Force balanced dual valve pulser system

Abstract

A pressure pulse generating device comprising a housing with a fluid passageway having first and second restriction flow channels. A first valve member is disposed in the fluid passageway and aligned with the first restriction flow channel and a second valve member is disposed in the fluid passageway and aligned with the second restriction flow channel. The second valve member being locomotively connected to the first valve member. The first valve member is movable by an actuator relative to the first restriction flow channel and the second valve member movable by the actuator relative to the second restriction flow channel to generate a pressure pulse in the fluid in the fluid passageway based on varying a relative position between the first and second valve member and the first and second restriction flow channel and creating a differential pressure across the fluid passageway. The differential pressure applies a first force on the first valve member and a second force on the second valve member.

Description

Attorney Docket No.: 65TEL-510983-WO-2 (000242)FORCE BALANCED DUAL VALVE PULSER SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U. S. Provisional Application Serial No. 63 / 728,561 filed on December 5, 2024, entitled “Force Balanced Dual Valve Pulser System”, U. S. Provisional Application Serial No. 63 / 728,551 filed on December 5, 2024, entitled “Mud Hydraulic Operated Rotary Steerable System”, and U. S. Provisional Application Serial No. 63 / 728,557 filed on December 5, 2024, entitled “Combined Rotary Steerable and Mud Pulse Telemetry Tool”.

[0002] This application is also related to co-pending International Patent Application filed on December 5, 2025, entitled “Combined Rotary Steerable and Mud Pulse Telemetry Tool” and naming Volker Peters as inventor and Baker Hughes Oilfield Operations LLC as Applicant (ref. 65DRL-510769-WO-2), co-pending International Patent Application filed on December 5, 2025, entitled “Mud Hydraulic Operated Rotary Steerable System” and naming Volker Peters as inventor and Baker Hughes Oilfield Operations LLC as Applicant (ref. 65DRL-510615-WO-2), co-pending U. S. Non-Provisional Application filed on December 5, 2025, entitled “Drill Bit Steering System” and naming Behrend Bode, Volker Peters, and Bastian Sauthoff as inventors and Baker Hughes Oilfield Operations LLC as Applicant (ref. 65DDR-511659-US-1), and co-pending U. S. Non-Provisional Application No. 19 / 410,852 filed on December 5, 2025, entitled “Force Balanced Dual Valve Systems For Steering Tool And Methods Of Using The Same” and naming Bastian Sauthoff and Thomas Wettmarshausen as inventors and Baker Hughes Oilfield Operations LLC as Applicant (ref. 65DDR-511601-US-1).-1- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)BACKGROUND OF THE INVENTION1. Field of Invention

[0003] The present invention relates generally to downhole tools and more particularly to mud pulse telemetry systems and methods of use.2. Description of Prior Art

[0004] Drilling systems having earth boring drill bits on an end of a drill string are commonly used in the oil and gas industry for creating wells drilled into hydrocarbon bearing geologic formations. The drill bit is rotationally affixed to the drill string in some drilling systems. A drilling system has a drill string having a bottom hole assembly (BHA) connected to the drill bit which is rotatably driven from a drilling rig on the surface having either a top drive or rotary table to rotate the drill string and the drill bit to bore through the subterranean formation. In other varieties of drilling systems, the drill bit rotates with respect to the drill string. Mud motors are sometimes employed for rotating the drill bits while the drill string does not rotate or rotates at a different speed.

[0005] During drilling operations, a drilling fluid or drilling mud is pumped from the surface down the drill string through the BHA and the drill bit into an annulus between the drill string and the borehole wall and then returned to the surface along with cuttings from the formation.

[0006] The BHA can include various downhole tools and components for gathering downhole data while drilling without needing to remove the drill pipe from the borehole. Such tools include, but are not limited to, measurement-while-drilling (MWD) tools and logging-while-drilling (LWD) tools.

[0007] Communication between the downhole tools and the surface is commonly accomplished using mud pulse telemetry. Mud pulse telemetry involves using pressure pulsesIM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)in the borehole fluid, as for example drilling mud, to transmit data to the surface. The downhole data can be converted into a digital format and pressure pulses are transmitted from a downhole pulser to a receiver on the surface,SUMMARY OF THE INVENTION

[0008] The present invention is a force balanced dual valve pulser system for generating fluid pressure signals and communicating with the surface via mud pulse telemetry. The pulser system includes a pair of valve members movable relative to a pair of restrictions in a restriction member located in a fluid passageway (or bore). Fluid pulses are generated by moving the pair of valve members in an oscillating manner to create pressure differentials that are transmitted though fluid to a receiver at the surface. The pulser system includes a force balancing arrangement to cancel out the majority of the hydraulic forces acting on the pair of valves.

[0009] An embodiment of a method of generating pressure pulses includes receiving a communication at a controller / electronics module which is configured to control an actuator module including a first and a second valve member and a restriction disposed in a fluid passageway, controlling, by the actuator, movement of the first and second valve members relative to the restriction to generate pressure pulses in a fluid in the passageway based on varying a relative position between the first and second valve members and the restriction and creating a differential pressure across tire passageway. The fluid flow' and differential pressure apply a first force on the first valve member and a second force on the second valve member, the first and second valve members having a locomotive mechanical connection. The first and second forces having a direction and magnitude at least partially balanced by the locomotive connection, in turn reducing the amount of force required to move the first and second valves relative to the restriction member and transmitting the pressure pulses through the fluid to a receiver at a surface location.-3- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)

[0010] The force balanced dual valve pulser system provides or includes one or more of the following advantages: force balancing valves cancel out most of the hydraulic valve forces, signal pressure is adjustable with respect to fluid flow rate and density, signal coding method is adaptable to secure communication at highest possible rate, one size for one tool size, no hardware changes required to cover entire flow and density ranges, no bypass is required, reciprocating valves are known to be plugging resistant, low power required for actuation; therefore applicable for high data rate telemetry, two valves open and close simultaneously; therefore advantageous for large tool sizes (for e.g., 9-‘ / 2”), complementary to applicant’s U. S. Patent No. 11,892,093 for “Force Balanced Reciprocating Valve (the “’093 patent”)”, requires only half the stroke compared to the '093 patent for similar signal pressure, and lower open pressure drop at the same stroke as the '093 patent (lower wear and erosion).BRIEF DESCRIPTION OF DRAWINGS|0011] Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

[0012] FIG. 1 illustrates a partial cross-sectional view of a directional drilling system of an onshore well having a bottom hole assembly including a mud pulse telemetry tool according to embodiments of the present invention;

[0013] FIG. 2 is a sectional view of a force balanced dual valve pulser system according to a first embodiment of tire present invention, the dual valves shown in a restricted position;

[0014] FIG. 3 is a view similar to FIG, 2, but showing the dual valves in a medial position;

[0015] FIG. 4 is a view similar to FIGS. 2 and 3, but showing the valves in a fully retracted position;-4- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)

[0016] FIGS. 5 and 6 are section views of examples of control electronics and power sources for the force balanced dual valve pulser system;

[0017] FIG. 7 is a sectional view of an alternate embodiment of the force balanced dual valve pulser system, the dual valves shown in a medial position;

[0018] FIGS. 8-10 are sectional views of further alternate embodiments of the force balanced dual valve pulser system shown with valve members operating near and in restriction channels;

[0019] FIGS. 11-13 are sectional views of another alternative embodiment of the force balanced dual valve pulser system shown in open and closed configurations; and

[0020] FIGS. 14 and 15 are sectionals views of another alternate embodiment of the force balanced dual valve pulser system.DETAILED DESCRIPTION OF INVENTION

[0021] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure can be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure w ill be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes + / - 5% of a cited magnitude. In an embodiment, the term “substantially” includes + / - 5% of a cited magnitude, comparison, or description. In an embodiment, usage of the term “generally” includes + / - 10% of a cited magnitude.-5- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)

[0022] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.

