Patent Description:
Wells are generally drilled into land surface or ocean bed to recover natural deposits of oil and gas, and other natural resources that are trapped in subterranean rock formations in the Earth's crust. Testing and evaluation of completed and partially finished wells has become commonplace, such as to increase well production and return on investment. Downhole measurements of formation pressure, formation permeability, and recovery of formation fluid samples, may be useful for predicting economic value, production capacity, and production lifetime of geological formations. Completion and stimulation operations of wells, such as perforating and fracturing operations, may also be performed to optimize well productivity. Plugging and perforating tools may be utilized to set plugs within a wellbore to isolate portions of the wellbore and rock formations surrounding the wellbore from each other and to perforate the well in preparation for fracturing. Each fracturing stage interval along the wellbore can be perforated with one or more perforating tools forming one or more clusters of perforation tunnels along the wellbore. Intervention operations in completed wells, such as installation, removal, or replacement of various production equipment, may also be performed as part of well repair or maintenance operations or permanent abandonment. Such testing, completion, intervention, and other downhole operations have become complicated, as wellbores are drilled deeper and often include extensive horizontal or otherwise non-vertical (i.e., deviated) portions.

Downhole tools that have conventionally been used in vertical and near-vertical wellbores may encounter problems when used in non-vertical portions of a wellbore. Such downhole tools may be lowered into a wellbore as part of a tool string utilizing gravity to facilitate transport or movement therethrough. In non-vertical wellbores, gravity may be negated by frictional forces between the tool string and sidewalls of the wellbore, thus resisting movement of the tool string through the wellbore.

In addition to the increased friction due to an increased horizontal gradient, movement of a tool string along a non-vertical portion of a wellbore may be impeded further by the presence of various obstacles. For example, washouts, sharp bends, misaligned tubular joins, transitions between lining, casing, and bare sidewalls of the wellbore, and other uneven surfaces may present an increased resistance or impediments to the movement of the tool string through the wellbore. Furthermore, particularly with open-hole wellbores not lined with a casing, outer surface of the tool string may stick to the sidewall of the wellbore, or an edge of the tool string may dig into or jam against imperfections along the sidewall of the wellbore.

The <CIT> discloses a guide for use in a string of sucker rods rotated in tubing in a borehole, each guide being formed of an elongated, upright, cylindrical coupling body having female threads at the upper and lower ends for attachment in a string of sucker rods, and including a plurality of at least three recesses in the body cylindrical surfaces, there being a recess in at least each <NUM> DEG quadrant around the body, an axle received in each recess, the axis of each axle being parallel and spaced from the body longitudinal axis, and a roller rotatably received on each axle, the periphery of each roller extending exteriorly of the external cylindrical surface of the coupling body, the rollers being conical shaped on each end, and the roller serving to contact the interior wall of tubing in which the sucker rod string is rotated to prevent wear of the tubing and the sucker rod string.

This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.

The current invention is defined by the subject-matter of independent claims <NUM> and <NUM>; other aspects of the invention are defined by the dependent claims.

These and additional aspects of the present disclosure are set forth in the description that follows, and/or may be learned by a person having ordinary skill in the art by reading the material herein and/or practicing the principles described herein.

The present disclosure is best understood from the following detailed description when read with the accompanying figures.

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. This repetition is for simplicity and clarity, and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows, may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

Terms, such as upper, upward, above, lower, downward, and/or below are utilized herein to indicate relative positions and/or directions between apparatuses, tools, components, parts, portions, members and/or other elements described herein, as shown in the corresponding figures. Such terms do not necessarily indicate relative positions and/or directions when actually implemented. Such terms, however, may indicate relative positions and/or directions with respect to a wellbore when an apparatus according to one or more aspects of the present disclosure is utilized or otherwise disposed within the wellbore. For example, the term upper may mean in the uphole direction, and the term lower may mean in the downhole direction.

<FIG> is a schematic view of at least a portion of an example implementation of a wellsite system <NUM> according to one or more aspects of the present disclosure, representing an example environment in which one or more aspects of the present disclosure may be implemented. The wellsite system <NUM> is depicted in relation to a wellbore <NUM> formed by rotary and/or directional drilling and extending from a wellsite surface <NUM> into a subterranean formation <NUM>. A lower portion of the wellbore <NUM> is shown enlarged compared to an upper portion of the wellbore <NUM> adj acent the wellsite surface <NUM> to permit a larger and therefore a more detailed depiction of various tools, tubulars, devices, and other objects disposed within the wellbore <NUM>. The wellsite system <NUM> may be utilized to facilitate recovery of oil, gas, and/or other materials that are trapped in the subterranean formation <NUM> via the wellbore <NUM>. At least a portion of the wellbore <NUM> may be a cased-hole wellbore <NUM> comprising a casing <NUM> secured by cement <NUM>, and/or a portion of the wellbore <NUM> may be an open-hole wellbore <NUM> lacking the casing <NUM> and cement <NUM>. The wellbore <NUM> may also or instead contain a fluid conduit (e.g., a production tubing) (not shown) disposed within at least a portion of the casing <NUM> and/or an open-hole portion of the wellbore <NUM>. Thus, one or more aspects of the present disclosure are applicable to and/or readily adaptable for utilizing in a cased-hole portion of the wellbore <NUM>, an open-hole portion of the wellbore <NUM>, and/or a fluid conduit disposed within a cased-hole and/or open-hole portion of a wellbore <NUM>. It is also noted that although the wellsite system <NUM> is depicted as an onshore implementation, it is to be understood that the aspects described below are also generally applicable to offshore implementations.

The wellsite system <NUM> includes surface equipment <NUM> located at the wellsite surface <NUM>. The wellsite system <NUM> also includes or is operable in conjunction with a downhole intervention and/or sensor assembly, referred to as a tool string <NUM>, conveyed within the wellbore <NUM> via a conveyance line <NUM> operably connected with one or more pieces of the surface equipment <NUM>. The conveyance line <NUM> may be operably connected with a conveyance device <NUM> operable to apply an adjustable downward-and/or upward-directed force to the tool string <NUM> via the conveyance line <NUM> to convey the tool string <NUM> within the wellbore <NUM>. The conveyance line <NUM> may be or comprise coiled tubing, a cable, a wireline, a slickline, a multiline, or an e-line, among other examples. The conveyance device <NUM> may be, comprise, or form at least a portion of a sheave or pulley, a winch, a draw-works, an injector head, and/or another device coupled to the tool string <NUM> via the conveyance line <NUM>. The conveyance device <NUM> may be supported above the wellbore <NUM> via a mast, a derrick, a crane, and/or other support structure <NUM>. The surface equipment <NUM> may further comprise a reel or drum <NUM> configured to store thereon a wound length of the conveyance line <NUM>, which may be selectively wound and unwound by the conveyance device <NUM> to selectively convey the tool string <NUM> into, along, and out of the wellbore <NUM>.

Instead of or in addition to the conveyance device <NUM>, the surface equipment <NUM> may comprise a winch conveyance device <NUM> comprising or operably connected with the drum <NUM>. The drum <NUM> may be rotated by a rotary actuator <NUM> (e.g., an electric motor) to selectively unwind and wind the conveyance line <NUM> to apply an adjustable tensile force to the tool string <NUM> to selectively convey the tool string <NUM> into, along, and out of the wellbore <NUM>.

The conveyance line <NUM> may comprise one or more metal support wires or cables configured to support the weight of the downhole tool string <NUM>. The conveyance line <NUM> may also comprise one or more insulated electrical and/or optical conductors <NUM> operable to transmit electrical energy (i.e., electrical power) and electrical and/or optical signals (e.g., downlink control data and/or uplink sensor data) between the tool string <NUM> and one or more components of the surface equipment <NUM>, such as a power and control system <NUM>. The conveyance line <NUM> may comprise and/or be operable in conjunction with means for communication between the tool string <NUM>, the conveyance device <NUM>, the winch conveyance device <NUM>, and/or one or more other portions of the surface equipment <NUM>, including the power and control system <NUM>.

The wellbore <NUM> may be capped by a plurality (e.g., a stack) of fluid control devices <NUM>, which may include a Christmas tree comprising fluid control valves, spools, and fittings individually and/or collectively operable to direct and control the flow of fluid out of the wellbore <NUM>. The fluid control devices <NUM> may also or instead comprise a blowout preventer (BOP) stack operable to prevent the flow of fluid out of the wellbore <NUM>. The fluid control devices <NUM> may be mounted on top of a wellhead <NUM>.

