Variable flow resistance system for use with a subterranean well

A variable flow resistance system for use with a subterranean well includes a first flow path to receive a fluid, a flow rate sensor to measure a flow rate of the fluid received into the first flow path, and an actuator to control an inflow rate of the fluid received into the first flow path based upon the measured flow rate of the fluid.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides a selectively variable flow restrictor.

In a hydrocarbon production well, it is many times beneficial to be able to regulate flow of fluids from an earth formation into a wellbore, from the wellbore into the formation, and within the wellbore. A variety of purposes may be served by such regulation, including prevention of water or gas coning, minimizing sand production, minimizing water and/or gas production, maximizing oil production, balancing production among zones, transmitting signals, etc.

Therefore, it will be appreciated that advancements in the art of variably restricting fluid flow in a well would be desirable in the circumstances mentioned above, and such advancements would also be beneficial in a wide variety of other circumstances.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.

Turning now to the present figures,FIG. 1shows a well system10that can embody principles of the present disclosure. As depicted inFIG. 1, a wellbore12has a generally vertical uncased section14extending downwardly from casing16, as well as a generally horizontal uncased section18extending through an earth formation20.

A tubular string22(such as a production tubing string) is installed in the wellbore12. Interconnected in the tubular string22are multiple well screens24, variable flow resistance systems25, and packers26. The packers26seal off an annulus28formed radially between the tubular string22and the wellbore section18. In this manner, fluids30may be produced from multiple intervals or zones of the formation20via isolated portions of the annulus28between adjacent pairs of the packers26.

Positioned between each adjacent pair of the packers26, a well screen24and a variable flow resistance system25are interconnected in the tubular string22. The well screen24filters the fluids30flowing into the tubular string22from the annulus28. The variable flow resistance system25variably restricts flow of the fluids30into the tubular string22, based on certain characteristics of the fluids.

At this point, it should be noted that the well system10is illustrated in the drawings and is described herein as merely one example of a wide variety of well systems in which the principles of this disclosure can be utilized. It should be clearly understood that the principles of this disclosure are not limited at all to any of the details of the well system10, or components thereof, depicted in the drawings or described herein.

For example, it is not necessary in keeping with the principles of this disclosure for the wellbore12to include a generally vertical wellbore section14or a generally horizontal wellbore section18, as a wellbore section may be oriented in any direction, and may be cased or uncased, without departing from the scope of the present disclosure. It is not necessary for fluids30to be only produced from the formation20as, in other examples, fluids could be injected into a formation, such as injected through the tubular string22and out into the formation20, or fluids could be both injected into and produced from a formation, etc. Further, it is not necessary for one each of the well screen24and variable flow resistance system25to be positioned between each adjacent pair of the packers26. It is not necessary for a single variable flow resistance system25to be used in conjunction with a single well screen24. Any number, arrangement and/or combination of these components may be used.

It is not necessary for any variable flow resistance system25to be used with a well screen24. For example, in injection operations, the injected fluid could be flowed through a variable flow resistance system25, without also flowing through a well screen24.

It is not necessary for the well screens24, variable flow resistance systems25, packers26or any other components of the tubular string22to be positioned in uncased sections14,18of the wellbore12. Any section of the wellbore12may be cased or uncased, and any portion of the tubular string22may be positioned in an uncased or cased section of the wellbore, in keeping with the principles of this disclosure.

It should be clearly understood, therefore, that this disclosure describes how to make and use certain examples, but the principles of the disclosure are not limited to any details of those examples. Instead, those principles can be applied to a variety of other examples using the knowledge obtained from this disclosure.

It will be appreciated by those skilled in the art that it would be beneficial to be able to regulate flow of the fluids30into the tubular string22from each zone of the formation20, for example, to prevent water coning32or gas coning34in the formation. Other uses for flow regulation in a well include, but are not limited to, balancing production from (or injection into) multiple zones, minimizing production or injection of undesired fluids, maximizing production or injection of desired fluids, etc.

