Preventing downhole loss of artificial lift system upon unintended component disconnection

Abstract

A loss prevention assembly is installable to an artificial lift system suspended from a tubing string. The artificial lift system may be an electric submersible pump system. The loss prevention assembly can include an uphole coupler and a downhole coupler. The uphole coupler may be coupled to the tubing string at a location uphole of the artificial lift system. The downhole coupler may be coupled to a component of the artificial lift system, such as a downhole-most component of the artificial lift system. One or more tethers can securely connect the uphole coupler to the downhole coupler. The one or more tethers can support the weight of the artificial lift system. The loss prevention assembly can prevent a downhole loss of all or a portion of the artificial lift system in the event of an unintended disconnection of an artificial lift system component.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to hydrocarbon well operations, and more particularly although not necessarily exclusively, to preventing all or a portion of an artificial lift system from downhole loss in a wellbore upon an unintended disconnection of an artificial lift system component.BACKGROUND

[0002] In hydrocarbon well operations, production operations may follow the drilling and completion of a wellbore. The completion operations may include, among other operations, casing and cementing the wellbore. The production operations may initially involve, for example, placing production equipment such as conveyance (production) tubing and various components and devices that may be coupled thereto, downhole in the wellbore. For example, a production tubing string may be deployed into the wellbore and may support an artificial lift system. The artificial lift system may be an electric submersible pump (ESP) system. The ESP system may include, among other components, a pump, a seal section, an intake, a motor, and a sensor. In some examples, more than one of at least some of the components may be present. For example, an ESP system may include multiple pumps and multiple seal sections. The components of an artificial lift system may be coupled to each other, and at least one of the components may also be coupled to the production tubing string. An unintended disconnection of one or more of the components of the artificial lift system may cause a portion of the artificial lift system located below the disconnection point to fall downhole into the wellbore.BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 is a schematic diagram of a completed hydrocarbon well including an artificial lift system according to one example of the present disclosure.

[0004] FIG. 2 is schematic diagram of another artificial lift system located in a wellbore of a hydrocarbon well and equipped with a loss prevention assembly according to one example of the present disclosure.

[0005] FIGS. 3A-3B are isometric views of a coupler component of an artificial lift system loss prevention assembly according to one example of the present disclosure.

[0006] FIG. 4 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0007] FIG. 5 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0008] FIG. 6 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0009] FIG. 7 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0010] FIG. 8 is flowchart illustrating a method of preventing a downhole loss of an artificial lift system upon an unintended disconnection of a component of the artificial lift system according to one example of the present disclosure.DETAILED DESCRIPTION

[0011] Certain aspects and examples of the present disclosure relate to a loss prevention assembly that can be installed to an artificial lift system of a well. The loss prevention assembly can prevent a downhole loss of all or a portion of the artificial lift system due to an unintended disconnection of a component of the artificial lift system. An unintended disconnection of a component of the artificial lift system may result from, for example, a mechanical failure of a system component, which can include connection between system components. While examples provided herein are shown and described as being associated with a hydrocarbon well for purposes of illustration, it should be understood that a loss prevention assembly according to the present disclosure can also be used with other types of wells such as, for example, municipal water wells, mine dewatering wells, geothermal wells, brine wells, etc.

[0012] The artificial lift system may be a part of (e.g., may be suspended from) a tubing string, such as a production tubing string, which is installed in a completed wellbore. The tubing string may function to conduct hydrocarbon fluids extracted from a formation surrounding the wellbore to a surface of the well, such as to a wellhead. The artificial lift system can help to increase the volume of hydrocarbon fluids transferred to the well surface, and may be especially beneficial, for example, in cases where the reservoir lacks enough pressure to lift the hydrocarbon fluids naturally.

[0013] In some examples, an artificial lift system may be an electric submersible pump (ESP) system. Example ESP system may include a number of components, such as for example, one or more pumps, an intake, one or more seal sections, a motor, and a sensor.

[0014] In some examples, the loss prevention assembly may include an uphole coupler, a downhole coupler, and a tether that extends between and is securely affixed to each of the uphole coupler and the downhole coupler. The uphole coupler can be coupled to the tubing string. For example, the uphole coupler can be coupled to the tubing string at a location uphole of the artificial lift system, such as to a top end of an electric submersible pump (ESP) system. The downhole coupler can be coupled to a component of the artificial lift system. In some examples, the downhole coupler may be coupled to a downhole-most component of the artificial lift system. For example, when the artificial lift system is an electric submersible pump system, the downhole coupler may be coupled to a sensor of the electric submersible pump system. In examples where there may not be sufficient clearance to pass the tether between the outside surface of a particular artificial lift system component (e.g., and ESP system motor) and a wall of a wellbore or a wellbore casing, the downhole coupler may be coupled to a more uphole component of the artificial lift system. For example, the downhole coupler may be coupled to another ESP system component such as, without limitation, ancillary tooling suspended below the motor, the motor, a seal section, an intake, a gas separator, or a lower pump assembly.

[0015] The tether can be, in various examples, a mechanism such as a wire rope, a synthetic fiber rope, a sling, or a chain. In some examples, only a single tether may be used. In other examples, multiple tethers may be used. When only a single tether is used, the single tether should have sufficient tensile strength to support the weight of the artificial lift system in the event of an unintended disconnection of all or a part of the artificial lift system from the tubing string. When multiple tethers are used, the collective tensile strength of the tethers should be sufficient to support the weight of the artificial lift system in the event of an unintended disconnection of all or a part of the artificial lift system from the tubing string.

[0016] Each of the uphole coupler and the downhole coupler may include tether coupling features. For example, each of the uphole coupler and the downhole coupler may include one or a plurality of tether slots and accompanying tether anchoring cavities to receive and retain respective ends of the tether. The tether slots and accompanying tether anchoring cavities can be formed in or machined into an outer surface of the couplers. In another example each of the uphole coupler and the downhole coupler may include a tether retention feature in the form of a rib or a spline that protrudes outwardly from the coupler outer surface. The protruding tether retention features of the uphole coupler and the downhole coupler may each extend axially over all or a portion of an axial length of the couplers, and a tether passageway can extend axially through the tether retention feature to receive and retain the tether.

[0017] The ends of the tether may be designed to engage with or otherwise enable the tether to be securely coupled to the uphole coupler and the downhole coupler. For example, the ends of the tether may have termination elements affixed thereto. In one example, the termination elements may be receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler. In another example, the termination elements may be of a shape or dimension that prevents the tether from being withdrawn from the tether passageway in the protruding tether retention feature of each of the uphole coupler and the downhole coupler after being passed therethrough.

[0018] Use of a loss prevention assembly according to the present disclosure can thus prevent a downhole loss of an artificial lift system in the event of an unintended disconnection of an artificial lift system component. Also, because the loss prevention assembly maintains a coupled relationship between the artificial lift system and the tubing string on which it is deployed after an unintended disconnection of an artificial lift system component, retrieval and repair of the artificial lift system can be accomplished simply by lifting the tubing string from the wellbore.

[0019] Use of a loss prevention assembly according to the present disclosure can also eliminate or reduce the costs that may result from an unintended disconnection of an artificial lift system component. For example, use of a loss prevention assembly according to the present disclosure can eliminate possibly significant costs resulting from one or more of an operation to retrieve an artificial lift system that has disconnected from a tubing string and fallen downhole, lost production time, damage to components of the fallen artificial lift system, or damage to the wellbore, a wellbore casing, or other downhole well equipment resulting from the fallen artificial lift system.

[0020] Illustrative examples follow and are given to introduce the reader to the general subject matter discussed herein rather than to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects, but, like the illustrative aspects, should not be used to limit the present disclosure.

[0021] FIG. 1 is a schematic diagram of a completed hydrocarbon well 100 including an artificial lift system according to one example of the present disclosure. The hydrocarbon well 100 includes a wellbore 102 that extends from a well (ground) surface 104 into a subterranean formation 106. The formation may include a reservoir from which hydrocarbon fluids (e.g., oil or gas) may be recovered. In other examples, the hydrocarbon well 100 may instead be drilled into the floor beneath a body of water, such as an ocean floor or a floor of a body of fresh water.

[0022] In this example, the wellbore 102 of the hydrocarbon well 100 is depicted as being entirely vertical. In other examples, one or more portions of the wellbore 102 may also be horizontal, deviated at any other suitable angle, or curved. In this example, the hydrocarbon well 100 includes a wellbore casing 108, which may be cemented into the wellbore 102 by introducing cement 110 into an annular space between the wall of the wellbore 102 and the wellbore casing 108. In other examples, all or a portion of the wellbore 102 may be uncased or partially cased.

[0023] The hydrocarbon well 100 can additionally include a wellhead 112, which can be positioned at the well surface 104 as shown. Hydrocarbons extracted from the reservoir through the wellbore 102 may be conveyed to the wellhead 112 at the well surface 104 by way of a downhole tubing string. In this example, the downhole tubing string is a production tubing string 114 that extends from the wellhead 112 into the wellbore 102 in the subterranean formation 106. When the wellbore 102 includes one or more horizontal or other non-vertical portions, the production tubing string 114 may also extend through those portions of the wellbore 102. The production tubing string 114 may comprise, for example, multiple individual sections of connected hollow pipe. Consecutive sections of the hollow pipe may be releasably coupled end-to-end, such as by threaded connection between the pipe sections.

[0024] The production tubing string 114 can include other components in addition to the pipe sections. In this example, the production tubing string 114 includes the artificial lift system 116, which includes a pump 118 and associated components for lifting hydrocarbon fluids from downhole in the wellbore 102 up to the wellhead 112 at the well surface 104. The pump 118 may be one of multiple pumps. The pump 118 may be, for example, an electric submersible pump. The artificial lift system 116 can also include a motive device for operating the pump 118. In this example, the motive device may be, for example, an electric motor 120 or any of various other devices that can generate the rotary motion necessary to operate the pump 118 and can function in a hydrocarbon well environment. The artificial lift system 116 may further include, for example, intake ports 122 for drawing hydrocarbon fluid from within the wellbore 102 into the production tubing string 114, and a seal section 124 that may carry a thrust of the pump 118 and equalize pressure to the electric motor 120.

[0025] FIG. 2 is schematic diagram of another artificial lift system located in a wellbore 200 of a hydrocarbon well 202 and equipped with a loss prevention assembly 250 according to one example of the present disclosure. In this example, the artificial lift system is an electric submersible pump (ESP) system 204. This example of the ESP system includes, from uphole to downhole, multiple pumps 206, 208, 210, an intake 212, multiple seal sections 214, 216, a motor 218, and a sensor 220. The pumps 206, 208, 210, the intake 212, the multiple seal sections 214, 216, the motor 218, and the sensor 220 may be connected in series to form the complete ESP system 204. The ESP system 204 may be suspended from a downhole end of a tubing string 222, which may be connected at an uphole end to a wellhead 224 located at a surface 226 of the hydrocarbon well 202. In this example, the uphole pump 206 of the series of multiple pumps 206-210 of the ESP system 204, may be connected to a (e.g., bolt-on) discharge head 228 that is coupled to a downhole end of the tubing string 222. A cable 230 may carry power, communication signals (e.g., operating commands), or both, from equipment at the well surface 226 to the motor 218 of the ESP system 206.

[0026] The tubing string 222 is depicted in FIG. 2 as being very short for purposes of illustration. It should be realized, however, that in actual well installations, the tubing string 222 can be thousands of feet in length such as may be required to position the ESP system 204 at a depth in the wellbore 200 where the ESP system 204 is in fluid communication with hydrocarbon fluids from a surrounding reservoir of hydrocarbon fluids.

[0027] It is possible for the ESP system 204 to experience an unintended disconnection of one or more of the system components. For example, one or more of the pumps 206, 208, 210, the intake 212, the seal sections 214, 216, the motor 218, or the sensor 220 may experience a mechanical failure that can cause an unintended disconnection of the failed component. Alternatively, an unintended disconnection may also result from a failure of a connection between any of the components. When an unintended disconnection occurs at any component location other than the last (most downhole) component of the ESP system 204, all of the components of the ESP system 204 that reside downhole of the disconnection point may fall downhole into the wellbore 200. Thus, depending on the point of disconnection, a portion or the entirety of the ESP system 204 can be lost downhole when an unintended disconnection of an ESP system component occurs. The components of a fallen ESP system 204 may be damaged during such a fall. A fallen ESP system 204 can also damage the wall of the wellbore 200, or other equipment within the wellbore 200. Additionally, subsequent retrieval of a fallen ESP system 204 from what may be deep within the wellbore 200 can be difficult, time consuming, and costly.

