EXTENDED REACH AND JARRING TOOL FOR A BOTTOM HOLE ASSEMBLY

A downhole tool configured for inclusion in a drill string, typically as part of a bottom hole assembly. The downhole tool configured to improve passage of the drill string through a borehole. Additionally, the downhole tool is suitable for use in a method for improving passage of a drill string through a borehole.

BACKGROUND

In the drilling and completion industry, wellbores are drilled to significant depths for the purpose of production and/or injection of fluids, including hydrocarbons. Oftentimes frictional forces between the tubing being lowered into the well and the casing or formation wall are such that it is difficult to reach the required depth. In some cases, the tubing may actually lock up, such that the snubbing force applied from the surface is unable to overcome the frictional forces. Extended reach tools are utilized to assist in overcoming the frictional forces.

DETAILED DESCRIPTION

The drawings included with this application illustrate certain aspects of the embodiments described herein. However, the drawings should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art with the benefit of this disclosure.

The present disclosure may be understood more readily by reference to these detailed descriptions. For simplicity and clarity of illustration, where appropriate, reference numerals may be repeated among the different figures to indicate corresponding or analogous elements. The following description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may have been exaggerated to better illustrate details and features of the present disclosure. Also, the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting except where indicated as such.

Throughout this disclosure, the terms “about,” “approximate,” and variations thereof are used to indicate that a value includes the inherent variation or error for the device, system, or measuring method being employed as recognized by those skilled in the art.

Unless otherwise specified, use of the terms “connect,” “engage,” “couple,” “attach,” or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described.

Unless otherwise specified, use of the terms “up,” “upper,” “upward,” “up-hole,” “upstream,” or other like terms shall be construed as generally toward the surface; likewise, use of “down,” “lower,” “downward,” “down-hole,” “downstream,” or other like terms shall be construed as generally away from the surface, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical axis. A wellbore can include vertical, inclined or horizontal portions, and can be straight or curved.

The disclosed downhole tool10provides improved movement of drill strings through a borehole. Downhole tool10as shown in the FIGS. is suitable for use in drill strings in the form of coiled tubing or drill strings of solid tubulars. Both types of drill strings are commonly used in hydrocarbon production. When used with coiled tubing, downhole tool10is configured for incorporation into the bottom hole assembly (BHA)5commonly used in such drill strings. When used with tubulars, the downhole tool10is configured for incorporation at one or more of the joints between the tubulars. Tool10is shown lowered on a drill string2, which in one embodiment may be a coiled tubing into a wellbore4. Wellbore4may have a casing6therein but also may be an open hole wellbore. The downhole tool10may be used in vertical or deviated wells which like wellbore4have a vertical section7and a deviated section8. Although in the disclosed embodiment downhole tool10is depicted as lowered on a coiled tubing with a drill bit at an end thereof, it is understood that the downhole tool10may be conveyed into the well on jointed pipe as well, and may be any pipe or tubing such as a completion string, logging string, drill string or other type of string or piping employed in a downhole operation.

Downhole tool10can be activated in one of two active modes. In the first mode, the downhole tool imparts an oscillation frequency to the drill string thereby reducing friction between the drill string and the borehole walls. In the second mode, the downhole tool imparts a jarring effect to the drill string suitable for releasing the drill string or a downhole tool that has become stuck within the borehole. In addition to enhancing the movement of a drill string through a borehole, the configuration of downhole tool10permits unmodulated or unimpeded flow of fluid through downhole tool10when not in an active mode. The method of operating downhole tool10will be described in more detail below.

The optional configurations of downhole tool10will be described with reference to theFIG.1none embodiment, downhole tool10includes a proximal or first end12and a distal or second end14positioned at opposing ends of a tool housing20. First and second ends12and14may be configured either for attachment within a BHA5or as part of a joint between tubulars making up a traditional drill string.

