

[0141] It will be recognized that various components or technologies can provide certain requisite or beneficial functionality or features. Accordingly, such functionality and features, which can be necessary or beneficial to support the appended claims and their variants, are considered inherent to the teachings hereof and part of the disclosure.

[0142] While the embodiments described herein have been described with reference to various embodiments, it will be understood that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications can be made to adapt a particular instrument, situation, or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out the described features, but that the disclosure will include all embodiments falling within the scope of the appended claims.

[0143] Therefore, the embodiments of the disclosure should not be considered to be limited by the foregoing description, but rather only by the scope of the appended claims.

Claims

1. A pulser assembly (300, 1100, 1200, 1300) configured to be positioned along a tubing string (106) through which drilling fluid (102) flows, the pulser assembly (300, 1100, 1200, 1300) comprising: Housings (312, 506, 722, 1112, 1212, 1310), the housings being configured to be supported along the column (106); Valve stators (304, 402, 1104, 1204, 1304), the valve stators being supported by the housing (312, 506, 722, 1112, 1212, 1310), the valve stators (304, 402, 1104, 1204, 1304) having at least one flow path extending from an upstream end to a downstream end of the valve stators (304, 402, 1104, 1204, 1304); A valve rotor (302, 404, 1102, 1202, 1302) is positioned adjacent to the valve stator (304, 402, 1104, 1204, 1304), the valve rotor (302, 404, 1102, 1202, 1302) being configured to selectively block at least one flow path, wherein an axial clearance exists between the valve rotor (302, 404, 1102, 1202, 1302) and the valve stator (304, 402, 1104, 1204, 1304); Motors (308, 1106, 1206, 1306), operably coupled to the valve rotors (302, 404, 1102, 1202, 1302), wherein the motors (308, 1106, 1206, 1306) are operable to rotate the valve rotors (302, 404, 1102, 1202, 1302) relative to the valve stators (304, 402, 1104, 1204, 1304); An axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312), the axial release assembly including a rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318), the rotating element being configured to adjust the axial clearance between the valve rotor (302, 404, 1102, 1202, 1302) and the valve stator (304, 402, 1104, 1204, 1304) based on the rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318); and Clutch assembly (1210) configured to selectively operate the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) based on the torque applied to the valve rotor (302, 404, 1102, 1202, 1302).

2. The pulse generator assembly (300, 1100, 1200, 1300) according to claim 1, wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) further comprises: Axial moving elements (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322). The rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) relative to the housing (312, 506, 722, 1112, 1212, 1310) causes axial movement of the axially moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322).

3. The pulser assembly (300, 1100, 1200, 1300) according to claim 2, the pulser assembly further comprising a biasing element (1132) configured to bias the axial movement of the axial movement elements (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322).

4. The pulser assembly (300, 1100, 1200, 1300) according to claim 2 or 3, wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) further includes at least one rolling body (806) disposed between the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) and the axial moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322).

5. The pulser assembly (300, 1100, 1200, 1300) according to claim 2 or 3, wherein the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) includes a first end stop (814), and the axially moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322) includes a second end stop (816), wherein the first end stop and the second end (713b) stop are configured to restrict the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) relative to the axially moving element (504, 604, 702, 802, 902, 1002, 1120, 1318). Rotation amounts of 704, 804, 1008, 1010, 1122, 1124, 1320, and 1322.

6. The pulser assembly (300, 1100, 1200, 1300) according to claim 2 or 3, wherein one of the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) and the axially moving elements (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322) is axially constrained relative to the housing (312, 506, 722, 1112, 1212, 1310), and the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) and the axially moving elements (504, 604, 702, 802, 902, 1002, 1120, 1318) and the axially moving elements (504, 604, 702, 802, 902, 1002, 1120, 1318) are axially constrained relative to the housing (312, 506, 722, 1112, 1212, 1310). Another of 704, 804, 1008, 1010, 1122, 1124, 1320, 1322 is rotatably constrained relative to the housing (312, 506, 722, 1112, 1212, 1310).

7. The pulse generator assembly (300, 1100, 1200, 1300) according to any one of claims 1 to 3, wherein the motor (308, 1106, 1206, 1306) comprises a motor stator (1114) and a motor rotor (1116).

8. The pulse generator assembly (300, 1100, 1200, 1300) according to claim 7, wherein the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) is coupled to the motor stator (1114), or wherein the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) is coupled to the motor rotor (1116).

