Patent Publication Number: US-2023137244-A1

Title: Downhole tractor with wheel assembly

Description:
BACKGROUND 
     This section is intended to provide relevant background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, these statements are to be read in this light and not as admissions of prior art. 
     In well bores that include horizontal sections and horizontal landing sections, logging tools, perforating devices, bridge plugs, and other well interventions tools need to be connected to a downhole tractor so that the tool or device can be transported to a location in the wellbore. The range of a tractor and the amount of payload that can be conveyed are determined by the tractor&#39;s ability to provide sufficient traction between the wheels and a wall of the wellbore. The higher the traction, the longer the range and the larger amount of payload will be. Often, the traction for open hole wellbore applications is low due to the presence of debris such as mud, sand, metal chips, etc. within the wellbore. As the wheels of the tractor rotate, debris will accumulate and adhere to the wheel surfaces. This will reduce the grip capability of the wheels and the traction will drop significantly 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the downhole tractor with wheel assembly are described with reference to the following figures. The same or sequentially similar numbers are used throughout the figures to reference like features and components. The features depicted in the figures are not necessarily shown to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form, and some details of elements may not be shown in the interest of clarity and conciseness. 
         FIG.  1    is an illustration of a wellsite and control system utilizing a downhole tractor; 
         FIGS.  2 A and  2 B  are illustrations of tractor wheel assemblies of the downhole tractor; and 
         FIGS.  3 A- 3 D  are illustrations of a tractor wheel of the tractor wheel assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates, in general, to downhole tractors used in wellbores and, in particular, to downhole tractors and tractor wheels. 
     The systems, devices, and methods presented herein maintain traction of downhole tractors to achieve a longer tractoring distance and an increased payload capacity when used for running tools or devices downhole into a well bore. These systems, devices, and methods describe a tractor wheel having a wheel tooth geometry that enhances traction with casing wall to propel the tractor. The traction of the tractor wheels is complemented by the actuation of an actuator or actuators that control the position of the tractor wheels. In wellbore applications, the tractor may be employed to convey equipment along an open wellbore, along the interior of a casing, and/or along the interior of another tubular structure. 
     The wheels of the tractor include a plurality of teeth on the circumference. Arced grooves that are parallel to the wheel axis are made in between adjacent teeth. Each tooth includes an outer face including face grooves on each side of the outer face and that extend less than across the wheel. Conveyance is achieved when the wheels rotate and push against the wellbore. The contact force from the wellbore will channel debris in the wellbore out from the wheel via the grooves and the face grooves. This will prevent the accumulation of debris over the wheel surfaces and increase the tractoring distance and the payload capacity of the tractor. In addition, the teeth outer faces enable a low contact stress between the wheel and wellbore wall. The low contact stress ensures that the wheel will grip onto the formation without damaging the formation. 
     In certain embodiments, the wheel may comprise an outer diameter of about 2 inches (about 50 mm) to about 3.5 inches (about 90 mm), or about 2 inches (about 50 mm) to about 3 inches (about 75 mm), or about 3 inches (about 75 mm) to about 3.5 inches (about 90 mm), and/or any value or range of values therein. The wheel may be of any suitable width for a given application. Suitable wheel widths may include, but are not limited to, about 0.125 inches (about 3 mm) to about 0.75 inches (about 19 mm), or about 0.125 inches (about 3 mm) to about 0.5 inches (about 13 mm), or about 0.5 inches (about 13 mm) to about 0.75 inches (about 19 mm), and/or any value or value of ranges therein. The wheel may comprise a substrate and tread. 
     Any suitable substrate capable of withstanding downhole temperatures and pressure may be used and the disclosed apparatus is not limited to any particular material for the substrate. In certain embodiments, the substrate may comprise a metal, a metal alloy, the like, or any combination of these materials. As used herein, the term “metal alloy” may refer to a mixture of two or more elements, wherein at least one of the elements is a metal. The metal or metal alloy may be selected from the group consisting of beryllium, aluminum, tin, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, tantalum, tungsten, graphite, carbon, silicon, boron nitride, magnesium, rare earth elements, oxides of any of the foregoing, derivatives thereof, the like, or any combinations of these materials. 
