Patent Description:
In one aspect, disclosed is an apparatus for use in a wellbore. The apparatus may include a drill string configured to drill the wellbore, a non-rotating section disposed along the drill string and having a bore and at least one biasing member engaging an adjacent wall, a rotating section disposed in the bore of the non-rotating section, a bearing between the rotating section and the non-rotating section that allows relative rotation between the rotating section and the non-rotating section, at least one relative rotation sensor configured to generate signals representative of a rotation of the rotating section relative to the non-rotating section, at least one orientation sensor configured to generate signals representative of an orientation of the non-rotating section relative to a selected frame of reference, and a controller in signal communication with the at least one relative rotation sensor and the at least one orientation sensor. The controller adjusts at least one of: (i) a force applied by the at least one biasing element, and (ii) a position of the at least one biasing element, the adjusting being in response to the generated signals from the at least one relative rotation sensor and the generated signals from the at least one orientation sensor.

A related method for using the apparatus includes disposing the above-described apparatus in an earth formation, varying a rotational frequency of the rotating section to transmit a control signal, using the controller to determine the control signal by detecting the rotational frequency variances using the at least one relative rotation sensor, and controlling a force and/or position of the at least one biasing element by using the determined control signal and the generated signals from the at least one orientation sensor.

In aspects, the present disclosure provides an apparatus for use in a wellbore. The apparatus may include a drill string configured to drill the wellbore; a non-rotating section disposed along the drill string, the non-rotating section having a bore and at least one biasing element engaging a wall of the wellbore; a rotating section disposed in the bore of the non-rotating section; at least one relative rotation sensor configured to generate signals representative of a rotation of the rotating section relative to the non-rotating section; at least one orientation sensor within the non-rotating section configured to generate signals representative of an orientation of the non-rotating section relative to a selected frame of reference; and a controller. The controller may be in signal communication with the at least one relative rotation sensor and the at least one orientation sensor, the controller being configured to adjust at least one of: (i) a force applied by the at least one biasing element, and (ii) a position of the at least one biasing element, the adjusting being in response to the generated signals representative of a rotation of the rotating section relative to the non-rotating section from the at least one relative rotation sensor and the generated signals representative of an orientation of the non-rotating section relative to a selected frame of reference from the at least one orientation sensor, wherein the non-rotating section is configured to receive energy from the rotation of the rotating section.

In aspects, the present disclosure provides a method of using an apparatus in a wellbore. The method may include disposing a drill string in the wellbore, the drill string being configured to drill the wellbore. The drill string may include (i) a non-rotating section disposed along the drill string, the non-rotating section having a bore and at least one biasing element configured to engage a wall of the wellbore, (ii) a rotating section disposed in the bore of the non-rotating section, (iii) at least one relative rotation sensor configured to generate signals representative of a relative rotation between the rotating section and the non-rotating section, (iv) at least one orientation sensor in the non-rotating section and configured to generate signals representative of an orientation of the non-rotating section relative to a selected frame of reference, and (v) a controller in signal communication with the at least one relative rotation sensor and the at least one orientation sensor. The method may include the further steps of varying a speed of the rotation of the rotating section to transmit a control signal; using the controller to determine the control signal by detecting the rotational frequency variances using the at least one relative rotation sensor; receiving energy within the non-rotating section from the rotation of the rotating section and controlling a force and/or position of the at least one biasing element by using the determined control signal and the generated signals representative of the orientation of the non-rotating section relative to the selected frame of reference from the at least one orientation sensor.

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:.

Apparatuses, systems and methods for directional drilling through an earth formation are described herein. An embodiment of a directional drilling device or system includes a self-contained module configured to be incorporated in a downhole component that may include a substantially non-rotating sleeve. The module is hermetically sealed and is modular, i.e., the self-contained module may be easily exchanged for other modules to reduce turn-around time. In accordance with an exemplary aspect, the self-contained module can be installed on and/or removed from the downhole component or the substantially non-rotating sleeve without having to electrically disconnect the module or otherwise impact other components of the system such as the downhole component, the directional drilling device, the substantially non-rotating sleeve and/or a steering system.

The self-contained module houses and at least partially encloses or encapsulates one or more of a variety of components to facilitate or perform functions such as steering, measurement and/or others. In one embodiment, the self-contained module houses and at least partially encloses a biasing device (e. a cylinder and piston assembly) that can be actuated to affect changes in drilling direction. The self-contained module may include an energy storage device (e. , a battery, a rechargeable battery, a capacitor, a supercapacitor, or a fuel cell). In one embodiment, the self-contained module may house an energy transmitting/receiving device configured to supply energy, such as electrical energy to components in the module. The energy transmitting/receiving device may generate electricity, e. via inductive coupling with a magnetic field generated due to rotation of a drive shaft or other component of a drill string.

<FIG> illustrates an exemplary embodiment of a well drilling, exploration, productions, measurement (e. , logging) and/or geosteering system <NUM>, which includes a drill string <NUM> configured to be disposed in a borehole <NUM> that penetrates an earth formation <NUM>. Although the borehole <NUM> is shown in <FIG> to be of constant diameter and direction, the borehole is not so limited. For example, the borehole <NUM> may be of varying diameter and/or direction (e. , varying azimuth and inclination). The drill string <NUM> is made from, for example, a pipe, multiple pipe sections or coiled tubing. The system <NUM> and/or the drill string <NUM> includes a drilling assembly (including, e. , a drill bit <NUM> and steering assembly <NUM>) and may include various other downhole components or assemblies, such as measurement tools <NUM> and communication assemblies, one or more of the drilling assembly, the measurement tools <NUM>, and the communication assemblies may be collectively called a bottomhole assembly (BHA) <NUM>. Measurement tools may be included for performing measurement regimes such as logging-while-drilling (LWD) applications and measurement-while-drilling (MWD) applications. Sensors may be disposed at one or multiple locations along a borehole string, e. , in the BHA <NUM>, in the drill string <NUM>, in measurement tool <NUM>, such as a logging sonde, or as distributed sensors.

The drill string <NUM> drives a drill bit <NUM> that penetrates the earth formation <NUM>. Downhole drilling fluid, such as drilling mud, is pumped through a surface assembly <NUM> (including, e. , a derrick, rotary table or top drive, a coiled tubing drum and/or standpipe), the drill string <NUM>, and the drill bit <NUM> using one or more pumps, and returns to the surface through the borehole <NUM>.

Steering assembly <NUM> includes components configured to steer the drill bit <NUM>. In one embodiment, steering assembly <NUM> includes one or more biasing elements <NUM> configured to be actuated to apply lateral force to the drill bit <NUM> to accomplish changes in direction. One or more biasing elements <NUM> may be housed in a module <NUM> that can be removably attached to a sleeve (not separately labeled) in the steering assembly <NUM>.

Various types of sensors or sensing devices may be incorporated in the system and/or drill string. For example, sensors such as magnetometers, gravimeters, accelerometers, gyroscopic sensors and other directional and/or location sensors can be incorporated into steering assembly <NUM> or in a separate component. Various other sensors can be incorporated into the BHA <NUM>, such as into the steering assembly <NUM> and/or into the measurement tool <NUM>. Examples of measurement tools include resistivity tools, gamma ray tools, density tools, or calipers.

Other examples of devices that can be used to perform measurements include temperature or pressure measurement tools, pulsed neutron tools, acoustic tools, nuclear magnetic resonance tools, seismic data acquisition tools, acoustic impedance tools, formation pressure testing tools, fluid sampling and/or analysis tools, coring tools, tools to measure operational data, such as vibration related data, e. acceleration, vibration, weight, such as weight-on-bit, torque, such as torque-on-bit, rate of penetration, depth, time, rotational velocity, bending, stress, strain, any combination of these, and/or any other type of sensor or device capable of providing information regarding earth formation <NUM>, borehole <NUM> and/or operation.

Types of sensors may include discrete sensors (e. , strain and/or temperature sensors) along the drill string sensors or sensor systems comprising one or more transmitter, receiver, or transceivers at some distance, as well as distributed sensor systems with various discrete sensors or sensor systems distributed along the system <NUM>. It is noted that the number and type of sensors described herein are exemplary and not intended to be limiting, as any suitable type and configuration of sensors can be employed to measure properties.

A processing unit <NUM> is connected in operable communication with components of the system <NUM> and may be located, for example, at a surface location. The processing unit <NUM> may also be incorporated at least partially in the drill string <NUM> or the BHA <NUM> as part of downhole electronics <NUM>, or otherwise disposed downhole as desired. Components of the drill string <NUM> may be connected to the processing unit <NUM> via any suitable communication regime, such as mud pulse telemetry, electro-magnetic telemetry, acoustic telemetry, wired links (e. , hard wired drill pipe or coiled tubing), wireless links, optical links or others. The processing unit <NUM> may be configured to perform functions such as controlling drilling and steering (e.g., by steering assembly <NUM>), transmitting and receiving data (e. , to and from the BHA <NUM> and/or the module <NUM>), processing measurement data and/or monitoring operations. The processing unit <NUM>, in one embodiment, includes a processor <NUM>, a communication and/or detection member <NUM> for communicating with downhole components, and a data storage device (or a computer-readable medium) <NUM> for storing data, models and/or computer programs or software <NUM>. Other processing units may comprise two or more processing units at different locations in system <NUM>, wherein each of the processing units comprise at least one of a processor, a communication device, and a data storage device.