Examples of the variable flow resistance systems25described more fully below can provide these benefits by increasing resistance to flow if a fluid velocity increases beyond a selected level (e.g., to thereby balance flow among zones, prevent water or gas coning, etc.), or increasing resistance to flow if a fluid viscosity decreases below a selected level (e.g., to thereby restrict flow of an undesired fluid, such as water or gas, in an oil producing well).

Whether a fluid is a desired or an undesired fluid depends on the purpose of the production or injection operation being conducted. For example, if it is desired to produce oil from a well, but not to produce water or gas, then oil is a desired fluid and water and gas are undesired fluids.

Note that, at downhole temperatures and pressures, hydrocarbon gas can actually be completely or partially in liquid phase. Thus, it should be understood that when the term “gas” is used herein, supercritical, liquid and/or gaseous phases are included within the scope of that term.

Referring additionally now toFIG. 2, a schematic view of a variable flow resistance system25in accordance with one or more embodiments of the present disclosure is shown. In this example, a fluid36(which can include one or more fluids, such as oil and water, liquid water and steam, oil and gas, gas and water, oil, water and gas, etc.) may be filtered by a well screen (24inFIG. 1), and may then flow into a first flow path38(e.g., an inlet flow path) of the variable flow resistance system25. A fluid can include one or more undesired or desired fluids. Both steam and water can be combined in a fluid. As another example, oil, water and/or gas can be combined in a fluid. Flow of the fluid36through the variable flow resistance system25is resisted to control a flow rate of the fluid flowing through the system25. The fluid36may then be discharged from the variable flow resistance system25, such as to an interior or exterior of the tubular string22via a second flow path40(e.g., an outlet flow path). As used herein, the first flow path38and the second flow path40may be generally described and function as an inlet flow path and an outlet flow path, respectively. However, the present disclosure is not so limited, as the flow of the fluid36may be reversed, such as during injection applications, through the variable flow resistance system25such that the first flow path38and the second flow path40may be generally described and function as an outlet flow path and an inlet flow path, respectively.

In other examples, the well screen24may not be used in conjunction with the variable flow resistance system25(e.g., in injection operations), the fluid36could flow in an opposite direction through the various elements of the well system10(e.g., in injection operations), a single variable flow resistance system could be used in conjunction with multiple well screens, multiple variable flow resistance systems could be used with one or more well screens, the fluid could be received from or discharged into regions of a well other than an annulus or a tubular string, the fluid could flow through the variable flow resistance system prior to flowing through the well screen, any other components could be interconnected upstream or downstream of the well screen and/or variable flow resistance system, etc. Thus, it will be appreciated that the principles of this disclosure are not limited at all to the details of the example depicted in the figures and described herein. Further, additional components (such as shrouds, shunt tubes, lines, instrumentation, sensors, inflow control devices, etc.) may also be used in accordance with the present disclosure, if desired.

The variable flow resistance system25is depicted in simplified form inFIG. 2, but in a preferred example, the system25can include various passages and devices for performing various functions, as described more fully below. In addition, the system25preferably at least partially extends circumferentially about the tubular string22, or the system25may be formed in a wall of a tubular structure interconnected as part of the tubular string.

In other examples, the system25may not extend circumferentially about a tubular string or be formed in a wall of a tubular structure. For example, the system25could be formed in a flat structure, etc. The system25could be in a separate housing that is attached to the tubular string22, or it could be oriented so that the axis of the second flow path40is parallel to the axis of the tubular string. The system25could be on a logging string, production string, drilling string, coiled tubing, or other tubular string or attached to a device that is not tubular in shape. Any orientation or configuration of the system25may be used in keeping with the principles of this disclosure.

Referring now back toFIG. 2, the variable flow resistance system25includes the first flow path38to receive fluid into the system25and a second flow path40to send fluid out of the system25. When fluid exits the system25, the fluid may, for example, enter into the interior of a tool body or out of the exterior of a tool body used in conjunction with the variable flow resistance system25. The variable flow resistance system25may further include a sensor42and an actuator44. The sensor42is included to measure one or more properties or characteristics of the fluid received into the system25, such as measure the flow rate of the fluid received into the system25. Though not so limited, and as discussed below, the sensor42may be positioned near or within the first flow path38to measure the property or characteristic of the fluid received into the system25through the first flow path38.