The surface equipment <NUM> may further comprise a sealing and alignment assembly <NUM> mounted on the fluid control devices <NUM> and operable to seal the conveyance line <NUM> during deployment, conveyance, intervention, and other wellsite operations. The sealing and alignment assembly <NUM> may comprise a lock chamber (e.g., a lubricator, an airlock, a riser, etc.) mounted on the fluid control devices <NUM> and a stuffing box operable to seal around the conveyance line <NUM> at top of the lock chamber, although such details are not shown in <FIG>. The stuffing box may be operable to seal around an outer surface of the conveyance line <NUM>, for example via annular packings applied around the surface of the conveyance line <NUM> and/or by injecting a fluid between the outer surfaces of the conveyance line <NUM> and an inner wall of the stuffing box. The tool string <NUM> may be deployed into or retrieved from the wellbore <NUM> via the conveyance device <NUM> and/or winch conveyance device <NUM> through the wellhead <NUM>, the control devices <NUM>, and/or the sealing and alignment assembly <NUM>.

The power and control system <NUM> (e.g., a control center) may be utilized to monitor and control various portions of the wellsite system <NUM>. The power and control system <NUM> may be located at the wellsite surface <NUM> or on a structure located at the wellsite surface <NUM>. However, the power and control system <NUM> may instead be located remote from the wellsite surface <NUM>. The power and control system <NUM> may include a source of electrical power <NUM>, a memory device <NUM>, and a surface controller <NUM>. The electrical power source <NUM> (e.g., a battery, an electrical generator, etc.) may supply electrical power to various equipment of the well site system <NUM>, including the memory device <NUM>, the surface controller <NUM>, the tool string <NUM>, the conveyance device <NUM>, and/or the winch conveyance device <NUM>. The surface controller <NUM> (e.g., a processing device, a computer, etc.) may store executable programs and/or instructions, including for implementing one or more aspects of methods, processes, and operations described herein. The surface controller <NUM> may be communicatively connected with various equipment of the wellsite system <NUM>, such as may permit the surface controller <NUM> to monitor operations of one or more portions of the wellsite system <NUM> and/or to provide automatic control of one or more portions of the wellsite system <NUM>, including the tool string <NUM>, the conveyance device <NUM>, and/or the winch conveyance device <NUM>. The surface controller <NUM> may also or instead be used by wellsite personnel (i.e., a human operator) to manually control one or more portions of the wellsite system <NUM>, including the tool string <NUM>, the conveyance device <NUM>, and/or the winch conveyance device <NUM>. The surface controller <NUM> may include input devices for receiving commands from the wellsite personnel and output devices for displaying information to the wellsite personnel.

The tool string <NUM> may be conveyed within the wellbore <NUM> to perform various downhole sampling, testing, intervention, and other downhole operations. The tool string <NUM> may further comprise one or more downhole tools <NUM> (e.g., devices, modules, subs, etc.) operable to perform such downhole operations. The downhole tools <NUM> of the tool string <NUM> may include one or more of an acoustic tool, a cable head, a casing collar locator (CCL), a cutting tool, a density tool, a depth correlation tool, a directional tool, an electrical power module, an electromagnetic (EM) tool, a formation testing tool, a fluid sampling tool, a gamma ray (GR) tool, a gravity tool, a formation logging tool, a hydraulic power module, a magnetic resonance tool, a formation measurement tool, a jarring tool, a mechanical interface tool, a monitoring tool, a neutron tool, a nuclear tool, a perforating tool, a photoelectric factor tool, a plug, a plug setting tool, a porosity tool, a power module, a ram, a reservoir characterization tool, a resistivity tool, a seismic tool, a stroker tool, a surveying tool, and/or a telemetry tool, among other examples also within the scope of the present disclosure.

A plurality of wheel assemblies <NUM> may be connected to the tool string <NUM> to reduce friction between the tool string <NUM> and a sidewall (e.g., an internal surface) of the wellbore <NUM>, and thus facilitate or help with conveyance of the tool string <NUM> along the wellbore <NUM>. As described herein, the sidewall of the wellbore <NUM> may include a sidewall of the rock formation <NUM> if the wellbore <NUM> is an open-hole wellbore, a sidewall of the casing <NUM> along locations at which the casing <NUM> is installed in the rock formation <NUM>, or a sidewall of a fluid conduit if such fluid conduit is installed within an open-hole wellbore or the casing <NUM>. The wheel assemblies <NUM> may be or form a portion of the tool string <NUM>.

Each wheel assembly <NUM> may comprise an axle (not shown) and a wheel rotatably connected with the axle. The axle of each wheel assembly <NUM> may be detachably connected to a corresponding downhole tool <NUM> to detachably connect the wheel assembly <NUM> to the tool string <NUM>. Each wheel assembly <NUM> may be detachably connected with a body (e.g., a housing, a frame, a block, etc.) of a corresponding downhole tool <NUM> of the tool string <NUM>. The wheel assemblies <NUM> may be connected to the tool string <NUM> when the wheel assemblies <NUM> are needed to help convey the tool string <NUM> along the wellbore <NUM>, and disconnected from the tool string <NUM> when the wheel assemblies <NUM> are not needed to help convey the tool string <NUM> along the wellbore <NUM>. The wheel assemblies <NUM> may be detachably connected on opposing sides of the tool string <NUM>. The wheel assemblies <NUM> may be connected to the tool string <NUM> at various axial (i.e., longitudinal) locations along the tool string <NUM>, such as at an upper (i.e., uphole) end of the tool string <NUM>, at a lower (i.e., downhole) end of the tool string <NUM>, and/or at intermediate positions along the tool string <NUM>. Although the tool string <NUM> is shown comprising wheel assemblies <NUM> at three locations along the tool string <NUM>, it is to be understood that the wheel assemblies <NUM> may be detachably connected to the tool string <NUM> at a lesser or greater number of locations.

<FIG> is a sectional view of an example implementation of a body <NUM> (e.g., a housing, a frame, a block, etc.) of a downhole tool of a tool string <NUM> according to one or more aspects of the present disclosure. <FIG> is a side view of the body <NUM> shown in <FIG> according to one or more aspects of the present disclosure. The tool string <NUM> may comprise one or more features and/or modes of operation of the tool string <NUM> described above and shown in <FIG>. The body <NUM> may be, comprise, or form at least a portion of a downhole tool <NUM> or another portion of the tool string <NUM>. Accordingly, the following description refers to <FIG>, collectively.

A sidewall (i.e., outer surface) of the body <NUM> may comprise a mounting surface <NUM> configured to accommodate or otherwise facilitate detachable connection of a wheel assembly with the body <NUM>. The surface <NUM> may be recessed, extending inwardly into the body <NUM>. The sidewall of the body <NUM> may thus comprise a transition shoulder <NUM> between the recessed mounting surface <NUM> and a larger diameter portion of the body <NUM>. The surface <NUM> may be substantially planar (i.e., flat) and/or comprise a substantially rectangular geometry. The body <NUM> may comprise one or more cavities <NUM> (e.g., openings, bores) extending partially into the sidewall of the body <NUM>. For example, the cavities <NUM> may extend into or below the surface <NUM> of the body <NUM>. Each cavity <NUM> may be configured to accommodate or otherwise facilitate detachable connection with a corresponding fastener of the wheel assembly. Each cavity <NUM> may be or comprise a threaded bore (i.e., threaded mounting bore) configured to threadedly engage with or otherwise receive a threaded fastener of the wheel assembly. The sidewall of the body <NUM> may further comprise additional one or more mounting surfaces <NUM> on the same and/or opposing side of the body <NUM>. Each additional surface <NUM> may be configured to accommodate or otherwise facilitate detachable connection of a corresponding additional wheel assembly with the body <NUM>. Opposing surfaces <NUM> may be or extend parallel with respect to each other. The body <NUM> may further comprise additional one or more cavities <NUM> extending partially into the sidewall of the body <NUM>. For example, each additional cavity <NUM> may extend into or below the surface <NUM> of the body <NUM>. Each additional cavity <NUM> may be configured to accommodate or otherwise facilitate detachable connection with a corresponding fastener of an additional wheel assembly. For example, each additional cavity <NUM> may be or comprise a threaded bore configured to threadedly engage with or otherwise receive a threaded fastener of an additional wheel assembly. Although the cavities <NUM> are shown extending into the body <NUM> along the mounting surfaces <NUM>, the body <NUM> may not have mounting surfaces <NUM> that are recessed, and the cavities <NUM> may extend into a rounded portion of the sidewall of the body <NUM>.

<FIG> is a sectional view of an example implementation of a wheel assembly <NUM> according to one or more aspects of the present disclosure. <FIG> is a side view of the wheel assembly <NUM> shown in <FIG>. The wheel assembly <NUM> may comprise one or more features and/or modes of operation of the wheel assemblies <NUM> described above and shown in <FIG>. The wheel assembly <NUM> may be detachably connectable with the body <NUM> of the tool string <NUM> shown in <FIG>. Accordingly, the following description refers to <FIG>, collectively.

