The activation of downhole tools is commonly achieved by workstring movement, hydraulic pressure, mechanical shifting or with the use of balls, darts or other devices passed through the ID of the workstring. Use of hydraulic pressure requires isolation of the workstring from the annulus or formation. This is also commonly achieved by the use of balls, darts or other plugging devices. The dependency on these devices restricts the internal diameters of the tools in the workstring and imposes limitations on the sizes and numbers of such devices that can be used in a single trip. The use of balls and darts also increases rig time, introduces operational risks and challenges with high well deviation. Furthermore, if a tool needs to be activated multiple times in single trip, the use of balls or darts may limit the number of activation cycles before it is necessary for the tool to be tripped out of hole.
These drawings illustrate certain aspects of some of the embodiments of the present disclosure and should not be used to limit or define the method.
The present disclosure relates to controlling downhole tools using signals encoded in fluid flow and interpreted via calorimetry. The fluid flow may be generated at the surface of a well site and directed down the well to the tool to be controlled. A tool control signal is encoded in a fluid flow down a well by varying one or more fluid flow parameters that will affect heat transfer at one or more sensor locations downhole. For example, a flow rate may be modulated at the surface based on the tool control signal using any of a variety of encoding schemes. Alternatively, the heat transfer is varied by changing other fluid flow parameters such as the composition of the fluid flow or the turbulence of the fluid flow. The fluid flow parameter(s) is/are varied in a way that causes changes in heat transfer that are detectable downhole using any of a variety of calorimetric flow sensor configurations. In particular, a temperature response due to the heat transfer may be detected at one or more temperature sensing locations downhole resulting from varying the one or more fluid flow parameters. The tool control signal is thereby interpreted according to the resulting temperature response and the downhole tool is controlled accordingly. In this way, the tool can be controlled without the use of balls, darts or other plugging devices, and may be activated multiple times in single trip. The tool control signal can also be encoded in fluids such as cement that are not suitable for conventional fluid pulse telemetry techniques. A finite number of example configurations are disclosed embodying different combinations of features, though other configurations may be constructed having any suitable combination of disclosed features.
A variety of tool strings are used to work on a well throughout its life, including during the drilling, completion, and production phases, for workover operations and maintenance, and to shut in or repurpose a well at the end of its service life. A representative tool string 20 is provided in
Fluids are circulated downhole during many kinds of wellbore operations. For example, during the completion phase of the well 12, cement 17 may be circulated down an appropriate tool string for cementing the casing 18 to the wellbore 16. In another example, pressurized stimulation fluids, such as acidizing or hydraulic fracturing fluids, may be circulated downhole through an appropriate tool string for enhancing production. Pressurized fluid may also be circulated downhole during hydraulic workover operations. Various tools in the tool string 20, i.e., downhole tools, may be operated using fluid flow and/or to help control the fluid flow during wellbore operations. Two tools are shown by way of example, although any number of downhole tools and tool configurations are possible using the principles of this disclosure.
The downhole tool 40 (“T1”) is actuated according to aspects of this disclosure using encoded tool control signals. A system for controlling the downhole tool 40 comprises a transmitter (“XMTR”) 24 for encoding a tool control signal into the fluid flow 21. The signal transmitter 24 may be located at the surface 14 and used to encode the tool control signal by varying one or more fluid flow parameters of the fluid flow 21 in relation to the tool control signal. For example, the transmitter 24 may include flow control elements such as a variable valve, e.g., a choke or variable flow orifice, to modulate the flow rate of fluid flow 21 from the pump 27 according to the tool control signal to be encoded. Thus, modulating a flow rate is an example of varying a fluid flow parameter to encode the tool control signal in the fluid flow 21.
The fluid source 28 in the system may also include a plurality of fluid components, e.g., at least two fluid components 23A, 23B, having different fluid compositions. The tool control signal in some embodiments may be encoded, at least in part, by varying a fluid composition of the fluid flow 21. Varying the fluid composition of the fluid flow 21 varies a thermal conductivity of the fluid flow 21 and corresponding heat transfer downhole even without varying the flow rate. For example, the transmitter 24 may be used to dynamically switch between the two fluid components 23A, 23B or dynamically adjust a ratio of the fluid components 23A/23B in relation to the tool control signal to produce a time-varying heat transfer detectable downhole using calorimetry.
