CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. The present application claims priority benefit of Brazilian Application No. BR 1020200134884, filed July 1, 2020, the entirety of which is incorporated by reference herein and should be considered part of this specification.

BACKGROUND

Field

[0002] The present disclosure relates to systems and methods for providing power to electrical devices installed, e.g., permanently installed, in an oil or gas well, for example, in production tubing of such a well.

Description of the Related Art

[0003] Reservoir monitoring includes the process of acquiring reservoir data for purposes of reservoir management. Permanent monitoring techniques are frequently used for long-term reservoir management. In permanent monitoring, sensors are often permanently implanted in direct contact with the reservoir to be managed. Permanent installations have the benefit of allowing continuous monitoring of the reservoir without interrupting production from the reservoir and providing data when well re-entry is difficult, e.g. subsea completions.

[0004] Permanent downhole sensors are used in the oil industry for several applications. For example, in one application, sensors are permanently situated inside the casing to measure phenomenon inside the well such as fluid flow rates or pressure.

[0005] Another application is in combination with so-called smart or instrumented wells with downhole flow control. An exemplary smart or instrumented well system combines downhole pressure gauges, flow rate sensors and flow controlling devices placed within the casing to measure and record pressure and flow rate inside the well and adjust fluid flow rate to optimize well performance and reservoir behavior.

[0006] Other applications call for using sensors permanently situated in the cement annulus surrounding the well casing. In these applications, formation pressure is measured using cemented pressure gauges; distribution of water saturation away from the well using resistivity sensors in the cement annulus; and seismic or acoustic earth properties using cemented geophones. Appropriate instrumentation allows other parameters to be measured.

[0007] These systems utilize cables to provide power and/or signal connection between the downhole devices and the surface. The use of a cable extending from the surface to provide a direct to connection to the downhole devices presents a number of well-known advantages.

[0008] There are however, a number of disadvantages associated with the use of a cable in the cement annulus connecting the downhole devices to the surface including: a cable outside the casing complicates casing installation; reliability problems are associated with connectors currently in use; there is a risk of the cable breaking; the cable needs to be regularly anchored to the casing with cable protectors; the presence of a cable in the cement annulus may increase the risk of an inadequate hydraulic seal between zones that must be isolated; added expense of modifications to the wellhead to accommodate the feed-through of large diameter multi-conductor cables; the cables can be damaged if they pass through a zone that is perforated and it is difficult to pass the cable across the connection of two casings of different diameters.

[0009] In efforts to alleviate these and other disadvantages of downhole cable use, so- called “wireless systems” have been developed.

SUMMARY

[0010] Systems and methods for downhole power generation for wireless multi-stage completions are provided.

[0011] In some configurations, a downhole system includes a turbine driven by fluid flow; an alternator driven by the turbine, the alternator configured to convert energy from the fluid flow to electrical energy; an electrical power storage and/or conversion device configured to be powered by the electrical energy generated from the fluid flow; and a connector configured to transfer power from the power device to a device requiring electrical power outside the downhole system. At least a portion of the downhole system can be configured to be removeably disposed in a completion installed in a wellbore.

[0012] The power storage device can be a rechargeable battery. In some configurations, components of the downhole system that are movable in use are retrievable from the completion. The turbine can be driven by annulus fluid flow, a portion of production fluid flow, and/or injection flow. The connector can be an inductive coupler. The inductive coupler can be configured to provide power and/or telemetry to the device requiring electrical power outside the downhole system. The downhole system can include or be integrated with a device configured to communicate with uphole equipment such as surface infrastructure. The communication device can communicate with uphole equipment via mud-pulse type communication, acoustic communication, and/or EM telemetry through a well casing of the well and subsurface layers. The downhole system can include sensors and/or one or more flow control devices. The downhole system can be configured to act as a communication gateway between the surface and lower completion equipment. In some configurations, all or a portion of data communication with the uphole equipment is also stored locally and available for future usage when the downhole system is retrieved.