The wheel assembly <NUM> may be operable to reduce friction between the tool string <NUM> and a sidewall (i.e., inner surface) of the wellbore <NUM> to facilitate downhole conveyance of the tool string <NUM>. The wheel assembly <NUM> may comprise an axle <NUM> configured to be detachably connected to the body <NUM> of the tool string <NUM> and a wheel <NUM> rotatably connected with the axle <NUM>. At least a portion of the axle <NUM> may have a cylindrical geometry, comprising opposing outer surfaces <NUM>, <NUM> (e.g., faces, planar surfaces, etc.) and an outer circumferential surface <NUM> extending between the outer surfaces <NUM>, <NUM>. The wheel assembly <NUM> may further comprise one or more fasteners <NUM> configured to engage (e.g., connect with, latch against, etc.) the axle <NUM> and extend from the axle <NUM>. Each fastener <NUM> may be configured to extend at least partially through the axle <NUM> and at least partially into the sidewall of the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body <NUM>. The axle <NUM> may comprise a plurality of bores, each extending between the outer surfaces <NUM>, <NUM> and each configured to accommodate or receive a corresponding fastener <NUM>. The axle <NUM> may comprise a shoulder (not shown) along each bore configured to engage (i.e., contact) a corresponding fastener <NUM>. Each fastener <NUM> may comprise a head or another feature (not shown) having a shoulder (not shown) configured to engage (i.e., contact, latch against, etc.) a corresponding shoulder along the bore of the axle <NUM>. Each fastener <NUM> may further comprise a shank configured to extend out of a corresponding bore of the axle <NUM> and into a corresponding cavity <NUM> of the body <NUM> to engage the body <NUM>, and thus connect the axle <NUM> to the body <NUM>. The shank of each fastener <NUM> and each cavity <NUM> may be threaded (not shown), facilitating threaded engagement between each fastener <NUM> and a corresponding cavity <NUM>, to thereby detachably connect the axle <NUM> to the body <NUM> of the tool string <NUM>. Although the wheel assembly <NUM> is shown comprising four fasteners <NUM> arranged in a square pattern, it is to be understood that the wheel assembly <NUM> may comprise one, two, three, five, six, or more fasteners <NUM> arranged in other patterns. Although the outer surfaces <NUM>, <NUM> are shown as being substantially flat or planar, the outer surface <NUM> may be curved (e.g., round, convex, etc.) and the outer surface <NUM> may be curved (e.g., round, concave, etc.) in a complementary manner to the outer surface <NUM>.

The wheel <NUM> may extend around at least a portion of the axle <NUM>. The wheel <NUM> may comprise an outer circumferential portion <NUM> (e.g., an end, a rim, an edge, etc.) configured to contact the sidewall of the wellbore <NUM>, and thus facilitate rolling of the wheel <NUM> along the sidewall of the wellbore <NUM>. The wheel <NUM> may further comprise an inner circumferential surface <NUM> configured to contact or accommodate the outer surface <NUM> of the axle <NUM>. The inner circumferential surface <NUM> may also or instead be configured to contact a bearing (not shown) disposed between the inner circumferential surface <NUM> and the outer circumferential surface <NUM> to reduce friction between the wheel <NUM> and the axle <NUM>.

<FIG> is a sectional view of an example implementation of a wheel assembly <NUM> according to one or more aspects of the present disclosure. <FIG> is a side view of the wheel assembly <NUM> shown in <FIG>. The wheel assembly <NUM> may comprise one or more features and/or modes of operation of the wheel assembly <NUM> described above and shown in <FIG>, including where indicated by the same reference numerals. The wheel assembly <NUM> may be detachably connectable with the body <NUM> of the tool string <NUM> shown in <FIG>. Accordingly, the following description refers to <FIG>, collectively.

The wheel assembly <NUM> may be operable to reduce friction between the tool string <NUM> and a sidewall of the wellbore <NUM> to help or facilitate downhole conveyance of the tool string <NUM>. The wheel assembly <NUM> may comprise an axle <NUM> configured to be detachably connected to the body <NUM> of the tool string <NUM> and a wheel <NUM> rotatably connected with the axle <NUM>. The wheel assembly <NUM> may further comprise one or more fasteners <NUM> configured to engage (e.g., connect with, latch against, etc.) the axle <NUM> and extend from the axle <NUM>. Each fastener <NUM> may be configured to extend at least partially through the axle <NUM> and at least partially into a sidewall of the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body <NUM>. The wheel <NUM> may extend around at least a portion of the axle <NUM>. The wheel <NUM> may comprise an outer circumferential portion <NUM> (e.g., an end, a rim, an edge, etc.) configured to contact a surface of the wellbore <NUM>, and thus facilitate rolling of the wheel <NUM> along the surface of the wellbore <NUM>. The wheel <NUM> may further comprise an inner circumferential surface <NUM> configured to contact or accommodate the outer surface <NUM> of the axle <NUM>. The inner circumferential surface <NUM> may also or instead be configured to contact a bearing (not shown) disposed between the inner circumferential surface <NUM> and the outer circumferential surface <NUM> to reduce friction between the wheel <NUM> and the axle <NUM>. The wheel <NUM> may further comprise an intermediate portion <NUM> (e.g., a cap, a cover, etc.) extending between the outer circumferential portion <NUM>. The intermediate portion <NUM> may comprise a convex or otherwise outwardly extending outer surface configured to contact (e.g., roll over) the sidewall of the wellbore <NUM>, such as when the tool string <NUM> rolls or otherwise rotates about its central longitudinal axis. The intermediate portion <NUM> may extend over and cover the outer surface <NUM> of the axle <NUM>.

<FIG>, and <FIG> are sectional side, side, and sectional axial views, respectively, of the wheel assembly <NUM> shown in <FIG> detachably connected with the body <NUM> of the tool string <NUM> shown in <FIG> according to one or more aspects of the present disclosure. Accordingly, the following description refers to <FIG>, and <FIG>, collectively.

The outer surface <NUM> of each wheel assembly <NUM> is shown disposed against (i.e., in contact with) a corresponding surface <NUM> of the body <NUM>. Each fastener <NUM> may extend into and engage a corresponding cavity <NUM> of the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body <NUM> of the tool string <NUM>. As shown in <FIG>, the cavities <NUM> may be located symmetrically with respect to a central longitudinal axis <NUM> of the body <NUM> and the tool string <NUM>, such that the wheel assemblies <NUM> connect symmetrically with respect to the central axis <NUM> and the body <NUM>. For example, the wheel assemblies <NUM> may connect with the body <NUM> such that axes of rotation <NUM> of the wheels <NUM> extend through the central axis <NUM>. Furthermore, the wheel assemblies <NUM> connected with the body <NUM> may collectively form or define an axial geometric profile having a geometric centerline <NUM>, which may coincide with the central axis <NUM> and intercept the axes of rotation <NUM> when the wheel assemblies <NUM> are connected with the body <NUM>. The geometric centerline <NUM> may be or define an axis of rotation of the body <NUM> and the wheel assemblies <NUM> connected to the body <NUM>, such as when the tool string <NUM> and the wheel assemblies <NUM> collectively roll or otherwise rotate axially within the wellbore <NUM>.

<FIG> is a sectional axial view of the wheel assemblies <NUM> shown in <FIG> detachably connected with a body <NUM> (e.g., a housing, a block, a frame, etc.) of the tool string <NUM> according to one or more aspects of the present disclosure. The body <NUM> may be or form at least a portion of a downhole tool <NUM> or another portion of the tool string <NUM> shown in <FIG>. The body <NUM> may comprise one or more features and/or modes of operation of the body <NUM> of the tool string <NUM> described above and shown in <FIG>, including where indicated by the same reference numerals. Accordingly, the following description refers to <FIG>, <FIG>, <FIG>, and <FIG>, collectively.

A sidewall (i.e., outer surface) of the body <NUM> may comprise a plurality of mounting surfaces <NUM> and a plurality of cavities <NUM>, each cavity <NUM> extending partially into the sidewall of the body <NUM> below the surface <NUM> and configured to accommodate a corresponding fastener <NUM> to facilitate detachable connection of the wheel assembly <NUM> with the body <NUM>. An outer surface <NUM> of each wheel assembly <NUM> is shown disposed against (i.e., in contact with) a corresponding surface <NUM> of the body <NUM>. The surfaces <NUM> may be or extend at an angle (e.g., diagonally and/or not parallel) with respect to each other and/or the cavities <NUM> may be located or extend asymmetrically with respect to the central axis <NUM> of the body <NUM>. Thus, the wheel assemblies <NUM> may connect asymmetrically with respect to the central axis <NUM> of the body <NUM>, and the axes of.

rotation <NUM> of each wheel <NUM> may extend at an angle (e.g., diagonally, not parallel, and/or not collinear) with respect to each other. Each fastener <NUM> is shown extending into a corresponding cavity <NUM> of the body <NUM>. Each fastener <NUM> may engage the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body <NUM>. The wheel assemblies <NUM> may connect with the body <NUM> such that axes of rotation <NUM> of the wheels <NUM> intercept at a point below the central axis <NUM> or otherwise extend through the body <NUM> below the central axis <NUM> when the body <NUM> is oriented horizontally, as shown in <FIG>. Although the axes of rotation <NUM> of the wheels <NUM> may extend and/or intercept below the central axis <NUM>, the axes of rotation <NUM> along or on the wheels <NUM>, as indicated by numerals <NUM>, may be located at the same level (i.e., vertical position) as or above the central axis <NUM>, as indicated by line <NUM>.