[0023] In one embodiment, a force balanced dual valve assembly includes two valves (e.g., a first and a second reciprocating valve) in pressure communication with the fluid passageway. Each of the tw o valves includes a plunger valve member and a restriction. The force balanced dual valve assembly includes a locomotive connection betw een the tw o plunger valve members that transmits valve forces from the first plunger valve member to the second plunger valve member and vice versa. The first plunger valve member is also referred to herein as outlet plunger valve member. The second plunger valve member is also referred to herein as inlet plunger valve member. The locomotive connection can be a locomotive mechanical connection or a locomotive hydraulic connection or any other type of locomotive connection. Tire transmitted force at least partially cancels out the valve force at the second plunger valve member or cancels out the valve force at the first plunger valve member, allowing the two plunger valve members to be actuated with lower mechanical power than would be needed without the locomotive connection or with one singular reciprocating valve.

[0024] Embodiments described herein provide a number of advantages and technical effects. Embodiments allow telemetry devices to be actuated with significantly less actuation force by balancing the hydraulic forces (valve forces) on the plunger valve members. With hydraulic forces being reduced or canceled, the required power to drive the plunger valve members is significantly reduced, Embodiments described herein allow for the realization of a mud pulser-6- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)for high data rate mud pulse telemetry, maintaining the benefits of a plunger valve in a mud pulser as used with respect to lost circulation material (LCM) capability, plugging resistance and wide flow range adaptivity at high signal strength (pulse pressure).

[0025] Hydraulically assisted pilot (or servo) valves (e.g. U. S. Patent No. 4,905,778A) are typically not actively position controlled and might have issues with plugging, sedimentation or wear in the pilot valve section. Lab and field testing of plunger valves demonstrate their advantages over rotary valves (e.g. U. S. Patent No. 6,626,253) in terms of ruggedness, flow rate and density spread, and plugging resistance. The embodiments described herein feature the advantages of plunger valve configurations while maintaining capability for high-speed mud pulse telemetry.

[0026] FIG. 1 shows an elevation, partial cross-sectional view of a typical onshore rotary well drilling system for forming a borehole H in a geological formation G in which the present invention can be utilized. Tire system includes a drilling rig R at the surface connected to a drill string 2. A bottom hole assembly (BHA) 20 at the lower end of the drill string 2 is connected to a lower drill bit B. Typically, the drilling rig R supports, lowers and rotates the drill string 2 and drill bit B. A drilling fluid system M delivers drilling fluid or mud F at the surface from a drilling fluid tank 4 into a fluid passageway or inner bore 24 of the drill string 2. lire drilling fluid F is pumped down the inner bore 24 and through the BHA 20 and the drill bit B. The drilling mud F exits the drill bit B and enters an annulus 6 between the drill string 2 and the wall W of the borehole and returns to the surface with cuttings from the borehole (arrows depicting flow direction of drilling mud F down through drilling string 2 and up through annulus 6). A surface data acquisition and control system C having a processor / con trailer is communicatively coupled to the BHA 20, including various downhole data acquisition tools and sensing devices. The surface data acquisition and control system C-7- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)can communicate with the downhole devices in various manners. The communication means can be. for example, mud pulse telemetry, hardwired, such as wired pipe, electromagnetic telemetry, fiber optic, or wireless. The BHA 20 can include various components and equipment, such as drill collars, stabilizers, reamers, shocks, hole-openers, logging-while-drilling (LWD) equipment, measurement-while-drilling (MWD) equipment, sensors, steering assemblies and other downhole instruments. The sensors commonly include inclination and azimuth sensors, for example accelerometers, inclinometers, magnetometers and rate gyros. Certain of the equipment, systems and techniques are used for gathering downhole data while drilling without needing to remove the drill pipe from the well. Tire design of the BHA 20 can vary greatly depending on the complexity of the to be drilled borehole H.

[0027] The BHA 20 includes a telemetry assembly including a pulser tool 10 for communicating with the surface and / or other downhole tools or devices. One or more downhole components and / or one or more surface components can be in communication with and / or controlled by a processor such as a downhole processor and / or the surface processing unit C. In one embodiment, the surface processing unit C is configured as a surface control unit which controls various parameters such as rotary speed, weight-on-bit, fluid flow parameters (e.g., fluid density, pressure and flow rate) and others. The surface processing unit C (or other processor) can also perform monitoring and communication functions (e.g., to gather tool status information and information regarding borehole conditions).

[0028] The surface processing unit C (and / or the downhole processor) can be configured to perform functions such as controlling drilling and steering, controlling the flow rate, fluid density and pressure of borehole fluid, transmitting and receiving data and communications using a communication module, processing measurement data, and / or monitoring operations of the system. The surface processing unit C, In one embodiment, includes an input / output-8- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242) device, a processor, and a data storage device (e.g., memory, computer-readable media, etc.) for storing data, models and / or computer programs or software that cause the processor to perform aspects of methods and processes described herein,

[0029] In one embodiment, the pulser tool 10 is configured as a mud pulse telemetry (MPT) device, which induces pressure fluctuations in the drilling fluid F. The pressure fluctuations travel along the inner bore 24 as pulses to a receiver 5, such as for example a pressure transducer or a flowmeter, in fluid communication with the drilling fluid F pumped down the drill string 2. Tire pulses can be transmitted with, for example, modulated amplitudes and / or frequencies, as an encoded pressure signal.