A fluid passageway16extends from first end12to second end14and provides a path for drilling mud or other fluid to pass through downhole tool10. Also located within tool housing20is an electric motor18, a flow control valve22, a flow detection module24, a motor control module26and a pilot valve28. In one embodiment pilot valve28is a generally cup-shaped cylindrical valve with one or more ports86in an outer wall29thereof. Flow control valve22and tool housing20define an annulus21therebetween. Annulus21forms a portion of fluid passageway16. An inner surface of tool housing20defines a fluid flow control seat23. Motor18and a gearbox32are positioned within a motor housing38. Electric motor18receives current from batteries30. Batteries30may take any convenient form provided that the stored electrical energy is sufficient for the intended operational duration of downhole tool10. Typically, a set of D cell batteries sufficient to supply 28 volts will suffice.

A drive shaft34connects gearbox32to pilot valve28. Flow detection module24, motor control module26, an accelerometer36and batteries30are all positioned within an electronics housing39. With reference toFIGS.2A-2D and4A and4B, fluid passageway16begins at first end12and passes through fluid flow control valve22, pilot valve28and an annulus40defined by the interior wall of housing20, the motor/gearbox housing38and the electronics housing39. Fluid passageway16exits through the distal end14of downhole tool10. In most embodiments, drive shaft34will be supported by bearings42within a drive shaft housing44. Motor housing38is connected at its first, or upper end to drive shaft housing44and at its second end to electronics housing39. An optional pressure compensation piston46may be positioned in drive shaft housing44as shown inFIG.3. An electronics chassis48is positioned in electronics housing39.

Fluid flow control valve22in one embodiment comprises a poppet valve with poppet mandrel50and a poppet52that is slidable relative to poppet mandrel50. Poppet mandrel50has outer surface51, an upper end54and a lower end56. Poppet mandrel50comprises a mandrel body58and a reduced diameter mandrel neck60defining an upward facing shoulder61. A longitudinal central flow passage64is defined through flow control valve22. A plurality of radially directed ports66are defined through a wall of poppet mandrel50, and specifically through mandrel neck60. An external upward facing shoulder68is defined on outer surface51of poppet mandrel50, and in the embodiment described on mandrel body58. Radial ports70(shown more clearly inFIGS.5A and5B) are defined in mandrel body58at the lower end thereof.

Poppet52comprises a poppet head72with a generally cylindrical wall74extending therefrom. Poppet52has downward facing shoulder62and defines a cavity76in which poppet mandrel50is received. Poppet52has first, or upper end78and second, or lower end80. As described in more detail below, when pilot valve28is in an open position, fluid in tool housing20is permitted to flow through longitudinal central flow passage64and radial exit ports70in fluid flow control valve22into fluid passageway16. Poppet52is slidable relative to poppet mandrel50.

Pilot valve28has first, or upper end82and second or lower end84. Second end84has internal threads to connect to drive shaft34. Pilot valve ports86are defined through pilot valve28, and in one embodiment in wall29of pilot valve28. Pilot valve28may be a rotating cylindrical valve that is rotated by motor18. Pilot valve28controls operation of fluid flow control valve22. However, pilot valve28does not have a direct mechanical linkage to fluid flow control valve22. Rather, pilot valve28controls the fluid flow through downhole tool10and fluid flow control valve22thereby managing the operation of fluid flow control valve22.

Fluid flow control valve22is located between pilot control valve28and first end (proximal end)12of downhole tool10. In the described embodiment fluid flow control valve22may be a poppet valve which lacks a return spring. As such movement of fluid flow control valve22in the form of a poppet valve without a spring is controlled solely by fluid pressure as regulated by pilot valve28. With reference toFIGS.2A,4A and4B, fluid passageway16begins at first end12and passes through annulus21and annulus40defined by the inner surface of a wall of tool housing20, the motor/gearbox housing38and the electronics housing39exiting through the distal end14of downhole tool10. As explained below, when pilot valve28is in an open position, fluid in tool housing20will flow through flow control valve22and pilot valve28into annulus40. More specifically, fluid will flow through longitudinal central flow passage64and radial exit ports70in flow control valve22and through pilot valve ports86. Tool housing20also has bypass passages90defined therein that allow fluid in tool housing20to flow into annulus21when fluid flow control valve22is in a closed position. A slotted mandrel92is threadedly connected to the lower end of poppet mandrel50at a first end thereof and to drive shaft housing44at a second end thereof. Slots94in slotted mandrel92allow fluid flow from fluid flow control valve22to pass therethrough into annulus40when pilot valve28is in the open position.