The actuator44may control or adjust an inflow rate of fluid received into the system25and the first flow path38. Additionally or alternatively, the actuator44may control or adjust the restriction of fluid inflow received into the system25and the first flow path38and/or control or adjust a drop in pressure between first flow path38and second flow path40. For example, the actuator44may be positioned or included within the system25to extend into and retract from the fluid flow path extending and formed through the system25. To increase the inflow rate of the fluid, or decrease the inflow fluid restriction or pressure drop across the system25, the actuator44may retract to enable more fluid to flow through the fluid flow path of the system25. To decrease the inflow rate of the fluid, or increase the inflow fluid restriction or pressure drop across the system25, the actuator44may extend to restrict the fluid flow through the fluid flow path of the system25. Further, in one or more embodiments, the actuator44may be used to fully stop or inhibit the fluid flow through the fluid flow path of the system25. For example, if the system25is turned or powered off, the actuator44may fully extend to prevent fluid flow through the fluid flow path of the system25. Accordingly, the actuator44may be used as or include an adjustable valve to be in a fully open position, a fully closed position, or an intermediate position to control the flow rate of fluid through the system25. Further, in one or more embodiments, the control or adjustment of the inflow rate of fluid, the restriction of fluid inflow, or the pressure drop may all be parameters related to each other. Accordingly, as used herein, when referring to control or adjustment of one parameter, such as the inflow rate of fluid, may also be referring to control or adjustment of another parameter without departing from the scope of the present disclosure.

The actuator44may include a mechanical actuator (e.g., a screw assembly), an electrical actuator (e.g., piezoelectric actuator, electric motor), a hydraulic actuator (e.g., hydraulic cylinder and pump, hydraulic pump), a pneumatic actuator, and/or any other type of actuator known in the art. For example, the actuator44may include a linear or axially driven actuator, in which the actuator44interacts with an orifice included in the first flow path38to operate as an adjustable valve and control the inflow rate of the fluid.

Referring still toFIG. 2, the variable flow resistance system25may include one or more power sources. For example, the system25may include a power generator48and/or a power storage device. The power generator48may be used to generate power for the system25, and the power storage device may be used to provide stored power for the system25and/or store power generated by the power generator48. In one embodiment, the power generator48may include a turbine and may be able to generate power from fluid received into the first flow path38and flowing through the system25. The power generator48may additionally or alternatively include other types of power generators, such as a flow induced vibration power generator and/or a piezoelectric generator, to generate power from the fluid received into the system25and/or from other energy sources present downhole (e.g., temperature and/or pressure sources).

The power storage device may be included within electronics46for the system25and may be used to provide stored power. In one embodiment, the power storage device may be able to store power generated by the power generator48and provide this stored powered for the system25. The power storage device may include a capacitor (e.g., super capacitor), battery (e.g., rechargeable battery), and/or any other type of power storage device known in the art. In one or more embodiments, as the sensor(s) and/or actuator(s) of the system25may require more power than generated by the power generator48, the power storage device may be used to store power, and then supplement the power generator48when running the sensor(s), actuator(s), and/or other components of the system25.

As discussed above, the system25, and more particularly the actuator44, may be used to control or adjust an inflow rate of fluid received into the system25through the first flow path38, control or adjust the restriction of fluid inflow received into the system25, and/or control or adjust a drop in pressure across the system25. The inflow rate of the fluid received into the system25may be controlled based upon a control signal received by the system25. A control signal may be sent to the system25from a transmitter, such as a transmitter uphole or upstream of the system25, or even on or close to the surface of the well. The control signal may be sent to the system25through the flow rate of the fluid, and more particularly by selectively fluctuating and varying the flow rate of the fluid received by the system25. A profile or pattern of flow rate fluctuations may be used to indicate a unique control signal, such as with communications involving flow rate telemetry. Accordingly, a transmitter, controlling the flow rate of the fluid, may be able to encode one or more control signals through flow rate fluctuations of the fluid, and a receiver, measuring the flow rate of the fluid, may be able to decode one or more controls signals through the flow rate fluctuations of the fluid.