Thus, varying the fluid flow rate and varying the fluid composition are two examples of varying a fluid flow parameter to encode the tool control signal in the fluid flow 21 in a way that is detectable downhole using calorimetry. In one or more embodiments, the tool control signal may be encoded just by varying the flow rate. In one or more embodiments, the tool control signal may instead be encoded just by varying the fluid composition. In one or more embodiments, the tool control signal may be encoded both by varying the flow rate and the fluid composition, such as to achieve a wider range of detectable heat transfer and corresponding signal bandwidth. In still other embodiments, any other fluid flow parameters may be varied in a way that is detectable downhole using calorimetry.
The system also includes a downhole receiver (“RX”) 26 positioned in the well in fluid communication with the fluid flow 21. The signal receiver 26 may comprise a calorimetric flow sensor that detects a temperature variation in the fluid flow resulting from varying the one or more fluid flow parameters at the transmitter 24. A controller 30 is in communication with the receiver 26 for controlling the downhole tool 40 based on the detected temperature response. For example, the receiver 26 may use calorimetry to obtain a time-varying temperature response resulting from the varying fluid flow parameters of the fluid flow 21 as it passes through the receiver 26. The time-varying temperature response may be interpreted by the controller 30 as a digital or analog signal (based on the encoding scheme), since the temperature response is expected to vary in relation to the modulation of the fluid flow parameters. The controller 30 then controls the downhole tool 40 in relation to the temperature response. Any number of additional tools (not shown) may be included in the tool string 20 controlled by calorimetry, which may be individually addressed by the tool control signal 29.
The tool string 20 may also include one or more other tools controlled in other ways, i.e., without necessarily encoding or interpreting a signal using calorimetry. For example, a second downhole tool 60 (“T2”) positioned downstream of the first downhole tool 40 may be operated by dropping a plugging member 13 into the well 12. The plugging member 13 may comprise a ball or dart, for example, that seats within a schematically-drawn ball seat 62 to close or reduce flow through the second downhole tool 60. The second downhole tool 60 may be a tool that is used after the downhole tool 40 has completed any number of cycles, in a wellbore operation that requires performing one or more repetitions of a first function with the downhole tool 40 followed by a second function with the second downhole tool 60. Desirably, since the first downhole tool 40 is not operated using a plugging member, its flow bore remains unobstructed for the plugging member 13 to pass through the first downhole tool 40 and further down the tool string 20 to the second downhole tool 60.
Various controller components are illustrated for controlling the downhole tool 40 in response to the tool control signal 29. These controller components are illustrated as separate components for ease of discussion, but may contain overlapping functionality, or additional components or sub-components that perform the control functionality as it is schematically described in
Thus, the downhole tool 40 may be controlled in response to the tool control signal 29. In some configurations, the actuator 34 may be directly coupled to the downhole tool 40, to open, close, shift, rotate, or otherwise mechanically operate the downhole tool 40. Alternatively, the actuator 34 may be coupled to a variable flow restrictor 36, such as a valve or choke, to indirectly control the first downhole tool by adjusting the flow restriction to the downhole tool 40 in response to the tool control signal 29. The variable flow restrictor 36 may be advantageous, for example, where mechanically operating the downhole tool 40 requires more force or power than the actuator 34 or power source 38 can directly provide, particularly with finite power available from the power source 38 (e.g. on-board battery). In that case, it can be more efficient or effective for the actuator 34 to perform a lower-power operation such as adjusting flow using the variable flow restrictor 36, and to use the pressurized flow resulting from that change to mechanically operate the downhole tool 40.