<FIG> is a side view of an example implementation of a body <NUM> (e.g., a housing, a block, a frame, etc.) of the tool string <NUM> according to one or more aspects of the present disclosure. <FIG> is a sectional axial view of the wheel assemblies <NUM> shown in <FIG> detachably connected with the body <NUM> according to one or more aspects of the present disclosure. The assembly of the body <NUM> and the wheel assemblies <NUM> is shown disposed within an example wellbore <NUM> through which the tool string <NUM> is conveyed. The body <NUM> may be or form at least a portion of a downhole tool <NUM> or another portion of the tool string <NUM> shown in <FIG>. The body <NUM> may comprise one or more features of the bodies <NUM>, <NUM> described above and shown in <FIG>, and <FIG>. Accordingly, the following description refers to <FIG> and <FIG>, collectively.

A sidewall (i.e., outer surface) of the body <NUM> may comprise a plurality of mounting surfaces <NUM> and a plurality of cavities <NUM>, each cavity <NUM> extending partially into the sidewall of the body <NUM> below the surface <NUM> and configured to accommodate a corresponding fastener <NUM> to facilitate detachable connection of the wheel assembly <NUM> with the body <NUM>. The cavities <NUM> may be located symmetrically with respect to (e.g., on each side of) the body <NUM> and/or the central axis <NUM> of the body <NUM> and the tool string <NUM>, such that the wheel assemblies <NUM> connect symmetrically with respect to the body <NUM> and/or the central axis <NUM>. For example, the wheel assemblies <NUM> may connect with the body <NUM> such that the axes of rotation <NUM> of the wheels <NUM> extend through or are at the same level (i.e., vertical position) as the central axis <NUM>.

The sidewall of the body <NUM> may further comprise one or more cavities <NUM> (e.g., openings, holes, bores, etc.) extending partially into the sidewall of the body <NUM> below each surface <NUM> instead of or in addition to the cavities <NUM>. Each cavity <NUM> may be configured to accommodate or otherwise facilitate detachable connection with a corresponding fastener <NUM> of the wheel assembly <NUM>. For example, each cavity <NUM> may be a threaded bore configured to threadedly engage with or otherwise receive a threaded fastener <NUM> of the wheel assembly <NUM>. The cavities <NUM> may be geometrically arranged (e.g., spaced) to align with corresponding fasteners <NUM> of the wheel assembly <NUM>. The cavities <NUM> may be located asymmetrically (e.g., eccentrically, offset from, etc.) with respect to the body <NUM> and/or the central axis <NUM>, such that each wheel assembly <NUM> connects asymmetrically with respect to the body <NUM> and/or the central axis <NUM>. Thus, when the wheel assemblies <NUM> are detachably connected with the body <NUM> via the fasteners <NUM> engaging the cavities <NUM>, the axes of rotation <NUM> of the wheels <NUM> may be located above and thus offset from the central axis <NUM> of the body <NUM> and the tool string <NUM> by an offset distance <NUM>.

The wheel assemblies <NUM> connected with the body <NUM> may collectively form or define an axial geometric profile having a geometric centerline <NUM>. The geometric centerline <NUM> may be an axis of rotation of the body <NUM> and the wheel assemblies <NUM> connected to the body <NUM>, such as when the tool string <NUM> and the wheel assemblies <NUM> collectively roll or otherwise rotate axially within the wellbore <NUM>. Because each wheel assembly <NUM> connects asymmetrically with respect to the body <NUM> and/or the central axis <NUM>, the geometric centerline <NUM> may be offset from the central axis <NUM> by the offset distance <NUM>. Accordingly, the center of mass of the body <NUM> (and the tool string <NUM>) coinciding approximately with the central axis <NUM>, may be located below the axes of rotation <NUM> of the wheels <NUM> and/or below the geometric centerline <NUM>, and thus offset from the axes of rotation <NUM> and/or the geometric centerline <NUM> by the offset distance <NUM>, when the body <NUM> is oriented horizontally as shown in <FIG>.

<FIG> is a sectional axial view of the wheel assemblies <NUM> shown in <FIG> detachably connected with a body <NUM> (e.g., a housing, a block, a frame, etc.) of the tool string <NUM> according to one or more aspects of the present disclosure. The assembly of the body <NUM> and the wheel assemblies <NUM> is shown disposed within an example wellbore <NUM> through which the assembly of the body <NUM> and the wheel assemblies <NUM> is conveyed. The body <NUM> may be or form at least a portion of a downhole tool <NUM> or another portion of the tool string <NUM> shown in <FIG>. The body <NUM> may comprise one or more features and/or modes of operation of the bodies <NUM>, <NUM>, <NUM> of the tool string <NUM> described above and shown in <FIG>, and <FIG>, including where indicated by the same reference numerals. Accordingly, the following description refers to <FIG> and <FIG>, collectively.

A sidewall (i.e., outer surface) of the body <NUM> may comprise a plurality of mounting surfaces <NUM> and a plurality of cavities <NUM>, <NUM>, each cavity <NUM>, <NUM> extending partially into the sidewall of the body <NUM> below the surface <NUM> and configured to accommodate a corresponding fastener <NUM> to facilitate detachable connection of the wheel assembly <NUM> with the body <NUM>. The outer surface <NUM> of each wheel assembly <NUM> is shown disposed against (i.e., in contact with) a corresponding surface <NUM> of the body <NUM>. The surfaces <NUM> may be or extend at an angle (e.g., diagonally, not parallel, etc.) with respect to each other and/or the cavities <NUM>, <NUM> may be located asymmetrically with respect the central axis <NUM> of the body <NUM>. Thus, the wheel assemblies <NUM> may connect asymmetrically with respect to central axis <NUM> and the body <NUM>, and the axes of rotation <NUM> of each wheel <NUM> may extend at an angle (e.g., diagonally, not parallel, not collinear, etc.) with respect to each other. Each fastener <NUM> is shown extending into a corresponding cavity <NUM> of the body <NUM>. Each fastener <NUM> may engage the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body <NUM>. The wheel assemblies <NUM> connected with the body <NUM> may collectively form or define an axial geometric profile having a geometric centerline <NUM>. The geometric centerline <NUM> may be an axis of rotation of the body <NUM> and the wheel assemblies <NUM> connected to the body <NUM>, such as when the tool string <NUM> and the wheel assemblies <NUM> collectively roll or otherwise rotate axially within the wellbore <NUM>. Connecting the wheel assemblies <NUM> to the body <NUM> via the cavities <NUM> offsets or shifts the geometric centerline <NUM> away from the central axis <NUM> of the body <NUM> by an offset distance <NUM>. Accordingly, the center of mass of the body <NUM> (and the tool string <NUM>) coinciding approximately with the central axis <NUM>, may be located below the geometric centerline <NUM>, and thus offset from the geometric centerline <NUM> by the offset distance <NUM>, when the body <NUM> is oriented horizontally as shown in <FIG>.

As shown in <FIG>, the geometric centerline <NUM> and/or the axes of rotation <NUM> may coincide with the central axis <NUM> when the wheel assemblies <NUM> are connected with the body <NUM>, <NUM> via the cavities <NUM>. However, as shown in <FIG> and <FIG>, the geometric centerline <NUM> and/or the axes of rotation <NUM> may be offset from (e.g., located above) the central axis <NUM> by an offset distance <NUM> when the wheel assemblies <NUM> are connected with a corresponding body <NUM>, <NUM> via the cavities <NUM>, <NUM>. The weight of the bodies <NUM>, <NUM> forming the tool string <NUM> may be much (e.g., several times) greater than the collective mass of the wheel assemblies <NUM> and may be represented by a downward gravitational force <NUM> (i.e., weight) applied at the center of mass (i.e., center of gravity) of the tool string <NUM>, which may substantially coincide with the central axes <NUM> of the bodies <NUM>, <NUM>. Because the mass of the tool string <NUM> is much greater than the collective mass of the wheel assemblies <NUM>, the offset <NUM> between the central axis <NUM> and the geometric centerline <NUM> and/or the axes of rotation <NUM> create a mechanical instability of the assembly of the tool string <NUM> and the wheel assemblies <NUM> when the center of mass of the tool string <NUM> and thus the central axis <NUM> is not located directly below the geometric centerline <NUM> and/or the axes of rotation <NUM>. Such mechanical instability can result in the gravitational force <NUM> (i.e., weight of the tool string <NUM>) causing a torque <NUM> about the geometric centerline <NUM> that urges rotation of the tool string <NUM> and wheel assemblies <NUM> toward a mechanically stable orientation in which the central axis <NUM> is located directly below the geometric centerline <NUM> and/or the axes of rotation <NUM>. The torque <NUM> and, thus, the tendency of the tool string <NUM> and wheel assemblies <NUM> to rotate (or roll) within the wellbore <NUM> about the geometric centerline <NUM> may be directly proportional to the offset distance <NUM> between the central axis <NUM> and the geometric centerline <NUM> and/or the axes of rotation <NUM>.