<FIG> and <FIG> illustrate an embodiment of a steering assembly <NUM> for use in directional drilling. The steering assembly <NUM> may be incorporated into the system <NUM> (e. , in BHA <NUM>) or may be part of any other system configured to perform drilling operations. The steering assembly <NUM> includes a drive shaft <NUM> configured to be rotated from the surface, e. by a top drive (not shown), that may be part of surface assembly <NUM>, or downhole (e. , by a mud motor or turbine (also not shown) that may be part of the BHA <NUM>. The drive shaft <NUM> can be connected at one end to a disintegrating device, such as a drill bit <NUM> via, e. , a connector, such as a bit box connector <NUM>. The disintegrating device, in combination with or in place of the drill bit <NUM>, may include any other device suitable for disintegrating the rock or earth formation, including, but not limited to, an electric impulse device (also referred to as electrical discharge device), a jet drilling device, or a percussion hammer.

The drive shaft <NUM> can be connected at the other end and/or at the same end between the disintegrating tool and the drive shaft <NUM> to a downhole component <NUM>, such as mud motor (not shown), a communication tool to provide communication from and to surface assembly <NUM>, a power generator (not shown) that generates power downhole for driving other tools in the BHA <NUM>, such as the downhole electronics, <NUM>, the measurement tool <NUM> including sensors, such as formation evaluation sensors, or operational sensors, a reamer (e. an underreamer, not shown) the steering assembly <NUM>, <NUM>, or a pipe section in drill string <NUM>, via a suitable string connection such as a pin-box connection. Some of the downhole components <NUM>, such as measurement tools, may benefit from the close position to the disintegrating device when connected at the lower end of drive shaft <NUM> between disintegrating device and the steering assembly <NUM>.

The steering assembly <NUM> also includes a sleeve <NUM> that surrounds a portion of the drive shaft <NUM>. The sleeve <NUM> may include one or more biasing elements <NUM> that can be actuated to control the direction of the drill bit <NUM> and the drill string <NUM>. Examples of biasing elements include devices such as cylinders, pistons, wedge elements, hydraulic pillows, expandable rib elements, blades, and others.

The sleeve <NUM> is mounted on the drive shaft via bearings <NUM> or another suitable mechanism so that the sleeve <NUM> is to at least some extent rotationally de-coupled from the drive shaft <NUM> or other rotating components. For example, the sleeve <NUM> is connected to bearings <NUM>, e. mud lubricated bearings, that may be any type of bearings including but not limited to contact bearings, such as sliding contact bearings or rolling contact bearings, journal bearings, ball bearings or bushings. The sleeve <NUM> may be referred to as a "non-rotating sleeve", or "slowly rotating sleeve" which is defined as a sleeve or other component that is to at least some extent rotationally decoupled from rotating components of the steering assembly <NUM>. During drilling, the sleeve <NUM> may not be completely stationary, but may rotate at a lower rotational speed compared to the drive shaft <NUM> due to the friction between sleeve <NUM> and drive shaft <NUM>, e. , friction that is generated by bearings <NUM>. The sleeve <NUM> may have slow or no rotational movement compared to the drive shaft <NUM> (e. , when biasing elements <NUM> are engaged with a borehole wall), or may rotate independent of the drive shaft <NUM> (usually the sleeve <NUM> rotates at a much lower rate than the drive shaft <NUM>) especially when the biasing elements <NUM> are actively engaged.

For example, while drive shaft <NUM> may rotate between about <NUM> to about <NUM> revolutions per minute (RPM), the sleeve <NUM> may rotate at less than about <NUM> RPM Thus, the sleeve <NUM> is substantially non-rotating with respect to the drive shaft <NUM> and is, therefore, referred to herein as the substantially non-rotating or non-rotating sleeve, irrespective of its actual rotating speed. In some instances, the biasing elements <NUM> can be supported by spring elements (not shown), such as a coil spring, or a spring washer, e. a conical spring washer to engage with the earth formation even when the biasing elements <NUM> are not actively powered.

In one embodiment, the biasing element <NUM> (or elements) is configured to engage the borehole wall and provide a lateral force component to the drive shaft <NUM> through the bearings <NUM> to cause the drive shaft <NUM> and the drill bit <NUM> to change direction. One or more biasing elements <NUM> are connected to the non-rotating sleeve <NUM> to apply relatively stationary forces to the borehole wall (also referred to as "pushing the bit") or to deflect the drive shaft <NUM>, causing the bend direction of the rotating drive shaft <NUM> to create a steering direction (also referred to as "pointing the bit").

Since the non-rotating sleeve <NUM> rotates significantly slower or does not rotate at all with respect to the earth formation <NUM>, the biasing elements <NUM>, and thus, the forces applied to the borehole wall have a direction that varies relatively slowly compared to the faster rotation of the drive shaft <NUM>. This allows for a force applied to the borehole wall to keep a desired steering direction with much less variation compared to a scenario where the biasing element <NUM> rotates with the drive shaft <NUM>. In this manner, the power required to achieve and/or keep a desired steering direction is significantly lower as compared to a system in which the biasing element <NUM> rotates with the drive shaft <NUM>. Thus, utilization of the non-rotating sleeve <NUM> allows for operation of steering systems with relatively low power demand.

The sleeve <NUM> may be a modular component of the steering assembly <NUM>. In aspects, the sleeve <NUM> can be installed on and removed from the steering assembly <NUM> without having to electrically disconnect the sleeve or otherwise impact other components of the steering system. Alternatively, or in addition, the sleeve <NUM> also includes one or more modules <NUM> configured to enclose or house one or more components for facilitating steering functions. Each module <NUM> is mechanically and electrically self-contained and modular, in that the module <NUM> can be attached to and removed from the sleeve <NUM> without affecting components in the module <NUM> or steering assembly <NUM>.

For example, each module <NUM> includes mechanical attachment features such as clamping elements (not shown), e. devices for thermal clamping, devices including shape memory alloy, press fit devices, or tapered fit devices, or screw holes <NUM> that allow the module <NUM> to be fixedly connected to the sleeve <NUM> with a removable fixing mechanism such as screws, bolts, threads, magnets, or clamping elements, e. mechanical clamping elements, thermal clamping elements, clamping elements including shape memory alloy, press fit elements, tapered fit elements, and/or any combination thereof. Further, in another example, module <NUM> may be fixedly connected to the sleeve <NUM> with removable fixing mechanism such as screws, bolts, threads, magnets, or clamping elements, e. mechanical clamping elements, thermal clamping elements, clamping elements including shape memory alloy, press fit elements, tapered fit elements, or any combination thereof without any non-removable fixing elements.

Each module <NUM> may at least partially enclose one or more biasing elements <NUM>, and may include one type of biasing element <NUM> or multiple types of biasing elements <NUM>. It is noted that each module <NUM> can include a respective biasing element <NUM> and associated controller, allowing each biasing element <NUM> to be operated independently.

In the embodiment of <FIG> and <FIG>, the sleeve <NUM> includes three modules <NUM> circumferentially arranged (e. , separated by the same angular distance). However, the sleeve <NUM> is not so limited and can include a single module <NUM> or any suitable number of modules <NUM>. Also, the module or modules <NUM> can be positioned at any suitable location or configuration.

Each module <NUM> and/or the sleeve <NUM> may include sealing components to allow for hermetically sealing the module <NUM> to the sleeve <NUM> so as to prevent fluid from flowing through the wall of the sleeve <NUM>. Alternatively, the module <NUM> may be attached to the sleeve <NUM> without sealing the module <NUM> to the sleeve <NUM>, e. without any fluid sealing elements beyond the mechanical attachment discussed above.

In one embodiment, each module <NUM> is configured to communicate with components outside of the module <NUM> without a physical electrical connection, such as a wire or cable. That is, the module <NUM> is electrically isolated while still be configured to receive energy and/or data.

The modules <NUM> can therefore be handled as enclosed units, even when they are detached from the sleeve <NUM>. Thus, as the modules <NUM> may be hermetically enclosed units, they can, for instance, be tested, verified, calibrated, maintained, and/or repaired, or it can exchange data (download or upload), without the need to attach the modules <NUM> to the sleeve <NUM>, or simply be cleaned, e. by using a regular high pressure washer. The modules <NUM> may further be exchanged when not working properly to quickly repair the steering assembly <NUM> during or in preparation of a drilling job. That is, modules <NUM> may be exchanged by accessing the BHA <NUM> or steering assembly <NUM> from the outer periphery of the BHA <NUM> or steering assembly <NUM>. This allows to exchange modules <NUM> without breaking string connections.