The system 100 may be used for any of a variety of tool control needs in a variety of wellbore operations. Examples include setting and unsetting of packers; opening, closing, and/or choking valves and sleeves, formation isolation or choking, hydraulic fracturing, work string connect and disconnect, swivel activation and deactivation; activation of drilling and wellbore cleaning tools (e.g., brushes, scrapers, and mills); operating tools requiring unlimited activation and deactivation cycles in a single trip; and tandem equipment runs where advanced control of specific tools are required. The system 100 could also be used in production flow, in which surface choke can be used to control flow rates downhole and initiate system response.
A myriad of systems can be constructed using different configurations of a heating element and any number of temperature sensors. In some cases, as few as one temperature sensor can be used to obtain a temperature response.
A first temperature sensor 104A is positioned at a first temperature sensing location upstream of a heating element 102. A second temperature sensor 104B is positioned at a second temperature sensing location downstream of the heating element 102. With this configuration, a temperature differential may be obtained between the first temperature sensor 104A and the second temperature sensor 104B as an indication of flow rate. The flow rate may be varied over time so that the temperature differential varies over time. The variation of time is useful for generating a signal, such as a digital signal encoded as a series of 0s and 1s, or an analog signal based on a time-varying value.
In
Any suitable encoding method may be used. By way of illustration,
The tool control signal may be interpreted based on the temperature response without necessarily decoding the tool control signal. For example, in at least some embodiments, it is not necessary to back-calculate the original value of the fluid parameter on the horizontal axis. As in the example of
However, in some configurations, the tool control signal could be decoded by measuring the temperature response (vertical axis) and applying the correlation to back-calculate the corresponding flow parameter values (horizontal axis) and using the back-calculated flow parameter values to control the downhole tool. Alternatively, the flow parameter values may be back-calculated as a check or confirmation to validate the tool control signal. For example, a back-calculated flow parameter value outside an expected range could be used to generate an error or flag, such as the need to repair or re-calibrate one or more components of the system.
The action of the downhole tool can be, for example, to change the flow restriction such as through the deployment of a flapper, a ball valve, a sliding sleeve, a needle valve, a packer element, or any mechanism that can restrict the flow. In some cases, the action may be performed by one tool or tool component in response to the tool control signal in a way that will cause a corresponding function of another tool or tool component. For example, a valve may be closed at one location in the tool string in response to the tool control signal, which may results in the activation of a tool at a second point due to the increased pressure from the flow. An increased flow rate may result in a higher activation pressure. In such applications, the tool at one location can be deactivated by removing the flow restriction at another location. The flow restriction at one location can be deactivated either by an elapsed time or by receiving a digital command from the surface such as through a predetermined sequence of different heat transfer. Some commands may be time based. For example, after an initial activation of a tool or tool component, a countdown may be performed according to a predetermined time interval before deactivating. Separate commands may also be used to perform different functions, such as to open the valve and then to close the valve, or to go to an intermediate restriction. The valve can be actuated with a motor, a solenoid, a hydraulic chamber, an air chamber, etc.
The calorimetric sensor 200 may comprise one or more heating element 202 and one or more temperature sensors 204. The heating element 202 and temperature sensor 204 are schematically shown in the figure to represent any of a variety of sensor configurations, examples of which are mentioned below. The sensors 202, 204 may at least partially reside inside a probe 206. Generally, the heating element 202 may heat the fluid flow, and varying the fluid flow parameters produces a time-varying temperature response that may be detected using the one or more temperature sensors 204.
In a first example, the one or more temperature sensors 204 include a first temperature sensor used as a reference temperature sensor as a control feedback for the heating element 202. A second temperature sensor is a variable temperature sensor and is placed away from the heating element 201. Typically, the reference temperature sensor is upstream and the variable temperature sensor is downstream of the heating element (see, e.g.,
A second example may use a single temperature sensor 204 and a single heating element 202. The flow rate is indicated by the absolute temperature measured by the single temperature sensor 204. If the temperature sensor is upstream of the heating element, but still close enough for heat transfer to occur from the heating element to the upstream temperature sensor, then higher temperatures indicate lower flow rates. Conversely, if the temperature sensor is downstream of the heating element, then higher temperatures indicate higher flow rates, at least up to a certain threshold flow rate. If the flow rate were to exceed the threshold flow rate then the temperature at the downstream sensor would start to decrease again.