[0030] FIG. 2 shows a cross-section of one embodiment of the force balanced dual valve pulser system or tool, generally referred to as 10. lire pulser tool 10 is part of the bottom hole assembly (BHA) 20 (FIG. 1) and includes a housing 22 having a passageway 24 therethrough. The lower end of the housing 22a can be connected to another portion of the BHA 20, such as another downhole tool, and / or a drill bit. Within the housing 22 is an actuator assembly 26 for controlling mud F flow into and through at least first and second channels 28 and 30, respectively, by means of an outlet valve 32 and an inlet valve 34. The first and second channels 28, 30 are in fluid communication with and form part of the drill string and fluid passageway 24 and can be formed in a restrictor unit 40, also referred to herein as restriction or restriction member. The first channel 28 is preferably parallel to and adjacent to the second channel 30. Tire first channel being adjacent to the second channel refers to a location inside the same passageway 24 and inside housing 22. The first and second channels 28, 30 have a first and second channel inlet end 28i, 30i and a first and second channel outlet end 28o, 30o, respectively.IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)

[0031] The actuator assembly 26 is depicted in FIG. 2 as a reciprocating actuator having a balancing mechanics 56, drive 58 and linkage 60 connected to an outlet valve rod 32r of the outlet valve 32 and an inlet valve rod 34r of the inlet valve 34. Tire outlet valve 32 also includes an outlet valve poppet 32p connected to the outlet valve rod 32r. lire inlet valve 34 also includes an inlet valve poppet 34p connected to the inlet valve rod 34r. The outlet valve rod 32r and the outlet valve poppet 32p form the first plunger valve member 32v. The inlet valve rod 34r and the inlet valve poppet 34p form the second plunger valve member 34v. In this embodiment, the first plunger valve member 32v and the second plunger valve 34v are locomotively connected. That is the outlet valve rod 32r is locomotively connected to the inlet valve rod 34r. In other words, as one plunger valve member (e.g. first plunger valve member 32v) moves axially the other plunger valve member (e.g. second plunger valve member 34v) concurrently moves axially the same distance but in the opposite direction. The actuator assembly 26 can be sealed and filled with an appropriate lubrication fluid, such as mineral or synthetic oil. The oil-filled actuator assembly 26 can further include a pressure compensator 70 (Fig. 2) such as a piston, bellows, or similar device to compensate the internal lubricant pressure L to the drilling fluid F pressure PL. Tire pressure compensator 70 shown in FIG. 2 features a cylinder 72, a piston 74, and a seal 76. Referring to FIG. 2, the outlet valve poppet 32p is on the downstream side of the first channel 28 and the outlet valve rod 32r extends through the first channel 28, through a first rod guide 33 of the actuator assembly 26 and then coupled to a first end of the linkage 60 via a first pivotable connection 59a. The first pivotable connection 59a can include a first bearing 61a. The inlet valve poppet 34p is on the upstream side of the second channel 30 and the inlet valve rod 34r extends through a second rod guide 35 and is then coupled to a second end of the linkage 60 via a second pivotable connection 59b. The second pivotable connection 59b can include a second bearing 61b. lire linkage 60 is pivotable via a fulcrum 62. The fulcrum 62 can include a third bearing 61c. In one embodiment-10- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)the fulcrum 62 is located in a middle portion of the linkage 60, so that the linkage tilts around the fulcrum symmetrically ( transmission ratio of 1:1). The first and second rod guides 33 and 35 can additionally include sealsto protectthe locomotive connection 61 and the bearings from the drilling fluid F. Preferably, the outlet valve 32 is axially aligned with the first channel 28 and the inlet valve 34 is axially aligned with the second channel 30. That is, the outlet valve rod 32r is aligned with the first channel 28 and the inlet valve rod 34r is aligned with the second channel 30. In an alternative embodiment the locomotive connection 61 and the first and second plunger valve members 32v, 34v are balanced in a way that the fulcrum 62 is offset from a middle portion in the linkage 60. The valve poppets can also be referred to herein as closing members. In an embodiment the actuator assembly can be an electric motor and can either be an oscillating motor or a rotating motor, in an alternative embodiment the actuator assembly¬ can be a hydraulic device. In the embodiment in FIG. 2 the outlet valve poppet 32p is fully outside the first channel 28 and the inlet valve poppet 34p is fully outside the second channel 30. In FIG. 2 the outlet and / or inlet valve poppet size (e.g. diameter) is greater than the diameter of the respective first and / or second channel 28, 30. In an alternative embodiment the outlet and / or inlet valve poppet 32p, 34p can partially enter the respective first and / or second channel 28, 30 when in the restricted position. In this case the outlet and / or inlet valve poppet size (e.g. diameter) is smaller than the diameter of the respective first and / or second channel 28, 30. The first and second channel can have a cylindrical opening.|0032] Each of the outlet and inlet plunger valve members 32v and 34v, respectively, is allowed to move between a restricted position and a fully retracted position. FIGS. 2, 3 and 4 show the valves 32 and 34 with the outlet plunger valve member 32v and the inlet plunger valve member 34v in the restricted position, a medial position, and the fully retracted position, respectively. In the restricted position as shown in FIG. 2, the outlet valve poppet 32p is the same or substantially the same distance from the first channel outlet 28o as the inlet valve -II- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)poppet 34p is from the second channel inlet end 30;. The first channel outlet 28o includes a first channel outlet valve seat 28<w,s. The second channel inlet 30 / includes a second channel inlet valve seat 30ivs, Preferably, the outlet and inlet plunger valve members 32v, 34v and with them, the inlet valve poppet 34p and the outlet valve poppet 32p, move together synchronously. For example, as the outlet valve poppet 32p moves a certain distance towards the first channel outlet end 28o, the inlet valve poppet 34p moves the same distance towards the second channel inlet end 30 / .

[0033] As discussed above, FIG. 2 shows the valves 32, 34 in the restricted position. In the restricted position, the outlet plunger valve member 32v restricts tire flow of the drilling mud F exiting the first channel 28 and the inlet plunger valve member 34v restricts the flow of the drilling mud F entering the second channel 30. A pressure drop occurs on the downstream side of the valves 32, 34 in the restricted position. The fluid pressure upstream of the valves 32, 34 is pressure Pl and the fluid pressure downstream of the valves 32, 34 is pressure P2. Pressure Pl is greater than pressure P2 in the restricted valve position shown in FIG. 2. The pressure Pl acts on the outlet valve poppet 32p resulting in an outlet valve force Fo in the axial downstream direction and on the inlet valve poppet 34p resulting in an inlet valve force F in the axial downstream direction as shown in FIG. 2. The valves 32, 34 can be designed such that the forces Fo and Fz are equal or substantially equal so as to cancel each other. Another way of saying this is that the valves 32 and 34 are force balanced. This reduces the power required to move and axially reposition the outlet and inlet plunger valve members 32v and 34v and reduces tire energy consumption of the actuator assembly 26. Designing the valves 32, 34 to be balanced includes dimensioning the first channel 28 diameter and length, and second channel 30 diameter and length, the outlet rod 32r diameter and length, the inlet rod 34r diameter and length, the outlet valve poppet 32p shape and diameter, the inlet valve poppet 34p shape and diameter (e.g. cross section or surface area of outlet and inlet valve poppets -12- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)perpendicular to fluid flow direction), the configuration of the locomotive connection 61, such as length of linkage 60 and position of the fulcrum 62 along the linkage 60. The design of the valves can be supported by simulation and hydraulic modeling. Balancing the valves 32, 34 and the locomotive connection 61 can include different diameters for first channel 28 (first channel diameter) and second channel 30 (second channel diameter). First channel 28 includes outlet rod 32r. Rod 32r reduces the flow cross section in first channel 28. A greater channel diameter of first channel 28 compensates for that. The first channel 28 can allow 50% of the flow rate to pass through and the second channel 30 can allow the other 50% of the flow rate to pass through. This is the cross section of the first channel 28 and the second channel 30 open for fluid flow are of the same size. In case of slightly differing channel configurations the first channel 28 can allow 30%, or 20%, or 10% ofthe fluid flow rate to pass through and the second channel can correspondingly allow 70%, or 80, or 90% of the fluid flow rate to pass through or vice versa. This is, the cross section of the first channel 28 is 30%, or 20%, or 10%, the cross section of the second channel 30 is correspondingly 70%, or 80%, or 90% of the total cross section of both channels 28, 30 together, or vice versa. A difference in fluid flow rate through the first and second channel is to be compensated by corresponding adaption of other possible design parameters of the force balanced dual valve, such as the diameter or shape of the vale poppets to still achieve force balancing of the valve 32 and 34. When the force balanced dual valve pulser system is properly balanced, tire actuation force (actuation power) used to move the plunger valve members 32v, 34v does not need to overcome hydraulic forces on the plunger valve members caused by the pressure differential. The actuation power is thus limited to other factors such as inertia factors (inertial loads and losses), friction, actuator losses and others.