[0028] As represented in FIG. 2, the loss prevention assembly 250 can be installed to the ESP system 204 to prevent a downhole loss of all or any portion of the ESP system 204 upon the occurrence of an unintended disconnection of an ESP system component. The loss prevention assembly 250 may include, for example, an uphole coupler 252, a downhole coupler 254, and a tether 256 that extends between and couples the uphole coupler 252 to the downhole coupler 254.

[0029] Employing the uphole coupler 252 for coupling to an uphole end of the tether 256 rather than, for example, a fixed coupling element on a pipe section of the tubing string 222, allows for flexibility in the uphole anchoring point location of the loss prevention assembly 250. Likewise, using the uphole coupler 252 obviates the need to produce a special tubing string pipe section and to set aside and install the special pipe section at the location of the tubing string 222 at which an artificial lift system will be connected. Similarly, using the downhole coupler 254 for coupling to a downhole end of the tether 256 allows for flexibility in the downhole anchoring point location of the loss prevention assembly 250. For example, use of the downhole coupler 254 can allow the downhole anchoring point of the loss prevention assembly 250 to be located downhole of the downhole-most component of an artificial lift system, or at or between artificial lift system components located further uphole when needed (as discussed in more detail below).

[0030] As illustrated in FIG. 2, the uphole coupler 252 may be securely affixed to the tubing string 222 at a location uphole of the uphole-most component of the ESP system 204 in some examples, such as at a location uphole of the first pump 206. For example, the uphole coupler 252 may be coupled between the tubing string 222 and a top end of the ESP system 204. In various implementations, the top end of the ESP system 204 may be a pump head, the bolt-on discharge head 228, a discharge pressure sub, a sand fallback prevention tube, a centralizer assembly, a production tubing coupling, or a section of production. In some examples, the uphole coupler 252 may include threads at uphole and downhole ends thereof to facilitate threaded engagement with complimentary-threaded pipe sections of the tubing string 222 or other components of the tubing string 222 or the ESP system 204.

[0031] The downhole coupler 254 can be securely affixed to the downhole-most component of the ESP system 204 in some examples. In the example of FIG. 2, the downhole coupler 254 is affixed to the sensor 220 of the ESP system 204. For example, an extension tube 258 may be affixed to a downhole end of the sensor 220 and the downhole coupler 254 may be affixed to a downhole end of the extension tube 258. In one such arrangement, affixation of the extension tube 258 to the sensor 220 and affixation of the downhole coupler 254 to the extension tube 258 may be by threaded engagement.

[0032] In examples where there is an insufficient annulus between an outside surface of the motor 218 and the wall of the wellbore 200 or a wellbore casing to permit passage of the tether 256, the downhole coupler 254 may instead be affixed to the ESP system 204 at, for example, a location between the second seal section 216 and the motor 218, or at another location that is uphole of the motor 218 and is accessible by the tether 256. In such an example, the downhole coupler 254 may include threads at uphole and downhole ends thereof to facilitate threaded engagement with the second seal section 216 and the motor 218 or with other components of the ESP system 204. In any case, the downhole coupler 254 is preferably affixed to the ESP system 204 as far downhole as is feasible so that as many of the ESP system 204 components as possible can be prevented from falling downhole in the event of an unintended component disconnection.

[0033] When only a single tether 256 is utilized, the tether 256 should have sufficient tensile strength to support the weight of the ESP system 204 or a given portion of the ESP system 204 in the event of a component failure. When multiple tethers 256 are utilized, the collective tensile strength of the tethers 256 should be sufficient to support the weight of the ESP system 204 or a given portion of the ESP system 204 in the event of a component failure. In some examples, the tether 256 may need to support a weight of between approximately 15,000 pounds to 20,000 pounds. A selected tether 256 should also have an outside dimension (e.g., diameter) that can fit within the annulus between the components of the ESP system 204 and the wall of the wellbore 200 or a wellbore casing. In some installations, the annulus space may be less than one inch and sometimes less than one half of one inch. The material from which the tether 256 is constructed should also be able to withstand long-term exposure to potentially harsh conditions in the wellbore 200, including contact with various hydrocarbons and other fluids, high temperatures, etc.

[0034] In various examples, the tether 256 may be, without limitation, a wire rope, a synthetic fiber rope, a sling, a chain, or another mechanism that can meet the above criteria. Some wire rope, such as compacted wire rope, for example, can support loads in excess of 16,000 pounds at a diameter of nine millimeters (i.e., 0.354 inches) and loads in excess of 20,000 pounds at a diameter of 10 millimeters (i.e., 0.394 inches). Wire rope may also be coated, which may increase its resistance to the downhole environment of the wellbore 200. Synthetic fiber rope is constructed from synthetic fibers such as nylon, polyester, or polypropylene that are drawn out into strands and woven together. Synthetic fiber rope can also support heavy loads, sometimes in excess of those that can be supported by wire rope. For example, certain synthetic fiber ropes can support loads of 20,000 pounds or more at a rope diameter of approximately 0.375 inches. Synthetic fiber rope can also be lighter and more flexible than wire rope but may be less resistant to damage from abrasion. Certain types of chain may also be capable of supporting the load presented by the ESP system 204 while being compact enough to pass between the components of the ESP system 204 and the wall of the wellbore 200 or a wellbore casing.

[0035] The tether 256 may be coupled to the uphole coupler 252 and to the downhole coupler 254 in various ways. For example, each of the uphole coupler 252 and the downhole coupler 254 may have tether coupling elements that are molded into, machined into, or welded to, bolted to, or otherwise affixed thereto. Likewise, the ends of the tether 256 may include end terminations that cooperate with the coupling elements on the uphole coupler 252 and the downhole coupler 254. For example, the ends of a wire rope tether 256 may be swaged to form an eye or a loop. Alternatively, the ends of the tether 256 may terminate, without limitation, in an attached (e.g., swaged) closed socket, open socket, open or closed spelter socket, wedge socket, sleeve (round or otherwise), threaded stud, or another element that can securely couple the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254. In some examples, the connections of the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254 may be permanent connections. In other examples, the connections of the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254 may be releasable by deliberate action. For example, one or both ends of the tether 256 may be coupled to respective coupling elements on the uphole coupler 252 and the downhole coupler 254 by shackles, hooks, clevis links, or other hardware via which the tether 256 can be decoupled by deliberate action of a user.

[0036] The tether 256 can, in conjunction with the uphole coupler 252 and the downhole coupler 254, securely couple the lowest or the lowest feasible component of the ESP system 204 to a location on the tubing string 222 that is uphole of the ESP system 204. Consequently, if a component of the ESP system 204 experiences an unintended disconnection while the ESP system 204 is deployed downhole in the wellbore 200, the tether 256 can prevent the ESP system 204 from falling downhole. The tubing string 222 can thereafter be lifted from the wellbore 200 while the ESP system 204 remains secured thereto by the loss prevention assembly 250. After being lifted from the wellbore 200, the loss prevention assembly 250 can be released as needed, and the cause of the unintended disconnection can be remedied. The loss prevention assembly 250 can then be reinstalled and the ESP system 204 can be redeployed to the wellbore 200 along with the tubing string 222.

[0037] While FIG. 2 illustrates only a single tether 256 coupled between the uphole coupler 252 and the downhole coupler 254, more than one tether 256 may be utilized in other examples, as described above. For example, a pair of tethers 256 may be used instead of a single tether. In such a case, the tethers 256 may be coupled to the uphole coupler 252 and the downhole coupler 254 at diametrically opposed locations on the couplers. Such a positioning of the pair of tethers 256 can help mitigate any twisting or moment forces that might be imparted to the ESP system 204 by tension in a single tether 256 upon an unintended disconnection of a ESP system component. More than two tethers 256 can also be used and arranged about the ESP system 204 at various intervals. For example, three tethers 256 may be arranged at equally spaced 120 degree intervals or four tethers may be arranged at equally spaced ninety degree intervals around the ESP system 204. In any case, each of the uphole coupler 252 and the downhole coupler 254 can include an appropriate number of coupling elements or an appropriately designed single coupling element to enable coupling of multiple tethers 256 thereto.

[0038] As depicted in FIG. 2, one or more standoffs may be arranged along the length of the ESP system 204 to guide and maintain a desired position of the tether 256 relative to the ESP system 204. For example. A plurality of tether guides 260 may be affixed to or may be integrated into various ones of the components of the ESP system 204. In this example, a tether guide 260 is shown to be located on each of the second pump 208, the second seal section 216, and the sensor 220, but the number and location of the tether guides 260 may vary in other examples. In addition to being affixed to or integrated into an ESP system component such as a pump 206, 208, 210 or a seal section 214, 216, tether guides 260 may also be a part of a connecting element between ESP system components or a part of the tubing string 222. In some examples, the tether 256 may simply slip through an aperture (e.g., eye) in each of the tether guides 260, whereby the position of the tether 256 relative to the ESP system 204 may be maintained. In other examples, one or more of the tether guides 260 may act as additional points of securement of the tether 256 to the ESP system 204. For example, a given tether guide 260 may include a coupling element by which the tether 256 may be fixedly coupled to the tether guide 260.

[0039] In some examples of the loss prevention assembly 250, additional tension applied to the tether 256 as a result of an unintended disconnection of an ESP system component, may be usable to indicate the unintended disconnection. For example, a sensor 262 such as a load cell, etc., may be connected to the tether 256 in a manner by which the additional tension can be detected (e.g., as strain on the tether). The sensor 262 may generate a signal in response to application of the additional tension to the tether 256. The signal may be transmitted, by cable or wirelessly, to receiving equipment at the well surface 226 to indicate an unintended disconnection of an ESP system component. The use of other types of sensors for the same purpose may also be possible, whether coupled to the tether 256, to one or both of the uphole coupler 252 and the downhole coupler 254, or otherwise. In any case, after an indication of an unintended disconnection of an ESP system component, conveyance of well fluid to the well surface may be halted and the tubing string 222 may be raised to the well surface 226 at least to a point where the component disconnection can be remedied.

[0040] FIGS. 3A-3B are isometric views of a coupler 300 component of an artificial lift system string loss prevention assembly according to one example of the present disclosure. In this example, the coupler 300 is depicted in FIG. 3A as an uphole coupler, which may be coupled to a tubing string or a component of an artificial lift system in a like or similar manner to that shown in FIG. 2 relative to the uphole coupler 252 of the loss prevention assembly 250. In some examples, the coupler 300 may be a hollow cylinder (e.g., sleeve) as shown. The coupler may include a first end 302 and a second end 304, each of which may be an uphole end or a downhole end depending on the orientation of the coupler 300. That is, as represented in FIG. 3B, the coupler 300 of FIG. 3A may also serve as a downhole coupler by simply inverting the coupler 300 such that a downhole end of the coupler 300 when in an uphole orientation becomes the uphole end of the coupler 300 when in a downhole orientation.

[0041] In some examples, a portion of an inside wall 306 at one or both ends 302, 304 of the coupler 300 may be threaded to engage with mating threads of an artificial lift system component, tubing string pipe, etc. Alternatively, the entirety of the inside wall 306 of the coupler 300 may be threaded.

[0042] As may be most clearly observed in FIG. 3B, an outer surface 308 of the coupler 300 may include a tether slot 310 and a tether anchoring cavity 312. The tether slot 310 and the tether anchoring cavity 312 may be formed (e.g., cast) or machined into the outer surface 308 of the coupler 300. The tether slot 310 and the tether anchoring cavity 312 may be used to couple one end of a tether 314 to the coupler 300. The tether slot 310 may accommodate a portion (e.g., one half of the diameter) of the tether 314, while the tether anchoring cavity 312 similarly accommodates a tether end termination element 316 affixed to the tether 314. In this example, the tether end termination element 316 is shown to be a cylindrical sleeve or a similar element and the tether anchoring cavity 312 is shown to have an accommodating shape. Other tether end termination element types and shapes may be used in other examples, and the tether anchoring cavity 312 may be shaped and dimensioned as required to receive and retain the tether end termination element used.