In particular, module <NUM> may be exchanged without disconnecting the string connections at the upper and/or lower end of the steering assembly and without disassembling the steering assembly <NUM> from the BHA <NUM> or drill string <NUM>. In particular, module <NUM> may be exchanged while the steering assembly <NUM> is connected, e. mechanically connected to at least a part of the BHA <NUM> or drill string <NUM> via one or more drill string connections. Exchanged modules may be sent to an offsite repair and maintenance facility for further investigation and maintenance without the need to ship the steering assembly <NUM> or to disconnect the steering assembly <NUM> from at least a part of the BHA <NUM> or drill string <NUM>. That is, testing, verification, calibration, data transfer (upload or download data), maintenance, and repair can be done on a module level rather than on a tool level. This allows for a quick exchange of modules to repair assemblies and to ship relatively small modules rather than complete downhole drilling tools.

In addition, exemplary embodiments allows for a quick exchange of modules from an outer periphery of steering assembly <NUM> to affect a repair while the steering assembly <NUM> is still physically connected to the BHA <NUM> and/or the drill string <NUM>. The capability for a quick exchange of modules to repair steering assembly <NUM> and the option to ship relatively small modules rather than complete downhole drilling tools and/or the capability for a quick exchange of modules to repair assemblies while the steering assembly <NUM> is still physically connected to the BHA <NUM> and/or drill string <NUM>, for example via the string connector, is a major benefit that facilitates a significant reduction in operational cost.

As noted, one or more of modules <NUM> may be configured to communicate wirelessly with a communication device, such as an antenna <NUM> and/or an inductive coupling device at a component such as a pipe segment, BHA <NUM>, the drill bit <NUM>, the drive shaft <NUM> or other downhole component <NUM> or another module <NUM> in the same or in another component.

<FIG> and <FIG> show perspective views of module <NUM>. As shown, in one embodiment, the module <NUM> includes a housing <NUM> that has a shape configured to be removably attached (e. , via screws, bolts, threads, magnets, or clamping elements, e. mechanical clamping elements, thermal clamping elements, clamping elements including shape memory alloy, press fit elements, tapered fit elements, or any combination thereof) to a correspondingly shaped cutout (not separately labeled) in the wall of the sleeve <NUM>. The module <NUM> may have a thickness equal to or similar to the thickness of the sleeve <NUM>, and thereby form part of the wall. Alternatively, the module <NUM> may have a thickness that is less than the thickness of the sleeve <NUM>, and can be mounted at a recess (not separately labeled) formed in the sleeve wall. The thickness of the module <NUM> may be sized to house the various parts and components included in the module <NUM> as discussed further below. The module <NUM> may also be curved so as to conform to the curvature of the sleeve <NUM>, which is typically cylindrical. Optionally, module <NUM> may be covered by a hatch cover (not separately labeled).

The housing <NUM> may be an integral part that is accessible via openings, such as open holes or ports may also include a number of housing components, such as a lower housing component <NUM>, which can be a single integral housing component or have multiple housing components. An upper housing component <NUM> may also be a single integral housing component or have multiple housing components, and can be attached to the lower housing component <NUM> via a permanent joining (e. , by welding, gluing, brazing, adhesive attachment) or a removable joining (e. , screws, bolts, threads, magnets, or clamping elements, e. mechanical clamping elements, thermal clamping elements, clamping elements including shape memory alloy, press fit elements, tapered fit elements, or any combination thereof). It is noted that the terms "upper" and "lower" are not intended to prescribe any particular orientation of the module <NUM> with respect to, e. , a drill string, sleeve or borehole.

As shown in <FIG> and <FIG>, the housing <NUM>, lower housing component <NUM> and/or upper housing component <NUM> can be made from multiple sections <NUM>. For example, the housing <NUM> is divided into multiple sections <NUM> that can house different components and can be removably (such as by screws, bolts, threads, magnets, or clamping elements, e. mechanical clamping elements, thermal clamping elements, clamping elements including shape memory alloy, press fit elements, tapered fit elements, or any combination thereof) or permanently (such as by welding, gluing, brazing, or adhesive attachment) joined together.

<FIG> and <FIG> show an example of components that can be housed in the module <NUM>. It is noted that the components are not limited to those shown in <FIG> and <FIG>, and are further not limited to the specific orientations, shaped and positions shown. Each component may be secured in any suitable manner. For example, the module <NUM> can include recesses shaped to conform to respective devices to be disposed therein. In one embodiment, the devices may be encapsulated and secured in place via the upper housing component <NUM> and/or one or more panels. In another embodiment, the devices may be installed into the modules <NUM> via ports or open holes, such as between upper and lower housing components <NUM>, <NUM>. The devices may also be disposed separately in sections <NUM>.

In the example of <FIG> and <FIG>, the module <NUM> includes the biasing element <NUM>, the antenna <NUM> and various devices for performing functions related to steering, communication, power supply, processing and others. Such devices may include power supply devices, power storage devices, data storage devices, biasing control devices, communication devices, and electronics such as one or more controllers/processors, or data storage devices. Examples of devices that can be housed in the module <NUM> are discussed below, however the module <NUM> and constituent devices are not so limited. In particular, antenna <NUM> is an optional device that may be omitted without significantly reducing the system's functionality. That is, as further discussed herein, communication from and to self-contained modules <NUM> can be accomplished via magnets <NUM> and secondary shaft <NUM> (e.g. magnets <NUM> and secondary shaft <NUM> of energy transmitting/receiving device <NUM>). Hence, one embodiment is a steering assembly <NUM> featuring a non-rotating sleeve <NUM> with one or more self-contained modules <NUM> that do not comprise an antenna such as antenna <NUM>.

The module <NUM> may also include a control mechanism for operating the biasing element <NUM>. Examples of the control mechanism include, a hydraulic pump and/or a hydraulically controlled actuator, and a motor, such as an electric motor.

In the example of <FIG> and <FIG>, the module <NUM> includes a biasing control assembly for controlling the biasing element <NUM> (e. , a hydraulic piston assembly), which includes a pump, comprising a motor <NUM>, such as an electric motor and a linear motion device <NUM> such as a spindle drive or ball screw drive. Optionally, a gear (not shown) might be included between the motor <NUM> and the linear motion device <NUM> to increase the efficiency of rotary movement of the motor <NUM> and the linear movement of the linear motion device <NUM>. The linear motion device <NUM> is coupled to the biasing element <NUM> via, e. , a hydraulic coupling <NUM> utilizing a working fluid such as a hydraulic oil. In addition, or alternatively, valves (not shown) may be controlled by a controller <NUM> to direct the working fluid to apply appropriate pressure to the biasing element <NUM> via the hydraulic coupling <NUM>. Optionally, a linear variable differential transformer (LVDT) (not shown) may be included to monitor, confirm, and/or measure the movement and/or an amount of engagement of a biasing member. As noted above, the utilization of the non-rotating sleeve <NUM> in conjunction with the operation of the biasing elements <NUM> allows for operation of steering systems with relatively low power demand. For example, the module <NUM> features low power stationary (hydrostatic) hydraulics to decrease the overall power demand.

To control the force and position of the biasing element <NUM>, the module <NUM> includes control electronics or controller <NUM> that may include a data storage device. Controller <NUM> controls operation of the biasing control assembly by controlling at least one of the pump, the motor <NUM>, the linear motion device <NUM>, and/or one or more valves (not separately labeled). The module <NUM> may include or be in communication with (e. , via the antenna <NUM>) one or more directional sensors to measure directional characteristics of the BHA <NUM> or parts of the BHA <NUM>, such as the measurement tool <NUM>, the steering assembly <NUM> and/or the drill bit <NUM>. In one embodiment, the directional sensors are configured to detect or estimate the azimuthal direction, the toolface direction, or the inclination of the sleeve <NUM>. Examples of directional sensors include bending sensors, accelerometers, gravimeters, magnetometers, and gyroscopic sensors.

Any other suitable sensors may be included in the module or in communication with the module that might benefit from a position close to the bit. Examples of such sensors include formation evaluation sensors such as but not limited to sensors to measure resistivity, gamma, density, caliper, and/or chemistry, or sensors to measure operational data, such as time, drilling fluid properties, temperature, pressure, vibration related data, e. acceleration, weight, such as weight-on-bit, torque, such as torque-on-bit, depth, rate of penetration, rotational velocity, bending, stress, strain, and/or any other type of sensor or device capable of providing information regarding an earth formation, borehole and/or operation.