[0013] In some configurations, a downhole power generation system includes a docking station disposed in a completion installed in a wellbore, the docking station comprising a stator and a first connector; and a shuttle comprising a rotor and a second connector, the shuttle configured to be removeably disposed in the completion, wherein the shuttle is configured to be retrieved from the completion while the docking station remains in the completion, and wherein the second connector is configured to operably couple to the first connector when the shuttle is disposed in the completion.

[0014] In some configurations, the stator is disposed adjacent an inner surface of tubing of the completion. The rotor can be disposed radially within the stator when the shuttle is disposed in the completion. The rotor can be driven by fluid flow circumferentially within and through the rotor. The rotor can be hollow and configured to allow for fluid flow and the passage of intervention tools through the rotor.

BRIEF DESCRIPTION OF THE FIGURES

[0015] Certain embodiments, features, aspects, and advantages of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.

[0016] Figure 1 illustrates an example of a wired multi-stage completion.

[0017] Figure 2 illustrates an example wireless transmission system. [0018] Figure 3 illustrates an example multi-stage wireless transmission system.

[0019] Figure 4 illustrates an example wireline retrievable shuttle station and the wireline retrievable shuttle station installed in a completion.

[0020] Figure 5 illustrates an example electric generator.

DETAILED DESCRIPTION

[0021] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

[0022] As used herein, the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms "up" and "down"; "upper" and "lower"; "top" and "bottom"; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point at the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.

[0023] After being drilled and tested, a production well receives a permanent completion, i.e., the production string where effluent flows in use. The completion typically includes tubing and various safety equipment, such as a packer, safety valve, and/or other equipment. If the completion is damaged or maintenance is required, the completion can be removed and replaced, but doing so is expensive and often requires a rig. Therefore, components of the completion are expected to have a long lifespan (for example, typically more than 10 years). However, some existing electrical components, such as batteries, do not have sufficiently long lifespans. Many wells include electronic devices, for example, for downhole measurements. Traditionally, the link for power and/or data transmission between the surface and downhole tools and devices was an electric cable. Newer techniques, for example using acoustic or electro-magnetic transmission, allow for wireless communication, which can simplify installation and improve reliability. Such techniques are often used for short durations (for example, up to several weeks), such as during testing operations. However, the size, cost, and short life expectancy of batteries used to power electronic devices in wireless systems are problematic. At the end of the economical producing life of a well, the well is decommissioned and abandoned via a process called plug and abandonment (or P&A). This process follows strict practices to prevent or reduce the likelihood of future leaks. A common practice includes retrieving part of the completion to obtain a good quality cement plug. Control lines pose an obstacle to cement plug quality by creating channeling along the control line(s).

[0024] Figure 1 illustrates a wired multi-stage completion for providing power to and/or telemetry communication with downhole device(s), for example, for reservoir monitoring and control. As shown, the system includes an upper completion 70 and a lower completion 72. The lower completion 72 includes various reservoir monitoring and control tools 74. As shown, the upper completion includes a tubing hanger 110 supporting production tubing 18. In use, power and/or telemetry current flows from a surface power and telemetry system 29 through a cable 60, which extends through the tubing hanger 110 to an inductive coupler pair 61. The inductive coupler pair 61 can be positioned at or near a bottom of the upper completion 70 or at or near a junction of the upper completion 70 and the lower completion 72. Power flows from the inductive coupler pair 61 to the tools 74 along a cable 62. Telemetry signals can also flow to and from the tools 74 along cable 62.

[0025] Figure 2 illustrates an example of a wireless transmission system 200 or tubing casing transmission system, in which an insulated system of tubing and casing serve as a coaxial line. Additional details regarding such a tubing-casing transmission system can be found in U.S. Pat. No. 4,839,644 and U.S. Pat. No. 6,515,592, each of which is hereby incorporated herein by reference. Both power and two-way communication (telemetry) signal transmission are possible in the tubing-casing system.