[0034] As is to be understood from FIGS. 2-4, the plunger valve members 32v, 34v move together simultaneously and move the same distance as a result of the locomotive connection 61 formed by linkage 60, inlet valve rod 34r, outlet valve rod 32r, fulcrum 62 and first, second -13- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)and third bearings 61a, b, c. Since the outlet and inlet plunger valve members 32v, 34v move together to restrict fluid flow into and through the first and second channel 28 and 30, respectively, a short stroke generates the pressure signal. For example, the present invention uses only half the valve stroke as compared to that required in applicant’s ‘093 patent to generate a similar signal pressure. Outlet plunger valve member 32v in combination with the linkage 60 and fulcrum 62 is configured to perform an outlet plunger valve member stroke Ors. Inlet plunger valve member 34 in combination with linkage 60 and fulcrum 62 is configured to perform an inlet plunger valve member stroke Iix. The outlet plunger valve member stroke Ovs has an outlet plunger valve member stroke length OL S. The inlet plunger valve member stroke I S has an inlet plunger valve member stroke length ILvs. The shorter stroke required and the force balancing of the valves 32, 34 results in lower power requirements for actuation which makes it very' applicable for high data rate telemetry with the inlet and outlet plunger valve members 32v, 34v moving quickly to achieve the fast pressure pulse generation that allows the high data rate transmission of data from a downhole location to the surface. The outlet plunger valve member stroke OVS has an outlet plunger valve member stroke direction and the inlet plunger valve member stroke IVS has an inlet plunger valve member stroke direction. The outlet plunger valve member stroke direction and the inlet plunger valve member stroke direction can be parallel to each other and parallel to a longitudinal axis of the first channel and the second channel and the longitudinal axis A of the forced balanced dual valve pulser 10.|0035] As discussed above, the actuator assembly 26 controls the positioning of the outlet and inlet plunger valve members 32v, 34v. The position of the outlet and inlet valve poppets 32p, 34p in the outlet and inlet plunger valve members 32v, 34v relative to the outlet end 28o and the inlet end 30; of the first and second channel 28, 30 impacts the values of the fluid pressure Pl upstream of the outlet and inlet valves 32, 34 and upstream of the outlet and inlet valve poppets 32p, 34p and the fluid pressure P2 downstream of the outlet and inlet valves 32, 34-14- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)and downstream of the outlet and inlet valve poppets 32p, 34p and within the flow passageway 24. The fluid pressure in the annulus 6 between an outer surface 23 of the housing 22 and the borehole wall W (FIG. 1) is P3, Assuming a constant fluid F flow through the fluid passageway 24 and a constant density of fluid F, in the restricted position of the valves 32, 34 as shown in FIG. 2, fluid pressure Pl is greater than fluid pressure P2 resulting in a relatively high differential pressure PD (PD = P1-P2), With tilting of the linkage 60 around a fulcrum 61c, driven by actuator assembly 26, the outlet and inlet valve poppets 32p, 34p move further away from the outlet end 28o and the inlet end 30 / of the channels 28, 30 as shown in FIGS. 3 and 4, the fluid flow' through tire channels is less restricted or impeded and the difference between fluid pressures Pl and P2 lessens. FIG. 2 shows the linkage 60 in a fully restricted position (first fully tilted position of locomotive connection), FIG. 3 shows tlie linkage 60 in a medial position (halfway between first and second fully tilted positions of the locomotive connection), FIG. 4 shows the linkage 60 in a fully open position (second fully tilted position of the locomotive connection). It is to be understood that the outlet valve 32 (or first plunger valve member 32v) and tlie inlet valve 34 (or second plunger valve member 34v) simultaneously move from a restricted to an retracted (unrestricted) configuration when the locomotive connection toggles from first fully tilted position to the second fully tilted position, while the outlet rod and the inlet rod move into opposite stroke directions, in other words, the outlet valve poppet 32p restricts the first channel 28 at the outlet end 28o (valve 32 closed) when the inlet valve poppet 34p restricts the second channel 30 at the inlet end 30 / (valve 34 closed). Tire outlet valve poppet 32p moves towards the first channel outlet end 28o when inlet valve poppet 34p moves towards the second channel inlet end 30 / . The fluid flow' through the first channel 28 is unrestricted (valve 32 open), when the fluid flow' through the second channel 30 is unrestricted (valve 34 open). The outlet valve poppet 32p moves away from the first channel outlet end 28o when inlet valve poppet 34p moves away from tlie second channel inlet end 30 / .-15- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)The fluid flow through the first channel 28 and the second channel 30 is restricted simultaneously or is unrestricted simultaneously. The first channel 28 is never restricted when the second channel 30 is unrestricted and vice versa. In the fully restricted position, it is not required to fully close the valve (prohibit any fluid flow through tire channel or restriction). It is sufficient to restrict fluid flow through the channel or restriction to reduce the fluid flow through the restriction or channel. In the fully restricted position the outlet and inlet valve poppets 32p, 34p are not required to contact the outlet and inlet valve seats 28ovs, 30ivs, respectively. It is to be understood that through the valves 32 and 34 or through channels 28 and 30 flows all the fluid flow (100%) that is pumped from the surface through the BIIA 20 down to the drill bit B. In an embodiment there can be a bypass (e.g. in housing 22) allowing some fluid to bypass the valves 32, 34. The bypass can allow in up to 1%, 5%, 10%, 30%, or 50% of tire fluid, which is diverted away from valves 32 and 34.|0036] The magnitude of the pressure difference between the fluid pressures Pl and P2 is affected by the current flow parameters, such as the flow rate and density of the drilling fluid F. The present invention allows for the magnitude of the pressure difference between the fluid pressures Pl and P2, also referred to as the signal pressure, to be adjustable with respect to the existing flow rate and density of the fluid F. Such adjustment is desired to omit complex preparation before deploying the tool. Without such adjustment and with fixed open and close valve positions, the signal pressure (P 1 minus P2) would be greatly affected by the current flow rate and fluid density situation for a particular deployment, which would require the tool to be disassembled and mechanically adjusted prior to each deployment. As an example, the flow rate between two different deployments can vary by 100% (first deployment flow rate x 1 / s, second deployment flow rate 2x 1 / s). lire fluid density between two consecutive deployments can vary as well (first deployment fluid density x, second deployment fluid density 2x). Since there exists a quadratic relation between flow rate and pressure drop and a linear relation -16- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)between fluid density and pressure drop, the signal pressure for the second deployment of the above example would be 8 times (22• 2) the signal pressure from the first deployment, considering fixed valve positioning for both deployments, regardless of current flow rate and fluid density. Such deviation in pressure drop would not be acceptable and thus demands either manual adaption (adjustment) or positioning of the plunger valve poppets in the restricted and open position (e.g. adaption of the outlet and inlet plunger valve member strokes Ovs, Iv« ) with respect to current flow rate and fluid density in the respective deployment. There are several methods known in the art to detect current flow rate and fluid density at a downhole location and inside a downhole tool. Both values can be obtained from a turbine 80 / alternator 82 device, such as a downhole generator assembly 83 (FIG. 5). Alternatively, such valves as disclosed here, can also be used to measure current flow rate and fluid density situations, applying certain routines and algorithms as described in patent application US20250020033. Yet another method to react on changing flow rate and fluid density situations and thus position the valves accordingly can include sending respective parameter values from the surface to the downhole tool (e.g. by telemetry downlink), lire fluid flow and density can be detected downhole during a downhole deployment (in real time) and within the BHA 20. A downhole processor / controller 84 (FIG. 1) can determine from the detected fluid flow parameters a preferred outlet and inlet plunger valve member position for the restricted and open position or alternatively an outlet and inlet plunger valve member stroke length OLrs, OI rs. This way the pulser tool is adapted to changing fluid flow parameters in an automated fashion during the deployment (in real time) and without the interaction of a human being. In an embodiment the outlet and inlet plunger valve member position for the restricted and open position or alternatively an outlet and inlet plunger valve member stroke Ovs, Ivsare adapted by sending adapted actuator assembly parameters from the surface (surface acquisition and control system C) during the deployment (in real time) to the BHA 20 in the borehole. It is to be understood-17- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)that in embodiments the outlet plunger valve member stroke length OLvs and the inlet plunger valve member stroke length ILvs do not need to be the same magnitude. The stroke length is the difference between the open and closed position.