Accordingly, when the assembly of the tool string <NUM> and wheel assemblies <NUM> is oriented in its intended and most stable position within the wellbore <NUM>, the central axis <NUM> is located directly below geometric centerline <NUM> at its lowermost position (i.e., closest to a lower side of the wellbore <NUM>), as shown in <FIG> and <FIG>, and/or the axes of rotation <NUM> or the line <NUM> extend horizontally above the central axis <NUM>, as shown in <FIG> and <FIG>. However, during downhole conveyance, when the assembly of the tool string <NUM> and wheel assemblies <NUM> is not oriented in a mechanically stable position within the wellbore <NUM>, the gravitational force <NUM> applied at the central axis <NUM> may cause a torque <NUM> about the geometric centerline <NUM> urging rotation of the assembly of the tool string <NUM> and wheel assemblies <NUM> toward the most stable position.

The present disclosure is further directed to wheel assemblies comprising axles and wheels having different relative dimensions (e.g., diameter, length, width, etc.), which may be selected based on job type and/or wellbore specifications. <FIG> is a sectional axial view of a body <NUM> of a tool string <NUM> described above and shown in <FIG>, and a plurality of wheel assemblies <NUM>, <NUM>, <NUM>, each configured to be detachably connected with the body <NUM>. The wheel assemblies <NUM>, <NUM> may each comprise one or more features of the wheel assembly <NUM> as described above and shown in <FIG>. Accordingly, the following description refers to <FIG>, and <FIG>, collectively.

The wheel assembly <NUM> may be detachably connected with the body <NUM> of the tool string <NUM> via fasteners <NUM> engaging corresponding cavities <NUM>, as described above. The wheel assembly <NUM> may be similarly detachably connected with the body <NUM> of the tool string <NUM> via fasteners <NUM> engaging corresponding cavities <NUM>. However, the wheel assembly <NUM> may comprise a wheel <NUM> having an outer diameter that is substantially greater than an outer diameter of the wheel <NUM> of the wheel assembly <NUM>. Thus, when the body <NUM> is oriented horizontally, the wheel assembly <NUM> may increase vertical height of an assembly comprising the body <NUM> and the wheel assemblies <NUM>, but not increase horizontal width of the assembly comprising the body <NUM> and the wheel assemblies <NUM>. The wheel assembly <NUM> may be detachably connected with the body <NUM> of the tool string <NUM> via fasteners <NUM> extending through an axle <NUM> and engaging corresponding cavities <NUM>. The axle <NUM> may be substantially longer than the axles <NUM> of the wheel assemblies <NUM>, <NUM>. The wheel assembly <NUM> may comprise a wheel <NUM> having an outer diameter that is substantially greater than an outer diameter of the wheel <NUM> of the wheel assembly <NUM>. Thus, when the body <NUM> is oriented horizontally, the wheel assembly <NUM> may further increase vertical height of an assembly comprising the body <NUM> and the wheel assemblies <NUM>, and increase horizontal width of the assembly comprising the body <NUM> and the wheel assemblies <NUM>. The axle <NUM> may offset the wheel <NUM> further away from the body <NUM>, such that the wheel <NUM> clears the transition shoulder <NUM> between the recessed mounting surface <NUM> and a larger diameter portion of the body <NUM> to prevent the wheel <NUM> from contacting the body <NUM>.

Before conveying the tool string <NUM> downhole, wellsite personnel (e.g., a field engineer) may select a set of one of the wheel assemblies <NUM>, <NUM>, <NUM> for connection with the body <NUM> or another body <NUM>, <NUM>, <NUM> within the scope of the present disclosure, based on one or more factors, such as downhole operation (i.e., job) type and wellbore specifications (e.g., inclination, inner diameter, depth, etc.), among other examples. Furthermore, the wheel assemblies connected to the tool string <NUM> may be changed during a job or between jobs. For example, if the tool string <NUM> is not successfully conveyed downhole to an intended depth, the tool string <NUM> may be retrieved to the wellsite surface and one or more of the wheel assemblies may be disconnected and replaced with different wheel assemblies having different dimensions or other specifications. Also, if a job requires conveyance of the tool string <NUM> through different portions of the wellbore <NUM> and each portion has different specifications, the tool string <NUM> may be conveyed within a first portion of the wellbore <NUM> via a first set of wheel assemblies to perform the downhole operations. The tool string <NUM> may then be retrieved to the wellsite surface <NUM> and the wheel assemblies may be disconnected and replaced with a second set of wheel assemblies having different dimensions or other specifications. The tool string <NUM> may then be conveyed within a second portion of the wellbore <NUM> via the second set of wheel assemblies to perform the downhole operations.

<FIG> is a perspective view of an example implementation of a wheel assembly <NUM> according to one or more aspects of the present disclosure. <FIG> is a perspective view of a different side of the wheel assembly shown in <FIG> is a side view of the wheel assembly <NUM> shown in <FIG>. <FIG> is an exploded view of the wheel assembly <NUM> shown in <FIG>. The wheel assembly <NUM> may comprise one or more features and/or modes of operation of the wheel assemblies <NUM>, <NUM> described above and shown in <FIG>, <FIG>. The wheel assembly <NUM> may be detachably connectable with the bodies <NUM>, <NUM>, <NUM>, <NUM> of the tool string <NUM> shown in <FIG>, and <FIG>. The following description refers to <FIG> and <FIG>, collectively.

The wheel assembly <NUM> may be operable to reduce friction between a tool string <NUM> and a sidewall (i.e., inner surface) of a wellbore <NUM> to facilitate downhole conveyance of the tool string <NUM>. The wheel assembly <NUM> may comprise an axle <NUM> detachably connectable to a body <NUM> (or another body <NUM>, <NUM>, <NUM> shown in <FIG>) of the tool string <NUM> and a wheel <NUM> rotatably connected with the axle <NUM>. At least a portion of the axle <NUM> may have a cylindrical geometry, comprising opposing outer surfaces <NUM>, <NUM> (e.g., faces, planes, etc.) and an outer circumferential surface <NUM> extending between the outer surfaces <NUM>, <NUM>. The outer surface <NUM> may be configured to abut or contact a sidewall (i.e., an outer surface) of the body <NUM>, such as a mounting surface <NUM>. The outer circumferential surface <NUM> may comprise an outer circumferential groove <NUM> (e.g., a channel, a track, etc.). The wheel assembly <NUM> may further comprise one or more fasteners <NUM> configured to engage (e.g., connect to, latch against, etc.) the axle <NUM> and extend from the axle <NUM>. Each fastener <NUM> may be configured to extend at least partially through the axle <NUM> and at least partially into the sidewall of the body <NUM> to detachably connect the axle <NUM>, and thus the wheel assembly <NUM>, to the body. Each fastener <NUM> may be configured to extend into a corresponding cavity <NUM> (or another cavity <NUM> shown in <FIG>) and engage the body <NUM> of the tool string <NUM> to detachably connect the axle <NUM> to the body <NUM>. The axle <NUM> may comprise a plurality of bores <NUM> (e.g., passages), each extending axially though the axle <NUM> between the opposing outer surfaces <NUM>, <NUM> and configured to receive a corresponding fastener <NUM>. The axle <NUM> may comprise a shoulder <NUM> (i.e., a surface transitioning between a larger diameter portion of the bore <NUM> and a smaller diameter portions of the bore <NUM>) along each bore <NUM> configured to engage (e.g., contact, latch against, etc.) a corresponding fastener <NUM>. Each fastener <NUM> may comprise a head <NUM> or another feature having a shoulder configured to engage (i.e., contact) a corresponding shoulder <NUM> along the bore <NUM> of the axle <NUM>. Each fastener <NUM> may further comprise a shank <NUM> configured to extend out of a corresponding bore <NUM> and into a corresponding cavity <NUM> of the body <NUM> to engage the body <NUM>, and thus connect the axle <NUM> to the body <NUM>. The shank <NUM> of each fastener <NUM> and each cavity <NUM> may be threaded, facilitating threaded engagement between each fastener <NUM> and a corresponding cavity <NUM> to detachably connect the axle <NUM> to the body <NUM> of the tool string <NUM>. Although the axle <NUM> is shown comprising four bores <NUM> arranged in a rectangular pattern, it is to be understood that the axle <NUM> may comprise one, two, three, five, six, or more bores <NUM> arranged in other patterns.