[0026] In the example of Figure 2, tubing 18, e.g., production tubing, is installed in a casing string 22. In use, injected current flows along current lines 12, with the tubing 18 serving as the conductive conduit and the casing 22 serving as the return path for electrical signal(s) flowing along current lines 12 and providing power transmission to and/or communication with a downhole device 28. The tubing 18 is electrically isolated from the casing 22 by, for example, non- conductive or insulating fluid 19 in the interior annulus (the space between the tubing 18 and casing 22), non-conductive or insulating centralizers 21 disposed about the tubing 18, and/or an insulating coating on the tubing 18. A conductive packer 71 establishes an electrical connection between the tubing 18 and the casing 22 for the electrical signal return path.

[0027] An upper coupler or toroidal transformer 23 is linked to a surface modem and power supply 23 by a cable 60. In use, current is injected into upper coupler 23 via source 24 through the cable 60, thereby inducing a current in tubing 18. The induced current flows along current paths 12 through the tubing to a lower coupler or toroidal transformer 26. The induced current flowing through the tubing 18 inductively generates a voltage in the lower coupler 26 that is used to provide power and/or communication to the downhole device 28. Communication signals from the downhole device 28 induce a second voltage in the lower coupler 26, which creates a second current. The second current flows along current paths 12 from the lower coupler 26, through the tubing 18, through the conductive packer 71, and along the return path through the casing 22 to a surface electronic detector 25 to be recorded, stored, and/or processed.

[0028] The present disclosure provides wireless transmission systems and methods for providing power to and/or communication with one or more permanent downhole devices 28 or tools (e.g., downhole valves, flow control devices, sensors (for example, a formation evaluation system, a pressure/temperature monitoring system, and/or acoustic or electro-magnetic transmitter), packers, downhole tool setting modules, downhole isolation devices, and/or anchoring devices) in multi-stage completions. In such systems and methods, the casing 22 is deployed in the well, then the tubing 18 is deployed within the casing 22 in separated runs, leading to a multi-stage completion. Similar to the system 200 of Figure 2, the tubing 18 and casing 22 in systems for wireless multi-stage completions can serve as a coaxial line for transmission of power and/or telemetry signals. [0029] The present disclosure provides systems and methods to harvest power, for example, at the bottom of an upper completion, so that there is no need for wires between the surface or subsurface system and the interface between upper and lower completions. The harvested power can advantageously be used to generate telemetry signals from downhole devices for wireless telemetry using electro-magnetic or acoustic wave propagation.

[0030] Figure 3 illustrates an example of a multi-stage wireless transmission system. A tubing hanger 110 at or near the top of the production string or in the upper completion supports the tubing 18. The tubing hanger 110 and/or an upper production packer also acts as an upper section short between the casing 22 and tubing 18. A liner hanger 120 provides attachment for and/or supports the production liner 122 for the lower completion. The liner hanger 120 and/or a lower production packer act as a lower section short between the tubing 18 and the casing 22. The upper section short and lower section short close the tubing-casing system current loop.

[0031] As shown, the tubing 18 can be at least partially coated with an insulating coating (e.g., a polyamide material (Rilsan type)) 20, an insulating fluid 19 can be disposed in the annular space, and/or non-conductive or insulating centralizers 21 can be disposed about the tubing 18. Couplers or toroidal transformers 23, 26 provide electrical coupling between the tubing-casing transmission line and the surface and/or downhole device(s). The couplers 23, 26 are or include toroidal transformers electrically coupled to the tubing-casing line for receiving and/or transmitting power and/or telemetry signals.