Another component that can be included in the module <NUM> is a pressure compensation device such as a pressure compensator <NUM>. The pressure compensator <NUM> in this example is encapsulated within the module <NUM>, except for a surface that is movable or flexible and exposed to fluid pressure. The pressure compensator <NUM> may be utilized to provide reference pressure that may equal or be related to fluid pressure external of the module <NUM> and/or to provide compensation fluid volume. The reference pressure may be provided to the motion device <NUM> and/or motor <NUM> in order to create a pressure difference with respect to the reference pressure to direct the working fluid to apply appropriate pressure to the biasing element <NUM> via the hydraulic coupling <NUM>. Alternatively, or in addition, the compensation fluid volume may be utilized for compensating fluid-filled volume that varies in response to moving motion device <NUM> or motor <NUM>.

In another embodiment, the motion device <NUM> and/or motor <NUM> are moving with respect to a mechanical barrier such as a mechanical shoulder that prevents the motion of the motion device <NUM> in at least one direction. In yet another embodiment, the compensation fluid volume may be taken from a confined volume of compressible fluid such as gas, e. Hence, if the motion device <NUM> and/or motor <NUM> are moving with respect to a mechanical barrier that prevents the motion in at least one direction, and the compensation fluid volume is taken from a confined volume of compressible fluid such as gas, e. air, the configuration may be operable without a pressure compensator <NUM>.

Components housed in the module <NUM> may be powered via an energy storage device <NUM>, such as a battery, a capacitor, a supercapacitor, a fuel cell, and/or a rechargeable battery.

In addition to, or in place of, energy storage device <NUM>, the module <NUM> may include the energy transmitting/receiving device <NUM> to provide power to control the steering direction and perform other functions. Using energy transmitting/receiving device <NUM>, energy may be transmitted to and/or received from surface assembly <NUM> via conductors (not shown) extending along the drill string <NUM> to an energy storage device (also not shown), such as batteries, rechargeable batteries, capacitors, supercapacitors, or fuel cells, arranged within the rotating part of the BHA, or to energy converters that converts one energy form (e. vibration, fluid flow such as the flow of the drilling fluid, relative motion/rotation of parts, such as the relative motion between the drive shaft <NUM> and the non-rotating sleeve <NUM>) into another energy form (e. electrical energy, chemical energy within a battery or any combination thereof). Commonly known energy converters used downhole are, for example, turbines converting fluid flow into rotation of mechanical parts, generators/dynamos to convert rotation of mechanical parts into electrical energy, charging devices to convert electric energy into chemical energy of batteries. If the energy is provided downhole for other reasons than to provide energy those energy converters are sometimes referred to as energy harvesting devices.

In one embodiment, the energy transmitting/receiving device <NUM> includes one or more coils (e. energy harvesting coils) that are enclosed within the module <NUM>. The coils are positioned so that they are within a magnetic field generated by a magnetic device (or devices) mounted on the drive shaft <NUM> or at other suitable locations.

In one embodiment, the magnetic device includes one or more magnets <NUM> (<FIG>), such as electromagnets (e. coils, such as coils wound around magnetic material) or permanent magnets or a combination of both, that are attached to and rotate with the drive shaft <NUM> or other rotating component, thereby generating an alternating magnetic field that is received by the coils of the energy transmitting/receiving device <NUM>. Electromagnets may include one or more conductive coils on the rotating drive shaft <NUM>. Current can be applied to the conductive coils to generate a magnetic field. The current that is applied to the conductive coils may be modulated to create a modulated magnetic field, which may be used for communication and/or which may allow energy transfer into the module even when the drive shaft <NUM> is not rotating (or there is at least no substantial relative rotation between the drive shaft <NUM> and the sleeve <NUM>). Communication via antenna <NUM> and/or energy transmitting/receiving device <NUM> may be controlled by communication controller <NUM>.

The energy transmitting/receiving device <NUM> described herein uses magnetic energy transmission through a separator into an encapsulated unit (e. , the energy harvesting coils). The magnetic energy coupling is accomplished, in one embodiment, by generating and varying a primary magnetic field by the magnetic device, which is received by a secondary device. The secondary device can be one or more stationary coils mounted in an appropriate direction and position with respect to the time-varying or alternating magnetic field created by the magnetic device. In this way, mechanical energy is converted directly into electrical energy.

The energy transmitting/receiving device <NUM> may include an energy controller <NUM> that may include a data storage device, for controlling power supply to components in the module, and/or to control the charge and re-charge of the energy storage device <NUM>. The energy controller <NUM> may include a rectifier to generate a DC current from the received electrical energy that will be provided to other electronics within the module <NUM> by the energy controller <NUM>. The energy controller <NUM> can be a distinct controller, or can be configured to control multiple components in the module, such as the energy transmitting/receiving device <NUM>, the communication device for wireless communication, such as antenna <NUM>, and/or the biasing element <NUM>. As such, one or more of the energy controller <NUM>, the communication controller <NUM>, and the controller <NUM> to control the biasing element <NUM> may be actually the same or distinct controlling devices or control circuits with various control functions as appropriate. That is, the scope of this invention is not limited as to where which control function is implemented.

In one embodiment, the secondary device includes another magnetic device disposed in the primary magnetic field. The secondary device can be configured to be rotated or otherwise moved by the primary magnetic field and/or generate a secondary magnetic field.

<FIG> show an example of a secondary magnetic device configured to be positioned in the primary magnetic field. In this example, the secondary magnetic device includes a secondary shaft <NUM> disposed inside or connected to the module <NUM>. The secondary shaft <NUM> is supported by bearings or another suitable mechanism so that the secondary shaft <NUM> is able to rotate independent of the sleeve and the module <NUM> as a response to the primary magnetic field created by the magnets <NUM> rotating with the drive shaft <NUM>. The secondary shaft <NUM> can feature magnets, electrical coils or other devices attached to allow a torque transfer from the primary magnetic field to the secondary magnetic field. The secondary magnetic field can be created by, e. , permanent magnets, eddy current devices, electrical coils and/or hysteresis materials. As shown in <FIG>, the secondary shaft can be operably connected to an alternator device <NUM> to convert mechanical energy into electrical energy that can be provided to various components, e. , to provide power to the motor <NUM> and/or charge an energy storage device. Optionally, a gear box (not shown), including a gear (also not shown), e. a planetary gear may be connected between the secondary shaft <NUM> and the alternator device <NUM> to achieve a more efficient energy transfer.

The modules described herein improve and facilitate the application of directional force (e. , via biasing elements) to control the direction of a drilling assembly. In one embodiment, the modules are configured to house active biasing mechanisms, such as pistons, levers and pads that are actively controlled via a controller. In another embodiment, the biasing mechanisms can be supported by passive mechanisms such as springs, e. , to engage the earth formation even in the event of a loss of the ability to actively control the biasing mechanisms. Both passive and active elements can be confined. For example, the biasing element <NUM> can be partially energized by springs. If the energy storage capacity of the energy storage device <NUM> turns out to be too small to provide communication and active earth formation engagement, the biasing element <NUM> can be energized by the springs exclusively or as an adjunct to an active biasing element.

In certain embodiments, a conventional communication device is not used to transfer information between a rotating section and a non-rotating section of a drill string. By conventional communication device, it is meant an arrangement wherein information is encoded into electrical, electromagnetic, or optical signals that are transmitted from a transmitter to a receiver, either with wires or wirelessly. Instead of using such encoded signal transmissions, downhole tools according to the present disclosure may be configured to directly or indirectly estimate a rotational speed (RPM) of the rotating section relative to the non-rotating section. At the surface, such relative rotation may be controlled in a manner that instructs one or more components of the non-rotating section to take one or more desired actions. Such instructions may be referred to as "downlinks" or "command signals.

Referring to <FIG>, there is illustrated in functional block diagram format a bottomhole assembly (BHA) <NUM> that uses drill string rotation variances in order to send downlinks / command signals. The BHA <NUM> may include a non-rotating section <NUM> that at least partially surrounds a rotating section <NUM> of a drill string <NUM> (<FIG>). In embodiments, the non-rotating section <NUM> may be similar to the non-rotating sleeve <NUM> of <FIG>, <FIG> and the rotating section <NUM> may be similar to the drive shaft <NUM> of <FIG>, <FIG>. For brevity, the term "non-rotating section" <NUM> may be used interchangeably with the term "non-rotating sleeve" <NUM>. Additionally, the term "rotating section" <NUM> may be used interchangeably with the term "drive shaft" or "rotating shaft" <NUM>.