The transmitter is able to transmit a control signal by generating flow rate fluctuations of the fluid uphole or downstream of the system25. Accordingly, to generate the flow rate fluctuations, the transmitter may include or control a choke, a bypass around a choke, a valve, a pump, or control the backpressure of the fluid at the surface, thereby selectively generating fluctuations in the flow rate of the fluid into and out of the system25.

The receiver may be able to receive a control signal by measuring flow rate fluctuations of the fluid at the system25. The receiver may include or be coupled to a flow rate sensor or flow meter that is able to measure a flow rate of the fluid received into the system25. For example, with respect toFIG. 2, the sensor42may be used to measure the flow rate of the fluid received into the flow path38. An example of a flow rate sensor42may include an accelerometer or a hydrophone that may be able to measure a flow rate of fluid flow, or a differential pressure gage positioned across the system25to detect a flow rate through the system25.

Additionally or alternatively, the power generator48may be used as the flow rate sensor. For example,FIG. 3shows a detailed view of a variable flow resistance system25in accordance with one or more embodiments of the present disclosure. The variable flow resistance system25inFIG. 3may be an alternative embodiment to the variable flow resistance system25inFIG. 2, in which like features have like reference numbers. As shown inFIG. 3, the power generator48may include a turbine or rotor that rotates at a rate directly related or proportional to the fluid flow rate through the power generator48. The turbine or rotor may, thus, be used to measure the flow rate of fluid through the system25. In another embodiment, the power generator48may include a vortex generator that vibrates at a rate directly related or proportional to the fluid flow rate through the power generator48. The power generator48may thus be used in addition or in alternative to a flow rate sensor to measure fluid flow rate through the system25.

A table is provided below of simulated results for a well through a zone when choking or restricting the flow rate at the surface of the well. This table is only an example, as the present disclosure is not limited to only the flow rates, pressures, and ranges used within the table. As shown, a 10% change or reduction in the flow rate at the surface produces only a relatively small change in downhole pressure (5 psi (34 kPa) pressure change) in a tubular string. This small of a pressure change is difficult to measure without sensitive equipment (e.g., a power intensive pressure transducer), and may also be lost in noise or leaks along the tubular string. However, a 10% change or reduction in the flow rate at the surface still results in a 10% change or reduction in flow rate at the zone with the variable flow resistance system25, within an error range of only 1%. This relationship between the change in flow rate at the surface and the change in flow rate at a particular flow resistance system is more predictable and easier to measure, as opposed to measuring changes in pressure at a particular flow resistance system.

Furthermore, though only one sensor and one actuator are shown inFIG. 2, the present disclosure is not so limited, as more than one sensor and/or more than one actuator may be used in accordance with the present disclosure. In such an embodiment, if using multiple sensors or actuators, the sensors and actuators used may be different from each other and/or may have different thresholds or tolerances than each other. For example, multiple different sensors may be used to measure different ranges of fluid flow rate through the system25or be used redundantly with respect to each other, and multiple different actuators may be used to control the inflow rate of the fluid using different techniques or at different thresholds.

The variable flow resistance system25may further include a controller and corresponding electronics46to control and manage the operation of the components of the system25. In one embodiment, the controller may be in communication with or coupled to the flow rate sensor and the actuator44to control the actuator44based upon the measured flow rate and/or measured fluctuations of flow rate. The controller may be used to receive the measured flow rates and compare the measured flow rates and fluctuations with a predetermined value. Based upon the comparison of the measured flow rates with that of the predetermined value, the controller may then move the actuator44to adjust the inflow rate of fluid received into the first flow path38of the system25appropriately.