In a third example, the heating element 202 also functions as the temperature sensor 204. The internal resistance of the heater will vary with temperature. With a consistent power being delivered to the heating element, its temperature will vary with flow rate. At low flow rate, the heating element will get hotter than at higher flow rate. As it gets hotter, it will exhibit greater internal resistance which would be directly measured.
In a fourth example, the heating element 202 is collocated with the temperature sensor 204. As the heater/thermometer element is cooled by increased flow, the electronics can measure the variation with temperature and applied electrical power. The electronics can maintain a consistent temperature and measure the changes in the applied power to the heater that is necessary to maintain that consistent temperature. The electronics can maintain a consistent power to the heater and measure the changes in the resulting temperature. Thus, the third and fourth embodiments are similar in some respects, but with at least a difference in the configuration of the thermometer.
The heating element 202 has the option of either being constantly heated or being periodically heated above ambient temperature. When there is fluid flowing past the sensor probe, heat will be carried away from the heating element 202. Each time when the heating element needs to heat up, it would require current which is supplied by the power supply (chemical battery, wireline connection, or downhole power generator).
Due to different thermal conductivity of different fluids, it may be difficult to predict the exact flow rate. A user may calibrate each fluid used downhole and pre-program the data into the downhole tools to be controlled. Another way is to use the rate of current drawn by the heating element and only use low flow rate or high flow rate as “0” and “1” for communication from surface to downhole tools. Another encoding uses the changes in flow rate as the digital signal rather than the absolute flow rate. In some encoding a pulse position encoding is used. In other embodiments, the digital command is encoded in the rate of change of the flow rate, the time over which the flow changes, the time over which the flow is constant, the relative flow rates at different times, or combinations thereof.
In the examples disclosed herein, the probe does not necessarily need to be at the center of the insert, and may be positioned to avoid interfering with the ball or dart operation required for other downhole tools. For instance,
Dynamically varying the fluid flow parameters affects the temperature response. For example, varying the fluid flow rate will affect the alacrity of the temperature response (e.g., a steeper slope). Generally, increasing the flow rate will result in a faster temperature increase at the downstream sensor 304, and vice-versa. Also, cycling the heating element 302 off will result in a subsequent cooling downstream that is also detectable as a temperature response. The velocity of flow may be determined based on the rate of temperature change and the known distance D. Similarly, varying the fluid composition will affect the thermal conductivity and corresponding temperature response. Varying the fluid composition to increase thermal conductivity will generally result in faster temperature increases downstream, and vice-versa.
Other embodiments may employ additional temperature sensors downstream to measure a heat wave moving downhole. This may provide more complete information about the temperature response, or may provide more granularity for encoding the tool control signal, for example.
Accordingly, the present disclosure may provide systems and methods for controlling a downhole tool by varying fluid flow parameters to encode a tool control signal and using calorimetry to detect a temperature response corresponding to the tool control signal. The systems and methods may include any of the various features disclosed herein, in any suitable combination, including one or more of the following examples.
A method of controlling a downhole tool, comprising: encoding a tool control signal in a fluid flow down a well by varying one or more fluid flow parameters of the fluid flow; obtaining a temperature response downhole resulting from varying the one or more fluid flow parameters; and controlling the downhole tool responsive to the detected temperature response.
The method of Example 1, wherein varying the one or more fluid flow parameters comprises varying a flow rate of the fluid flow.
The method of any of Examples 1 to 2, further comprising: heating the fluid flow downhole in proximity to a temperature sensing location at which the temperature response is obtained.
The method of any of Examples 1 to 3, wherein obtaining the temperature response comprises detecting a time-varying temperature change at a single temperature sensing location.