[0043] More than one tether slot 310 and accompanying tether anchoring cavity 312 may be located in the outer surface 308 of the coupler 300 in other examples. For example, a pair of tether slots 310 and accompanying tether anchoring cavities 312 may be used instead of a single tether. In such a case, the pair of tether slots 310 and accompanying tether anchoring cavities 312 may be arranged in the coupler 300 at diametrically opposed locations. More than two tether slots 310 and accompanying tether anchoring cavities 312 may also be present in the outer surface 308 of the coupler 300. For example, three tether slots 310 and accompanying tether anchoring cavities 312 may be arranged at equally spaced 120 degree intervals or four tether slots 310 and accompanying tether anchoring cavities 312 may be arranged at equally spaced ninety degree intervals in the outer surface 308 of the coupler 300.

[0044] When the coupler 300 is installed at an uphole location and a downhole location relative to a deployed artificial lift system, the tether 314 can retained in the couplers 300 and the artificial lift system can secured to an associated tubing string by only tension produced in the tether 314. Alternatively, the tether anchoring cavity 312 may be designed to require a press fit of the tether end termination element 316 thereto, a retainer may be placed over the tether end termination element 316 and the tether anchoring cavity 312 or the tether 314 and the tether slot 310 and secured to the outer surface 308 of the coupler 300, or other techniques may be employed to further ensure retention of the tether ends in the coupler 300.

[0045] FIG. 4 is an isometric view of another coupler 400 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 400 may serve as either an uphole coupler or a downhole coupler without requiring inversion or any other reorientation. The coupler 400 may be coupled to a tubing string or a component of an artificial lift system in a like or similar manner to either the uphole coupler 252 or the downhole coupler 254 of the loss prevention assembly 250. In some examples, the coupler 400 may be a hollow cylinder (e.g., sleeve) as shown. The coupler may include a first end 402 and a second end 404, either of which may be an uphole end or a downhole end depending on the orientation of the coupler 400.

[0046] In some examples, a portion of an inside wall 406 at one or both ends 402, 404 of the coupler 400 may be threaded to engage with mating threads of an artificial lift system component, tubing string pipe, etc. Alternatively, the entirety of the inside wall 406 of the coupler 400 may be threaded.

[0047] In this example of the coupler 400, a tether retention feature 408 protrudes from an outer surface 410 of the coupler 400. The tether retention feature 408 may be, for example, a rib or spline that extends axially over all or a portion of the axial length of the coupler 400. The tether retention feature 408 may instead be a tab that extends radially outwardly from the outer surface 410 of the coupler 400. A tether passageway 412 may extend axially through the tether retention feature 408. The tether passageway 412 permits a tether, such as the tether 256 of the loss prevention assembly 250 of FIG. 2 or the tether 314 of FIG. 3A, to be securely coupled to the coupler 400. More specifically, a tether may be passed through the tether passageway 412 until an end termination of the tether (e.g., the end termination 316 of the tether 314 of FIG. 3A) is placed in mating contact with the surrounding material of the tether retention feature 408. Alternatively, an end termination may installed to a tether (e.g., swaged when the tether is a wire rope) after the tether is passed through the tether passageway 412. The end terminations used may be any one or more of several possible existing end terminations that can prevent the tether from being withdrawn from the tether passageways 412 of the tether retention features 408. For example, the shape or dimension of the end terminations may prevent the end terminations from passing through the tether passageways 412.

[0048] Although only a single retention feature 408 is shown in FIG. 4, more than one tether retention feature 408 may be arranged along the outer surface 410 of the coupler 400 in other examples. For example, a pair of tether retention features 408 may be provided instead of a single tether retention feature 408. In such a case, the pair of tether retention features 408 may protrude from the outer surface 410 of the coupler 400 at diametrically opposed locations. More than two tether retention features 408 may also be provided and may be arranged at various intervals along the outer surface 410 of the coupler 400. For example, three tether retention features 408 may be arranged at equally spaced 120 degree intervals or four tether retention features 408 may be arranged at equally spaced ninety degree intervals in the outer surface 410 of the coupler 400. When the coupler 400 includes two or more tether retention features 408, the protruding nature of the tether retention features 408 may enable the coupler 400 to help center an artificial lift system and an associated tubing string in a wellbore.

[0049] FIG. 5 is an isometric view of another coupler 500 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 500 again encircles a tubing string member 514 (e.g., pipe section) and is of reversible orientation. In FIG. 5, the coupler 500 is depicted as an uphole coupler that includes a tether slot 502 and a tether anchoring cavity 504 like or similar to the tether slot 310 and the tether anchoring cavity 312 of the coupler 300 of FIGS. 3A-3B. The coupler 500 may include a first end 506 and a second end 508, each of which may be an uphole end or a downhole end depending on the orientation of the coupler 500. That is, the coupler 500 may also serve as a downhole coupler by simply inverting the coupler 500 such that a downhole end of the coupler 500 when in the uphole orientation shown in FIG. 5 becomes the uphole end of the coupler 500 when in a downhole orientation. While the coupler 500 of FIG. 5 is shown to include the tether slot 502 and cooperating tether anchoring cavity 504 in this example, the coupler 500 may instead include a protruding tether retention feature like or similar to the protruding tether retention feature 408 of the coupler 400 shown in FIG. 4, or any other tether coupling / retention element shown or described herein (see, e.g., FIGS. 6 and 7).

[0050] As shown, this example of the coupler 500 is a split coupler comprising two halves 510, 512, each of which may be slipped over a tubing string member 514 (e.g., pipe section) to form the complete coupler 500. The halves 510, 512 of the coupler 500 may thereafter be secured to one another, such as for example, by one or more threaded fasteners 516. In at least some examples, the uphole coupler 500 may be installed uphole of an expanded portion 518 of the tubing string member 514, such as a portion of the tubing string member 514 that is expanded to receive and connect to another downhole tubing string member or to an artificial lift system component. Installing the uphole-oriented coupler 500 to the tubing string member 514 uphole of and adjacent to the expanded portion 518 the tubing string member 514 as shown in FIG. 5 can help prevent a downhole movement of the coupler 500 along the tubing string member 514 if a downhole force is applied to the coupler 500 by a tether as a result of an unintended disconnection of a downhole artificial lift system component coupled to the tether. Likewise, a downhole-oriented coupler 500 may be installed to a downhole component of an artificial lift system at a location downhole of and adjacent to a larger diameter portion of the artificial lift system component. By such an installation, a downhole movement of the artificial lift system component through the coupler 500 may be prevented upon an unintended disconnection of the artificial lift system component from the tubing string.

[0051] FIG. 6 is an isometric view of another coupler 600 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 600 includes an expanded or enlarged first portion 602 for engagement of the coupler 600 with a tubing string member (e.g., pipe section), and a flanged second portion 604 for engagement of the coupler 600 with another flanged coupler, a flanged component of an artificial lift system, etc. According to some configurations of the coupler 600, an intermediary portion 606 may be interposed between and connect the first portion 602 to the second portion 604. In some examples, the intermediary portion 606 may have a diameter that is the same as or similar to a diameter of the pipe sections of a tubing string to which the coupler 600 is coupled.

[0052] An inside wall of the first portion 602 of the coupler 600 may be partially or fully threaded to engage with complimentary threads of a tubing string pipe section, another threaded component coupled to the tubing string, or a threaded component of an artificial lift system. The flanged second portion 604 of the coupler 600 may include holes 608 to receive threaded fasteners that can be used to secure the flanged second portion 604 to a cooperating flange of another coupler designed to mate with the coupler 600 or to a cooperating flange of another tubing string component, such as but not limited to, an artificial lift system component.

[0053] In the example of FIG. 6, coupling of a tether to the coupler 600 is enabled by at least one threaded tether connector 610, each of which can be threadedly engaged with a complimentarily threaded connector receiving bore 612 in an outside wall of the coupler 600. A plurality of threaded tether connectors 610 and threaded connector receiving bores 612 may be provided and may be spaced apart at selected intervals along the outside of the coupler 600 in different implementations. In this example, only one threaded tether connector 610 and associated connector receiving bore 612 is shown and each is located in the first portion 602 of the coupler 600. One or more threaded tether connectors 610 and associated connector receiving bores 612 may instead be located on the flanged second portion 604 or the intermediary portion 606 of the coupler 600 in other examples. To facilitate coupling of a tether to the coupler 600, the threaded tether connector 610 may include a tether connecting hole 614 that passes through a portion of the threaded tether connector 610. A tether to be coupled to the threaded tether connector 610 may include a tether end termination element (e.g., a hook) that is designed to engage with and be releasably retained by the tether connecting hole 614.

[0054] The coupler 600 is depicted in FIG. 6 in an uphole orientation wherein the first portion 602 may be engaged with an uphole tubing string component such as, for example, a pipe section and the flanged second portion 604 may be engaged with a downhole component such as, for example, an artificial lift system component. However, the coupler 600 may also function as a downhole coupler by simply inverting the coupler 600 such that a downhole end of the coupler 600 when in the uphole orientation shown in FIG. 6 becomes the uphole end of the coupler 600 when in a downhole orientation. For example, an uphole-oriented coupler 600 may be coupled to the tubing string at a location uphole of an artificial lift system and a downhole-oriented coupler 600 may be located downhole of the uphole-oriented coupler 600 such as to couple together components of the artificial lift system or to couple another component to (e.g., a downhole end of) the artificial lift system. A tether may then be connected between the threaded tether connector 610 of the uphole coupler 600 and the threaded tether connector 610 of the downhole coupler to prevent all or a portion of the artificial lift system from being lost downhole in the event of an unintended disconnection of an artificial lift system component, as described above.

[0055] FIG. 7 is an isometric view of another coupler 700 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 700 includes an expanded or enlarged first portion 702 for engagement of the coupler 700 with a tubing string member (e.g., pipe section), and a flanged second portion 704 for engagement of the coupler 600 with another flanged coupler, a flanged component of an artificial lift system, etc. According to some configurations of the coupler 700, an intermediary portion 706 may be interposed between and connect the first portion 702 to the second flanged portion 704. In some examples, the intermediary portion 706 may have a diameter that is the same as or similar to a diameter of the pipe sections of a tubing string to which the coupler 700 is coupled.

[0056] An inside wall of the first portion 702 of the coupler 700 may be partially or fully threaded to engage with complimentary threads of a tubing string pipe section, another threaded component coupled to the tubing string, or a threaded component of an artificial lift system. The flanged second portion 704 of the coupler 700 may include holes 708 to receive threaded fasteners that can be used to secure the flanged second portion 704 to a cooperating flange of another coupler designed to mate with the coupler 700 or to a cooperating flange of another tubing string component, such as but not limited to, an artificial lift system component.

[0057] In the example of FIG. 7, coupling of a tether to the coupler 700 is enabled by at least one integrated tether connector 708 that can be a cast or molded integral element of the coupler 700, or an element that is otherwise permanently affixed to the coupler 700, such as by welding. In this example, each of the pair of integrated tether connectors 708 forms an open connecting loop to which a tether may be coupled. The integrated tether connectors 708 are shown to extend from the first portion 702 of the coupler 700 in the example of FIG. 7 but the integrated tether connector(s) 708 may instead be located on the flanged second portion 704 or the intermediary portion 706 of the coupler 700 in other examples. To facilitate coupling of a tether to the coupler 700, a tether to may include a tether end termination element (e.g., a hook or shackle) that is designed to engage with and be releasably retained by the integrated tether connector 708 to which the tether is connected.

[0058] The coupler 700 is depicted in FIG. 7 in an uphole orientation wherein the first portion 702 may be engaged with an uphole tubing string component such as, for example, a pipe section and the flanged second portion 704 may be engaged with a downhole component such as, for example, an artificial lift system component. However, the coupler 700 may also function as a downhole coupler by simply inverting the coupler 700 such that a downhole end of the coupler 700 when in the uphole orientation shown in FIG. 7 becomes the uphole end of the coupler 700 when in a downhole orientation. For example, an uphole-oriented coupler 700 may be coupled to the tubing string at a location uphole of an artificial lift system and a downhole-oriented coupler 700 may be located downhole of the uphole-oriented coupler 700 such as to couple together components of the artificial lift system or to couple another component to (e.g., a downhole end of) the artificial lift system. A tether may then be connected between one or more of the integrated tether connectors 708 of the uphole coupler 700 and one or more of the integrated tether connectors 708 of the downhole coupler to prevent all or a portion of the artificial lift system from being lost downhole in the event of an unintended disconnection of an artificial lift system component, as previously described.