[0037] Although not shown in FIGS. 2 to 4, it can be appreciated that there can be a further guidance or bearing feature at channel 28 and as a support of outlet valve rod 32r, given the extended length as compared to inlet valve rod 34r. Such a feature is shown and described below with respect to Fig. 7.

[0038] FIGS. 5 and 6 show examples of control electronics and power sources. Figure 5 shows a turbine 80 coupled to an alternator 82, and the controller / electronics module 84. Tire controller / electronics module 84 is electrically connected to the alternator 82, preferably by an electrical conductor or wire 86, and the actuator assembly 26 is connected, preferably by electrical conductor or wire 88, to the controller / electronics module 84. As the drilling fluid F flows through the fluid passageway or inner bore 24, the drilling fluid F flows through the turbine 80 before passing the actuator assembly 26 and then through the channels 28, 30, The turbine 80 and alternator 82 convert the mechanical energy into electricity to power the controller / electronics module 84 and the actuator assembly 26. In Fig. 6, the turbine 80 and alternator 82 (Fig, 5) have been replaced by a battery 90 which powers the controller / electronics module 84 and the actuator assembly 26. The controller / electronics module 84 has been repositioned within the housing 22 and is located in a probe within the inner bore 24 instead of in a pocket in the sleeve like housing 22 as shown in FIG. 5. Like displayed in Fig. 7, the locomotive connection 61, the actuator, the turbine 80 (not shown), alternator 82 (not shown) and / or the controller 84 (not shown), or only parts therefrom can also be positioned downstream of the restrictor 40.-18- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)

[0039] One embodiment of the present invention is a method of generating pressure pulses that includes receiving communication at the controller / electronics module 84 which is configured to control the actuator assembly 26. The information can be downhole generated data such as formation evaluation (FE) data from a sensor in the BHA 20, data on a condition of the BHA 20, or data on a downhole operation (e.g.: drilling, reaming, geo-steering, tripping, circulating fluid, rotating the drill string, taking downhole surveys), Tire actuator 26 controls the movement of the outlet plunger valve member 32v and the inlet plunger valve member 34v relative to the restrictor 40 disposed in the fluid passageway 24 to generate pressure pulses in the fluid F in the fluid passageway 24. The pressure pulses in the fluid passageway 24 are generated by varying the relative position between the outlet and inlet plunger valve members 32v, 34v and the outlet end 28o and the inlet end 30? of the channel 28 and 30 in the restriction member 40 and creating a differential pressure or a differential pressure increase (pressure pulse) across the fluid passageway 24. The first (outlet) and second (inlet) plunger valves members 32v, 34v have a locomotive connection 61. The fluid flow and differential pressure PD applies a first force Fo (outlet valve force) on the first plunger valve member 32v and a second force Fz (inlet valve force) on the second plunger valve member 34v. The first and second forces Fo and Fz have a direction and magnitude at least partially balanced by the locomotive connection 61, in turn reducing the amount of force required to move the first and second valves relative to the restriction member 40 and transmitting the pressure pulses through the fluid F to a receiver 5 (FIG. 1) at a surface location. That is, the first force Fo acts on the outlet plunger valve member 32v. Through the locomotive connection 61 the force Fo acts on the inlet plunger valve member 34v in a reversed direction and acts in the opposite direction to the second force Fz. Fo balances Fz and reduces the force required to be applied by the actuator assembly 26 to move the inlet plunger valve member 34v in a direction opposite to the fluid-19- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)flow direction from upstream to downstream. The actuator 26 applies a third force E / on the locomotive connection 61.

[0040] FIG. 7 shows an alternative embodiment of the force balanced dual valve pulser system, generally referred to as 100. The pulser system 100 is very similar to the pulser system 10 shown in FIGS. 2-4. Notably, the alternative embodiment of the pulser system 100 has the actuator assembly 26 located downstream of the restrictor 40 and the first and second channels 28 and 30, respectively. The first channel 28 is preferably parallel to and adjacent to the second channel 30. The first and second channels 28, 30 have an inlet end 28 / , 30 / and an outlet end 28o, 30o, respectively. It is to be understood that the features, advantages and description as described above also apply to the embodiment shown in FIG. 7.