The wheel <NUM> may extend around at least a portion of the axle <NUM>. The wheel <NUM> may comprise an outer circumferential portion <NUM> (e.g., an end, a rim, an edge) configured to contact a sidewall of the wellbore <NUM>, and thus help or facilitate rolling of the wheel <NUM> along the sidewall of the wellbore <NUM>. The wheel <NUM> may further comprise an inner circumferential surface <NUM> comprising an inner circumferential groove <NUM> (e.g., a channel, a track, etc.). The outer circumferential groove <NUM> of the axle <NUM> and the inner circumferential groove <NUM> of the wheel <NUM> may collectively form or otherwise define a circumferential space <NUM> (shown in <FIG>) (e.g., a ring or annular shaped space or gap) between the axle <NUM> and the wheel <NUM>. The wheel <NUM> may further comprise an intermediate portion <NUM> (e.g., a cap, a cover) extending between the outer circumferential portion <NUM>. The intermediate portion <NUM> may comprise a convex or otherwise outwardly extending outer surface configured to contact the sidewall of the wellbore <NUM>, such as when the tool string <NUM> and the wheel assemblies <NUM> collectively roll or otherwise rotate about a longitudinal axis (e.g., the geometric centerline <NUM> shown in <FIG>, <FIG>, and <FIG>) of the tool string <NUM> within the wellbore <NUM>. The intermediate portion <NUM> may cover an end of the axle <NUM>, such as the outer surface <NUM> of the axle <NUM>. The wheel <NUM> may comprise a bore <NUM> (e.g., a passage) extending through the intermediate portion <NUM>. The bore <NUM> may be offset from an axis of rotation <NUM> of the wheel <NUM>. The bore <NUM> may be aligned with each of the bores <NUM> and each of the fasteners <NUM> (if located within a corresponding bore <NUM>), one at a time, by rotating the wheel <NUM> with respect to the axle <NUM>. A fill plug <NUM> may be inserted into the bore <NUM> to permit injection and/or retention of grease or another lubricant within the space between the axle <NUM> and the wheel <NUM> to reduce friction between the axle <NUM> and the wheel <NUM>.

The wheel assembly <NUM> may further comprise a plurality of ball bearings <NUM> disposed within the circumferential space <NUM>. The ball bearings <NUM> may be configured to reduce friction between the axle <NUM> and the wheel <NUM>. The ball bearings <NUM> may also connect or lock the wheel <NUM> to the axle <NUM>. For example, the ball bearings <NUM> disposed within the circumferential space <NUM> may contact and bear against opposing sidewalls or shoulders of the circumferential grooves <NUM>, <NUM> to latch the wheel <NUM> to the axle <NUM>, thereby preventing the wheel <NUM> from separating from the axle <NUM>.

The axle <NUM> may further comprise a passage <NUM> (e.g., a channel, a bore, a space, etc.) extending through or along the axle <NUM> between the outer surface <NUM> and the circumferential outer surface <NUM> (along the circumferential outer groove <NUM>). The passage <NUM> may thus connect with or intercept the circumferential space <NUM>. Accordingly, the passage <NUM> may connect the space external to the outer surface <NUM> and the circumferential space <NUM>, thereby forming a pathway between the space external to the outer surface <NUM> and the circumferential space <NUM>. The passage <NUM> may also or instead extend through or along the axle <NUM> between the outer surface <NUM> and the circumferential outer surface <NUM> (along the circumferential outer groove <NUM>). Accordingly, the passage <NUM> may connect the space external to the outer surface <NUM> and the circumferential space <NUM>, thereby forming a pathway between the space external to the outer surface <NUM> and the circumferential space <NUM>. The passage <NUM> may extend radially through or along the axle <NUM>, such as perpendicularly or otherwise laterally with respect to a central axis of the axle <NUM>. The passage <NUM> may connect with or intercept the outer circumferential groove <NUM> and the circumferential space <NUM> at a substantially right angle. For example, the passage <NUM> may connect with or intercept the outer circumferential groove <NUM> and the circumferential space <NUM> at an angle ranging between about <NUM> degrees and about <NUM> degrees, at an angle ranging between about <NUM> degrees and about <NUM> degrees, at an angle ranging between about <NUM> degrees and about <NUM> degrees, or at an angle ranging between about <NUM> degrees and about <NUM> degrees. The passage <NUM> may connect with or intercept the outer circumferential groove <NUM> and the circumferential space <NUM> at a right angle (i.e., at an angle of <NUM> degrees). The passage <NUM> may also extend axially through the axle <NUM> between the opposing outer surfaces <NUM>, <NUM>. However, the passage <NUM> may extend axially into the outer surface <NUM> of the axle <NUM> without extending axially through the axle <NUM> between the opposing outer surfaces <NUM>, <NUM>. The axle <NUM> may further comprise a retaining feature <NUM> extending longitudinally along the passage <NUM>. For example, the retaining feature <NUM> may be or comprise a groove (e.g., a track) extending longitudinally along the passage <NUM> or a protrusion (e.g., a rail, a lip, etc.) extending longitudinally along the passage <NUM>. The axle <NUM> may further comprise a cavity <NUM> extending axially (i.e., parallel with respect to the central axis of the axle <NUM>) into the outer surface <NUM> (or the outer surface <NUM>) of the axle <NUM> below the outer surface <NUM>. The cavity <NUM> may have a larger inner diameter than a width of the passage <NUM>. The cavity <NUM> may be located along or otherwise intercept the passage <NUM>.

The wheel assembly <NUM> may further comprise a blocking member <NUM> (e.g., a plug, a stopper, etc.) disposed within the passage <NUM>. The blocking member <NUM> may be movable (e.g., slidable) within the passage <NUM> between a first position in which the ball bearings <NUM> can be inserted into the circumferential space <NUM> via the passage <NUM> and a second position in which the blocking member <NUM> prevents the ball bearings <NUM> from exiting the circumferential space <NUM> via the passage <NUM>. The blocking member <NUM> may comprise a retaining feature <NUM> extending longitudinally along the blocking member <NUM> and configured to engage the retaining feature <NUM> of the axle <NUM>. While engaged, the retaining features <NUM>, <NUM> may permit the blocking member <NUM> to move (e.g., slide) along the passage <NUM> and to retain the blocking member <NUM> within the passage <NUM> or otherwise prevent the blocking member <NUM> from moving out of the passage <NUM>. The retaining feature <NUM> may be or comprise a groove (e.g., a track) extending longitudinally along the blocking member <NUM> or a protrusion (e.g., a rail, a lip, etc.) extending longitudinally along the blocking member <NUM>. The blocking member <NUM> may form a portion of the outer circumferential groove <NUM> of the axle <NUM> when the blocking member <NUM> is in the second position, as shown in <FIG>. For example, the blocking member <NUM> may comprise a groove <NUM> (e.g., a track) forming a portion of the outer circumferential groove <NUM> of the axle <NUM>, and thus defining a portion of the circumferential space <NUM>, when the blocking member <NUM> is in its second position. The blocking member <NUM> may further comprise a bore <NUM> extending into or through the blocking member <NUM>. The bore <NUM> may be or comprise a threaded bore.

Although the retaining feature <NUM> is shown extending the entire length of the passage <NUM>, the retaining feature <NUM> may not necessarily extend the entire length of the passage <NUM>. For example, the retaining feature <NUM> may extend along a radially outward portion (i.e., closer to the surface <NUM>) of the passage <NUM>, but not along a radially inward portion (i.e., closer to the central axis of the axle <NUM>) of the passage <NUM>. Such configuration may permit the blocking member <NUM> to be retained within the passage <NUM> when the blocking member <NUM> is in its second position and permit the blocking member <NUM> to be removed from the passage <NUM> when the blocking member <NUM> is in its first position.

The wheel assembly <NUM> may further comprise a fastener <NUM> configured to engage the axle <NUM> and the blocking member <NUM> to fixedly connect the blocking member <NUM> in its second position within the passage <NUM>. The fastener <NUM> may be disposed within the cavity <NUM> of the axle <NUM> and extend into the bore <NUM> of the blocking member <NUM> to fixedly connect the blocking member <NUM> in its second position within the passage <NUM>. The fastener <NUM> may comprise a head <NUM> and a shank <NUM>. The shank <NUM> can be inserted into the bore <NUM> to engage (i.e., connect) the fastener <NUM> to the retaining member <NUM> and the head <NUM> can be inserted into the cavity <NUM> to engage (i.e., connect or latch) the fastener <NUM> to the axle <NUM>. The sidewalls of the cavity <NUM> may bear against or otherwise contact the head <NUM> to prevent the fastener <NUM>, and thus the blocking member <NUM>, from moving along the passage <NUM> or otherwise with respect to the axle <NUM>, thereby fixedly connecting the blocking member <NUM> in the second position within the passage <NUM>. The shank <NUM> may be a threaded shank and the bore <NUM> may be a threaded bore. Accordingly, the fastener <NUM> may be fixedly connected to the blocking member <NUM> when the blocking member <NUM> is the second position within the passage <NUM> by threadedly engaging the shank <NUM> with the bore <NUM>.