The non-rotating sleeve <NUM> may include one or more biasing elements <NUM>, one or more orientation sensors <NUM>, one or more relative rotation sensors <NUM>, and a controller <NUM>. All of these components may be enclosed in a module <NUM>. The biasing elements <NUM> may be similar to the biasing elements <NUM> of <FIG> or the biasing elements <NUM> of <FIG>. Examples of biasing elements include devices such as cylinders, pistons, wedge elements, hydraulic pillows, expandable rib elements, blades, and others. The biasing elements <NUM> may be actuated using any of the mechanisms discussed previously in connection with the biasing elements <NUM> (<FIG>) and the biasing elements <NUM> (<FIG>). Examples of the control mechanism include, a hydraulic pump and/or a hydraulically controlled actuator, and a motor, such as an electric motor. The controller <NUM> may be similar to the controller <NUM> of <FIG> with respect to the components for operating the biasing elements <NUM>. For example, the controller <NUM> may be programmed with suitable algorithms <NUM> in memory modules <NUM> in order to actuate the actuators <NUM> associated with the biasing members <NUM>. By way of example, the actuators <NUM> may include the pumps and valves discussed described above with respect to the controller <NUM> (<FIG>). The module <NUM> may be similar to the self-contained and modular module <NUM> as described above (e. , with respect to <FIG> and <FIG>).

Additionally, the controller <NUM> may include suitable algorithms to use information from the orientation sensor <NUM> and the relative rotation sensor <NUM> in order to control the biasing elements <NUM>. For example, the controller <NUM> may be configured to adjust a force applied by one or more biasing element(s) <NUM> and / or adjust a physical position of one or more biasing elements (<NUM>). Generally, the relative rotation sensor <NUM> generates information representative of the rotational speed of the rotating section <NUM> relative to the non-rotating section <NUM>, or the "relative rotational speed" of the rotating section <NUM>. Additionally in some applications the relative rotation sensor <NUM> might also detect momentary (angular) position between the rotating section <NUM> relative to the non-rotating section <NUM>. As described above, relative rotation sensor <NUM> may also serve as the energy transmitting/receiving device <NUM> (<FIG>) and/or the communication device (e.g., in combination with the magnetic device or secondary magnetic device). In such an embodiment the one or more coils (e. energy harvesting coils of energy transmitting/receiving device <NUM>) might be enclosed within e. the module <NUM> (<FIG>) and may be also utilized to sense the magnetic field created by the magnets <NUM> rotating with the drive shaft <NUM>. The coils are positioned so that they are within a magnetic field generated by a magnetic device (or devices) mounted on the drive shaft <NUM> or at other suitable locations. In one embodiment, the magnetic device includes one or more magnets <NUM> (<FIG> or <NUM> in <FIG>). The orientation sensor <NUM> generates information regarding the orientation of the non-rotating section <NUM> relative to selected reference frame such as the earth's magnetic field or the earth's gravitational field. Illustrative orientation sensors <NUM> include, but are not limited to, a single axis accelerometer, a multi-axis accelerometer, a single axis or multi axis magnetometer, a gyroscope, etc. Optionally, module <NUM> may include a wireless communication unit <NUM> to enable signal exchange between the components of modules <NUM> and components outside of modules <NUM>, such as components within the drive shaft <NUM> (<FIG> and <FIG>). As will be discussed in greater detail below, the controller <NUM> uses the information from the relative rotation sensor <NUM> to decode a command signal embedded in variances in the rotation of the rotating section <NUM> relative to the non-rotating section <NUM>. The command signal may be an instruction to implement a change in a drilling path. The controller <NUM> implements the change in drilling direction after first determining the orientation of the biasing elements <NUM> with reference to the selected reference frame and then appropriately positioning or repositioning one or more of the biasing elements <NUM>.

While <FIG> depicts an embodiment wherein a non-rotating sleeve <NUM> includes a plurality of biasing elements <NUM> controlled by one controller <NUM>, the teachings of the present disclosure are not limited to such an embodiment. For example, as shown in <FIG>, the non-rotating sleeve <NUM> may include a plurality of self-contained modules <NUM>, each of which includes a biasing element <NUM>, associated actuator <NUM>, controller <NUM>, orientation sensor <NUM>, and relative rotation sensor <NUM>. The modules <NUM> may be similar to the self-contained and modular module <NUM> as described above (e. <FIG> and <FIG>). Optionally, one or more of modules <NUM> may include a wireless communication unit <NUM> to enable signal exchange between the components of the individual modules <NUM> and/or components outside of modules <NUM>, such as components within the drive shaft <NUM> (<FIG> and <FIG>). It should be understood that the embodiments of the present disclosure are not limited any particular number of biasing elements per module <NUM>. For example, some modules <NUM> may include one biasing element <NUM> and other modules <NUM> could include two or more biasing elements <NUM>. Optionally, one or more of modules <NUM> may include a wireless communication unit <NUM> to enable signal exchange between the components of modules <NUM> and components outside of modules <NUM>, such as components within the drive shaft <NUM> (<FIG> and <FIG>) or components in one or more of the other modules <NUM>. In an alternative embodiment, one or more of modules <NUM> do not have at least one of the relative rotation sensor and the orientation sensor but receive at least one of the relative rotation information and the orientation information via wireless unit <NUM> from one of the other modules <NUM>, that has a relative rotation sensor and/or an orientation sensor included. Alternatively the orientation information and the relative rotation information may be received in modules <NUM> via wireless communication unit <NUM> from sensors that are installed in sleeve <NUM> outside of any of the modules <NUM>.

Referring to <FIG>, there are shown illustrative rotational speed variances of the rotating section <NUM> that may be used to convey downlinks / command signals from a surface location to the controller(s) <NUM> of the non-rotating sleeve <NUM>. Time is shown along the "X" axis in units such as minutes. Rate of rotation is shown along the "Y" axis in RPM. Generally, the variances involve switching between two specified rotational speeds and specified time durations at each of the specified RPM. While <FIG> show the use of two discrete relative rotational speeds, some coding schemes may use three or more discrete relative rotational speeds.

<FIG> illustrates a downlink represented by a relative rotational speed signature <NUM> that begins with a relatively high rate of rotation (RPM) <NUM> of the rotating section <NUM> (<FIG>) that drops to a relatively lower rate of rotation (RPM) <NUM> after a specified duration of a first time period <NUM>. After a specified duration of a second time period <NUM>, the rate of rotation returns to the higher RPM <NUM> for the specified duration of the first time period <NUM>. The time durations of the first and the second time periods <NUM>, <NUM> may be of equal duration or different durations. Such a pattern of higher and lower RPM and associated time durations may uniquely identify a desired change in direction such as "turn left".

<FIG> illustrates a downlink represented by a relative rotational speed signature <NUM> that begins with a relatively low rate of rotation (RPM) <NUM> of the rotating section <NUM> (<FIG>) that increases to a relatively higher rate of rotation (RPM) <NUM> after a specified duration of a first time period <NUM>. After a specified duration of a second time period <NUM>, the rate of rotation returns to the lower RPM <NUM> for the specified duration of the first time period <NUM>. The time durations of the first and the second time periods <NUM>, <NUM> may be the same or different. Such a pattern of lower and higher RPM and associated time durations may also may uniquely identify a desired change such as "turn right".

<FIG> illustrates a downlink represented by a relative rotational speed signature <NUM> that begins with a relatively high rate of rotation (RPM) <NUM> of the rotating section <NUM> (<FIG>) that drops to a relatively lower rate of rotation (RPM) <NUM> after a specified duration of a first time period <NUM>. After a specified duration of a second time period <NUM>, the rate of rotation returns to the higher RPM <NUM>. Thereafter, the rate of rotation oscillates twice between the higher and lower RPM's <NUM>, <NUM> for relatively shorter third and fourth time periods <NUM>, <NUM>. The pattern may then begin again. Such a pattern of higher and lower RPM and associated time durations may uniquely identify a desired change in direction such as "turn up".

<FIG> illustrates a downlink represented by a relative rotational speed signature <NUM> that begins with a relatively low rate of rotation (RPM) <NUM> of the rotating section <NUM> (<FIG>) that increases to a relatively higher rate of rotation (RPM) <NUM> after a specified duration of a first time period <NUM>. After a specified duration of a second time period <NUM>, the rate of rotation returns to the lower RPM <NUM>. Thereafter, the rate of rotation oscillates twice between the lower and higher RPM's <NUM>, <NUM> for relatively shorter third and fourth time periods <NUM>, <NUM>. The pattern may then begin again. Such a pattern of higher and lower RPM and associated time durations may uniquely identify a desired change in direction such as "turn down".

Thus, it should be understood that manipulating drill string rotation at the surface can be used to convey downlinks to execute a variety of actions downhole hole. As described above, the downlinks may instruct a change in a drilling direction with respect to inclination and / or azimuth. The downlinks may also adjust a force applied by one or more biasing elements, which may vary a rate at which a drilling direction is changed. The downlinks may also include non-drilling direction commands such as to turn off / on components. While <FIG> are described with respect to simple commands (such as "turn up", "turn down", "turn left", "turn right") by relatively simple RPM pattern, those skilled in the art will understand that patterns like those described with respect to <FIG> are suitable to convey more complicated commands and messages by encoding schemes and protocols as known in the art (such as series of "I" and "<NUM>" signals, a pulse position scheme, etc.). More complex commands would enable to support "hold" commands, such as commands to hold a steering parameter (e.g. inclination or azimuth) at a particular value or within a particular range. An example is a command like "hold inclination at <NUM>°". Receiving such a command by RPM patterns via antenna <NUM> and/or energy transmitting/receiving device <NUM> (<FIG>) would cause the controller <NUM> to control the biasing elements <NUM> in a way that the steering parameter will be held at a particular value or within a particular range.