As an example, in one or more embodiments, the controller may receive the flow rate fluctuations measured by the sensor42and/or the power generator48. The controller may then compare the measured flow rate fluctuations with one or more predetermined patterns for the flow rate fluctuations of the fluid to determine if a control signal has been included within the measured flow rate fluctuations. If, based upon the comparison, a control signal has been received through the measured flow rate or flow rate fluctuations, the controller may be used to adjust the actuator44appropriately, such as to increase or decrease fluid flow through the system25. A control signal may indicate not only what position to move the actuator44to control the flow rate into the system25, but the control signal may also indicate when to move or adjust the position of the actuator44. The control signal may be used to indicate that the wellbore is in a preliminary phase or a “startup mode,” in an intermediate phase, or in a final phase or a “late production mode,” in which different control parameters may be used for each of these different phases of the well.

While control signals may be received by the system25, such as through measuring the flow rate of fluid received by the system25discussed above, one or more signals may also be sent from the system25to other systems or receivers. For example, by controlling fluid flow rate from a transmitter upstream, the system25may receive a control signal. Accordingly, the system25may also control the fluid flow rate such that other systems or receivers downstream, either further downhole, uphole, or even close to the surface, depending on the direction of fluid flow, may receive a signal from the system25. A signal may be sent to report properties measured by the system25and/or characteristics of the system25(e.g., fluid inflow rate into the system25). Further, a signal may be used to confirm that the system25is working properly and/or confirm downhole conditions of the well. The controller may, thus, use flow rate telemetry to not only receive a control signal, but may also use flow rate telemetry to control the actuator44as desired to send a signal through the flow rate of the fluid. Alternatively, the system25may be capable of using other types of telemetry besides flow rate telemetry, such as mud-pulse telemetry, pressure profile telemetry, acoustic pulse telemetry, and/or pseudo-static pressure profile telemetry.

As shown and discussed above, an actuator may be used with a controller to selectively adjust, enable, and restrict fluid flow to perform as a fluid flow rate controller. In one or more embodiments, a fluid flow rate controller may be positioned in series or in parallel with a power generator within a variable flow resistance system. Accordingly,FIGS. 4-8show different schematic arrangements for the fluid flow through a variable flow resistance system with a fluid flow rate controller400and a power generator402positioned in series or in parallel within the system.

InFIG. 4, a schematic view is shown of a variable flow resistance system400with the fluid flow rate controller402and the power generator404positioned in series within the system400. This arrangement of the system400is similar to the system25shown in the embodiment ofFIG. 2. InFIG. 4, the flow path is arranged such that fluid flows through the fluid flow rate controller402and then the power generator404, as indicated by the directional arrows. Fluid may also flow in the reverse direction such that fluid flows through the power generator404and then the fluid flow rate controller402.

InFIG. 5, a schematic view is shown of a variable flow resistance system500with the fluid flow rate controller402and the power generator404still positioned in series within the system500. In this embodiment, a check valve406is included within the system500and is positioned in parallel with the fluid flow rate controller402. This embodiment enables the fluid flow rate controller402to control the fluid flow rate through the system500in one direction, while the power generator404is able to generate power from fluid flow in both directions through the system500. In another embodiment, the check valve406may be additionally or alternatively be positioned in parallel with the power generator404.

InFIG. 6, a schematic view is shown of a variable flow resistance system600with the fluid flow rate controller402and the power generator404positioned in series within the system600. In this embodiment, a nozzle408and/or a relief valve410may be included within the system600. As shown, the nozzle408may be positioned in parallel with the fluid flow rate controller402, and the relief valve410may be positioned in parallel with the power generator404. The nozzle408is used in this embodiment to restrict but allow minimum fluid flow around the fluid flow rate controller402. This arrangement enables fluid to still flow to the power generator404to generate power, even in a scenario when the fluid flow rate controller402is completely closed and preventing fluid flow therethrough. Further, the relief valve410may be used to relieve fluid pressure above a predetermined amount around the power generator404.