[0059] In addition to being affixed to or integrated into a coupler as described above, tether connecting / coupling elements may also be a part of an artificial lift system component. For example, one or more tether connecting / coupling elements may be affixed to or integrated into an artificial lift system component such as a pump, a seal section, etc., and a tether may be connected between such an artificial lift system component and a cooperating uphole coupler.

[0060] FIG. 8 is a flowchart 800 illustrating a method of preventing a downhole loss of an artificial lift system upon an unintended disconnection of an artificial lift system component according to one example of the present disclosure.

[0061] As represented in block 802 of the flowchart 800, a loss prevention assembly is installed to an artificial lift system of a tubing string. The loss prevention assembly may include an uphole coupler. The uphole coupler can be coupled to the tubing string. The uphole coupler can be coupled to the tubing string at a location uphole of the artificial lift system. The loss prevention assembly can also include a downhole coupler. The downhole coupler can be coupled to a downhole component of the artificial lift system. In some examples, the downhole coupler may be coupled to a downhole-most component of the artificial lift system. For example, when the artificial lift system is an electric submersible pump system, the downhole may be coupled to a sensor of the electric submersible pump system. The loss prevention assembly may further include a tether. The tether can be securely connected between the uphole coupler and the downhole coupler. In various examples, the tether may be a wire rope, a synthetic fiber rope, a sling, or a chain. In some examples, only a single tether may be used. When only a single tether is used, the single tether should have sufficient tensile strength to support the weight of the artificial lift system. In other examples, multiple tethers may be used. When multiple tethers are used, the collective tensile strength of the tethers should be sufficient to support the weight of the artificial lift system.

[0062] Each of the uphole coupler, the downhole coupler, and the tether may include features that cooperate to enable secure connection of the tether to the couplers. For example, each of the uphole coupler and the downhole coupler may include tether coupling features. In some examples, the tether coupling features may be recessed into an outer surface of the uphole coupler and the downhole coupler. For example, each of the uphole coupler and the downhole coupler may include one or a plurality of tether slots and accompanying tether anchoring cavities that receive and retain respective ends of the tether. In another example, the tether coupling features may protrude from an outer surface of the uphole coupler and the downhole coupler. For example, each of the uphole coupler and the downhole coupler may include one or more tether retention features in the form of a rib or a spline that protrudes outwardly from the coupler outer surface and extends axially over all or a portion of an axial length of the coupler. A tether passageway can extend axially through the tether retention feature to receive and retain the tether.

[0063] The ends of the tether may enable the tether to be securely coupled to the uphole coupler and the downhole coupler. For example, the ends of the tether may have termination elements (end terminations) affixed thereto. In one example, the end terminations may be receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler. In another example, the end terminations may be of a shape or dimension that prevents the tether from being withdrawn from the tether passageway in the protruding tether retention feature of each of the uphole coupler and the downhole coupler after being passed therethrough.

[0064] As represented in block 804 of the flowchart 800, the artificial lift system is deployed downhole in a wellbore such that the artificial lift system is suspended from the tubing string. In some examples, the wellbore may be a wellbore of a hydrocarbon well. In some examples, the hydrocarbon well may be a completed well and the conveyance tubing string may be a production tubing string.

[0065] Use of a loss prevention assembly according to the present disclosure can eliminate or reduce costs typically associated with an unintended disconnection of an artificial lift system component. For example, preventing the downhole loss of an artificial lift (e.g., ESP) system in the event of an unintended disconnection of an artificial lift system component can eliminate the cost associated with retrieving a fallen artificial lift system from possibly deep within a wellbore. Likewise, preventing the downhole loss of an artificial lift system upon an unintended disconnection of an artificial lift system component can eliminate the cost associated with lost well production time, damage to components of the fallen artificial lift system, or damage to the wellbore, a wellbore casing, or other downhole well equipment resulting from the fallen artificial lift system.

[0066] In some aspects, a loss prevention assembly, a hydrocarbon well system, and a method for preventing the downhole loss of all or a portion of an artificial lift system in the event of an unintended disconnection of an artificial lift system component are provided according to one or more of the following examples. As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).

[0067] As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).

[0068] Example 1 is a loss prevention assembly including an uphole coupler couplable to a well tubing string uphole of an artificial lift system connected to the tubing string, a downhole coupler couplable to a downhole component of the artificial lift system, and a tether connectable between the uphole coupler and the downhole coupler.

[0069] Example 2 is the loss prevention assembly of example 1, wherein the uphole coupler includes internal threads to couple the uphole coupler to complimentary threads of the tubing string.

[0070] Example 3 is the loss prevention assembly of example 1 or example 2, wherein the uphole coupler comprises a first tether slot and an accompanying first tether anchoring cavity in an outer surface of the uphole coupler, the downhole coupler comprises a second tether slot and an accompanying second tether anchoring cavity in an outer surface of the downhole coupler, and the tether comprises a first termination element affixed to an uphole end of the tether and a second termination element affixed to a downhole end of the tether. A portion of the tether is receivable by and retainable in the tether slot of each of the uphole coupler and the downhole coupler and a portion of the termination element is receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler.

[0071] Example 4 is the loss prevention assembly of example 3, wherein a plurality of the first tether slots and the accompanying first tether anchoring cavities and a plurality of the second tether slots and the accompanying second tether anchoring cavities are arranged at circumferentially-spaced intervals in the outer surface of each of the uphole coupler and the downhole coupler.

[0072] Example 5 is the loss prevention assembly of example 1, wherein a tether retention feature protrudes outwardly from an outer surface of and extends axially over all or a portion of an axial length of each of the uphole coupler and the downhole couple, a tether passageway extends axially through the tether retention feature, and a termination element is affixed to each end of the tether. A respective portion of the tether is passable through the tether passageway in the tether retention feature of the uphole coupler and the downhole coupler and the termination elements are shaped or dimensioned to overlie outer surfaces of the respective tether retention features around the tether passageways thereof to prevent a decoupling of the tether from the uphole coupler and the downhole coupler.

[0073] Example 6 is the loss prevention assembly of example 1, wherein a plurality of tether retention features are arranged at circumferentially-spaced intervals along an outer surface of each of the uphole coupler and the downhole coupler, each tether retention feature protrudes outwardly from the outer surface of and extends axially over all or a portion of an axial length of the uphole coupler and the downhole coupler, and a tether passageway extends axially through each of the tether retention features. A plurality of tethers are connected between corresponding pairs of the tether retention features of the uphole coupler and the downhole coupler, and a termination element is affixed to each end of each tether. A respective portion of each tether is passable through the tether passageway of the tether retention feature of the uphole coupler and the downhole coupler between which the tether is connected and the termination elements are shaped or dimensioned to overlie outer surfaces of the respective tether retention features around the tether passageways thereof to prevent a decoupling of the tethers from the uphole coupler and the downhole coupler.

[0074] Example 7 is the loss prevention assembly of example 1, wherein the tether is a wire rope, a synthetic fiber rope, a sling, or a chain.

[0075] Example 8 is a well system including an artificial lift system suspended from a tubing string deployed in a wellbore of the well, an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system, a downhole coupler coupled to a downhole component of the artificial lift system, and a tether connected between the uphole coupler and the downhole coupler.

[0076] Example 9 is the well system of example 8, wherein the artificial lift system is an electric submersible pump system.

[0077] Example 10 is the well system of example 8 or example 9, wherein the uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

[0078] Example 11 is the well system of any of examples 8-10, wherein the downhole component is a sensor, the sensor is a downhole-most component of the electric submersible pump system, and the downhole coupler is coupled to a downhole end of the sensor.

[0079] Example 12 is the well system of any of examples 8-11, wherein the tether passes through or is coupled to a plurality of tether guides extending radially outwardly from one or more components of the artificial lift system.

[0080] Example 13 is the well system of any of examples 8-12, wherein the tether is selected from the group consisting of a wire rope, a synthetic fiber rope, a sling, and a chain.

[0081] Example 14 is the well system of any of examples 8-13, wherein a sensor is coupled to the tether to detect an increase in tension in the tether and to resultantly output a signal that is interpretable upon receipt as being indicative of an unintended disconnection of an artificial lift system component.

[0082] Example 15 is a method that includes installing a loss prevention assembly to an artificial lift system of a tubing string. The loss prevention assembly can include an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system, a downhole coupler coupled to a downhole component of the artificial lift system, and a tether connected between the uphole coupler and the downhole coupler. The method also includes deploying the artificial lift system downhole in a wellbore of a well such that the artificial lift system is suspended from the tubing string within the wellbore.

[0083] Example 16 is the method of example 15, wherein the artificial lift system is an electric submersible pump system.

[0084] Example 17 is the method of example 15 or example 16, wherein the uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

[0085] Example 18 is the method of any of examples 16-17, wherein the downhole component of the electric submersible pump system is a sensor and the downhole coupler is coupled to a downhole end of the sensor.

[0086] Example 19 is the method of any of examples 15-18, wherein a plurality of tethers are connected between the uphole coupler and the downhole coupler and collectively support a weight of the artificial lift system.

[0087] Example 20 is the method of any of examples 15-19, wherein each tether is a wire rope, a synthetic fiber rope, a sling, or a chain.

[0088] The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.

Examples

Embodiment Construction

[0011]Certain aspects and examples of the present disclosure relate to a loss prevention assembly that can be installed to an artificial lift system of a well. The loss prevention assembly can prevent a downhole loss of all or a portion of the artificial lift system due to an unintended disconnection of a component of the artificial lift system. An unintended disconnection of a component of the artificial lift system may result from, for example, a mechanical failure of a system component, which can include connection between system components. While examples provided herein are shown and described as being associated with a hydrocarbon well for purposes of illustration, it should be understood that a loss prevention assembly according to the present disclosure can also be used with other types of wells such as, for example, municipal water wells, mine dewatering wells, geothermal wells, brine wells, etc.

[0012]The artificial lift system may be a part of (e.g., may be suspended from)...

TECHNICAL FIELD

[0001] The present disclosure relates generally to hydrocarbon well operations, and more particularly although not necessarily exclusively, to preventing all or a portion of an artificial lift system from downhole loss in a wellbore upon an unintended disconnection of an artificial lift system component.BACKGROUND

[0002] In hydrocarbon well operations, production operations may follow the drilling and completion of a wellbore. The completion operations may include, among other operations, casing and cementing the wellbore. The production operations may initially involve, for example, placing production equipment such as conveyance (production) tubing and various components and devices that may be coupled thereto, downhole in the wellbore. For example, a production tubing string may be deployed into the wellbore and may support an artificial lift system. The artificial lift system may be an electric submersible pump (ESP) system. The ESP system may include, among other components, a pump, a seal section, an intake, a motor, and a sensor. In some examples, more than one of at least some of the components may be present. For example, an ESP system may include multiple pumps and multiple seal sections. The components of an artificial lift system may be coupled to each other, and at least one of the components may also be coupled to the production tubing string. An unintended disconnection of one or more of the components of the artificial lift system may cause a portion of the artificial lift system located below the disconnection point to fall downhole into the wellbore.BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 is a schematic diagram of a completed hydrocarbon well including an artificial lift system according to one example of the present disclosure.

[0004] FIG. 2 is schematic diagram of another artificial lift system located in a wellbore of a hydrocarbon well and equipped with a loss prevention assembly according to one example of the present disclosure.

[0005] FIGS. 3A-3B are isometric views of a coupler component of an artificial lift system loss prevention assembly according to one example of the present disclosure.

[0006] FIG. 4 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0007] FIG. 5 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0008] FIG. 6 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0009] FIG. 7 is an isometric view of another coupler component of an artificial lift system loss prevention assembly according to another example of the present disclosure.

[0010] FIG. 8 is flowchart illustrating a method of preventing a downhole loss of an artificial lift system upon an unintended disconnection of a component of the artificial lift system according to one example of the present disclosure.DETAILED DESCRIPTION

[0011] Certain aspects and examples of the present disclosure relate to a loss prevention assembly that can be installed to an artificial lift system of a well. The loss prevention assembly can prevent a downhole loss of all or a portion of the artificial lift system due to an unintended disconnection of a component of the artificial lift system. An unintended disconnection of a component of the artificial lift system may result from, for example, a mechanical failure of a system component, which can include connection between system components. While examples provided herein are shown and described as being associated with a hydrocarbon well for purposes of illustration, it should be understood that a loss prevention assembly according to the present disclosure can also be used with other types of wells such as, for example, municipal water wells, mine dewatering wells, geothermal wells, brine wells, etc.