It should be appreciated that manipulating drill string rotation by utilizing two or more discrete RPMs and selecting distinct time periods at which the RPM are maintained can allow numerous downlinks / command signals to be communicated to the controller(s) <NUM> (<FIG>, <FIG>) on the non-rotating section <NUM>. Of course, there may be practical considerations such as incorporating sufficient magnitude of changes or sufficiently long time durations to enable downhole instruments to detect a change in RPM that is attributed to a communication of command signals as opposed to "noise" associated with drilling operations. However, the teachings of the present disclosure may utilize any scheme, pattern, or regime of changes in rates of rotation and associated time durations, and are not limited to those discussed in connection with <FIG>. For example, while the <FIG> signals imply the use of a particular relative rotational speed, a coding scheme may use other methodologies. For example, schemes may use a difference between the higher and lower rotational speeds without regard to the actual rotational speeds. Also, schemes may use ranges to form a signature such as an RPM greater than or less than a threshold value; e. , greater than <NUM> RPM or less than <NUM> RPM.

<FIG> schematically illustrates one non-limiting configuration of the BHA <NUM> according to the present disclosure having the functionalities described in connection with <FIG> and <FIG>. The BHA <NUM> may include the non-rotating sleeve <NUM> having a bore <NUM> in which a rotating section <NUM> of the drill string <NUM> (<FIG>) is disposed. One or more bearings <NUM> may be positioned between the non-rotating sleeve <NUM> and the rotating section <NUM> to allow relative rotation there between. As described previously, the non-rotating sleeve <NUM> may include one or more biasing elements <NUM>, one or more orientation sensors <NUM>, one or more relative rotation sensors <NUM>, and a controller <NUM>. These components may be housed in a self-contained module as described previously.

Optionally, the BHA <NUM> may include one or more anti-rotation elements <NUM> positioned on the non-rotating sleeve <NUM>. In some embodiments, the biasing elements <NUM> may provide sufficient friction against a borehole wall <NUM> to anchor the non-rotating sleeve <NUM> substantially stationary relative to the borehole wall <NUM>. In other embodiments, the anti-rotation element(s) <NUM> either cooperatively with the biasing elements <NUM> or primarily generate the required friction to anchor the non-rotating sleeve <NUM> substantially stationary relative to the borehole wall <NUM>. The anti-rotation element(s) <NUM> may utilize mechanisms similar to the biasing elements <NUM> such as springs, pads, etc. In embodiments, the anti-rotation elements <NUM> may be static and continuously frictionally engage the borehole wall <NUM>. In other embodiments, the anti-rotation elements <NUM> may be retractable to disengage from the borehole wall <NUM> in response to a suitable control signal. It should be understood that the borehole wall <NUM> is only illustrative of an adjacent surface against which the biasing elements <NUM> and anti-rotation elements <NUM> may act. Other adjacent surfaces may be an inner surface of casing, liner, or other wellbore tubular.

In embodiments, the energy transmitting / receiving device <NUM> (e. , <FIG>) may function as the relative rotation sensor <NUM> in addition to transmitting and receiving energy for the non-rotating sleeve <NUM>. In such embodiments, the relative rotation sensor <NUM> includes one or more coils <NUM> (e. , energy harvesting coils, alternator coils) and positioned so that they are within a magnetic field generated by a magnetic device <NUM> (or devices) mounted on a section of the rotating section <NUM>.

<FIG> illustrates a cross-section view of one non-limiting embodiment of an energy transmitting / receiving device that also functions as the relative rotation sensor <NUM>. The relative rotation sensor <NUM> may include one or more coils <NUM> disposed in the non-rotating section <NUM>. In the depicted arrangement there are three coil sets <NUM>, each of which has two coils <NUM>. It should be understood that greater or fewer coil sets <NUM> may be used. The relative rotation sensor <NUM> also includes a magnetic arrangement <NUM> distributed on a section of the rotating section <NUM>. For example, the magnetic arrangement <NUM> may include one or more magnets <NUM> or magnetic elements circumferentially arrayed within or on an outer surface of the rotating section <NUM>. As used herein, terms such as magnets, magnetic elements, or magnetic material refers to any object or member that generates a magnetic field including loops of energized electrical conduits such as coils that are flown by an electrical current. In a conventional manner, during relative rotation between the rotating section <NUM> and the non-rotating sleeve <NUM> at a constant RPM, the magnetic field generated by the magnetic arrangement <NUM> creates an alternating voltage in the coil(s) <NUM> that have a constant frequency and a constant peak voltage.

Referring to <FIG> and <FIG>, there are shown voltage signals associated with two different constant RPM's that may be generated by the relative rotation of sensor <NUM> of <FIG>. In both graphs, time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. In <FIG>, the voltage signal <NUM> may have an amplitude of app. <NUM> Volts and a period of app. <NUM> milliseconds. The <FIG> voltage signal <NUM> may occur at a rotational speed of <NUM> RPM. In <FIG>, the voltage signal <NUM> may have an amplitude of spp. <NUM> Volts and a period of <NUM> milliseconds. The <FIG> voltage signal <NUM> may occur at a rotational speed of <NUM> RPM. The <FIG> and <FIG> voltage signals and associated rotational speeds are merely exemplary and not intended to represent actual voltage signals at particular rotational speeds. Nevertheless, it should be appreciated that relative rotational speed may be indirectly estimated by analyzing the characteristics of the corresponding voltage signal. The voltage variations shown in <FIG>, B and their associated current flows through coils <NUM> of coil sets <NUM> may be also used to provide power to components within non-rotating sections <NUM>, such as to controllers <NUM> or biasing members <NUM> of <FIG> and <FIG> or to charge one or more capacitor, supercapacitor, battery, fuel cell, or rechargeable battery within at least one of self-contained modules <NUM> of <FIG> and <FIG>.

Referring to <FIG>, there is shown a voltage signal <NUM> representative of a transition from a higher RPM to a lower RPM that may be generated by the relative rotation sensor <NUM> of <FIG> or <FIG>. Time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. The voltage signal <NUM> may have a first segment <NUM> associated with a given rotational speed and a second segment <NUM> associated with a relatively lower rotational speed. Due to the relatively higher rotational speed, the first segment <NUM> has a larger amplitude and a shorter period than the second segment <NUM>. As described in connection with <FIG>, these variances in relative rotational speed, which are detected by measuring voltage signals in the relative rotation sensor <NUM>, may be used to create unique signatures and convey desired downlinks / command signals from the surface to the controller <NUM> (<FIG>).

It should be noted that the energy transmitting/ receiving device described in connection with <FIG> may also be used to detect drill string rotation variances as described above. For example, magnets <NUM> may be used to convey energy from the rotation of drive shaft <NUM> via secondary shaft <NUM> into self-contained and sealed module <NUM>. The voltage and current variations in module <NUM> that correspond to the received energy within module <NUM> are also sensed to gain information about the rotation (e.g. rotation speed) of the drive shaft relative to the sleeve <NUM>. Identified rotation pattern can then be used to identify commands or messages thereby receiving information from the rotating drive shaft and associated surface assembly <NUM> at the surface (<FIG>).

Referring to <FIG>, in embodiments, the controller <NUM> may include algorithms, programs, or other suitable machine-readable instructions that estimate variances indicative of relative rotational speeds using the voltage signals from the relative rotation sensor <NUM>. These instructions may estimate parameters such as the amplitude, frequency, and / or duration of the signals indicative of relative rotational speeds. The controller <NUM> may use one or more of the estimated parameters to determine whether command signals are being conveyed via variations in rotational speed and, if so, decode the command signal to determine the instructions to be executed. It should be understood that it is not necessary that the controller <NUM> estimates any given rotational speed. Rather, the controller <NUM> may determine a command signal associated with a given pattern or sequence of rotational speed variances using only the associated voltage signals without performing a calculation to determine the RPM for a detected voltage signal.

Referring to <FIG>, there is shown another embodiment of a relative rotation sensor <NUM> that also provides a signal to estimate a relative position between the rotating section <NUM> and the non-rotating section <NUM>. The relative rotation sensor <NUM> may include one or more coils <NUM> disposed in the non-rotating section <NUM> as discussed in connection with the <FIG> embodiment. To estimate relative position, the relative rotation sensor <NUM> includes a magnetic arrangement <NUM> that generates a non-homogeneous magnetic field. By "non-homogeneous," it is meant that the magnetic field has a localized engineered variation in a strength of a magnetic field. By "engineered," it is meant that the variation in the magnetic field is an intended feature and has a predetermined signature or characteristic, as opposed to an incidental feature. The magnetic field strength variations, in one arrangement, may be obtained by varying a volume magnetic material at a specified location as compared to the volume of other magnetic material distributed on a section of the rotating section <NUM>. For example, the magnetic arrangement <NUM> may have a sector <NUM> that does not have any magnetic material. Thus, the sector <NUM> will have a magnetic field that is weaker than the magnetic field in the remainder of the magnetic arrangement <NUM>.