With reference toFIGS.4B,4C, and5Bwith pilot valve28in the closed position flow through the lower end of poppet mandrel50is blocked. As a result, fluid flow through radial exit ports70is blocked, and fluid begins to flow into radial ports66. The fluid is trapped, however, so the pressure on the bottom, i.e., downstream or distal end, of poppet52of fluid flow control valve22is greater than pressure on the top side, i.e., upstream or proximal end, of fluid flow control valve22. The imbalanced fluid pressure drives poppet52of fluid control valve22upwards until it seals against fluid flow control valve seat23. Thus, with pilot valve28in the closed position, fluid flow control valve22is moved into and held in the closed position. However, as reflected inFIG.4C, fluid bypass passages90in tool housing20provide for continued flow into annulus40and through downhole tool10. When pilot valve28is open flow through radial exit ports70is permitted and the pressure on the bottom of poppet52of fluid flow control valve22is less than pressure on the top side of fluid flow control valve22. The resulting imbalance of fluid pressure drives the poppet52downwardly towards the distal end of downhole tool10, i.e., the open position. Fluid flow control valve22is configured to move between an open position as depicted inFIG.4Aand a closed position as depicted inFIG.4B. When held in the open position, as depicted inFIG.4A, fluid flow control valve22permits unmodulated, i.e., unimpeded fluid flow through downhole tool10.FIGS.4A-4Dare representative of the sequence of operations that occur when the fluid flow control valve22, and thus the tool10cycle between open and closed positions. When the pilot valve is open, as shown inFIG.4A, fluid flow control valve22is likewise open. To move the fluid flow control valve22to the closed position, pilot valve28is moved to the closed position as shown inFIG.4B.FIG.4Bshows the fluid flow control valve22still in the open position. As soon as pilot valve28moves to the closed position fluid flow control valve22will move to its closed position as shown inFIG.4C.FIG.4Dshows the pilot valve28rotated to the open position. When this occurs, fluid flow control valve22will move back to the open position shown inFIG.4A.

As will be described below in relation to the operation of downhole tool10, pilot valve28transitions between the open and closed positions during operation of downhole tool10. Thus, until fluid pressures on the top and bottom of poppet52of fluid flow control valve22react to the change in pilot valve28movement, fluid flow control valve22does not reflect the change in pilot valve28positioning. The closed position of the pilot valve is the position in which no flow therethrough is permitted.

Control of motor18, gearbox32and pilot valve28is provided by electronics chassis48located within electronics housing39. As noted above, electronics chassis48includes flow detection module24, motor control module26, accelerometer36and batteries30. Flow detection module24includes programming suitable for monitoring accelerometer36and detecting changes in fluid flow characteristics of a fluid passing through downhole tool10. In most instances, flow detection module24includes programming for monitoring accelerometer36and detecting vibrations produced by a fluid flowing through downhole tool10. Altering the fluid velocity will alter the vibrations generated by the fluid and hence the vibrations sensed by the accelerometer36. Further, flow detection module24includes programming which interprets the detected changes in the passing fluid such as a distinct series of vibrations and in response to the detected series of vibrations transmits any one of a plurality of operating mode signals to motor control module26.

Motor control module26includes programming suitable for receiving the operating mode signal and implementing an operating mode corresponding to the received operating mode signal. Implementation of the operating mode includes managing the operation of motor18which in turn controls operation of pilot valve28via gearbox32and drive shaft34. As discussed above, pilot valve28manages operation of fluid flow control valve22.

The foregoing discussion describes one embodiment of downhole tool10. However, modifications may be made to downhole tool10as described herein without negatively impacting the ability of downhole tool10to unmodulated fluid flow when fluid flow control valve22is in the open or inactive position. For example, downhole tool10may replace pilot valve28with a linear actuator which in turn drives fluid flow control valve22. A typical linear actuator is a solenoid. When using a solenoid in place of pilot valve28, fluid flow control valve22will typically be a linear motion poppet valve.