9. The pulser assembly (300, 1100, 1200, 1300) of claim 8, further comprising a drive shaft (1108, 1208, 1308) operably connecting the motor (308, 1106, 1206, 1306) to the valve rotor (302, 404, 1102, 1202, 1302), wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) is configured to adjust the axial position of the drive shaft (1108, 1208, 1308) to adjust the valve rotor (302, 404, 1102, 1202, 1302) and the valve stator (304, 1106, 1206, 1302). The axial clearance between 402, 1104, 1204, and 1304.

10. The pulser assembly (300, 1100, 1200, 1300) according to any one of claims 1 to 3, wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) is configured such that (i) rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from its initial position in a first rotational direction and rotation from its initial position in a second rotational direction opposite to the first rotational direction cause the axial clearance to increase, or (ii) rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from its initial position in the first rotational direction and rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from its initial position in the first rotational direction and rotation of the rotating element (502, 602, 1318) in a second rotational direction opposite to the first rotational direction cause the axial clearance to increase, or (ii) rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from its initial position in the first rotational direction and rotation of the rotating element (502, 602, 1318) in the second rotational direction cause the axial clearance to increase. 702, 802, 902, 1002, 1120, 1318) Rotation from the initial position in a second rotational direction opposite to the first rotational direction causes the axial clearance to decrease.

11. The pulser assembly (300, 1100, 1200, 1300) according to any one of claims 1 to 3, wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) comprises: Rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318); First axial moving elements (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322), the first axial moving elements being operatively coupled to the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318); and A second axial moving element (1010) is operatively coupled to a first axial moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322). The rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) causes axial movement of at least one of the first axial moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322) and the second axial moving element (1010).

12. The pulser assembly (300, 1100, 1200, 1300) according to claim 11, wherein the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) is configured such that rotation of the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from its initial position in a first rotational direction causes rotation of the first axial moving element (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322) relative to the rotating element (502, 602, 702, 802, 902, 1002, ... The second axial moving element (1010) moves axially relative to the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318) from the initial position in a second rotation direction opposite to the first rotation direction, causing the second axial moving element (1010) to move axially relative to the rotating element (502, 602, 702, 802, 902, 1002, 1120, 1318).

13. The pulser assembly (300, 1100, 1200, 1300) according to any one of claims 1 to 3, the pulser assembly further comprising a gap release motor configured to drive the rotation of the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) depending on the torque acting on the valve rotor (302, 404, 1102, 1202, 1302).

14. The pulse generator assembly (300, 1100, 1200, 1300) according to claim 4, wherein one of the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) and the axially moving elements (504, 604, 704, 804, 1008, 1010, 1122, 1124, 1320, 1322) includes at least one inclined surface (708), and one of the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) and the axially moving elements (504, 604, 704, 804, 1008, 1010, 1122) includes at least one inclined surface (708), and one of ... Another of 1124, 1320, and 1322 includes at least one slot (714), and the at least one rolling body (806) is disposed within the at least one slot (714) and configured to roll freely within the at least one slot (714) along the at least one inclined surface (708).

15. The pulser assembly (300, 1100, 1200, 1300) of claim 14, wherein the at least one tilted surface (708) comprises a symmetrical configuration including two peaks (906a) and an inflection point (908) between the two peaks.

16. The pulse generator assembly (300, 1100, 1200, 1300) according to claim 9, wherein the drive shaft (1108, 1208, 1308) is axially freely coupled to the motor rotor (1116) via a slide (1130).

17. A method for generating pulses in drilling fluid (102), the method comprising: The valve rotors (302, 404, 1102, 1202, 1302) of the drive pulser assemblies (300, 1100, 1200, 1300) rotate relative to the valve stators (304, 402, 1104, 1204, 1304), wherein the pulser assemblies (300, 1100, 1200, 1300) include housings (312, 506, 722, 1112, 1212, 1310), wherein motors (308, 1106, 1206, 1306) are arranged within the housings (312, 506, 722, 1112, 1212, 1310) and configured to drive the valve rotors (302, 404, 1102, 1202). The rotational movement of 1302); and The rotation of the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318) is used to selectively operate the clutch assembly (1210) of the axial release assembly (500, 600, 700, 800, 900, 1000, 1118, 1218, 1312) to adjust the axial clearance between the valve rotor (302, 404, 1102, 1202, 1302) and the valve stator (304, 402, 1104, 1204, 1304), the axial release assembly including the rotating elements (502, 602, 702, 802, 902, 1002, 1120, 1318).

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