Referring to <FIG>, there is shown an illustrative voltage signal <NUM> that may be generated by the <FIG> embodiment. Time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. The voltage signal of <FIG> comprises of voltage oscillations that are caused by the localized variations in the strength of the magnetic field that is generated by the magnetic arrangement <NUM> (<FIG>). The voltage signal <NUM> may have a segment <NUM> associated with the sector <NUM> (<FIG>) wherein voltage drops due to the weakened magnetic field and a segment <NUM> which is the baseline voltage attributable to the remainder of the magnetic arrangement <NUM>. Thus, the instances when the segment <NUM> is detected, the rotating section <NUM> has a known orientation or alignment relative to the non-rotating section <NUM>.

Referring to <FIG>, there is shown another embodiment of a relative rotation sensor <NUM> that provides a signal to estimate a relative position or rotation between the rotating section <NUM> and the non-rotating section <NUM> as well as other information. The relative rotation sensor <NUM> may include one or more coils <NUM> disposed in the non-rotating section <NUM> as discussed in connection with the <FIG> embodiment. The relative rotation sensor <NUM> also includes a magnetic arrangement <NUM> positioned on the rotating section <NUM> and that generates a non-homogeneous magnetic field. In this arrangement, the magnetic arrangement <NUM> may have two or more sectors <NUM>, <NUM> wherein a strength of the magnetic field is lower or higher than that of the adjacent magnetic field. As illustrated, the sectors <NUM>, <NUM> are gaps that have no magnetic material. Thus, the sectors <NUM>, <NUM> will have magnetic fields that are weaker than the magnetic field in the remainder of the magnetic arrangement <NUM>. In one embodiment, the magnetic arrangement <NUM> comprises a set of magnetic multipoles (e.g. magnetic dipoles, quadrupoles, etc.) that are distributed around the circumference of the rotating section <NUM>, wherein the multipole direction is arranged to create a periodic pattern around the circumference of the rotating section. Sectors <NUM>, <NUM> comprise a magnetic signature that is different from the periodic pattern of magnetic multipoles.

Referring to <FIG>, there is shown an illustrative voltage signal <NUM> that may be generated by the <FIG> embodiment. Time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. The voltage signal <NUM> may have a first segment <NUM> associated with the sector <NUM> (<FIG>) and a second segment <NUM> associated with the sector <NUM> (<FIG>), wherein voltages drop due to the weakened magnetic fields or due to the lower frequency of the magnetic arrangement in sectors <NUM>, <NUM>. Thus, the instances when the segments <NUM>, <NUM> are detected, the rotating section <NUM> has a known orientation or alignment relative to the non-rotating section <NUM>. Further, it should be appreciated that the distance or angular separation between the segments <NUM>, <NUM> is known and the time between the detection of the segments <NUM>, <NUM> corresponding to the time between first and second segments <NUM> and <NUM> can be determined. This information may be used to better evaluate downhole conditions and drilling dynamics. For example, detection of segments <NUM>, <NUM> may be used as a cross-check that validates the voltage signals. That is, if the two segments <NUM>, <NUM> generate similar voltage signals at expected times, then it is more likely that accurate data is being obtained. Further, for a given rotational speed, a theoretical time gap between the detection of the segments <NUM>, <NUM> may be calculated. Discrepancies in the measured time gap may indicate drilling dysfunctions such as stick-slip. As illustrated, the segments <NUM>, <NUM> may be asymmetrically distributed such that there are different time gaps between successive detections. That is, assuming rotation is clockwise, there is a relatively short time gap from detection of segment <NUM> to segment <NUM> due to a ninety degree angular separation <NUM> and a longer time gap from detection of segment <NUM> to segment <NUM> due to the two hundred seventy degree angular separation <NUM>. It should be understood that other embodiments may use three or more segments and / or that the segments may be uniformly distributed with equal angular separation or with unequal angular separations. The gaps may have any angular value, not just the ninety degrees and two hundred seventy degrees depicted.

It should be understood that the teachings of the present disclosure are not limited to only reductions in a magnetic field that are obtained by reducing the volume of a magnetic material (e. , height, width, and / or depth of a magnetic element). For example, an option for a magnetic marker and without weakening the magnetic field would include shaping the magnetic field output.

Referring to <FIG>, there is shown an embodiment of a relative rotation sensor <NUM> that provides a signal to estimate a relative position between the rotating section <NUM> and the non-rotating section <NUM> using a Halbach array. By flipping magnetic elements into a direction <NUM>° from adjacent magnetic elements, a non-homogeneous field is generated, which creates a magnetic field variation in the form of a directed peak of magnetic strength at the Halbach array. The relative rotation sensor <NUM> may include one or more coils <NUM> disposed in the non-rotating section <NUM> as discussed in connection with the <FIG> embodiment. The relative rotation sensor <NUM> also includes a magnetic arrangement <NUM> positioned on the rotating section <NUM> and that generates the non-homogeneous magnetic field. In this arrangement, the magnetic arrangement <NUM> may have a sector <NUM> wherein a magnet <NUM> is offset <NUM>° relative to a neighboring magnet. Additionally, sets of magnetic elements having an offset <NUM>° relative to a neighboring magnet may be used. Thus, the sector <NUM> will have a magnetic field peak relative to the remainder of the magnetic arrangement <NUM>. While <FIG> uses a technique of <NUM>° offsets for adjacent magnets, other suitable techniques to shape the magnetic field include, but are not limited to, alternative orientation or alternative magnetization of the permanent magnets.

Referring to <FIG>, there is shown a voltage signal <NUM> representative of a constant RPM that may be generated by the relative rotation sensor <NUM> of <FIG>. Time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. The voltage signal <NUM> may have a nominal voltage amplitude <NUM> during a majority of the rotation and a peak voltage amplitude <NUM> associated with a sector <NUM> (<FIG>), the voltage spike being caused by the offset magnets <NUM> at the sector <NUM> (<FIG>).

Referring to <FIG>, there is shown a voltage signal <NUM> representative of a transition from a higher RPM to a lower RPM that may be generated by the relative rotation sensor <NUM> of <FIG>. A full rotation is shown at the higher RPM and at the lower RPM. As before, time (ms) is along the "X" axis and voltage (V) is along the "Y" axis. The voltage signal <NUM> may have a first segment <NUM> associated with a given rotational speed and a second segment <NUM> associated with a relatively lower rotational speed. Due to the relatively higher rotational speed, the first segment <NUM> has a larger voltage amplitude and a shorter period that the second segment <NUM>. Further, due to the Halbach array at the sector <NUM> (<FIG>), voltage peaks <NUM> are generated, which as described before provide a momentary indication of relative orientation between the rotating section <NUM> and the non-rotating section <NUM>. While the magnetic peak, or signature, would occur at say each <NUM> for the first rotary speed, the marker signature would occur every <NUM> for the second rotary speed.

Alternatively, a dedicated sensor element can be used to detect the momentary position between rotating stationary components. For example, referring to <FIG>, a sensor assembly <NUM> may include a sensor element <NUM> on the non-rotating sleeve <NUM> and a triggering element <NUM> on the rotating section <NUM>. One or more biasing elements <NUM> may be positioned on the non-rotating sleeve <NUM>. The sensor element <NUM> may use a variety of interactions in order to detect the proximity of the triggering element <NUM>; e. , physical contact, electrical interaction, magnetic interactions, etc. In effect, the interaction causes a "tick" to occur once per rotation. For simplicity, this will be referred to as a "singular tick". A non-limiting example may be a hall sensor for the sensor element <NUM> and a magnetic element for the triggering element <NUM>. However, it should be understood that different types of sensing elements and respective triggering elements can also be used.

The previously described relative rotation sensor <NUM> according to <FIG>, <FIG>, <FIG>, <FIG>, as well as the configuration shown in <FIG> allow detection of momentary position of the rotating section <NUM> relative to the non-rotating section <NUM>. The momentary relative position can additionally be utilized to count the revolutions over time (rpm measurement). This signal can be used individually for the above described downlink methods (e. according to <FIG>) or as verification, in combination, supporting the alternating voltage detection. For applications where sensor communication between the rotating MWD and the non-rotating section is established (e. <FIG>), the momentary relative position can be used to synchronize measurements from the rotating section <NUM> and the non-rotating section <NUM>. Such synchronized measurements can be also used for formation evaluation, dynamics, directional and other measurements that beneficially combine the content from the rotating and the non-rotating section. In certain embodiments, a MWD sensor on a rotating section of the string and a processor configured to calculate a steering vector using the identified momentary relative position between the drive shaft and the sleeve and information from the MWD sensor.