With continued reference to the FIGS., the operation of downhole tool10will be described. When running a coiled tubing drill string into a borehole, the operator may elect to use a friction reducing tool commonly known as an extended reach tool. Currently available extended reach tools are mechanically operated. These tools lack the option of an inactive mode. Thus, current extended reach tools operate during the entire drill string insertion and frequently damage the drill string and/or bottom hole assembly5. In contrast, downhole tool10provides for an inactive mode which permits unmodulated fluid flow through downhole tool10. As a result, downhole tool10is activated only when a need exists to reduce insertion drag or to free a drill string or tool that has become hung up.

Thus, use of downhole tool10provides an improved method for running drill string into a borehole. When the drill string is coiled tubing, downhole tool10will be included in BHA5. As known to those skilled in the art, BHA5is located at the distal end of the drill string. Downhole tool10may be located anywhere within BHA5. When the drill string is made up of conventional tubular pipe, downhole tool10may be located at one or more joints between adjacent tubulars. Downhole tool10may be used in connection with any number of downhole processes, including, in non-limiting examples, drilling operations for drilling out frac plugs or other drilling operations. In such a case a drill bit will be connected in the coiled tubing or other string below the downhole tool10. Although downhole tool10may be used in drilling operations, downhole tool10may be used in connection with other operations, including, in non-limiting examples, fishing and cleanout operations.

During the insertion process, one or more pumps located either at the surface or in the drill string at locations above BHA5force working fluid through the drill string. In the initial insertion, the working fluid will be pumped through passageway16in downhole tool10, and tool10will be in an inactive mode. If the tubing on which downhole tool10can be moved through the wellbore in which it is inserted without the need for activating downhole tool10, flow will continue unimpeded until the tubing reaches the desired location in the well. If during insertion it is desired to impart oscillations to the tubing, or to generate a jarring impact to the tubing, the pumps delivering the fluid can be operated to achieve both.

Operation of the pumps will impart vibrations within the fluid flowing through the drill string. Thus, controlled operation of the pumps can impart a series of detectible vibrations in the flowing fluid. The well operator can select a series of vibrations which correspond to an operating mode stored within the memory components of flow detection module24and motor control module26. By managing operation of the pumps, the selected vibration signal is transmitted downhole to downhole tool10. Using onboard programming, flow detection module24senses the series of vibrations. In most embodiments, flow detection module24includes an accelerometer36suitable for detecting fluid vibrations.

Flow detection module24includes programming suitable for reading the sensed vibrations and correlating the sensed vibrations to one of a plurality of operating modes and operating mode signals. When the flow detection module24identifies a series of vibrations which correspond to an operating mode stored in its memory, flow detection module24will select and send the corresponding operating mode signal to motor control module26. Upon receipt of an operating mode signal, motor control module26will manage operation of electric motor18and gearbox32in accordance with the received operating mode signal. Alternatively, motor control module26will manage the operation of the linear actuator or other control mechanism managing operation of fluid flow control valve22.

While a plurality of operating modes may be programmed into motor control module26, at a minimum, the following operating modes will be provided: Default Mode=OFF; Mode 1=ON at Frequency1; Mode 2=ON at Frequency2; and, Mode 3=intermittent jarring action.

In the Default Mode, motor control module26turns off motor18. In this mode, pilot valve28is inactive and resting in the open position. As a result, fluid flow control valve22is held open by fluid pressure exerted against the top or proximal end of poppet52of fluid flow control valve22which is greater than fluid pressure exerted against the bottom or distal end of poppet52. Thus, in the Default Mode, fluid flowing through the drill string enters BHA5and passes through downhole tool10through fluid passageway16unimpeded by fluid flow control valve22. Thus, the fluid flows through unmodulated and downhole tool10does not impart any vibrations or oscillations to the drill string. Thus, the Default Mode reduces stress on the drill string during insertion operations that do not require friction reduction.