[0032] In the illustrated configuration, the multi-stage wireless transmission system includes an upper coupler 23 and a lower coupler 26. The upper coupler 23 is driven by surface electronics (e.g., AC power supply and control electronics, such as source 24 and detector 25). The upper coupler 23 can transmit and detect low frequency signals (e.g., AC current) propagating along the pipe to and/or from the lower coupler 26. The lower coupler 26 is connected to downhole electronics, e.g., downhole device(s) 28, for detection of telemetry signals, recovery of electrical power, and/or uplink data transmission. The lower completion can also include a battery or any type of energy storage device. Any type(s) of modulation/demodulation technique(s) (e.g., FSK, PSK, ASK) can be used for communication between the upper 23 and lower 26 couplers. Multi stage wireless transmission systems and methods according to the present disclosure therefore establish wireless communication between lower and upper sections of the production string. [0033] Turbines, for example as traditionally used during drilling, may not be reliable for very long durations. The effluent contains solid particles, such as sand or debris, and paraffin or other chemical products that can eventually block the turbine. Additionally, batteries deployed downhole and powered by the turbines are exposed to high temperatures, and therefore have a limited life expectancy and must be replaced after several years. The present disclosure provides systems and methods for installing components that may require maintenance (e.g., the turbine, one or more batteries) in a compact package that can be retrieved and replaced with light operations not requiring a rig, e.g., with slick-line or wireline. In some configurations, such components that may require maintenance (for example, due to being components that move in use, such as components of a rotor) are retrievable, while stationary components, such as components of a stator, remain in the well.

[0034] The present disclosure provides a downhole power generator that is energized by fluid flow. In some configurations, the downhole power generator, or a portion thereof, is retrievable, for example, via wireline, for maintenance or replacement. The ability to perform maintenance can advantageously extend the life expectancy of elements, such as battery(ies) and/or turbine(s), that may otherwise not be reliable enough for a permanent installation. In some configurations, systems and methods according to the present disclosure provide or allow for electrically powered monitoring and control equipment in the lower completion 72 without control lines extending from the upper completion 70 to the lower completion 72. The removal of control lines can advantageously allow for improved cement plug quality in an eventual plug and abandonment process.

[0035] A downhole power generation system according to the present disclosure can include a receptacle device deployed and installed downhole at a certain well depth. The receptacle device acts as a docking station. The receptacle device or docking station is connected to the lower completion 72 and/or other permanent reservoir monitoring and/or control device(s) installed in the well. The downhole power generation system also includes a retrievable shuttle station that is retrievably deployed, for example, above the lower completion 72, and releasably and retrievably coupled with the docking station. The retrievable shuttle station can include a turbine that can function as either or both of a power generator and communication device with the surface by modulating the fluid flow. The retrievable shuttle station can also include one or more batteries. [0036] As shown in Figure 4, the shuttle 1 can include an electric generator 13 (for example, an alternator, such as a mud lubricated alternator), a rotating element 12 including blades actuated by fluid flow (for example, a turbine), an electronic board 14, a rechargeable battery 15, a connector 16 (for example, a wet mate or inductive coupler), a lock or latch 11, and/or a latch or other coupling mechanism 17. The lock or latch 11 can removably couple to a wireline, slick line, or other suitable conveyance mechanism for deployment or retrieval of the shuttle 1. In some configurations, one or more active or passive devices can be included in the power generation system to reduce flow on or in the area of the rotating element 12 to maintain flow in an acceptable range and limit or reduce the likelihood of wear on the rotating element 12. As an example of a passive device, a protector or flow diverter can limit the maximum pressure drop across the shuttle 1 or area of the shuttle 1. An active flow limiting device can be controlled by the electronics of the shuttle 1, e.g., the electronic board 14.