The method of any of Examples 1 to 4, wherein obtaining the temperature response comprises sensing temperature at a first temperature sensing location, sensing temperature at a second temperature sensing location spaced from the first temperature sensing location, and detecting a time-varying temperature differential between the first and second temperature sensing locations.
The method of any of Examples 1 to 5, wherein varying the one or more fluid flow parameters comprises varying a fluid composition of the fluid flow thereby varying a thermal conductivity of the fluid flow.
The method of any of Examples 1 to 6, wherein encoding the tool control signal comprises encoding a digital “1” by controlling the fluid flow parameters to within a first value range and encoding a digital “0” by controlling the fluid flow parameters to within a second value range, wherein the first and second value range are distinguishable based on the detected temperature response.
The method of any of Examples 1 to 7, wherein controlling the downhole tool comprises: electronically signaling a tool actuator coupled to the downhole tool in response to the tool control signal; and powering the tool actuator with a power source coupled to the tool actuator to activate the downhole tool.
The method of any of Examples 1 to 8, wherein controlling the downhole tool comprises: adjusting a variable flow restriction in response to the tool control signal; and using a pressure change resulting from adjusting the variable flow restriction to activate or deactivate the downhole tool.
The method of any of Examples 1 to 9, further comprising: conveying the fluid flow down the well through a tubular conveyance; obtaining the temperature response at an insert positioned along the tubular conveyance, the insert defining a flow passage for passing the fluid flow through the insert; dropping a plugging member down the well and through the flow passage of the insert to a second downhole tool; and plugging a tool flow bore of the second downhole tool with the plugging member.
A system for controlling a downhole tool, comprising: a signal transmitter comprising a signal encoder that encodes a tool control signal by varying one or more fluid flow parameters of a fluid flow down a well; a signal receiver positionable in the well in fluid communication with the fluid flow, the signal receiver detecting a temperature response in the fluid flow resulting from varying the one or more fluid flow parameters; and a controller for controlling the downhole tool according to the temperature response.
The system of Example 11, wherein the downhole tool comprises a variable flow restrictor and wherein the controller comprises an actuator for operating the variable flow restrictor.
The system of Example 12, wherein the downhole tool further comprises: a tool component activated in response to a pressure increase from the actuator restricting flow through the variable flow restrictor.
The system of any of Examples 11 to 13, wherein the signal receiver comprises an insert positionable inside a tubular conveyance that conveys the fluid flow down the well, the insert defining a flow passage for passing the fluid flow through the insert, with the calorimetric flow sensor coupled to the insert in fluid communication with the flow passage.
The system of Example 14, wherein the flow passage of the insert further comprises a main bore having an inner diameter (ID) for passing a plugging member and an annular recess radially outwardly of the main bore, with one or both of a heating element and a temperature sensor positioned in the annular recess.
The system of any of Examples 11 to 15, further comprising: a second downhole tool downstream of the flow insert having a tool flow bore and a seat for receiving a plugging member to close the tool flow bore, wherein the plugging member is sized to pass through the main bore of the insert to the second downhole tool to plug the tool flow bore.
The system of any of Examples 11 to 16, wherein the calorimetric flow sensor comprises a heating element for heating the fluid flow downhole in proximity to a temperature sensing location at which the temperature response is obtained.
The system of any of Examples 11 to 17, wherein the calorimetric flow sensor detects a time-varying temperature change at a single temperature sensing location.
The system of any of Examples 11 to 18, wherein the calorimetric flow sensor senses temperature at a first temperature sensing location and at a second temperature sensing location spaced from the first temperature sensing location, and detects a temperature variation as a time-varying temperature differential between the first and second temperature sensing locations.
The system of any of Examples 11 to 19, wherein the controller interprets a first range of the temperature response as a digital “1” and interprets a second range of the temperature response as a digital “0”.
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
Therefore, the present embodiments are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, all combinations of each embodiment are contemplated and covered by the disclosure. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure.
This is a continuation of U.S. application Ser. No. 17/984,713, filed Nov. 10, 2022, which is a nonprovisional application, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 17984713 | Nov 2022 | US |
Child | 18625037 | US |