When the drill string does not slide through the borehole at a desired rate, the operator may operate the pumps in a manner to send vibration signals to flow detection module24corresponding to one of a plurality of modes, e.g., Mode 1 or Mode 2. Note, while only two “On Modes” are described herein for exemplary purposes, additional On Modes operating at other frequencies could be programmed into flow detection module24and motor control module26. When flow detection module24identifies a vibration pattern corresponding to one of the On Modes, flow detection module24selects the corresponding operating mode signal and transmits the signal to motor control module26. Upon receipt of the operating mode signal, motor control module26activates motor18. Operation of motor18through gearbox32drives pilot valve28. As noted above, pilot valve28does not have a direct mechanical connection to fluid flow control valve22. Rather, actuation of pilot valve28in response to operation of motor18manages the position of fluid flow control valve22through controlling the position of pilot valve28. Shifting pilot valve28between the open and closed position causes corresponding opening and closing of fluid flow control valve22.

In the open position of the fluid flow control valve22and pilot valve28fluid flows through longitudinal central flow passage64of fluid flow control valve22, through radial ports70, pilot valve ports86which are aligned with ports70and slots94in slotted mandrel92into annulus40. To close fluid flow control valve22, motor18rotates pilot valve28in response to a signal received from flow detection module24. The rotation of pilot valve28creates a misalignment between radial exit ports70and pilot valve ports86and blocks flow therethrough. As a result, fluid is pushed radially outwardly into ports66in poppet mandrel50. Ports66have no exit and fluid pressure is created that pushes upwardly on poppet52, urging poppet52upwardly on poppet mandrel50into fluid flow valve seat23defined on tool housing20. Continued rotation of pilot valve28will realign radial ports70and pilot valve ports86allowing flow therethrough and releasing the upward fluid pressure applied to poppet52. Poppet52will slide downwardly on poppet mandrel50and move to the open position of fluid flow control valve22.

In one optional embodiment, fluid flow control valve22cycles between fully closed, i.e., seated against fluid flow control valve seat23, and fully open. However, in other embodiments, the stroke of fluid flow control valve22may be limited through actuation of pilot valve28to preclude seating. In this embodiment, the operator has the ability to control the amplitude of the resulting pressure pulses through selection of the appropriate Operating Mode.

The longer the fluid flow control valve22is held in the closed position, the greater fluid pressure develops behind or upstream of fluid flow control valve22. During the pressure buildup, the drill string stiffens. Upon release of the increased fluid pressure through fluid flow control valve22, the drill string in turn relaxes. Without intending to be limited by theory, it is believed that the cycling of stiffening and relaxing of the drill string improves movement of the drill string through the borehole. Thus, an operating signal corresponding to an On Mode will produce lower resistance to the insertion of the drill string into the borehole.

The On Mode may cycle fluid flow control valve22between the open and closed positions at a rate between about 1 to 8 cycles per second. More typically, the cycle rate of fluid flow control valve22will be between about 3 to 8 cycles per second with the most likely cycle rate being between 3 to 5 cycles per second. Lower cycle rates per second will increase the pressure associated with each cycle. Conversely, higher cycle rates per second will lower the pressure associated with each cycle as fluid flow control valve22spends a reduced period of time in the off position thereby limiting fluid pressure build up.

In one embodiment motor18rotates pilot valve28at a non-constant speed in response to signals received from the flow detection module24. The non-constant rotation will provide for a snap open and snap closed operation and an increase in the dwell time of the flow control valve22in the open/closed positions, along with a reduction in transition time as a proportion of the overall cycle time. For example, during the initial insertion downhole tool10will be in a fully open position to allow unimpeded flow therethrough. When it is initially desired to impart a vibratory signal to downhole tool10to generate a desired oscillation pattern, the pilot valve28will begin rotation and will rotate to generate an almost immediate closure of radial exit ports70in fluid flow control valve22to prevent flow therethrough. Poppet52will snap upwardly to engage seat23and move fluid flow control valve22to the closed position. The speed of rotation of pilot valve28will then slow to increase the dwell time in the closed position of fluid flow control valve22, which provides for a pressure buildup.