[0041] Referring to FIG. 7, an outlet plunger valve member 132v is on the downstream side of the first channel 28 and connected to the actuator assembly 26 via an outlet valve rod 132r. An inlet plunger valve member 134v is on the upstream side of the second channel 30 and an inlet valve rod 134r extends through the second channel 30 before connecting to the actuator assembly 26. Preferably, the outlet plunger valve member 132v is axially aligned with the first channel 28 and the inlet plunger valve member 134v is axially aligned with the second channel 30, It can be desirable to provide additional guidance for the inlet plunger valve member 134v and support of the inlet valve rod 134r given its extended length. Further referring to FIG. 7, a rod guide 136, as for example a sleeve, washer or bearing, can be installed in the second channel 30 via one or more supports 138 to provide lateral alignment and support of the inlet valve rod 134r while allowing fluid flow around or through the rod guide 136 for the fluid to pass through the second channel 30. It is to be understood that a rod guide can also be installed in the first channel in tire embodiments displayed in FIGS. 2-6 (not shown). In the embodiment-20- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)displayed in FIGS. 2-6 the rod guide can support outlet valve rod 32r while allowing fluid flow around or through the rod guide.

[0042] As discussed above with respect to the first embodiment, the actuator assembly 26 controls mud F flow into and through the first and second channels 28 and 30, respectively, by means of the outlet plunger valve member 132v and the inlet plunger valve member 134v. The first and second channels 28, 30 are in fluid communication with and form part of the drill string and fluid passageway 24. The actuator assembly 26 is depicted in FIG. 7 as a reciprocating actuator as previously discussed and the outlet and inlet plunger valve members 132v and 134v are locomotively connected.

[0043] As discussed above with respect to the first embodiment, each of the outlet and inlet plunger valve members 132v and 134v, respectively, is allowed to move between a restricted position and a fully retracted position (open position). FIG. 7 shows the inlet and outlet plunger valve members 132v and 134v in a medial position. Preferably, in the medial position, the outlet plunger valve member 132v is the same or substantially the same distance from the first channel outlet 28o as the inlet plunger valve member 134 is from the second channel inlet 30 / . Preferably, the outlet and inlet plunger valve members 132s, 134s move together synchronously. For example, as the outlet plunger valve member 132v moves a certain distance towards the first channel outlet 28o, tire inlet plunger valve member 134v moves the same distance towards the second channel inlet 30 / .

[0044] As discussed above, FIG 7 shows the inlet and outlet plunger valve members 132v, 134v in the medial position. It is to be understood that the pressure differentials between Pl and P2 as described above with reference to FIGS. 2-4 also applies to the alternative embodiment 100. As described above with respect to FIG. 2, in the restricted position, the outlet plunger valve member 132v restricts the flow of the drilling mud F exiting the first-21- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)channel 28 and the inlet plunger valve member 134v restricts the flow of the drilling mud F entering the second channel 30. A pressure drop occurs on the downstream side of the inlet and outlet plunger valve members 132v, 134v in the restricted position. The fluid pressure upstream of the inlet and outlet plunger valve members 132v, 134v is pressure P 1 and the fluid pressure downstream of the inlet and outlet plunger valve members 132v, 134v is pressure P2. Pressure Pl is greater than pressure P2 in the restricted valve position (shown in FIG. 2). The pressure P1 acts on the outlet plunger valve member 132v resulting in an outlet valve force Fo (first force) in the axial downstream direction and on the inlet plunger valve member 134v resulting in an inlet valve force FI (second force) in the axial downstream direction as shown in FIG. 7, The inlet and outlet plunger valve members 132v, 134v and the locomotive connection 61 formed by linkage 60, inlet valve rod 134r, outlet valve rod 132r, fulcrum 62 and first, second and third bearings 61a, b,c can be designed such that the forces Fo and FI are equal or substantially equal so as to cancel each other. Another way of saying this is that the inlet and outlet plunger valve members 132v and 134v are force balanced. This reduces the power required by the actuator assembly 26 (FIG. 2) to move and axially reposition the inlet and outlet plunger valve members 132v and 134v.

[0045] As discussed above with reference to FIGS. 2-4, the inlet and outlet plunger valve members 132v, 134v move together simultaneously and move the same distance because of the locomotive connection. Since the inlet and outlet plunger valve members 132v, 134v move together to restrict fluid flow into and through the first and second channels 28 and 30, respectively, only a short inlet and outlet plunger valve member stroke Ovs, Ivs is required to generate the signal pressure. For example, the present invention requires only half the valve member stroke as compared to that required in applicant’s ‘093 patent to generate a similar signal pressure. The shorter valve member stroke required and the force balancing of the inlet and outlet plunger valve members 132v, 134v results in lower power requirements for actuation -22- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)(e.g. actuator assembly 26 power requirement) which makes it very applicable for high data rate telemetry.

[0046] As discussed above, the actuator assembly 26 controls the positioning of the inlet and outlet plunger valve members 132v, 134v. The position of the inlet and outlet plunger valve members 132v, 134v relative to the outlet end 28o and inlet end 3'0 / of channels 28, 30 impacts the values of the fluid pressure P 1 upstream of the plunger valve members and the fluid pressure P2 downstream of the plunger valve members and within the flow' passageway 24. The fluid pressure in the annulus 6 is P3. Assuming a constant fluid F flow through the fluid passageway 24 and at a constant fluid density of fluid F, it is to be understood that in tire restricted position of the inlet and outlet plunger valve members 132v, 134v (similar to that shown in FIG. 2), fluid pressure Pl is greater than fluid pressure P2 resulting in a relatively high differential pressure PD. As the inlet and outlet plunger valve members 132v, 134v move further away from the channels 28, 30 as shown in FIG. 7, the fluid flow through the channels 28, 30 is less restricted or impeded and the difference between fluid pressures Pl and P2 lessens. The magnitude of the pressure difference PD between the fluid pressures P l and P2 is affected by the current flow parameters, such as the flow rate and density of the drilling fluid F. The present invention allows for the signal pressure to be adjustable, by adjusting the inlet and outlet plunger valve member stroke Ovs, Ivs, with respect to the existing flow rate and fluid density of the fluid F in the present deployment.

[0047] Shown in a side sectional view in FIG. 8 is an alternative embodiment with outlet and inlet valve poppet 32p, 34p diameters being smaller than diameters of the first and second channels 28, 30. Outlet and inlet valve poppets 32p, 34p can partially or completely enter the first and second channels 28, 30 and have the same or smaller diameters than the channel 28, 30 diameters, unlike the embodiments as shown in FIGS. 2-7, In the embodiment with the-23- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)poppets entering the channels 28, 30, the configuration of the valve is adjusted for the fluid flow parameters (density, flow rate), so that the gap be tween poppet outer diameter and channel diameter, or cross-sectional area of the gap between the outer diameter of the poppet and the channel diameter, is sized to accommodate the fluid flow, The configuration with the poppets not entering the channel (as described above) can easily be adapted to varying fluid flow parameters by modifying the stroke of the plunger valve members, which can be done during the deployment (in real time) by changing the actuator assembly parameters. The configuration of FIG. 8 with the poppets 32p, 34p entering the channels 28, 30, however, facilitates the assembly of the system, because the plunger valve member (rod plus poppet) as a whole can be fed from both ends through the channels 28, 30. A difference between the system with the poppets 32p, 34p entering tlie channels 28, 30 and known systems, e. g., valve-piston system as described in ‘093, is that both channels 28, 30 have plunger valve members (valve-valve system), as the embodiments described earlier in this application. The embodiment with the poppets entering the channel has still two symmetrically configured valves 32, 34 (flow rate is the same in both channels) and with it a symmetrical fluid flow in both valves or channels. Both valves 32, 34 open and close simultaneously, while in the prior art system ‘093 only the valve opens and the piston always restricts the fluid flow.