InFIG. 7, a schematic view is shown of a variable flow resistance system700with the fluid flow rate controller402and the power generator404positioned in parallel within the system700. In this embodiment, the flow path is arranged such that fluid flows separately to the fluid flow rate controller402and the power generator404. As such, fluid may flow to the power generator404to generate power, even when the fluid flow rate controller402is completely closed and preventing fluid flow therethrough.

InFIG. 8, a schematic view is shown of a variable flow resistance system800with the fluid flow rate controller402and the power generator404positioned in parallel within the system600. A nozzle408and a relief valve410are also included within the system600. The nozzle408is positioned in parallel with the fluid flow rate controller402to restrict the amount of fluid flow to the power generator404. Further, the relief valve410is positioned in parallel with the power generator404to bypass the power generator404when fluid pressure is above a predetermined amount.

Referring now toFIG. 9, a flowchart of a method900of variably controlling flow resistance or flow rate in a well in accordance with one or more embodiments of the present disclosure is shown. The method900includes receiving a fluid into a flow path902, such as by receiving fluid into the first flow path of a variable flow resistance device, tool, or system. The method900may follow with measuring a flow rate or flow rate fluctuations received into the flow path904, such as measuring with a sensor or power generator of the variable flow resistance system. The method900may further include controlling an inflow rate of the fluid received into the flow path based upon the measured flow rate of the fluid906, such as controlling with the actuator of the variable flow resistance system.

The controlling of the inflow rate of the fluid906may include comparing the measured flow rate or flow rate fluctuations of the fluid with a predetermined value908. For example, the measured flow rate fluctuations may be compared with one or more predetermined patterns or profiles for flow rate fluctuations of the fluid. If the measured flow rate fluctuations match or are similar to a predetermined pattern for the flow rate fluctuations of the fluid, this comparison may indicate that a control signal has been received by the variable flow resistance system. The controlling the inflow rate of the fluid906may then further include adjusting the inflow rate of the fluid received into the first flow path based upon the comparison of the measured flow rate or flow rate fluctuations of the fluid with the predetermined value910. In particular, in the example above, as the comparison of the measured flow rate with the predetermined value indicated that a control signal was received by the variable flow resistance system, the inflow fluid restriction through the variable flow resistance system may be adjusted in accordance with the direction or instructions of the control signal. Adjusting the inflow rate of the fluid may result in a variation in the inflow fluid restriction, a variation in the pressure drop across the system, or a variation in both the fluid restriction and pressure drop.

The method900may also include receiving a control signal at a variable flow resistance device, tool, or system912, such as similar as described with respect to steps906,908, and910, after the receiving the fluid into the first flow path902. The method900may then further include sending a signal from the variable flow resistance system914. For example, the variable flow resistance system may use flow rate telemetry to send a signal to a component or receiver downstream, such as described with respect to steps906,908, and910, or may use other types of telemetry, such as mud-pulse telemetry, pressure profile telemetry, acoustic pulse telemetry, and/or pseudo-static pressure profile telemetry.

Modifications, additions, or omissions may be made to method900without departing from the scope of the present disclosure. For example, the order of the steps may be performed in a different manner than that described and some steps may be performed at the same time. Additionally, each individual step may include additional steps without departing from the scope of the present disclosure.

A variable flow resistance system for use with a subterranean well, the system comprising:

a first flow path to receive a fluid

a flow rate sensor to measure a flow rate of the fluid received into the first flow path; and

an actuator to control an inflow rate of the fluid received into the first flow path based upon the measured flow rate of the fluid.

The variable flow resistance system of Example 1, wherein the flow rate sensor measures flow rate fluctuations of the fluid received into the first flow path, the system further comprising:

a receiver comprising the flow rate sensor to receive a control signal through the measured flow rate fluctuations of the fluid;

wherein the actuator controls the inflow rate of the fluid received into the first flow path based upon the control signal received by the receiver.

The variable flow resistance system of any of the above Examples, further comprising:

a transmitter to transmit the control signal by generating the flow rate fluctuations of the fluid.