     Referring to  FIG.  1   , illustrated is a well site  10  utilizing a downhole system  15  comprising a downhole tractor assembly  20  for well site intervention or other operations, in accordance with one or more embodiments. The well site  10  includes well casing  12  within a wellbore  11  within a formation  13 . The illustrated wellbore  11  is a deviated wellbore that is formed to extend from a surface to a subterranean zone including the formation  13  (e.g., a hydrocarbon bearing geologic formation) and includes a vertical portion, a radius portion, and a horizontal portion. Although portions are referred to as “vertical” and “horizontal,” respectively, it should be appreciated that such wellbore portions may not be exactly vertical or horizontal, but instead may be substantially vertical or horizontal to account for drilling operations. 
     The downhole system  15  includes the downhole tractor assembly  20  coupled by a downhole tool  18  and a length of wireline  16  to a control unit  14 . The downhole tractor assembly  20  includes adjustable tractor wheels  22 . The tractor wheels  22  engage with the casing  12  or the wall of the wellbore  11  and have a tread that improves traction so that the tractor assembly  20  can more effectively traverse the casing  12  when tractoring non-vertically. Electrical power and control signals to and from the downhole tractor assembly  20  are transmitted via the wireline  16 , which includes, for example, a single-strand or multi-strand conductor that is run through the wireline  16  downhole to the downhole tractor assembly  20 . In some embodiments, the wireline  16  may be an electrical cable to lower tools (e.g., the downhole tractor assembly  20  and/or other downhole tool) into the wellbore  11  and to facilitate the transmission of power and data. The wireline  16 , in some embodiments, may be a conductor for electric logging and cables incorporating electrical conductors. In certain embodiments, data may be transmitted to control unit  14  for storage and further processing. 
     The control unit  14  may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, the control unit  14  may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The control unit  14  may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the control unit  14  may include one or more disk drives, one or more network ports for communication with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The control unit  14  may also include one or more buses operable to transmit communications between the various hardware components. 
     The present disclosure may be implemented at least in part with non-transitory computer-readable media. Non-transitory computer-readable media may include any instrumentality or aggregation of instrumentalities that may retain data and/or instructions for a period of time. Non-transitory computer-readable media may include, for example, without limitation, storage media such as a direct access storage device (e.g., a hard disk drive or floppy disk drive), a sequential access storage device (e.g., a tape disk drive), compact disk, CD-ROM, DVD, RAM, ROM, electrically erasable programmable read-only memory (EEPROM), and/or flash memory; as well as communications media such wires, optical fibers, microwaves, radio waves, and other electromagnetic and/or optical carriers; and/or any combination of the foregoing. 
     Electrical and hydraulic power subs may also be included in the downhole tractor assembly  20  and may deliver electrical and hydraulic power to various portions of the downhole tractor assembly  20 . A lower coupling sub of the downhole tractor assembly  20 , as illustrated, is coupled to a downhole tool  18 , which may be, for example, a shifting tool, a logging tool, an explosive tool (e.g., a perforating gun or otherwise), a packer, or other type of downhole tool, or other payload. 
     The downhole tractor assembly  20  may comprise a body that comprises a tubular housing that may be subdivided into various subs, at least one of which includes one or more wheels  22  and another that is a coupling sub to connect to the wireline  16 . In one or more embodiments, the downhole tool  18  may be coupled to the tubular housing. Any suitable downhole tool  18  may be coupled to the tubular housing and should not be limited herein. Suitable downhole tools  18  may include, but are not limited to, a shifting tool, an explosive tool, a logging tool, a packer, the like, and/or any combination thereof. Although six wheels  22  are illustrated in  FIG.  1   , the downhole tractor assembly  20  may include any suitable number of wheels  22  and should not be limited herein. One or more wheels  22  may be powered wheel assemblies for propelling the downhole tractor assembly  20  through the wellbore  11  in order to run the wireline  16  into the wellbore  11 . Other wheels  22  or wheel assemblies of the downhole tractor assembly  20  may not be powered but instead be freely rotatable in contact with the wellbore  11  (or casing as appropriate) during operation of the downhole tractor assembly  20 . 
     Referring now to  FIGS.  2 A and  2 B , illustrated are tractor wheel  22 A and  22 B and actuator assemblies  30 A,  30 B, in accordance with one or more embodiments. Assemblies  30 A,  30 B can include actuators and actuator arms coupled to the tractor wheels  22 A and  22 B. The reciprocation of the tractor wheels can be responsive to any type of actuator, e.g. hydraulic, pneumatic, or electric. The actuator assemblies  30 A,  30 B can be activated by the control unit  14  either through power and control lines run with the wireline  16  or wirelessly. In addition, the actual number of tractor wheels  22 A and  22 B per downhole tractor assembly  20  can vary depending on requirements. It should also be understood that one actuator could be used to move multiple wheels. The actuator assemblies  30 A,  30 B are actionably coupled to the wheels  22 A,  22 B and the tractor body to extend and retract the wheels  22 A,  22 B. 