[0048] In FIGS. 9 and 10 are further alternative embodiments of a pulser tool 10A, 10B with shaped outlet and inlet valve poppets 32Ap, 34Ap, 32Bp, 34Bp, wherein the valve poppets 32Ap, 34Ap, 32Bp, 34Bp can enter, at least partially, the first and second channels 28A, 30A, 28B, 30B. Shaped poppets and / or channel ends can be beneficial for hydraulic reasons. FIG. 9 shows symmetrically shaped outlet and inlet valve poppets 32Ap, 34Ap. FIG. 10 shows outlet valve poppet 32Bp shaped differently than inlet valve poppet 34Bp. Outlet and inlet valve poppets 32Bp, 34Bp can be at different distances to the channel ends when in the restricted position. Different configuration of poppets (shape and position relative to channel) can be -24- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)used to compensate for different channel cross sections due to the outlet valve rod running through the first channel, while the second channel is having a fully open cross section.

[0049] Referring now to FIGS. 11 - 13, shown in a side sectional view are different configurations of an alternative embodiment with an inverted restrictor. The diameters of the first and second channels 28C, 30C each increase parabolically along a middle portion within the channels 28C, 30C. By reciprocating the poppets 32Cp, 34Cp within channels 28C, 30C, at different points in time both poppets 32Cp, 34Cp can simultaneously be in “restricted” or lower diameter portions of the channels 28C, 30C (FIGS. 11 and 13), and at another point in time of reciprocation, both poppets 32Cp, 34Cp can simultaneously be in “unrestricted” or the higher diameter portions of the channels 28C, 30C (FIG. 12. With a first and second plunger valve member stroke Ovs, Ivs located completely inside the channel 28C, 30C and symmetrically around the increased diameter area inside the channels 28C, 30C leads to the valve being in an open position (unrestricted position) at the medial position of the locomotive connection and the valve being in a closed position (restricted fluid flow position) at the two fully tilted positions of the locomotive connection. A reciprocating first and second plunger valve member movement leading to two differential pressure increases (pressure pulses) per stroke. This allows for higher pressure pulse rates (signal rates). Data rates of 40 to 100 bits per second are possible. In embodiments data rates of 40 to 150 bits per second are possible.

[0050] Shown in side sectional view' in FIGS. 14 and 15 is an alternative embodiment of a pulser tool 10D that generates two pressure pulses per stroke. Here, rods 32Dr, 34Dr disposed within each channel 28, 30 have a pair of valve poppets 32Dpl (third valve poppet), 32Dp2 (first valve poppet), 34Dpl (second valve poppet), 34Dp2 (fourth valve poppet), so that with lateral movement in a single direction of either rod 32Dr, 34Dr, one of the poppets 32Dpl, 32Dp2, 34Dpl, 34Dp2 is positioned adjacent an end of either channel 28, 30 to interfere with-25- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)flow through the channel 28D, 30D and generate a pressure pulse in the fluid flowing through the tool 10D. This configuration leads to two differential pressure increases (pressure pulses) per stroke.

[0051] Any of various configurations and mechanisms can be used to affect force balancing. In addition to or in place of the balancing mechanics described above, the locomotive connection 61 (force balancing mechanism) provided by linkage 60, inlet valve rod 134r, outlet valve rod 132r, fulcrum 62 and first, second and third bearings 61a, b, c can include rack and pinion gearboxes, crank or cam devices, wobble plates, hydraulic coupling (cylinder piston devices with hydraulic communication) rocker lever mechanisms and others.

[0052] It can also be appreciated that the drive 58 can be connected to the force balancing mechanism 61 by means of a bevel gear, a hypoid gear, a worm gear, a swash plate, or any other means to translate from a rotating or oscillating (motor) motion from the drive 58 to a rocking motion at the force balancing mechanism 61. The drive can include an electrical motor, or a hydraulic device,

[0053] In addition to what was explained above and with respect to adaptive plunger valve member positioning with respect to current flow rate and fluid density, further use of the adaptable position of the plunger valve members can be made to enhance the signal pressure, if required. In some situations, and depending on various circumstances, like elongated depth of borehole H, fluid F type and quality, and others, the signal (signal pressure variations) as sent to the surface can be distorted and decoding of the signal at the surface can be deteriorated. In such cases, it can be advisable to increase the signal pressure at the downhole pulser. Changes of signal pressure (adaption of plunger valve member stroke) can be sent as a command from a surface location (downlink) or the downhole device can detect deterioration or other issues automatically and adapt accordingly in an automated fashion without the -26- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)interaction of a human being or the reception of a downlink. Alternatively, to increasing signal pressure, the coding method of the signal and or transmission frequency can be changed to secure communication from downhole to the surface,

[0054] Signals can be encoded using various protocols, such as frequency shift keying (FSK), phase shift keying (PSK), amplitude shift keying (ASK). Other examples include more recent coding options such as quadrature phase shift keying (QPSK), quadrature amplitude shift keying (QASK), other time-based technologies such as pulse position modulation (PPM), and others.Especially for coding technologies typically using higher actuation frequencies, the force balancing mechanism technology is generally advantageous, since typically higher power demand is required to create such signals and using reciprocating valves.

[0055] It can be appreciated that even though there cannot be linear relation between plunger valve member position (plunger valve member stroke) and signal pressure generation, signal shaping methods can be applied to create certain demanded signal pressure shapes, such as sine, square, sawtooth, trapezoidal. For creation of such signals, the actuator assembly 26 actuation velocity or reciprocating frequency can be set to compensate for such non-linear relation and to create as accurate signal pressures as possible and in order to reduce high harmonic content and thus increase signal strength in a signal carrier frequency.