[0012] The artificial lift system may be a part of (e.g., may be suspended from) a tubing string, such as a production tubing string, which is installed in a completed wellbore. The tubing string may function to conduct hydrocarbon fluids extracted from a formation surrounding the wellbore to a surface of the well, such as to a wellhead. The artificial lift system can help to increase the volume of hydrocarbon fluids transferred to the well surface, and may be especially beneficial, for example, in cases where the reservoir lacks enough pressure to lift the hydrocarbon fluids naturally.

[0013] In some examples, an artificial lift system may be an electric submersible pump (ESP) system. Example ESP system may include a number of components, such as for example, one or more pumps, an intake, one or more seal sections, a motor, and a sensor.

[0014] In some examples, the loss prevention assembly may include an uphole coupler, a downhole coupler, and a tether that extends between and is securely affixed to each of the uphole coupler and the downhole coupler. The uphole coupler can be coupled to the tubing string. For example, the uphole coupler can be coupled to the tubing string at a location uphole of the artificial lift system, such as to a top end of an electric submersible pump (ESP) system. The downhole coupler can be coupled to a component of the artificial lift system. In some examples, the downhole coupler may be coupled to a downhole-most component of the artificial lift system. For example, when the artificial lift system is an electric submersible pump system, the downhole coupler may be coupled to a sensor of the electric submersible pump system. In examples where there may not be sufficient clearance to pass the tether between the outside surface of a particular artificial lift system component (e.g., and ESP system motor) and a wall of a wellbore or a wellbore casing, the downhole coupler may be coupled to a more uphole component of the artificial lift system. For example, the downhole coupler may be coupled to another ESP system component such as, without limitation, ancillary tooling suspended below the motor, the motor, a seal section, an intake, a gas separator, or a lower pump assembly.

[0015] The tether can be, in various examples, a mechanism such as a wire rope, a synthetic fiber rope, a sling, or a chain. In some examples, only a single tether may be used. In other examples, multiple tethers may be used. When only a single tether is used, the single tether should have sufficient tensile strength to support the weight of the artificial lift system in the event of an unintended disconnection of all or a part of the artificial lift system from the tubing string. When multiple tethers are used, the collective tensile strength of the tethers should be sufficient to support the weight of the artificial lift system in the event of an unintended disconnection of all or a part of the artificial lift system from the tubing string.

[0016] Each of the uphole coupler and the downhole coupler may include tether coupling features. For example, each of the uphole coupler and the downhole coupler may include one or a plurality of tether slots and accompanying tether anchoring cavities to receive and retain respective ends of the tether. The tether slots and accompanying tether anchoring cavities can be formed in or machined into an outer surface of the couplers. In another example each of the uphole coupler and the downhole coupler may include a tether retention feature in the form of a rib or a spline that protrudes outwardly from the coupler outer surface. The protruding tether retention features of the uphole coupler and the downhole coupler may each extend axially over all or a portion of an axial length of the couplers, and a tether passageway can extend axially through the tether retention feature to receive and retain the tether.

[0017] The ends of the tether may be designed to engage with or otherwise enable the tether to be securely coupled to the uphole coupler and the downhole coupler. For example, the ends of the tether may have termination elements affixed thereto. In one example, the termination elements may be receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler. In another example, the termination elements may be of a shape or dimension that prevents the tether from being withdrawn from the tether passageway in the protruding tether retention feature of each of the uphole coupler and the downhole coupler after being passed therethrough.

[0018] Use of a loss prevention assembly according to the present disclosure can thus prevent a downhole loss of an artificial lift system in the event of an unintended disconnection of an artificial lift system component. Also, because the loss prevention assembly maintains a coupled relationship between the artificial lift system and the tubing string on which it is deployed after an unintended disconnection of an artificial lift system component, retrieval and repair of the artificial lift system can be accomplished simply by lifting the tubing string from the wellbore.

[0019] Use of a loss prevention assembly according to the present disclosure can also eliminate or reduce the costs that may result from an unintended disconnection of an artificial lift system component. For example, use of a loss prevention assembly according to the present disclosure can eliminate possibly significant costs resulting from one or more of an operation to retrieve an artificial lift system that has disconnected from a tubing string and fallen downhole, lost production time, damage to components of the fallen artificial lift system, or damage to the wellbore, a wellbore casing, or other downhole well equipment resulting from the fallen artificial lift system.

[0020] Illustrative examples follow and are given to introduce the reader to the general subject matter discussed herein rather than to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects, but, like the illustrative aspects, should not be used to limit the present disclosure.

[0021] FIG. 1 is a schematic diagram of a completed hydrocarbon well 100 including an artificial lift system according to one example of the present disclosure. The hydrocarbon well 100 includes a wellbore 102 that extends from a well (ground) surface 104 into a subterranean formation 106. The formation may include a reservoir from which hydrocarbon fluids (e.g., oil or gas) may be recovered. In other examples, the hydrocarbon well 100 may instead be drilled into the floor beneath a body of water, such as an ocean floor or a floor of a body of fresh water.

[0022] In this example, the wellbore 102 of the hydrocarbon well 100 is depicted as being entirely vertical. In other examples, one or more portions of the wellbore 102 may also be horizontal, deviated at any other suitable angle, or curved. In this example, the hydrocarbon well 100 includes a wellbore casing 108, which may be cemented into the wellbore 102 by introducing cement 110 into an annular space between the wall of the wellbore 102 and the wellbore casing 108. In other examples, all or a portion of the wellbore 102 may be uncased or partially cased.

[0023] The hydrocarbon well 100 can additionally include a wellhead 112, which can be positioned at the well surface 104 as shown. Hydrocarbons extracted from the reservoir through the wellbore 102 may be conveyed to the wellhead 112 at the well surface 104 by way of a downhole tubing string. In this example, the downhole tubing string is a production tubing string 114 that extends from the wellhead 112 into the wellbore 102 in the subterranean formation 106. When the wellbore 102 includes one or more horizontal or other non-vertical portions, the production tubing string 114 may also extend through those portions of the wellbore 102. The production tubing string 114 may comprise, for example, multiple individual sections of connected hollow pipe. Consecutive sections of the hollow pipe may be releasably coupled end-to-end, such as by threaded connection between the pipe sections.

[0024] The production tubing string 114 can include other components in addition to the pipe sections. In this example, the production tubing string 114 includes the artificial lift system 116, which includes a pump 118 and associated components for lifting hydrocarbon fluids from downhole in the wellbore 102 up to the wellhead 112 at the well surface 104. The pump 118 may be one of multiple pumps. The pump 118 may be, for example, an electric submersible pump. The artificial lift system 116 can also include a motive device for operating the pump 118. In this example, the motive device may be, for example, an electric motor 120 or any of various other devices that can generate the rotary motion necessary to operate the pump 118 and can function in a hydrocarbon well environment. The artificial lift system 116 may further include, for example, intake ports 122 for drawing hydrocarbon fluid from within the wellbore 102 into the production tubing string 114, and a seal section 124 that may carry a thrust of the pump 118 and equalize pressure to the electric motor 120.

[0025] FIG. 2 is schematic diagram of another artificial lift system located in a wellbore 200 of a hydrocarbon well 202 and equipped with a loss prevention assembly 250 according to one example of the present disclosure. In this example, the artificial lift system is an electric submersible pump (ESP) system 204. This example of the ESP system includes, from uphole to downhole, multiple pumps 206, 208, 210, an intake 212, multiple seal sections 214, 216, a motor 218, and a sensor 220. The pumps 206, 208, 210, the intake 212, the multiple seal sections 214, 216, the motor 218, and the sensor 220 may be connected in series to form the complete ESP system 204. The ESP system 204 may be suspended from a downhole end of a tubing string 222, which may be connected at an uphole end to a wellhead 224 located at a surface 226 of the hydrocarbon well 202. In this example, the uphole pump 206 of the series of multiple pumps 206-210 of the ESP system 204, may be connected to a (e.g., bolt-on) discharge head 228 that is coupled to a downhole end of the tubing string 222. A cable 230 may carry power, communication signals (e.g., operating commands), or both, from equipment at the well surface 226 to the motor 218 of the ESP system 206.

[0026] The tubing string 222 is depicted in FIG. 2 as being very short for purposes of illustration. It should be realized, however, that in actual well installations, the tubing string 222 can be thousands of feet in length such as may be required to position the ESP system 204 at a depth in the wellbore 200 where the ESP system 204 is in fluid communication with hydrocarbon fluids from a surrounding reservoir of hydrocarbon fluids.

[0027] It is possible for the ESP system 204 to experience an unintended disconnection of one or more of the system components. For example, one or more of the pumps 206, 208, 210, the intake 212, the seal sections 214, 216, the motor 218, or the sensor 220 may experience a mechanical failure that can cause an unintended disconnection of the failed component. Alternatively, an unintended disconnection may also result from a failure of a connection between any of the components. When an unintended disconnection occurs at any component location other than the last (most downhole) component of the ESP system 204, all of the components of the ESP system 204 that reside downhole of the disconnection point may fall downhole into the wellbore 200. Thus, depending on the point of disconnection, a portion or the entirety of the ESP system 204 can be lost downhole when an unintended disconnection of an ESP system component occurs. The components of a fallen ESP system 204 may be damaged during such a fall. A fallen ESP system 204 can also damage the wall of the wellbore 200, or other equipment within the wellbore 200. Additionally, subsequent retrieval of a fallen ESP system 204 from what may be deep within the wellbore 200 can be difficult, time consuming, and costly.

[0028] As represented in FIG. 2, the loss prevention assembly 250 can be installed to the ESP system 204 to prevent a downhole loss of all or any portion of the ESP system 204 upon the occurrence of an unintended disconnection of an ESP system component. The loss prevention assembly 250 may include, for example, an uphole coupler 252, a downhole coupler 254, and a tether 256 that extends between and couples the uphole coupler 252 to the downhole coupler 254.

[0029] Employing the uphole coupler 252 for coupling to an uphole end of the tether 256 rather than, for example, a fixed coupling element on a pipe section of the tubing string 222, allows for flexibility in the uphole anchoring point location of the loss prevention assembly 250. Likewise, using the uphole coupler 252 obviates the need to produce a special tubing string pipe section and to set aside and install the special pipe section at the location of the tubing string 222 at which an artificial lift system will be connected. Similarly, using the downhole coupler 254 for coupling to a downhole end of the tether 256 allows for flexibility in the downhole anchoring point location of the loss prevention assembly 250. For example, use of the downhole coupler 254 can allow the downhole anchoring point of the loss prevention assembly 250 to be located downhole of the downhole-most component of an artificial lift system, or at or between artificial lift system components located further uphole when needed (as discussed in more detail below).

[0030] As illustrated in FIG. 2, the uphole coupler 252 may be securely affixed to the tubing string 222 at a location uphole of the uphole-most component of the ESP system 204 in some examples, such as at a location uphole of the first pump 206. For example, the uphole coupler 252 may be coupled between the tubing string 222 and a top end of the ESP system 204. In various implementations, the top end of the ESP system 204 may be a pump head, the bolt-on discharge head 228, a discharge pressure sub, a sand fallback prevention tube, a centralizer assembly, a production tubing coupling, or a section of production. In some examples, the uphole coupler 252 may include threads at uphole and downhole ends thereof to facilitate threaded engagement with complimentary-threaded pipe sections of the tubing string 222 or other components of the tubing string 222 or the ESP system 204.

[0031] The downhole coupler 254 can be securely affixed to the downhole-most component of the ESP system 204 in some examples. In the example of FIG. 2, the downhole coupler 254 is affixed to the sensor 220 of the ESP system 204. For example, an extension tube 258 may be affixed to a downhole end of the sensor 220 and the downhole coupler 254 may be affixed to a downhole end of the extension tube 258. In one such arrangement, affixation of the extension tube 258 to the sensor 220 and affixation of the downhole coupler 254 to the extension tube 258 may be by threaded engagement.