     Referring now to  FIGS.  3 A- 3 D , illustrated is tractor wheel  22 , in accordance with one or more embodiments. The tractor wheel  22  includes a geometry that improves the traction of the downhole tractor assembly  20 . The wheel  22  includes a plurality of teeth  40  on the circumference of the wheel  22 . Grooves  42  that are parallel to the wheel axis are made in between adjacent teeth  40 . As shown, the grooves  42  are v-shaped grooves. However, other shapes of grooves may be used as well. 
     In a plane parallel to the axis of rotation of the wheel  22 , the grooves  42  may include a profile  44  at the bottom of each groove  42 . The profiles  44  may be, for example, an arced profile that include an arc with, for example, the smallest radius of curvature that allows the grooves  42  to extend across the width of the wheel  22 . The grooves  42  and the profiles  44  assist in collecting and channeling debris away from the wheel  22  during rotation of the wheel  22  in use. However, it should be appreciated that the grooves  42  may include profiles other than an arced profile and that different grooves  42  on the same wheel may include different profiles. 
     Each tooth  40  includes an outer face  46  that includes pairs of face grooves  48 , with each face groove  48  being on each side of the outer face  46  and that extend less than across the width of the wheel  22 . Each outer face  46  includes an area contact engageable with a wall of the wellbore  11 . Each pair of the face grooves  48  is formed by an arced profile  50  in a plane parallel with the axis of the wheel  22  that extends past the outer face  46  such that the face grooves extend less than across the width of the wheel  22 . Like the grooves  42  between adjacent teeth  40 , the face grooves  48  are shaped to channel debris out from the wheel  22  as the wheel  22  rotates against a wall of the wellbore  11 . 
     In use, the downhole tractor  20  conveys in the wellbore  11  by using the actuator assemblies  30 A,  30 B to extend the wheels  22  into engagement with a wall of the wellbore  11  to grip the wall. The wheel or wheels  22  are rotated and the outer faces  46  of the teeth  40  around the circumference of the wheel and engage the wall of the wellbore  11  and covey the downhole tractor  20  within the wellbore  11 . The grooves  42  between the teeth  40  displace debris, as the wheel  22  rotates, out from the wheel  22 . The face grooves  48  on each outer face  46  also displace debris, as the wheel rotates, out from each tooth outer face  46 . The wall of the wellbore  11  may either be cased or lined, such as with casing  12 , or open hole. 
     As the downhole tractor  20  is conveying within the wellbore  11  or once the downhole tractor  20  reaches a destination in the wellbore  11 , the downhole tool  18  may be operated to perform a downhole operation. For example, the downhole tool  18  may be, but is not limited to, a shifting tool, an explosive tool, a logging tool, a packer, the like, and/or any combination thereof and may perform the downhole operations of such tools. 
     Examples of the Above Embodiments Include 
     Example 1 is a downhole tractor assembly operable in a wellbore. The assembly includes a tractor body and a tractor wheel assembly, The tractor wheel assembly includes a tractor wheel comprising teeth around a circumference of the wheel and grooves between adjacent teeth that include an arced profile in a plane parallel with the axis of the wheel, and wherein each tooth includes an outer face comprising face grooves on each side of the outer face and that extend less than across the wheel. 
     In Example 2, the embodiments of any preceding paragraph or combination thereof further include wherein a pair of the face grooves is formed by an arced profile in a plane parallel with the axis of the wheel that extends past the outer face such that the face grooves extend less than across the wheel. 
     In Example 3, the embodiments of any preceding paragraph or combination thereof further include wherein the arced profiles of the grooves comprise a smallest radius of curvature that allows the grooves to extend across the wheel. 
     In Example 4, the embodiments of any preceding paragraph or combination thereof further include wherein the tractor wheel assembly further comprises an actuator assembly actionably coupled to the tractor body to extend and retract the tractor wheel. 
     In Example 5, the embodiments of any preceding paragraph or combination thereof further include wherein the assembly is operable to convey in an open hole wellbore. 