Referring to <FIG>, there is shown one non-limiting method <NUM> of conveying command signals from a surface location to one or more components on a non-rotating sleeve without using convention communication devices such as transmitters and receivers. The method may be performed in conjunction with the systems and devices described above, but is not limited thereto. The method includes one or more stages, or steps, described below. In one embodiment, the method includes the execution of all of the stages in the order described. However, certain stages may be omitted, stages may be added, or the order of the stages changed.

In preparation for executing the method <NUM>, a drilling assembly connected to a drill string is deployed into a borehole, e. , as part of a LWD or MWD operation. Thereafter, the drilling assembly is operated by rotating a drive shaft and a drill bit via a surface or downhole device. In one embodiment, the drive shaft, the rotating section, is surrounded by a non-rotating sleeve, the non-rotating section, that includes one or more modules that house and at least partially enclose one or more biasing elements. In another embodiment, one or more modules are included in the rotating parts of the BHA. One or more components in each module are powered via an energy storage device and/or energy transmitting/receiving device, such as a coil receiving an alternating magnetic field, an inductive coupler, inductive transformer, an inductive power device, movable magnets, mechanical coupling, or magnetic coupling that transforms mechanical energy from drilling fluid flow, rotation of the drive shaft, or vibration of the BHA to electrical energy that power control devices, sensors, and/or actuation devices for the biasing elements.

At a first stage <NUM>, to cause relative rotation of the drive shaft and the non-rotating sleeve, the initial friction between the non-rotating sleeve and the adjacent surface, which may be a borehole wall or an inner surface of a wellbore tubular, may be generated by the initial actuation or expansion of the one or more biasing elements. For example, friction between biasing elements and the borehole wall might be increased up to a level that is close to or even higher than the friction of the bearing thereby creating an initial resistance of rotation of the non-rotating sleeve with respect to the borehole wall and thus initiate a relative rotation between the drive shaft and the non-rotating sleeve. Alternatively, or additionally, non-rotation elements may be used to physically contact the adjacent surfaces and generate the friction required to allow relative rotation. The relative rotation enables the energy receiving device to convert the energy from drill string rotation to energy for operating biasing elements, controllers, electronics, sensors, or to charge the energy storage device. The energy storage device may also be re-loaded during operation of the steering assembly by the energy receiving device.

Such biasing elements that are configured to be initially expanded or actuated to increase friction between non-rotating sleeve and borehole wall may be at least one of sliding pads, energized rollers, springs, blades, or rotating levers. Biasing elements that are configured to be initially expanded or actuated to increase friction between non-rotating sleeve and borehole wall may be active elements that require an external energy supply or passive elements that can be actuated or expanded without an external energy supply, such as, for example, springs. If initial expansion or actuation of the biasing elements is provided by active elements, the energy required to expand/actuate the biasing elements by the active elements may be provided by an energy storage device such as a capacitor, a supercapacitor, a battery, fuel cell, or a rechargeable battery. Such energy storage device may also be utilized to energize controllers or sensors within the module.

In a second stage <NUM>, a decision is made to adjust a direction of drilling. The decision may be human made, by machine, or a combination of both. The decision is converted to a downlink or command signal that has a unique signature / pattern of drill string rotation speeds and associated time durations at different speeds as discussed previously. Surface and downhole equipment is operated to manipulate the drill string rotation to obtain the unique signature / pattern. In case a mud motor is used, the surface rpm will be superimposed by the downhole rpm created by the mud motor. Since the mud motor rpm is a function of drilling fluid flow rate, which is pumped through a surface assembly <NUM>, the superimposed rotational speed of the rotating section <NUM> relative to the non-rotating section <NUM> is controlled by surface flow and surface rpm. The command signal signature / pattern send from the surface to the downhole tool is variation of surface rpm and / or drilling fluid flow rate for a BHA including a mud motor.

In the third stage <NUM>, controller(s) on the non-rotating sleeve detect the variations in drill string rotation and use the relative rotation sensor(s) to detect the unique signature of the drill string rotation variations. As discussed previously, the sensors(s) may generate a voltage signal representative of these drill string rotation variations. The controllers(s) may utilize a pre-programmed lookup table or other database to determine the desired action that is associated with the detected unique signature. The desired action may be to change a drilling direction, or other action. The controller(s) on the non-rotating sleeve also use information from the orientation sensor(s) to estimate an orientation or position of the non-rotating sleeve relative to a predetermined reference frame. This information may be used to set the orientation of the non-rotating sleeve with the predetermined reference frame and identify which biasing element(s) should be actuated in order to obtained the desired change in the drilling direction.

In certain embodiments, a MWD sensor on a rotating section of the string and a processor configured to calculate a steering vector using the identified momentary relative position between the drive shaft and the sleeve and information from the MWD sensor. The momentary relative position can also be used to synchronize measurements from the rotating section <NUM> and the non-rotating section <NUM>. Such synchronized measurements can be used for formation evaluation, dynamics, directional and other measurements that beneficially combine the content from the rotating and the non-rotating section.

In a fourth stage <NUM>, the controller(s) actuate the biasing elements, e. to contact the borehole wall. For example, the controllers(s) may operate the actuators to adjust a force applied by one or more biasing element and / or adjust a physical position of one or more of the biasing elements. In such a manner, the biasing element(s) are controlled to control the direction of the drilling assembly.

Set forth below are some embodiments of the foregoing disclosure:
One non-limiting embodiment described above includes an apparatus for use in a wellbore. The apparatus may include a non-rotating section and a non-rotating section disposed along a drill string. The non-rotating section has a bore and at least one biasing element engaging a wall of the wellbore. The rotating section is disposed in the bore of the non-rotating section. The apparatus also includes at least one relative rotation sensor configured to generate signals representative of a rotation of the rotating section relative to the non-rotating section and at least one orientation sensor within the non-rotating section configured to generate signals representative of an orientation of the non-rotating section relative to a selected frame of reference; and a controller. The apparatus further includes a controller in signal communication with the at least one relative rotation sensor and the at least one orientation sensor. The controller is configured to adjust at least one of: (i) a force applied by the at least one biasing element, and (ii) a position of the at least one biasing element, the adjusting being in response to the generated signals representative of a rotation of the rotating section relative to the non-rotating section from the at least one relative rotation sensor and the generated signals representative of an orientation of the non-rotating section relative to a selected frame of reference from the at least one orientation sensor.

One non-limiting embodiment of a method using the above-described apparatus may include disposing a drill string in the wellbore, the drill string including the above-described apparatus. The method may include the further steps of varying a speed of the rotation of the rotating section to transmit a control signal; using the controller to determine the control signal by detecting the rotational frequency variances using the at least one relative rotation sensor; receiving energy within the non-rotating section from the rotation of the rotating section and controlling a force and/or position of the at least one biasing element by using the determined control signal and the generated signals representative of the orientation of the non-rotating section relative to the selected frame of reference from the at least one orientation sensor.

In connection with the teachings herein, various analyses and/or analytical components may be used, including digital and/or analog subsystems. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, pulsed mud, optical or other), user interfaces, software programs, signal processors and other such components (such as resistors, capacitors, inductors, etc. ) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user, or other such personnel, in addition to the functions described in this disclosure.

One skilled in the art will recognize that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.

Claim 1:
An apparatus for use in a wellbore, comprising:
a drill string (<NUM>) configured to drill the wellbore;
a non-rotating section (<NUM>) disposed along the drill string (<NUM>), the non-rotating section (<NUM>) having a bore (<NUM>) and at least one biasing element (<NUM>) engaging a wall of the wellbore;
a rotating section (<NUM>) disposed in the bore (<NUM>) of the non-rotating section (<NUM>);
at least one relative rotation sensor (<NUM>) configured to generate signals representative of a rotation of the rotating section (<NUM>) relative to the non-rotating section (<NUM>);
at least one orientation sensor (<NUM>) within the non-rotating section (<NUM>) configured to generate signals representative of an orientation of the non-rotating section (<NUM>) relative to a selected frame of reference; and
a controller (<NUM>, <NUM>) in signal communication with the at least one relative rotation sensor (<NUM>) and the at least one orientation sensor (<NUM>), characterised in that:
the controller (<NUM>, <NUM>) is configured to adjust at least one of:
(i) a force applied by the at least one biasing element (<NUM>); and
(ii) a position of the at least one biasing element (<NUM>),
wherein the adjusting is in response to the generated signals representative of a rotation of the rotating section (<NUM>) relative to the non-rotating section (<NUM>) from the at least one relative rotation sensor (<NUM>) and the generated signals representative of an orientation of the non-rotating section (<NUM>) relative to a selected frame of reference from the at least one orientation sensor (<NUM>); and in that
the non-rotating section (<NUM>) is configured to receive energy from the rotation of the rotating section (<NUM>).