[0037] The electric generator 13 can include a stator 113, and the rotating element 12 can be considered or act as a rotor. In the illustrated configuration, rotation of the rotating element 12 (or rotor) drives production of fluid in an annulus between (e.g., radially or circumferentially between) the stator 113 and the production tubing 18. In some configurations, the electric generator 13 or alternator can be reversed to stand on the edge of the flow. In other words, the stator 113 could be positioned very close to the tubing 18 (or be integrated into the tubing 18), and the rotor or rotating element 12 could be positioned and rotate inside the stator 113, for example as shown in Figure 5. The rotor 12 can be hollow and allow for production or flow of fluid through (in other words, radially or circumferentially within) the rotor 12 (and therefore the stator 113) instead of between the stator 113 and the tubing 18. A hollow rotor 12 can also allow for the passage of intervention tools through the inner diameter or passage. Such a configuration could be considered or similar to a rim-driven design.

[0038] As also shown in Figure 4, the docking station 2 can include a latch or other coupling mechanism 30, a connection mechanism 27 (for example, a wet mate or inductive coupler), and/or an electrical wire 23 extending outside the tubing 18 to connect to the lower completion equipment. When the shuttle 1 is deployed in the tubing 18, the latch 17 of the shuttle 1 can couple to the latch 30 of the docking station 2. Similarly, the connector 16 of the shuttle 1 can couple (e.g., physically and/or operably couple) to the connection mechanism 27 of the docking station 2. [0039] In some configurations, the rotor 12 is retrievable, but the stator 113 is fixed or non- retrievable. In some such configurations, the stator 113 can be considered part of the docking station 2. For example, in the configuration of Figure 5, the retrievable shuttle 1 can include the rotor 12, connector 16, and lock 11 (or component including the lock 11). In some configurations, the connector 16 rotates with the rotor 12 in use. The docking station 2, which can remain in the tubing 18 if the shuttle 1 is retrieved and removed, can include the stator 113 and the connection mechanism 27. The retrievable shuttle 1 can include the parts that move in use, for example, the parts that rotate in use, and that therefore may become worn or damaged. The docking station 2 can include the parts that are stationary in use.

[0040] A portion of the shuttle 1, e.g., the connector 16 and the rotor 12, can be removably received in (radially or circumferentially within) a portion of the docking station 2, e.g., the connection mechanism 27 and a portion of the stator 113. The latch 17 of the shuttle 1 can removably couple to the latch 30 of the docking station 2. In some configurations, the connection mechanism 27 or another portion of the stator 113 can include stator windings or an inductive motor coupling. A wire 23 can extend from the connection mechanism 27, for example, outside of the tubing 18, to lower completion equipment to provide power to and/or communication to and/or from the lower completion equipment.

[0041] In use, the generator 13, e.g., the rotor 12, is positioned in the fluid flow (e.g., in the production tubing 18), and power is generated by the fluid flow velocity propelling the rotating element 12. Power can be generated from flow in either direction, in other words, from production fluid flow or injection fluid flow. The shuttle station can provide for communication with uphole equipment, for example, surface equipment, for example, via mud-pulse communication, acoustic communication (for example, on the tubing or fluid in the annulus between the tubing and casing), and/or electromagnetic telemetry. The shuttle 1 can be deployed, latched, unlatched, and/or retrieved via a wireline, slickline, coiled tubing, or another suitable conveyance.

[0042] When deployed, the shuttle 1 is electrically coupled to the lower completion 72, for example, via wet mate or inductive coupler. The electronic board 14 can control the generator 13 and/or downhole data acquisition and/or transmission. The electronic board 14 can be advantageously located on the shuttle 1 so that the electronic board 14 can be retrieved for service or replacement in case of failure. Retrieval of the electronic board 14 an also allow for acquisition of data logs stored in local memory on or associated with the electronic board 14. [0043] In some configurations, the shuttle 1 includes one or more sensors and/or flow control devices. The shuttle 1 can therefore act as an independent tool that can be deployed anywhere in the completion and/or can include various other features or devices, for example, production gauges.

[0044] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and/or within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” or “generally perpendicular” and “substantially perpendicular” refer to a value, amount, or characteristic that departs from exactly parallel or perpendicular, respectively, by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

[0045] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments described may be made and still fall within the scope of the disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosure. Thus, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above.