[0032] In examples where there is an insufficient annulus between an outside surface of the motor 218 and the wall of the wellbore 200 or a wellbore casing to permit passage of the tether 256, the downhole coupler 254 may instead be affixed to the ESP system 204 at, for example, a location between the second seal section 216 and the motor 218, or at another location that is uphole of the motor 218 and is accessible by the tether 256. In such an example, the downhole coupler 254 may include threads at uphole and downhole ends thereof to facilitate threaded engagement with the second seal section 216 and the motor 218 or with other components of the ESP system 204. In any case, the downhole coupler 254 is preferably affixed to the ESP system 204 as far downhole as is feasible so that as many of the ESP system 204 components as possible can be prevented from falling downhole in the event of an unintended component disconnection.

[0033] When only a single tether 256 is utilized, the tether 256 should have sufficient tensile strength to support the weight of the ESP system 204 or a given portion of the ESP system 204 in the event of a component failure. When multiple tethers 256 are utilized, the collective tensile strength of the tethers 256 should be sufficient to support the weight of the ESP system 204 or a given portion of the ESP system 204 in the event of a component failure. In some examples, the tether 256 may need to support a weight of between approximately 15,000 pounds to 20,000 pounds. A selected tether 256 should also have an outside dimension (e.g., diameter) that can fit within the annulus between the components of the ESP system 204 and the wall of the wellbore 200 or a wellbore casing. In some installations, the annulus space may be less than one inch and sometimes less than one half of one inch. The material from which the tether 256 is constructed should also be able to withstand long-term exposure to potentially harsh conditions in the wellbore 200, including contact with various hydrocarbons and other fluids, high temperatures, etc.

[0034] In various examples, the tether 256 may be, without limitation, a wire rope, a synthetic fiber rope, a sling, a chain, or another mechanism that can meet the above criteria. Some wire rope, such as compacted wire rope, for example, can support loads in excess of 16,000 pounds at a diameter of nine millimeters (i.e., 0.354 inches) and loads in excess of 20,000 pounds at a diameter of 10 millimeters (i.e., 0.394 inches). Wire rope may also be coated, which may increase its resistance to the downhole environment of the wellbore 200. Synthetic fiber rope is constructed from synthetic fibers such as nylon, polyester, or polypropylene that are drawn out into strands and woven together. Synthetic fiber rope can also support heavy loads, sometimes in excess of those that can be supported by wire rope. For example, certain synthetic fiber ropes can support loads of 20,000 pounds or more at a rope diameter of approximately 0.375 inches. Synthetic fiber rope can also be lighter and more flexible than wire rope but may be less resistant to damage from abrasion. Certain types of chain may also be capable of supporting the load presented by the ESP system 204 while being compact enough to pass between the components of the ESP system 204 and the wall of the wellbore 200 or a wellbore casing.

[0035] The tether 256 may be coupled to the uphole coupler 252 and to the downhole coupler 254 in various ways. For example, each of the uphole coupler 252 and the downhole coupler 254 may have tether coupling elements that are molded into, machined into, or welded to, bolted to, or otherwise affixed thereto. Likewise, the ends of the tether 256 may include end terminations that cooperate with the coupling elements on the uphole coupler 252 and the downhole coupler 254. For example, the ends of a wire rope tether 256 may be swaged to form an eye or a loop. Alternatively, the ends of the tether 256 may terminate, without limitation, in an attached (e.g., swaged) closed socket, open socket, open or closed spelter socket, wedge socket, sleeve (round or otherwise), threaded stud, or another element that can securely couple the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254. In some examples, the connections of the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254 may be permanent connections. In other examples, the connections of the tether 256 to the coupling elements on the uphole coupler 252 and the downhole coupler 254 may be releasable by deliberate action. For example, one or both ends of the tether 256 may be coupled to respective coupling elements on the uphole coupler 252 and the downhole coupler 254 by shackles, hooks, clevis links, or other hardware via which the tether 256 can be decoupled by deliberate action of a user.

[0036] The tether 256 can, in conjunction with the uphole coupler 252 and the downhole coupler 254, securely couple the lowest or the lowest feasible component of the ESP system 204 to a location on the tubing string 222 that is uphole of the ESP system 204. Consequently, if a component of the ESP system 204 experiences an unintended disconnection while the ESP system 204 is deployed downhole in the wellbore 200, the tether 256 can prevent the ESP system 204 from falling downhole. The tubing string 222 can thereafter be lifted from the wellbore 200 while the ESP system 204 remains secured thereto by the loss prevention assembly 250. After being lifted from the wellbore 200, the loss prevention assembly 250 can be released as needed, and the cause of the unintended disconnection can be remedied. The loss prevention assembly 250 can then be reinstalled and the ESP system 204 can be redeployed to the wellbore 200 along with the tubing string 222.

[0037] While FIG. 2 illustrates only a single tether 256 coupled between the uphole coupler 252 and the downhole coupler 254, more than one tether 256 may be utilized in other examples, as described above. For example, a pair of tethers 256 may be used instead of a single tether. In such a case, the tethers 256 may be coupled to the uphole coupler 252 and the downhole coupler 254 at diametrically opposed locations on the couplers. Such a positioning of the pair of tethers 256 can help mitigate any twisting or moment forces that might be imparted to the ESP system 204 by tension in a single tether 256 upon an unintended disconnection of a ESP system component. More than two tethers 256 can also be used and arranged about the ESP system 204 at various intervals. For example, three tethers 256 may be arranged at equally spaced 120 degree intervals or four tethers may be arranged at equally spaced ninety degree intervals around the ESP system 204. In any case, each of the uphole coupler 252 and the downhole coupler 254 can include an appropriate number of coupling elements or an appropriately designed single coupling element to enable coupling of multiple tethers 256 thereto.

[0038] As depicted in FIG. 2, one or more standoffs may be arranged along the length of the ESP system 204 to guide and maintain a desired position of the tether 256 relative to the ESP system 204. For example. A plurality of tether guides 260 may be affixed to or may be integrated into various ones of the components of the ESP system 204. In this example, a tether guide 260 is shown to be located on each of the second pump 208, the second seal section 216, and the sensor 220, but the number and location of the tether guides 260 may vary in other examples. In addition to being affixed to or integrated into an ESP system component such as a pump 206, 208, 210 or a seal section 214, 216, tether guides 260 may also be a part of a connecting element between ESP system components or a part of the tubing string 222. In some examples, the tether 256 may simply slip through an aperture (e.g., eye) in each of the tether guides 260, whereby the position of the tether 256 relative to the ESP system 204 may be maintained. In other examples, one or more of the tether guides 260 may act as additional points of securement of the tether 256 to the ESP system 204. For example, a given tether guide 260 may include a coupling element by which the tether 256 may be fixedly coupled to the tether guide 260.

[0039] In some examples of the loss prevention assembly 250, additional tension applied to the tether 256 as a result of an unintended disconnection of an ESP system component, may be usable to indicate the unintended disconnection. For example, a sensor 262 such as a load cell, etc., may be connected to the tether 256 in a manner by which the additional tension can be detected (e.g., as strain on the tether). The sensor 262 may generate a signal in response to application of the additional tension to the tether 256. The signal may be transmitted, by cable or wirelessly, to receiving equipment at the well surface 226 to indicate an unintended disconnection of an ESP system component. The use of other types of sensors for the same purpose may also be possible, whether coupled to the tether 256, to one or both of the uphole coupler 252 and the downhole coupler 254, or otherwise. In any case, after an indication of an unintended disconnection of an ESP system component, conveyance of well fluid to the well surface may be halted and the tubing string 222 may be raised to the well surface 226 at least to a point where the component disconnection can be remedied.

[0040] FIGS. 3A-3B are isometric views of a coupler 300 component of an artificial lift system string loss prevention assembly according to one example of the present disclosure. In this example, the coupler 300 is depicted in FIG. 3A as an uphole coupler, which may be coupled to a tubing string or a component of an artificial lift system in a like or similar manner to that shown in FIG. 2 relative to the uphole coupler 252 of the loss prevention assembly 250. In some examples, the coupler 300 may be a hollow cylinder (e.g., sleeve) as shown. The coupler may include a first end 302 and a second end 304, each of which may be an uphole end or a downhole end depending on the orientation of the coupler 300. That is, as represented in FIG. 3B, the coupler 300 of FIG. 3A may also serve as a downhole coupler by simply inverting the coupler 300 such that a downhole end of the coupler 300 when in an uphole orientation becomes the uphole end of the coupler 300 when in a downhole orientation.

[0041] In some examples, a portion of an inside wall 306 at one or both ends 302, 304 of the coupler 300 may be threaded to engage with mating threads of an artificial lift system component, tubing string pipe, etc. Alternatively, the entirety of the inside wall 306 of the coupler 300 may be threaded.

[0042] As may be most clearly observed in FIG. 3B, an outer surface 308 of the coupler 300 may include a tether slot 310 and a tether anchoring cavity 312. The tether slot 310 and the tether anchoring cavity 312 may be formed (e.g., cast) or machined into the outer surface 308 of the coupler 300. The tether slot 310 and the tether anchoring cavity 312 may be used to couple one end of a tether 314 to the coupler 300. The tether slot 310 may accommodate a portion (e.g., one half of the diameter) of the tether 314, while the tether anchoring cavity 312 similarly accommodates a tether end termination element 316 affixed to the tether 314. In this example, the tether end termination element 316 is shown to be a cylindrical sleeve or a similar element and the tether anchoring cavity 312 is shown to have an accommodating shape. Other tether end termination element types and shapes may be used in other examples, and the tether anchoring cavity 312 may be shaped and dimensioned as required to receive and retain the tether end termination element used.

[0043] More than one tether slot 310 and accompanying tether anchoring cavity 312 may be located in the outer surface 308 of the coupler 300 in other examples. For example, a pair of tether slots 310 and accompanying tether anchoring cavities 312 may be used instead of a single tether. In such a case, the pair of tether slots 310 and accompanying tether anchoring cavities 312 may be arranged in the coupler 300 at diametrically opposed locations. More than two tether slots 310 and accompanying tether anchoring cavities 312 may also be present in the outer surface 308 of the coupler 300. For example, three tether slots 310 and accompanying tether anchoring cavities 312 may be arranged at equally spaced 120 degree intervals or four tether slots 310 and accompanying tether anchoring cavities 312 may be arranged at equally spaced ninety degree intervals in the outer surface 308 of the coupler 300.

[0044] When the coupler 300 is installed at an uphole location and a downhole location relative to a deployed artificial lift system, the tether 314 can retained in the couplers 300 and the artificial lift system can secured to an associated tubing string by only tension produced in the tether 314. Alternatively, the tether anchoring cavity 312 may be designed to require a press fit of the tether end termination element 316 thereto, a retainer may be placed over the tether end termination element 316 and the tether anchoring cavity 312 or the tether 314 and the tether slot 310 and secured to the outer surface 308 of the coupler 300, or other techniques may be employed to further ensure retention of the tether ends in the coupler 300.

[0045] FIG. 4 is an isometric view of another coupler 400 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 400 may serve as either an uphole coupler or a downhole coupler without requiring inversion or any other reorientation. The coupler 400 may be coupled to a tubing string or a component of an artificial lift system in a like or similar manner to either the uphole coupler 252 or the downhole coupler 254 of the loss prevention assembly 250. In some examples, the coupler 400 may be a hollow cylinder (e.g., sleeve) as shown. The coupler may include a first end 402 and a second end 404, either of which may be an uphole end or a downhole end depending on the orientation of the coupler 400.

[0046] In some examples, a portion of an inside wall 406 at one or both ends 402, 404 of the coupler 400 may be threaded to engage with mating threads of an artificial lift system component, tubing string pipe, etc. Alternatively, the entirety of the inside wall 406 of the coupler 400 may be threaded.

[0047] In this example of the coupler 400, a tether retention feature 408 protrudes from an outer surface 410 of the coupler 400. The tether retention feature 408 may be, for example, a rib or spline that extends axially over all or a portion of the axial length of the coupler 400. The tether retention feature 408 may instead be a tab that extends radially outwardly from the outer surface 410 of the coupler 400. A tether passageway 412 may extend axially through the tether retention feature 408. The tether passageway 412 permits a tether, such as the tether 256 of the loss prevention assembly 250 of FIG. 2 or the tether 314 of FIG. 3A, to be securely coupled to the coupler 400. More specifically, a tether may be passed through the tether passageway 412 until an end termination of the tether (e.g., the end termination 316 of the tether 314 of FIG. 3A) is placed in mating contact with the surrounding material of the tether retention feature 408. Alternatively, an end termination may installed to a tether (e.g., swaged when the tether is a wire rope) after the tether is passed through the tether passageway 412. The end terminations used may be any one or more of several possible existing end terminations that can prevent the tether from being withdrawn from the tether passageways 412 of the tether retention features 408. For example, the shape or dimension of the end terminations may prevent the end terminations from passing through the tether passageways 412.