The present disclosure is further directed to methods (e.g., operations, processes) of assembling (e.g., putting together, constructing, etc.) a wheel assembly, such as the wheel assembly <NUM> shown in <FIG>, according to one or more aspects of the present disclosure. <FIG> are side views of the wheel assembly <NUM> during different stages of assembly operations. <FIG> is a sectional view of the wheel assembly <NUM> shown in <FIG>. <FIG> is a perspective view of the wheel assembly shown in <FIG> in still another stage of assembly operations. Accordingly, the following description refers to <FIG>, collectively.

A method of assembling the wheel assembly <NUM> may comprise disposing the wheel <NUM> around the axle <NUM> to form the circumferential space <NUM> between the wheel <NUM> and the axle <NUM>. As shown in <FIG>, the blocking member <NUM> may be moved (e.g., slid) along the passage <NUM> in a radially inward direction with respect to the axle <NUM>, as indicated by arrow <NUM>, to its first position in which the blocking member <NUM> is located at a radially inward end of the passage <NUM> (i.e., at a radially inward position with respect to the axle <NUM>), thereby opening (i.e., unblocking) the passage <NUM> such that the ball bearings <NUM> can be inserted into the circumferential space <NUM> via the passage <NUM>, as indicated by arrow <NUM>. Moving the blocking member <NUM> along the passage <NUM> may comprise sliding the blocking member <NUM> along the retaining feature <NUM> of the axle <NUM> while the retaining feature <NUM> is engaged with the retaining feature <NUM> of the blocking member <NUM> to retain the blocking member <NUM> within the passage <NUM>. If the axle <NUM> does not comprise the retaining feature <NUM> at the first position of the blocking member <NUM>, the blocking member <NUM> may be removed from the passage <NUM>. When the blocking member <NUM> is removed from the passage <NUM> or is in the first position within the passage <NUM>, the ball bearings <NUM> may be inserted into the passage <NUM> and moved into the circumferential space <NUM> via the passage <NUM>, as indicated by arrow <NUM>.

As shown in <FIG> and <FIG>, after all the ball bearings <NUM> are inserted into the circumferential space <NUM>, the blocking member <NUM> may be moved (e.g., slid) along the passage <NUM> in a radially outward direction with respect to the axle <NUM>, as indicated by arrow <NUM>, to its second position in which the blocking member <NUM> is at a radially outward position with respect to the axle <NUM> in which the blocking member <NUM> is located at a radially outward end of the passage <NUM> to close off (i.e., block) the passage <NUM> from the circumferential space <NUM> thereby preventing the ball bearings <NUM> from exiting the circumferential space <NUM> via the passage <NUM>. The ball bearings <NUM> may reduce friction between the axle <NUM> and the wheel <NUM> and prevent separation of the wheel <NUM> from the axle <NUM>, thereby connecting the wheel <NUM> to the axle <NUM>.

As shown in <FIG> and <FIG>, when the blocking member <NUM> is moved to the second position along the passage <NUM>, the blocking member <NUM> may then be fixedly connected or otherwise fastened to the axle <NUM> with the fastener <NUM>, such as by inserting the fastener <NUM> at least partially into, through, or between the axle <NUM> and the blocking member <NUM>. For example, the blocking member <NUM> may be fastened to the axle <NUM> with the fastener <NUM> by inserting the head <NUM> of the fastener <NUM> into the cavity <NUM> extending into the axle <NUM> along the passage <NUM> while inserting the shank <NUM> of the fastener <NUM> into the bore <NUM> of the blocking member <NUM>. If the shank <NUM> and bore <NUM> are threaded, the threaded shank <NUM> may be threadedly engaged with the threaded bore <NUM> to fixedly connect the fastener <NUM> with the blocking member <NUM>. The head <NUM> engages (i.e., latches against or contacts) the axle (i.e., sidewalls of the cavity <NUM>) to prevent the fastener <NUM> and thus the blocking member <NUM> from moving from it second position. Accordingly, the fastener <NUM> may engage both the blocking member <NUM> and the axle <NUM> when the blocking member <NUM> is in its second position to prevent the blocking member <NUM> from moving along the passage from its second position to its first position. Furthermore, the blocking member <NUM> may comprise a groove <NUM> (e.g., a track) forming a portion of the outer circumferential groove <NUM> of the axle <NUM> when the blocking member <NUM> is in its second position. It is noted that <FIG> shows the wheel assembly <NUM> without the wheel <NUM> and ball bearings <NUM> to more clearly show the axle <NUM> and the blocking member <NUM> while in its second position.

The present disclosure is further directed to methods (e.g., operations, processes) of detachably connecting (e.g., coupling, fastening) a wheel assembly, such as the wheel assembly <NUM> shown in <FIG>, to a sidewall (i.e., outer surface) of a downhole tool of a downhole tool string to reduce friction between the downhole tool and a sidewall (i.e., inner surface) of a wellbore to facilitate downhole conveyance of the downhole tool. <FIG> is a perspective sectional view of the wheel assembly <NUM> detachably connected with a body <NUM> of a downhole tool of a downhole tool string <NUM>. The tool string <NUM> may comprise one or more features and/or modes of operation of the tool strings <NUM>, <NUM> described above and shown in <FIG> and <FIG>. The body <NUM> may comprise one or more features of the bodies <NUM>, <NUM>, <NUM>, <NUM> described above and shown in <FIG>, <FIG>, <FIG>, and <FIG>.

An example method may include positioning the wheel assembly <NUM> against a sidewall of the body <NUM> of the tool string <NUM>. For example, the surface <NUM> of the axle <NUM> of the wheel assembly <NUM> may be disposed against or otherwise in contact with a corresponding mounting surface <NUM> of the body <NUM>, such that each of the bores <NUM> of the axle <NUM> is aligned with a corresponding one of the threaded bores <NUM> extending into the sidewall of the body <NUM> along the surface <NUM>. Thereafter, the fasteners <NUM> may be inserted at least partially through the axle <NUM> and inserted at least partially into the sidewall of the body <NUM> to connect the wheel assembly <NUM> to the body <NUM>. For example, the wheel <NUM> may be rotated about the axis of rotation <NUM>, as indicated by arrow <NUM>, to align the bore <NUM> extending through the cap <NUM> of the wheel <NUM> with a selected one of the bores <NUM> of the axle <NUM>. One of the fasteners <NUM> may then be inserted into the selected one of the bores <NUM> through the bore <NUM>, as indicated by arrow <NUM>, and positioned against the threaded bore <NUM> of the body <NUM>. A torqueing tool (e.g., a hand wrench, an automated torqueing tool) (not shown) may then be inserted into the bore <NUM> through the bore <NUM> and engaged with the head <NUM> of the fastener <NUM>. The torqueing tool may then be operated to rotate the fastener <NUM> to threadedly engage the fastener <NUM> within the threaded bore <NUM> until the shoulder of the head <NUM> of the fastener <NUM> contacts the shoulder <NUM> of the axle <NUM>. The wheel <NUM> may be rotated further to align the bore <NUM> extending through the cap <NUM> of the wheel <NUM> with another one of the bores <NUM> of the axle <NUM>. Another one of the fasteners <NUM> may then be inserted into the bore <NUM> through the bore <NUM> and threadedly engaged within the threaded bore <NUM>. The above process may be repeated until every fastener <NUM> is threadedly engaged with the body <NUM> to connect the axle <NUM> to the body <NUM>. The fill plug <NUM> may be inserted into the bore <NUM> and grease or another lubricant may then be injected into the space between the axle <NUM> and the wheel <NUM>, including the circumferential space <NUM>, to lubricate the ball bearings <NUM> and various surfaces of the axle <NUM> and the wheel <NUM>.

In view of the entirety of the present disclosure, a person having ordinary skill in the art will readily recognize that the present disclosure introduces an apparatus comprising a wheel assembly configured to detachably connect to a downhole tool to thereby reduce friction between the downhole tool and a sidewall of a wellbore through which the downhole tool is conveyed, wherein the wheel assembly comprises: an axle configured to contact a sidewall of the downhole tool; a wheel rotatably connected with the axle; and a fastener configured to extend into the sidewall of the downhole tool to detachably connect the axle to the downhole tool.