When pilot valve28rotates sufficiently such that pilot valve ports86nearly reach radial exit ports70, the rotational speed will increase such that pilot ports86and radial exit ports70in fluid flow control valve22come into alignment in an almost immediate fashion, thereby moving the fluid flow control valve to the open position. The rotation of pilot valve28may then again momentarily slow, or stop to increase dwell time in the open position. When the desired amount of dwell time has occurred, the pilot valve28will once again rotate quickly to block flow through radial exit ports70and generate an almost immediate closure of fluid flow control valve22. If desired, rather than slowing, or momentarily ceasing rotation in the open position of the fluid flow control valve, the rotation of pilot valve28may be such that ports86pass over radial exit ports70in fluid flow control valve22quickly to create an almost immediate snap from the closed to the open position and back to the closed positions of the fluid flow control valve22. The dwell time in the open and/or closed positions can therefore be controlled by varying the speed of rotation of the pilot valve28. Any number of variations in rotational speed may be used to create the desired oscillation of the downhole tool10. Thus, the fluid flow control valve22can be opened and closed in predetermined timing sequences correlating to the operating mode signals produced by the flow detection module.

From time to time, drill strings become hung up on the irregularities of a borehole. To free the drill string, downhole tool10provides for imparting a jarring action to the drill string. As described above, a jarring action is another operating mode. When flow detection module24identifies a series of vibrations corresponding to the operating mode for a jarring action, the appropriate operating mode signal is sent to the motor control module26. In this mode, motor control module26manages operation of motor18such that pilot valve28controls fluid flow control valve22at a much slower rate than any of the friction reduction modes. In a typical jarring mode, fluid control valve22will be controlled to cycle open and closed at rates between about 1 cycle per second to one cycle per thirty seconds. In some cases, cycle rates of about one per three seconds will provide the desired increase in fluid pressure necessary to impart a jarring action to the drill string. The dwell time in the closed position in this mode may be increased to a level such that when pilot valve28moves from the closed to the open position, the resulting movement of the poppet52of fluid flow control valve22is such that it creates the jarring impact.

The foregoing operational steps apply equally to the alternative embodiment configurations of downhole tool10discussed above. Additionally, the described operational steps are equally applicable to removal or retrieval of coiled tubing and tubular type drill strings from a borehole. Thus, operation of downhole tool10in accordance with the foregoing methods applies to both insertion and retrieval operations.

Other embodiments of the present invention will be apparent to one skilled in the art. As such, the foregoing description merely enables and describes the general uses and methods of the present invention. Accordingly, the following embodiments define the true scope of the present invention.

Embodiments Include

A downhole tool comprising a tool housing having first and second ends and configured for attachment within a drill string. A fluid passageway providing fluid communication through the downhole tool extends from the first end to the second end of the downhole tool. The downhole tool comprises a motor and a fluid flow control valve positioned within the fluid passageway, the fluid control valve movable between an open and a closed position in response to operation of the motor, the fluid flow control valve configured to permit unmodulated flow of a fluid through the fluid passageway when in the open position. A flow detection module is programmed to provide an operating mode signal in response to sensed fluid flow characteristics of the fluid passing through the fluid passageway. A motor control module in electronic communication with the flow detection module and the motor is programmed to receive the operating mode signal and programmed to manage operation of the motor to control movement of the flow control valve.

Embodiment 2. The downhole tool of embodiment 1, wherein the flow control valve is a poppet valve.

Embodiment 3. The downhole tool of embodiment 2, further comprising a pilot valve, the pilot valve positioned to control actuation of the poppet valve; a gearbox, the gearbox secured to the motor; and a drive shaft having a first end and a second end, the first end of the drive shaft secured to the gearbox and the second end of the drive shaft secured to the pilot valve.

Embodiment 4. The downhole tool of embodiment 3, wherein the pilot valve is a rotary valve.

Embodiment 5. The downhole tool of any of embodiments 1-4, wherein the flow detection module and motor control module are part of a single control circuit.

Embodiment 6. The downhole tool of any of embodiments 1-5, wherein the flow detection module includes an accelerometer and the flow detection module is programmed to use the accelerometer to produce the operating signal in response to the sensed fluid characteristics where the sensed fluid characteristics include vibrations in the fluid flowing through the friction reducing tool.