[0048] Although only a single retention feature 408 is shown in FIG. 4, more than one tether retention feature 408 may be arranged along the outer surface 410 of the coupler 400 in other examples. For example, a pair of tether retention features 408 may be provided instead of a single tether retention feature 408. In such a case, the pair of tether retention features 408 may protrude from the outer surface 410 of the coupler 400 at diametrically opposed locations. More than two tether retention features 408 may also be provided and may be arranged at various intervals along the outer surface 410 of the coupler 400. For example, three tether retention features 408 may be arranged at equally spaced 120 degree intervals or four tether retention features 408 may be arranged at equally spaced ninety degree intervals in the outer surface 410 of the coupler 400. When the coupler 400 includes two or more tether retention features 408, the protruding nature of the tether retention features 408 may enable the coupler 400 to help center an artificial lift system and an associated tubing string in a wellbore.

[0049] FIG. 5 is an isometric view of another coupler 500 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 500 again encircles a tubing string member 514 (e.g., pipe section) and is of reversible orientation. In FIG. 5, the coupler 500 is depicted as an uphole coupler that includes a tether slot 502 and a tether anchoring cavity 504 like or similar to the tether slot 310 and the tether anchoring cavity 312 of the coupler 300 of FIGS. 3A-3B. The coupler 500 may include a first end 506 and a second end 508, each of which may be an uphole end or a downhole end depending on the orientation of the coupler 500. That is, the coupler 500 may also serve as a downhole coupler by simply inverting the coupler 500 such that a downhole end of the coupler 500 when in the uphole orientation shown in FIG. 5 becomes the uphole end of the coupler 500 when in a downhole orientation. While the coupler 500 of FIG. 5 is shown to include the tether slot 502 and cooperating tether anchoring cavity 504 in this example, the coupler 500 may instead include a protruding tether retention feature like or similar to the protruding tether retention feature 408 of the coupler 400 shown in FIG. 4, or any other tether coupling / retention element shown or described herein (see, e.g., FIGS. 6 and 7).

[0050] As shown, this example of the coupler 500 is a split coupler comprising two halves 510, 512, each of which may be slipped over a tubing string member 514 (e.g., pipe section) to form the complete coupler 500. The halves 510, 512 of the coupler 500 may thereafter be secured to one another, such as for example, by one or more threaded fasteners 516. In at least some examples, the uphole coupler 500 may be installed uphole of an expanded portion 518 of the tubing string member 514, such as a portion of the tubing string member 514 that is expanded to receive and connect to another downhole tubing string member or to an artificial lift system component. Installing the uphole-oriented coupler 500 to the tubing string member 514 uphole of and adjacent to the expanded portion 518 the tubing string member 514 as shown in FIG. 5 can help prevent a downhole movement of the coupler 500 along the tubing string member 514 if a downhole force is applied to the coupler 500 by a tether as a result of an unintended disconnection of a downhole artificial lift system component coupled to the tether. Likewise, a downhole-oriented coupler 500 may be installed to a downhole component of an artificial lift system at a location downhole of and adjacent to a larger diameter portion of the artificial lift system component. By such an installation, a downhole movement of the artificial lift system component through the coupler 500 may be prevented upon an unintended disconnection of the artificial lift system component from the tubing string.

[0051] FIG. 6 is an isometric view of another coupler 600 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 600 includes an expanded or enlarged first portion 602 for engagement of the coupler 600 with a tubing string member (e.g., pipe section), and a flanged second portion 604 for engagement of the coupler 600 with another flanged coupler, a flanged component of an artificial lift system, etc. According to some configurations of the coupler 600, an intermediary portion 606 may be interposed between and connect the first portion 602 to the second portion 604. In some examples, the intermediary portion 606 may have a diameter that is the same as or similar to a diameter of the pipe sections of a tubing string to which the coupler 600 is coupled.

[0052] An inside wall of the first portion 602 of the coupler 600 may be partially or fully threaded to engage with complimentary threads of a tubing string pipe section, another threaded component coupled to the tubing string, or a threaded component of an artificial lift system. The flanged second portion 604 of the coupler 600 may include holes 608 to receive threaded fasteners that can be used to secure the flanged second portion 604 to a cooperating flange of another coupler designed to mate with the coupler 600 or to a cooperating flange of another tubing string component, such as but not limited to, an artificial lift system component.

[0053] In the example of FIG. 6, coupling of a tether to the coupler 600 is enabled by at least one threaded tether connector 610, each of which can be threadedly engaged with a complimentarily threaded connector receiving bore 612 in an outside wall of the coupler 600. A plurality of threaded tether connectors 610 and threaded connector receiving bores 612 may be provided and may be spaced apart at selected intervals along the outside of the coupler 600 in different implementations. In this example, only one threaded tether connector 610 and associated connector receiving bore 612 is shown and each is located in the first portion 602 of the coupler 600. One or more threaded tether connectors 610 and associated connector receiving bores 612 may instead be located on the flanged second portion 604 or the intermediary portion 606 of the coupler 600 in other examples. To facilitate coupling of a tether to the coupler 600, the threaded tether connector 610 may include a tether connecting hole 614 that passes through a portion of the threaded tether connector 610. A tether to be coupled to the threaded tether connector 610 may include a tether end termination element (e.g., a hook) that is designed to engage with and be releasably retained by the tether connecting hole 614.

[0054] The coupler 600 is depicted in FIG. 6 in an uphole orientation wherein the first portion 602 may be engaged with an uphole tubing string component such as, for example, a pipe section and the flanged second portion 604 may be engaged with a downhole component such as, for example, an artificial lift system component. However, the coupler 600 may also function as a downhole coupler by simply inverting the coupler 600 such that a downhole end of the coupler 600 when in the uphole orientation shown in FIG. 6 becomes the uphole end of the coupler 600 when in a downhole orientation. For example, an uphole-oriented coupler 600 may be coupled to the tubing string at a location uphole of an artificial lift system and a downhole-oriented coupler 600 may be located downhole of the uphole-oriented coupler 600 such as to couple together components of the artificial lift system or to couple another component to (e.g., a downhole end of) the artificial lift system. A tether may then be connected between the threaded tether connector 610 of the uphole coupler 600 and the threaded tether connector 610 of the downhole coupler to prevent all or a portion of the artificial lift system from being lost downhole in the event of an unintended disconnection of an artificial lift system component, as described above.

[0055] FIG. 7 is an isometric view of another coupler 700 component of an artificial lift system loss prevention assembly according to another example of the present disclosure. In this example, the coupler 700 includes an expanded or enlarged first portion 702 for engagement of the coupler 700 with a tubing string member (e.g., pipe section), and a flanged second portion 704 for engagement of the coupler 600 with another flanged coupler, a flanged component of an artificial lift system, etc. According to some configurations of the coupler 700, an intermediary portion 706 may be interposed between and connect the first portion 702 to the second flanged portion 704. In some examples, the intermediary portion 706 may have a diameter that is the same as or similar to a diameter of the pipe sections of a tubing string to which the coupler 700 is coupled.

[0056] An inside wall of the first portion 702 of the coupler 700 may be partially or fully threaded to engage with complimentary threads of a tubing string pipe section, another threaded component coupled to the tubing string, or a threaded component of an artificial lift system. The flanged second portion 704 of the coupler 700 may include holes 708 to receive threaded fasteners that can be used to secure the flanged second portion 704 to a cooperating flange of another coupler designed to mate with the coupler 700 or to a cooperating flange of another tubing string component, such as but not limited to, an artificial lift system component.

[0057] In the example of FIG. 7, coupling of a tether to the coupler 700 is enabled by at least one integrated tether connector 708 that can be a cast or molded integral element of the coupler 700, or an element that is otherwise permanently affixed to the coupler 700, such as by welding. In this example, each of the pair of integrated tether connectors 708 forms an open connecting loop to which a tether may be coupled. The integrated tether connectors 708 are shown to extend from the first portion 702 of the coupler 700 in the example of FIG. 7 but the integrated tether connector(s) 708 may instead be located on the flanged second portion 704 or the intermediary portion 706 of the coupler 700 in other examples. To facilitate coupling of a tether to the coupler 700, a tether to may include a tether end termination element (e.g., a hook or shackle) that is designed to engage with and be releasably retained by the integrated tether connector 708 to which the tether is connected.

[0058] The coupler 700 is depicted in FIG. 7 in an uphole orientation wherein the first portion 702 may be engaged with an uphole tubing string component such as, for example, a pipe section and the flanged second portion 704 may be engaged with a downhole component such as, for example, an artificial lift system component. However, the coupler 700 may also function as a downhole coupler by simply inverting the coupler 700 such that a downhole end of the coupler 700 when in the uphole orientation shown in FIG. 7 becomes the uphole end of the coupler 700 when in a downhole orientation. For example, an uphole-oriented coupler 700 may be coupled to the tubing string at a location uphole of an artificial lift system and a downhole-oriented coupler 700 may be located downhole of the uphole-oriented coupler 700 such as to couple together components of the artificial lift system or to couple another component to (e.g., a downhole end of) the artificial lift system. A tether may then be connected between one or more of the integrated tether connectors 708 of the uphole coupler 700 and one or more of the integrated tether connectors 708 of the downhole coupler to prevent all or a portion of the artificial lift system from being lost downhole in the event of an unintended disconnection of an artificial lift system component, as previously described.

[0059] In addition to being affixed to or integrated into a coupler as described above, tether connecting / coupling elements may also be a part of an artificial lift system component. For example, one or more tether connecting / coupling elements may be affixed to or integrated into an artificial lift system component such as a pump, a seal section, etc., and a tether may be connected between such an artificial lift system component and a cooperating uphole coupler.

[0060] FIG. 8 is a flowchart 800 illustrating a method of preventing a downhole loss of an artificial lift system upon an unintended disconnection of an artificial lift system component according to one example of the present disclosure.

[0061] As represented in block 802 of the flowchart 800, a loss prevention assembly is installed to an artificial lift system of a tubing string. The loss prevention assembly may include an uphole coupler. The uphole coupler can be coupled to the tubing string. The uphole coupler can be coupled to the tubing string at a location uphole of the artificial lift system. The loss prevention assembly can also include a downhole coupler. The downhole coupler can be coupled to a downhole component of the artificial lift system. In some examples, the downhole coupler may be coupled to a downhole-most component of the artificial lift system. For example, when the artificial lift system is an electric submersible pump system, the downhole may be coupled to a sensor of the electric submersible pump system. The loss prevention assembly may further include a tether. The tether can be securely connected between the uphole coupler and the downhole coupler. In various examples, the tether may be a wire rope, a synthetic fiber rope, a sling, or a chain. In some examples, only a single tether may be used. When only a single tether is used, the single tether should have sufficient tensile strength to support the weight of the artificial lift system. In other examples, multiple tethers may be used. When multiple tethers are used, the collective tensile strength of the tethers should be sufficient to support the weight of the artificial lift system.

[0062] Each of the uphole coupler, the downhole coupler, and the tether may include features that cooperate to enable secure connection of the tether to the couplers. For example, each of the uphole coupler and the downhole coupler may include tether coupling features. In some examples, the tether coupling features may be recessed into an outer surface of the uphole coupler and the downhole coupler. For example, each of the uphole coupler and the downhole coupler may include one or a plurality of tether slots and accompanying tether anchoring cavities that receive and retain respective ends of the tether. In another example, the tether coupling features may protrude from an outer surface of the uphole coupler and the downhole coupler. For example, each of the uphole coupler and the downhole coupler may include one or more tether retention features in the form of a rib or a spline that protrudes outwardly from the coupler outer surface and extends axially over all or a portion of an axial length of the coupler. A tether passageway can extend axially through the tether retention feature to receive and retain the tether.

[0063] The ends of the tether may enable the tether to be securely coupled to the uphole coupler and the downhole coupler. For example, the ends of the tether may have termination elements (end terminations) affixed thereto. In one example, the end terminations may be receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler. In another example, the end terminations may be of a shape or dimension that prevents the tether from being withdrawn from the tether passageway in the protruding tether retention feature of each of the uphole coupler and the downhole coupler after being passed therethrough.