The fastener may extend through at least a portion of the axle and out of the axle.

The fastener may be or comprise a threaded bolt.

The fastener may be or comprise a threaded fastener extending through at least a portion of the axle and out of the axle, and the fastener may be configured to threadedly engage a threaded bore extending into the sidewall of the downhole tool to detachably connect the axle to the downhole tool.

The axle may comprise a first bore extending therethrough, the fastener may be disposed within and extend out of the first bore, the wheel may comprise a second bore configured to accommodate the fastener therethrough, and rotating the wheel with respect to the axle may move the second bore into and out of alignment with the first bore. The first bore may be one of a plurality of first bores, the fastener may be one of a plurality of fasteners, and rotating the wheel with respect to the axle may move the second bore one at a time into alignment with each of the first bores. Each of the first bore and the second bore may be offset from an axis of rotation of the wheel.

The apparatus may further comprise the downhole tool, the fastener may be one of a plurality of fasteners, the downhole tool may comprise a plurality of threaded bores extending into the sidewall of the downhole tool, and each fastener may threadedly engage a corresponding threaded bore to detachably connect the axle to the downhole tool.

The wheel assembly may be one of a plurality of wheel assemblies, and when the wheel assemblies are detachably connected with the downhole tool: the wheel assemblies may collectively define an axial profile having an axis of rotation; and the axis of rotation may be offset from a central axis of the downhole tool.

The wheel assembly may be one of a plurality of wheel assemblies, each wheel may rotate about an axis of rotation, and, when the wheel assemblies are detachably connected with the downhole tool, the axes of rotation may be offset from a central axis of the downhole tool.

The apparatus may further comprise the downhole tool, the fastener may be one of a plurality of fasteners, the downhole tool may comprise a plurality of mounting bores extending into the sidewall of the downhole tool, the mounting bores may be located asymmetrically with respect to a central axis of the downhole tool, and each fastener may engage a corresponding mounting bore to detachably connect the wheel assembly to the downhole tool.

The present disclosure also introduces a method comprising connecting a wheel assembly to a downhole tool to reduce friction between the downhole tool and a sidewall of a wellbore through which the downhole tool is conveyed, wherein the wheel assembly comprises an axle and a wheel rotatably connected with the axle, and wherein connecting the wheel assembly to the downhole tool comprises inserting a fastener at least partially into a sidewall of the downhole tool to connect the axle to the downhole tool.

The fastener may be a threaded fastener and inserting the fastener at least partially into the sidewall of the downhole tool may comprise threadedly engaging the fastener within a threaded bore extending into the sidewall of the downhole tool to connect the axle to the downhole tool.

The fastener may be a threaded fastener, the downhole tool may comprise a threaded bore extending into the sidewall of the downhole tool, the axle may comprise a bore extending therethrough, the wheel may comprise a bore extending therethrough, the bore of the axle and the bore of the wheel may be offset from an axis of rotation of the wheel, and connecting the wheel assembly to the downhole tool may further comprise: disposing the axle against the sidewall of the downhole tool such that the bore of the axle is aligned with the threaded bore; rotating the wheel with respect to the axle to align the bore of the wheel with the bore of the axle; inserting the fastener into the threaded bore through the bore of the axle and the bore of the wheel; and threadedly engaging the fastener within the threaded bore to connect the axle to the downhole tool.

Connecting the wheel assembly to the downhole tool may further comprise, before inserting the fastener at least partially into the sidewall of the downhole tool, inserting the fastener at least partially through the axle.

The fastener may be a threaded fastener, the downhole tool may comprise a threaded bore extending into the sidewall of the downhole tool, the axle may comprise a bore extending therethrough, and connecting the wheel assembly to the downhole tool may further comprise: disposing the axle against the sidewall of the downhole tool such that the bore of the axle is aligned with the threaded bore; inserting the fastener into the threaded bore through the bore of the axle; and threadedly engaging the fastener within the threaded bore to connect the axle to the downhole tool.

The present disclosure also introduces an apparatus comprising a wheel assembly for a downhole tool, wherein the wheel assembly is operable to reduce friction between the downhole tool and a sidewall of a wellbore through which the downhole tool is conveyed, and wherein the wheel assembly comprises: an axle comprising an outer circumferential groove and a passage extending though the axle; a wheel disposed around the axle and comprising an inner circumferential groove, wherein the outer circumferential groove and the inner circumferential groove collectively define a circumferential space between the axle and the wheel, and wherein the passage intersects the circumferential space; a plurality of ball bearings disposed within the circumferential space and configured to reduce friction between the axle and the wheel; and a blocking member disposed within the passage, wherein the blocking member is movable within the passage between a first position in which the ball bearings can be inserted into the circumferential space via the passage and a second position in which the blocking member prevents the ball bearings from exiting the circumferential space via the passage.

The passage may extend laterally through the axle.

The passage may intersect with the outer circumferential groove at an angle ranging between about <NUM> and <NUM> degrees.

The first position may be a radially inward position of the blocking member with respect to the axle, and the second position may be a radially outward position of the blocking member with respect to the axle.

The blocking member may comprise a groove forming a portion of the outer circumferential groove of the axle when the blocking member is in the second position.

The axle may further comprise a first retaining feature extending along the passage, the blocking member may comprise a second retaining feature, and the first retaining feature and the second retaining feature may engage to retain the blocking member within the passage while permitting the blocking member to move along the passage between the first position and second position. The wheel assembly may further comprise a fastener connected to the blocking member when the blocking member is in the second position, and the fastener may engage the axle to prevent the blocking member from moving along the passage from the second position to the first position.

The wheel assembly may further comprise a fastener engaging both the blocking member and the axle when the blocking member is in the second position to prevent the blocking member from moving along the passage from the second position to the first position. The fastener may be a threaded fastener comprising a head and a threaded shank, and the threaded shank may threadedly engage the blocking member and the head may contact the axle to prevent the blocking member from moving along the passage from the second position to the first position.

The present disclosure also introduces a method comprising assembling a wheel assembly (e.g., operable to reduce friction between a downhole tool and a surface of a wellbore to facilitate downhole conveyance of the downhole tool), wherein assembling the wheel assembly comprises: disposing a wheel around an axle to form a circumferential (e.g., substantially torus-shaped or otherwise toroidal) space between the wheel and the axle, wherein a passage extends through the axle and connects with the circumferential space; inserting ball bearings into the circumferential space via the passage; moving a plug along the passage to an end of the passage to close off the circumferential space from the passage to prevent the ball bearings from exiting the circumferential space via the passage; and fastening the plug to the axle with a fastener.

The wheel assembly may further comprise a fastener, and the method may further comprise inserting the fastener at least partially into a sidewall of the downhole tool to connect the wheel assembly to the downhole tool.

The ball bearings may reduce friction between the axle and the wheel and prevent separation of the wheel from the axle.

Moving the plug along the passage may comprise sliding the plug along the passage from a first position in which the ball bearings can be inserted into the circumferential space via the passage and a second position in which the plug is located at the end of the passage.

Moving the plug along the passage may comprise sliding the plug along the passage from a radially inward position with respect to the axle in which the ball bearings can be inserted into the circumferential space via the passage to a radially outward position with respect to the axle in which the plug is located at the end of the passage.

The axle may further comprise a retaining feature extending along the passage, and moving the plug along the passage may comprise sliding the plug along the retaining feature to retain the plug within the passage while sliding the plug along the passage.

Fastening the plug to the axle with the fastener may comprise inserting the fastener at least partially through the plug and the axle.

Fastening the plug to the axle with the fastener may comprise: inserting a head of the fastener into a cavity extending into the axle and intersecting the passage; and while the head is in the cavity, threadedly engaging a threaded shank of the fastener with a threaded bore extending into the plug.

The axle may further comprise: a circumferential outer surface comprising the outer circumferential groove; and an outer face surface configured to be disposed against the downhole tool, wherein the passage may extend through the axle between the outer face surface and the circumferential outer surface.

Claim 1:
An apparatus comprising:
a wheel assembly (<NUM>) configured to connect to a downhole tool (<NUM>) to thereby reduce friction between the downhole tool and a sidewall of a wellbore (<NUM>) through which the downhole tool is conveyed, characterized in that the wheel assembly comprises:
an axle (<NUM>) comprising:
a first face (<NUM>);
a second face (<NUM>);
a circumferential surface (<NUM>) between the first face and the second face; and
a bore (<NUM>) extending through the axle between the first face and the second face;
a wheel (<NUM>) rotatably connected with the axle, wherein the wheel is disposed around the circumferential surface; and
a threaded fastener (<NUM>) configured to:
be disposed at least partially within the bore and extend out of the bore past the first face; and
threadedly engage a threaded bore (<NUM>) extending into a sidewall of the downhole tool to connect the axle to the downhole tool to thereby connect the wheel assembly to the downhole tool.