[0056] Nomenclature:1. drill bit B2. drilling fluid or mud F3. inlet valve force F / 4. outlet valve force Fo5. geological formation G6. borehole H7. drilling fluid system M8. fluid pressure Pl, P2, P39. drilling rig R-27- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)10 drill string 211 drilling fluid tank 412 receiver 513 annulus 614 pulser tool 1015 bottom hole assembly (BHA) 2016 housing 2217 passageway (or bore) 2418 actuator assembly 2619 first channel 2820 inlet end 28i21 outlet end 28o22 second channel 3023 inlet end 30i24 outlet end 30o25 outlet valve 3226 outlet valve rod 32r27 first rod guide 3328 inlet valve 3429 inlet valve rod 34r30 second rod guide 3531 restrictor 4032 balancing mechanics 5633 drive 5834 linkage 6035 bearing 6136 pressure compensator 7037 cylinder 7238 piston 7439 seal 7640 turbine 8041 alternator 8242 controller / electronics module 8443 wire 8644 wire 8845 battery 9046 pulser system 10047 outlet valve 13248 outlet valve rod 132r49 inlet valve 13450 inlet valve rod 134r51 guide 13652 support 138

[0057] The present invention described herein is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous-28- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)changes exist in the details of procedures for accomplishing the desired results. Although the invention has been described with reference to exemplary embodiments, it should be appreciated by those of skill in the art that various modifications are well within the scope and spirit of this disclosure. Further, those of skill in the art will appreciate that the invention is not limited to any specific embodiment and / or application and that the various embodiments described herein are illustrative and not restrictive.-29- IM-#J 0741876.5

Claims

Attorney Docket No.: 65TEL-510983-WO-2 (000242)CLAIMSWhat is claimed is:

1. A device for generating a differential pressure increase in a fluid in a fluid passageway in a housing, the device comprising:a first valve disposed in the fluid passageway, the first valve comprises a first restriction and a first plunger valve member;a second valve disposed in the fluid passageway, the second valve comprises a second restriction and a second plunger valve member;an actuator assembly configured to move the first plunger valve member relative to the first restriction and the second plunger valve member relative to the second restriction; a locomotive connection connecting the first plunger valve member and the second plunger valve member, the locomotive connection configured to move simultaneously the first plunger valve member in a first stroke direction to restrict fluid flow through the first restriction and the second plunger valve member in a second stroke direction, that is opposite the first stroke direction, to restrict fluid flow through the second restriction and to generate the differential pressure increase,2. Tire device of claim 1, wherein the differential pressure increase applies a first force on the first plunger valve member and a second force on the second plunger valve member, and the locomotive connection is configured to transmit the first force to the second plunger valve member in a direction opposite a direction of the second force.

3. The device of claims 1 or 2, wherein the actuator assembly applies a third force on the locomotive connection.-30- IM-#J 0741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)4. The device of claims 1-3, wherein the first plunger valve member comprises a first rod and a first closing member, the second plunger valve member comprises a second rod and a second closing member, the first restriction includes a first channel, the first channel includes a first channel inlet end and a first channel outlet end, the second restriction includes a second channel, the second channel includes a second channel inlet end and a second channel outlet end, and the first closing member restricts the first channel outlet end when the first plunger valve member moves in the first stroke direction and the second closing member restricts the second channel inlet end when the second plunger valve member moves in the second stroke direction,5. The device of claim 4, wherein the first rod reaches through the first channel and the first closing member is located outside the first channel when the first restriction is unrestricted.

6. The device of claims 1-3, wherein the first restriction includes a first channel and the second restriction includes a second channel, a diameter along the first channel changes from a first diameter to a second diameter to the first diameter, the second diameter greater than the first diameter, a diameter along the second channel changes from a third diameter to a fourth diameter to the third diameter, the fourth diameter greater than the third diameter, the first valve is restricted when the first plunger valve member restricts the fluid flow through the first diameter of the first channel, and the second valve is restricted when the second plunger valve member restricts the fluid flow through the third diameter of the second channel, wherein the first valve and the second valve create two differential pressure increases during a single first plunger valve member stroke and a single second plunger valve member stroke.

7. The device of claims 1-3, wherein the first plunger valve member includes a first rod, a first closing member and a third closing member, the second plunger valve member includes a second rod, a second closing member and a fourth closing member, the first restriction-31- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)includes a first channel, the first channel includes a first channel inlet end and a first channel outlet end, the second restriction includes a second channel, the second channel includes a second channel inlet end and a second channel outlet end, wherein the first closing member restricts fluid flow through the first channel outlet end, the third closing member restricts fluid flow through the first channel inlet end, the second closing member restricts fluid flow through the second channel inlet end and the fourth closing member restricts fluid flow through the second channel outlet end.8, The device of claim 7, wherein the first closing member moves towards the first channel outlet end when the third closing member moves away from the first channel inlet end, and the second closing member moves towards the second channel inlet end when the fourth closing member moves away from the second channel outlet end, and the first valve and the second valve create two differential pressure increases during a single first plunger valve member stroke and a single second plunger valve member stroke.

9. The device of claims 1-4, 6 or 7, wherein the fluid passageway is an inner bore in a bottom hole assembly (BHA) and at least 50% of the whole fluid flow through the BHA passes through the first restriction and the second restriction.

10. The device of claims 1-4, 6 or 7, wherein the fluid passageway is an inner bore in a bottom hole assembly (BHA) and at least 90% of the whole fluid flow through the BHA passes through the first restriction and the second restriction.11, The device of claims 1-3, wherein the first restriction includes a first channel, and the second restriction includes a second channel, and the first channel and the second channel are parallel.-32- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)12. The device of claims 1-4. 6, 7, and 9-11, wherein the actuator assembly includes an electric motor.

13. The device of claims 4, 6, and 7, further including a rod guide to support the first rod in the first channel.

14. The device of claims 1-13, further including a processor, the processor configured to:adjust a first plunger valve member stroke length and a second plunger valve member stroke length based on a change of fluid flow parameters.

15. A method of downhole operations comprising:directing fluid through a first channel and a second channel that are in a borehole; generating pressure pulses in tire fluid by selectively restricting fluid flowing from a downstream end of the first channel and flowing into an upstream end of the second channel; andmonitoring the pressure pulses at a location distal from the first and second channels, 16. The method of claim 15, wherein a first closing member is reciprocated relative to the downstream end of the first channel and a second closing member is reciprocated relative to the upstream end of the second channel to restrict the fluid flowing from the first channel and into the second channel.

17. The method of claim 16, wherein the first closing member is mounted on a first rod and the second closing member is mounted on a second rod, and the first rod and the second rod are connected by a locomotive connection, and wherein the first and second closing members are reciprocated by tilting the locomotive connection.-33- IM-#10741876.5Attorney Docket No.: 65TEL-510983-WO-2 (000242)18. The method of claims 16-17, wherein a stroke length of the first and second closing member is adjusted, using a processor.

19. The method of claims 16-18, wherein the first and second channel and the first and second closing member are part of a pulser tool that comprises a configuration that is selected from the group consisting of first and second closing members having diameters exceeding diameters of the first and second channels, closing members having diameters less than diameters of tire first and second channel, and closing members having diameters less than diameters of the first and second channels and the channels having portions with enlarged diameters.

20. The method of claims 15-19, wherein data is transmited to a surface location from the borehole in the pressure pulses, and wherein monitoring the pressure pulses at the surface location provides data about the borehole.-34- IM-#10741876.5

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