[0064] As represented in block 804 of the flowchart 800, the artificial lift system is deployed downhole in a wellbore such that the artificial lift system is suspended from the tubing string. In some examples, the wellbore may be a wellbore of a hydrocarbon well. In some examples, the hydrocarbon well may be a completed well and the conveyance tubing string may be a production tubing string.

[0065] Use of a loss prevention assembly according to the present disclosure can eliminate or reduce costs typically associated with an unintended disconnection of an artificial lift system component. For example, preventing the downhole loss of an artificial lift (e.g., ESP) system in the event of an unintended disconnection of an artificial lift system component can eliminate the cost associated with retrieving a fallen artificial lift system from possibly deep within a wellbore. Likewise, preventing the downhole loss of an artificial lift system upon an unintended disconnection of an artificial lift system component can eliminate the cost associated with lost well production time, damage to components of the fallen artificial lift system, or damage to the wellbore, a wellbore casing, or other downhole well equipment resulting from the fallen artificial lift system.

[0066] In some aspects, a loss prevention assembly, a hydrocarbon well system, and a method for preventing the downhole loss of all or a portion of an artificial lift system in the event of an unintended disconnection of an artificial lift system component are provided according to one or more of the following examples. As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).

[0067] As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).

[0068] Example 1 is a loss prevention assembly including an uphole coupler couplable to a well tubing string uphole of an artificial lift system connected to the tubing string, a downhole coupler couplable to a downhole component of the artificial lift system, and a tether connectable between the uphole coupler and the downhole coupler.

[0069] Example 2 is the loss prevention assembly of example 1, wherein the uphole coupler includes internal threads to couple the uphole coupler to complimentary threads of the tubing string.

[0070] Example 3 is the loss prevention assembly of example 1 or example 2, wherein the uphole coupler comprises a first tether slot and an accompanying first tether anchoring cavity in an outer surface of the uphole coupler, the downhole coupler comprises a second tether slot and an accompanying second tether anchoring cavity in an outer surface of the downhole coupler, and the tether comprises a first termination element affixed to an uphole end of the tether and a second termination element affixed to a downhole end of the tether. A portion of the tether is receivable by and retainable in the tether slot of each of the uphole coupler and the downhole coupler and a portion of the termination element is receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler.

[0071] Example 4 is the loss prevention assembly of example 3, wherein a plurality of the first tether slots and the accompanying first tether anchoring cavities and a plurality of the second tether slots and the accompanying second tether anchoring cavities are arranged at circumferentially-spaced intervals in the outer surface of each of the uphole coupler and the downhole coupler.

[0072] Example 5 is the loss prevention assembly of example 1, wherein a tether retention feature protrudes outwardly from an outer surface of and extends axially over all or a portion of an axial length of each of the uphole coupler and the downhole couple, a tether passageway extends axially through the tether retention feature, and a termination element is affixed to each end of the tether. A respective portion of the tether is passable through the tether passageway in the tether retention feature of the uphole coupler and the downhole coupler and the termination elements are shaped or dimensioned to overlie outer surfaces of the respective tether retention features around the tether passageways thereof to prevent a decoupling of the tether from the uphole coupler and the downhole coupler.

[0073] Example 6 is the loss prevention assembly of example 1, wherein a plurality of tether retention features are arranged at circumferentially-spaced intervals along an outer surface of each of the uphole coupler and the downhole coupler, each tether retention feature protrudes outwardly from the outer surface of and extends axially over all or a portion of an axial length of the uphole coupler and the downhole coupler, and a tether passageway extends axially through each of the tether retention features. A plurality of tethers are connected between corresponding pairs of the tether retention features of the uphole coupler and the downhole coupler, and a termination element is affixed to each end of each tether. A respective portion of each tether is passable through the tether passageway of the tether retention feature of the uphole coupler and the downhole coupler between which the tether is connected and the termination elements are shaped or dimensioned to overlie outer surfaces of the respective tether retention features around the tether passageways thereof to prevent a decoupling of the tethers from the uphole coupler and the downhole coupler.

[0074] Example 7 is the loss prevention assembly of example 1, wherein the tether is a wire rope, a synthetic fiber rope, a sling, or a chain.

[0075] Example 8 is a well system including an artificial lift system suspended from a tubing string deployed in a wellbore of the well, an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system, a downhole coupler coupled to a downhole component of the artificial lift system, and a tether connected between the uphole coupler and the downhole coupler.

[0076] Example 9 is the well system of example 8, wherein the artificial lift system is an electric submersible pump system.

[0077] Example 10 is the well system of example 8 or example 9, wherein the uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

[0078] Example 11 is the well system of any of examples 8-10, wherein the downhole component is a sensor, the sensor is a downhole-most component of the electric submersible pump system, and the downhole coupler is coupled to a downhole end of the sensor.

[0079] Example 12 is the well system of any of examples 8-11, wherein the tether passes through or is coupled to a plurality of tether guides extending radially outwardly from one or more components of the artificial lift system.

[0080] Example 13 is the well system of any of examples 8-12, wherein the tether is selected from the group consisting of a wire rope, a synthetic fiber rope, a sling, and a chain.

[0081] Example 14 is the well system of any of examples 8-13, wherein a sensor is coupled to the tether to detect an increase in tension in the tether and to resultantly output a signal that is interpretable upon receipt as being indicative of an unintended disconnection of an artificial lift system component.

[0082] Example 15 is a method that includes installing a loss prevention assembly to an artificial lift system of a tubing string. The loss prevention assembly can include an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system, a downhole coupler coupled to a downhole component of the artificial lift system, and a tether connected between the uphole coupler and the downhole coupler. The method also includes deploying the artificial lift system downhole in a wellbore of a well such that the artificial lift system is suspended from the tubing string within the wellbore.

[0083] Example 16 is the method of example 15, wherein the artificial lift system is an electric submersible pump system.

[0084] Example 17 is the method of example 15 or example 16, wherein the uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

[0085] Example 18 is the method of any of examples 16-17, wherein the downhole component of the electric submersible pump system is a sensor and the downhole coupler is coupled to a downhole end of the sensor.

[0086] Example 19 is the method of any of examples 15-18, wherein a plurality of tethers are connected between the uphole coupler and the downhole coupler and collectively support a weight of the artificial lift system.

[0087] Example 20 is the method of any of examples 15-19, wherein each tether is a wire rope, a synthetic fiber rope, a sling, or a chain.

[0088] The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.

Examples

Embodiment Construction

[0011]Certain aspects and examples of the present disclosure relate to a loss prevention assembly that can be installed to an artificial lift system of a well. The loss prevention assembly can prevent a downhole loss of all or a portion of the artificial lift system due to an unintended disconnection of a component of the artificial lift system. An unintended disconnection of a component of the artificial lift system may result from, for example, a mechanical failure of a system component, which can include connection between system components. While examples provided herein are shown and described as being associated with a hydrocarbon well for purposes of illustration, it should be understood that a loss prevention assembly according to the present disclosure can also be used with other types of wells such as, for example, municipal water wells, mine dewatering wells, geothermal wells, brine wells, etc.

[0012]The artificial lift system may be a part of (e.g., may be suspended from)...

Claims

1. A loss prevention assembly comprising:an uphole coupler couplable to a well tubing string uphole of an artificial lift system connected to the tubing string;a downhole coupler couplable to a downhole component of the artificial lift system; anda tether connectable between the uphole coupler and the downhole coupler to suspend at least a portion of the artificial lift system from the uphole coupler upon an unintended disconnection of a component of the artificial lift system, the tether of a construction to support a tensile load of between 12,000 pounds to 20,000 pounds.

2. The loss prevention assembly of claim 1, wherein the uphole coupler includes internal threads to couple the uphole coupler to complimentary threads of the tubing string.

3. The loss prevention assembly of claim 1, wherein:the uphole coupler comprises a first tether slot and an accompanying first tether anchoring cavity in an outer surface of the uphole coupler;the downhole coupler comprises a second tether slot and an accompanying second tether anchoring cavity in an outer surface of the downhole coupler;the tether comprises a first termination element affixed to an uphole end of the tether and a second termination element affixed to a downhole end of the tether; anda portion of the tether is receivable by and retainable in the tether slot of each of the uphole coupler and the downhole coupler and a portion of the termination element is receivable by and retainable in the tether anchoring cavity of each of the uphole coupler and the downhole coupler.

4. The loss prevention assembly of claim 3, wherein a plurality of the first tether slots and the accompanying first tether anchoring cavities and a plurality of the second tether slots and the accompanying second tether anchoring cavities are arranged at circumferentially-spaced intervals in the outer surface of each of the uphole coupler and the downhole coupler.

5. The loss prevention assembly of claim 1, wherein:the tether is a wire rope; andeach end of the wire rope has swaged thereto a closed socket, open socket, open or closed spelter socket, wedge socket, sleeve, or threaded stud by which the tether is securable to the uphole coupler and the downhole coupler.

6. The loss prevention assembly of claim 3, wherein the first termination element of the tether is retainable in the first tether anchoring cavity of the uphole coupler and the second termination element of the tether is retainable in the second tether anchoring cavity of the downhole coupler by a press fit of the first and second termination elements into the respective first and second tether anchoring cavities or by retainers that are positionable over the first and second tether anchoring cavities and respectively securable to the outer surfaces of the uphole coupler and the downhole coupler.

7. The loss prevention assembly of claim 1, wherein the tether is a synthetic fiber rope, a sling, or a chain.

8. A well system comprising:an artificial lift system suspended from a tubing string deployed in a wellbore of the well;an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system;a downhole coupler coupled to a downhole component of the artificial lift system; anda tether connected between the uphole coupler and the downhole coupler to suspend at least a portion of the artificial lift system from the uphole coupler upon an unintended disconnection of a component of the artificial lift system, the tether of a construction to support a tensile load of between 12,000 pounds to 20,000 pounds.

9. The well system of claim 8, wherein the artificial lift system is an electric submersible pump system.

10. The well system of claim 9, wherein the uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

11. The well system of claim 9, wherein the downhole component is a sensor, the sensor is a downhole-most component of the electric submersible pump system, and the downhole coupler is coupled to a downhole end of the sensor.

12. The well system of claim 8, wherein:the tether is a wire rope; andeach end of the wire rope has swaged thereto a closed socket, open socket, open or closed spelter socket, wedge socket, sleeve, or threaded stud by which the tether is securable to the uphole coupler and the downhole coupler.

13. The well system of claim 8, wherein the tether is a synthetic fiber rope, a sling, or a chain.

14. The well system of claim 8, further comprising a sensor coupled to the tether to detect an increase in tension in the tether and to resultantly output a signal that is interpretable upon receipt as being indicative of an unintended disconnection of an artificial lift system component.

15. A method comprising:installing a loss prevention assembly to an artificial lift system of a tubing string, the loss prevention assembly comprising:an uphole coupler coupled to the tubing string at a location uphole of the artificial lift system,a downhole coupler coupled to a downhole component of the artificial lift system, anda tether of a construction to support a tensile load of between 12,000 pounds to 20,000 pounds connected between the uphole coupler and the downhole coupler to suspend at least a portion of the artificial lift system from the uphole coupler upon an unintended disconnection of a component of the artificial lift system; anddeploying the artificial lift system downhole in a wellbore of a well such that the artificial lift system is suspended from the tubing string within the wellbore.

16. The method of claim 15, wherein:the artificial lift system is an electric submersible pump system; andthe uphole coupler is threaded at an uphole end to a pipe of the tubing string and at a downhole end to a top end of the electric submersible pump system.

17. The method of claim 15, wherein:the tether is a wire rope; andeach end of the wire rope has swaged thereto a closed socket, open socket, open or closed spelter socket, wedge socket, sleeve, or threaded stud by which the tether is secured to the uphole coupler and the downhole coupler.

18. The method of claim 16, wherein the downhole component of the electric submersible pump system is a sensor and the downhole coupler is coupled to a downhole end of the sensor.

19. The method of claim 15, wherein a plurality of tethers are connected between the uphole coupler and the downhole coupler and collectively support a weight of the artificial lift system.

20. The method of claim 19, wherein each tether is a synthetic fiber rope, a sling, or a chain.

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