Embodiment 7. A method for reducing friction in a drill string as the drill string moves through a borehole, the method comprising running the drill string into a borehole. The drill string includes a friction reduction tool comprising a first end configured for attachment within the drill string; second end configured for attachment within the drill string; fluid passageway providing fluid communication through the friction reducing tool, the fluid passageway extending from the first end to the second end of the friction reducing tool; a motor; a fluid flow control valve positioned within the fluid passageway, the fluid control valve movable between an open and a closed position; a flow detection module programmed to provide a plurality of operating mode signals; and a motor control module in electronic communication with the flow detection module and the motor, the motor control module programmed to receive the operating mode signals. The method comprises flowing a fluid through the friction reduction tool; sensing vibrations generated by the fluid flowing through the friction reduction tool with the flow detection module; selecting one of the plurality of operating mode signals in response to the sensed vibrations; transmitting the selected operating mode signal to the motor control module; and operating the fluid control valve in accordance with the selected operating mode to control fluid flow through the friction reduction tool.

Embodiment 8. The method of embodiment 7, the flowing step comprising pumping fluid through the friction reduction tool in a predetermined flow pattern, wherein the vibrations created by the flow pattern correlate to one of the plurality of operating mode signals, the method further comprising selecting the operating mode signal to which the vibrations correlate.

Embodiment 9. The method of embodiment 8, wherein the step of operating the fluid control valve in accordance with the selected operating mode produces within the fluid flowing through the drill string one of: an oscillation frequency, an intermittent jarring action or a free flow of fluid; and wherein use of the operating modes which produce an oscillation frequency or an intermittent jarring action overcomes friction during movement of the drill string through the borehole.

Embodiment 10. The method of either of embodiments 8 or 9, wherein the selected operating mode operates the fluid flow control valve to cycle the fluid flow control valve between open and closed positions in a predetermined pattern.

Embodiment 11. The method of embodiment 10, wherein during each cycle between the open and closed position, the fluid flow control valve is in the closed position for a longer period of time than in the open position.

Embodiment 12. The method of either of embodiments 10 or 11 wherein during each cycle between the open and closed position, the fluid flow control valve is in the closed position for a shorter period of time than in the open position.

Embodiment 13. A downhole tool comprising a tool housing defining a fluid passageway therethrough extending from a first to a second end of the tool housing. A fluid flow control valve movable between open and closed positions is disposed in the tool housing, the flow control valve having a plurality of radial exit ports defined therein. A pilot valve is positioned in the tool housing and is rotatable relative to the fluid flow control valve. A motor is connected to the pilot valve and operable to rotate the pilot valve at a predetermined rate of rotation in response to an operating mode signal produced by a flow detection module in the tool housing, wherein rotation of the pilot valve opens and closes the radial exit ports at the predetermined rate to open and close the fluid flow control valve in a predetermined timing sequence.

Embodiment 14. The downhole tool of embodiment 13, wherein the operating mode signal is produced based on a vibration pattern created by fluid flowing in the tool housing.

Embodiment 15. The downhole tool of embodiment 14, comprising a flow detection module for producing the operating mode signal; a motor control module disposed in the tool housing; and a drive shaft connecting the motor control module to the pilot valve, wherein the operating mode signal is received by the motor control module and the motor control module rotates the pilot valve.

Embodiment 16. The downhole tool of embodiment 15, wherein the flow detection module is configured to produce a plurality of operating mode signals and wherein each operating mode signal corresponds to a different rate of rotation of the pilot valve.

Embodiment 17. The downhole tool of embodiment 16, wherein each of a plurality of operating mode signals is produced in response to a distinct vibration pattern created by fluid flowing in the tool housing.

Embodiment 18. The downhole tool of any of embodiments 13-17, the fluid flow control valve comprising a poppet valve, wherein in the closed position of the pilot valve the poppet valve is urged upwardly in the housing to engage and seat against the tool housing.

Embodiment 19. The downhole tool of embodiment 18, the poppet valve comprising: a poppet; and a poppet mandrel, the poppet being vertically reciprocable on the poppet mandrel.

Embodiment 20. The downhole tool of embodiment 19, wherein the operating mode signal causes the pilot valve to rotate at a non-constant rotational speed.

Other embodiments of the present invention will be apparent to one skilled in the art. As such, the foregoing description merely enables and describes the general uses and methods of the present invention. Accordingly, the following claims define the true scope of the present invention.