The variable flow resistance system of any of the above Examples, wherein the transmitter is coupled to a choke, a valve, or a pump to generate the flow rate fluctuations of the fluid.

The variable flow resistance system of any of the above Examples, further comprising a controller configured to control the actuator based upon the measured flow rate of the fluid, wherein the actuator adjusts the inflow rate of the fluid received into the first flow path.

The variable flow resistance system of any of the above Examples, further comprising a power source to provide power to the variable flow resistance system.

The variable flow resistance system of any of the above Examples, wherein the power source comprises a power storage device to provide stored power for the variable flow resistance system.

The variable flow resistance system of any of the above Examples, wherein the power source comprises a power generator to generate power for the variable flow resistance system.

The variable flow resistance system of any of the above Examples, wherein the power generator comprises a turbine to generate power solely from fluid received into the first flow path.

The variable flow resistance system of any of the above Examples, wherein the flow rate sensor comprises the power generator such that the power generator measures the flow rate of the fluid received into the first flow path.

The variable flow resistance system of any of the above Examples, wherein the actuator and the power generator are positioned in series or in parallel within the first flow path with respect to each other.

The variable flow resistance system of any of the above Examples, wherein the flow rate sensor comprises a flow meter.

The variable flow resistance system of any of the above Examples, further comprising a tool body and a second flow path configured to send the fluid into an interior or exterior of the tool body.

The variable flow resistance system of any of the above Examples, further comprising a production tubing string, wherein the first flow path comprises a production orifice for the production tubing string.

The variable flow resistance system of any of the above Examples, wherein the actuator comprises at least one of a screw assembly, a piezoelectric actuator, a hydraulic cylinder, an electric motor, and a hydraulic pump.

A variable flow resistance system for use with a subterranean well, the system comprising:

a first flow path to receive a fluid;

a receiver to receive a control signal through flow rate fluctuations of the fluid received into the first flow path; and

an actuator to control an inflow rate of the fluid received into the first flow path based upon the control signal received by the receiver.

The variable flow resistance system of any of the above Examples, wherein the receiver comprises a flow rate sensor to measure the flow rate fluctuations of the fluid received into the first flow path, the system further comprising:

a transmitter to transmit the control signal by generating the flow rate fluctuations of the fluid.

The variable flow resistance system of any of the above Examples, wherein the actuator adjusts the inflow rate of the fluid received into the first flow path to generate second flow rate fluctuations of the fluid, further comprising:

a second receiver downstream of the actuator to receive a second control signal through the second flow rate fluctuations of the fluid.

A method of variably controlling flow resistance in a well, the method comprising:

receiving a fluid into a first flow path;

measuring a flow rate of the fluid received into the first flow path; and

adjusting an inflow rate of the fluid received into the first flow path based upon the measured flow rate of the fluid.

The method of any of the above Examples, wherein the adjusting the inflow rate comprises:

comparing the measured flow rate of the fluid with a predetermined value; and adjusting the inflow rate of the fluid received into the first flow path based upon the comparison of the measured flow rate of the fluid with the predetermined value.

The method of any of the above Examples, wherein the measuring the flow rate comprises measuring flow rate fluctuations of the fluid, and wherein the adjusting the inflow rate comprises:

comparing the measured flow rate fluctuations of the fluid with a predetermined pattern for the flow rate fluctuations of the fluid;

adjusting the inflow rate of the fluid received into the first flow path based upon the comparison of the measured flow rate fluctuations of the fluid with the predetermined pattern for the flow rate fluctuations of the fluid.

The method of any of the above Examples, wherein:

the measuring the flow rate comprises receiving a control signal through flow rate fluctuations of the fluid; and

the adjusting the inflow rate comprises adjusting the inflow rate of the fluid received into the first flow path based upon the control signal.

The method of any of the above Examples, further comprising generating the flow rate fluctuations of the fluid to transmit the control signal.

The method of any of the above Examples, further comprising generating power from the fluid received into the first flow path.