     In Example 6, the embodiments of any preceding paragraph or combination thereof further include wherein the grooves between adjacent teeth and the face grooves are shaped to channel debris out from the wheel as the wheel rotates against a wall of the wellbore. 
     In Example 7, the embodiments of any preceding paragraph or combination thereof further include wherein each of the outer surfaces comprise an area contact engageable with a wall of the wellbore. 
     In Example 8, the embodiments of any preceding paragraph or combination thereof further include wherein the grooves between each tooth comprise V-shaped grooves. 
     Example 9 is a method of operating a downhole tractor in a wellbore. The method includes engaging a wheel of the downhole tractor with a wall of the wellbore to grip the wall and rotating the wheel to engage outer faces of teeth around a circumference of the wheel and covey the downhole tractor within the wellbore. The method also includes displacing debris, as the wheel rotates, out from the wheel through grooves between adjacent teeth that include an arced profile parallel with the axis of the wheel. The method also includes displacing debris, as the wheel rotates, out from each tooth outer face through face grooves on each side of the outer face that extend less than across the wheel. 
     In Example 10, the embodiments of any preceding paragraph or combination thereof further include wherein a pair of the face grooves is formed by an arced profile parallel with the axis of the wheel that extends past the outer face such that the face grooves extend less than across the wheel. 
     In Example 11, the embodiments of any preceding paragraph or combination thereof further include wherein the arced profiles of the grooves comprise a smallest radius of curvature that allows the grooves to extend across the wheel 
     In Example 12, the embodiments of any preceding paragraph or combination thereof further include wherein engaging the wheel with the wall comprises operating an actuator assembly that is part of the downhole tractor to extend the tractor wheel into engagement with the wall. 
     In Example 13, the embodiments of any preceding paragraph or combination thereof further include engaging the wheel with an open hole wall of the wellbore and conveying the downhole tractor within the open hole wellbore. 
     In Example 14, the embodiments of any preceding paragraph or combination thereof further include wherein each of the outer surfaces comprise an area contact engageable with a wall of the wellbore. 
     In Example 15, the embodiments of any preceding paragraph or combination thereof further include wherein the grooves between each tooth comprise V-shaped grooves. 
     Example 16 includes a downhole tractor wheel for use with a downhole tractor in a wellbore. The wheel includes teeth around a circumference of the wheel and grooves between adjacent teeth that include an arced profile parallel with the axis of the wheel. Each tooth includes an outer face including face grooves on each side of the outer face and that extend less than across the wheel. 
     In Example 17, the embodiments of any preceding paragraph or combination thereof further include wherein a pair of the face grooves is formed by an arced profile parallel with the axis of the wheel that extends past the outer face such that the face grooves extend less than across the wheel. 
     In Example 18, the embodiments of any preceding paragraph or combination thereof further include wherein the arced profiles of the grooves comprise a smallest radius of curvature that allows the grooves to extend across the wheel. 
     In Example 19, the embodiments of any preceding paragraph or combination thereof further include wherein each of the outer surfaces comprise an area contact. 
     In Example 20, the embodiments of any preceding paragraph or combination thereof further include wherein the grooves between each tooth comprise V-shaped grooves. 
     Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. 
     For the embodiments and examples above, a non-transitory computer readable medium can comprise instructions stored thereon, which, when performed by a machine, cause the machine to perform operations, the operations comprising one or more features similar or identical to features of methods and techniques described above. The physical structures of such instructions may be operated on by one or more processors. A system to implement the described algorithm may also include an electronic apparatus and a communications unit. The system may also include a bus, where the bus provides electrical conductivity among the components of the system. The bus can include an address bus, a data bus, and a control bus, each independently configured. The bus can also use common conductive lines for providing one or more of address, data, or control, the use of which can be regulated by the one or more processors. The bus can be configured such that the components of the system can be distributed. The bus may also be arranged as part of a communication network allowing communication with control sites situated remotely from system. 
     In various embodiments of the system, peripheral devices such as displays, additional storage memory, and/or other control devices that may operate in conjunction with the one or more processors and/or the memory modules. The peripheral devices can be arranged to operate in conjunction with display unit(s) with instructions stored in the memory module to implement the user interface to manage the display of the anomalies. Such a user interface can be operated in conjunction with the communications unit and the bus. Various components of the system can be integrated such that processing identical to or similar to the processing schemes discussed with respect to various embodiments herein can be performed. 
     While compositions and methods are described herein in terms of “comprising” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. 
     Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques accepted by those skilled in the art. 
     The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.