Patent Publication Number: US-11661801-B2

Title: Anti-rotation coupling for use in a downhole assembly

Description:
RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 62/873,067 filed on Jul. 11, 2019, which is incorporated by reference herein in its entirety and for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present disclosure relates to an anti-rotation coupling between opposing surfaces of adjacent members of a downhole assembly. More specifically, the present disclosure relates to an interface between adjacent members that is formed by complementary profiles on opposing surfaces of the members of the downhole assembly. 
     2. Description of Prior Art 
     A number of devices for use in hydrocarbon producing wells employ tubular members coupled together with threaded connections. Tubular members making up a drill string are usually joints of pipe connected together with box and pin type connections which usually include shoulders adjacent the bases of their respective threaded portions. Typically, most of the torque loads transmitted between adjacent joints of pipe travels is transmitted across the threaded connections, while a smaller portion is transmitted across the box and pin shoulders. Some tubular members have other types of threaded connections which transmit a majority of the load across surfaces of the joined members that are in contact with one another. Frictional forces between the abutting surfaces keeps adjacent tubulars rotationally engaged. One drawback of transmitting torque loads across abutting surfaces is that sometimes the torque loads exceed the frictional forces, which allows relative rotation between adjacent tubulars causing the surfaces to be in sliding contact with one another. Due to the sliding contact, it is possible to introduce excessive torque into the connection; or conversely, loosen the connection. Moreover, the respective areas of the contact surfaces are generally smaller than that of a typical threaded connection, thereby subjecting the surfaces to greater unit forces than what is exerted on the threaded portion. Metal fatigue and localized fractures are types of damage experienced due to sliding contact. These types of damage may be especially problematic when the loads are cyclic, or are from high frequency torsional oscillations (“HFTO”). 
     SUMMARY OF THE INVENTION 
     Disclosed is an example of a downhole assembly that includes a drill bit, a tubular member, a shaft connected to the drill bit and configured to rotate within and relative to the tubular member to rotate the drill bit, and the shaft having a first shaft member with a first engagement area and a second shaft member with a second engagement area, the first and second engagement areas engaged with each other by a threaded connection, wherein at least one of the first and second engagement areas include one or more torsional locking elements. The one or more torsional locking elements alternatively include raised members on at least one of the first and second engagement areas. The threaded connection is optionally a connection with a compression element. In one embodiment, the shaft and the tubular member are coupled by one or more bearings between the shaft and the tubular member. In an example, the first and second engagement areas are under compression when engaged. The one or more torsional locking elements optionally include particles on of one of the first and second engagement areas and that press into the other of the first and second engagement areas when the first and second engagement areas are engaged. In an embodiment the threaded connection has an outer diameter and the tubular member has an inner diameter and the outer diameter of the threaded connection is smaller than the inner diameter of the tubular member. Examples of the assembly include a drilling motor having a stator and a rotor and with the shaft connected to the rotor. The second shaft member is optionally a ring element further including a third engagement area; and the shaft includes a third shaft member having a fourth engagement area, the third engagement area engaged with the fourth engagement area; and the one or more torsional locking elements are made of material that is harder than at least one of the first, the second, and the third shaft members. The first and second engagement areas are optionally at a distance of less than 5 m to the drill bit. 
     Also included is an example of a method to drill into a formation of the Earth that includes conveying a drilling assembly into a borehole, the drilling assembly having a tubular member and a drill bit, the drill bit in contact with the formation, rotating the drill bit in contact with the formation with a shaft connected to the drill bit, the shaft configured to rotate within and relative to the tubular member, the shaft equipped made up of a first shaft member with a first engagement area and a second shaft member with a second engagement area, and at least one of the first and second engagement areas having one or more torsional locking elements. The example method also includes engaging the first and second engagement areas with each other by a threaded connection. In an alternative, the one or more torsional locking elements have raised members on at least one of the first and second engagement areas, and optionally the threaded connection is a connection with a compression element. In an alternative, the method includes coupling the shaft and the tubular member by one or more bearings between the shaft and the tubular member. In some instances the first and second engagement areas are under compression when engaged. The one or more torsional locking elements optionally include particles on of one of the first and second engagement areas, and the particles press into the other of the first and second engagement areas when the first and second engagement areas are engaged. In an embodiment, the threaded connection has an outer diameter and the tubular member has an inner diameter and the outer diameter of the threaded connection is smaller than the inner diameter of the tubular member. Examples exist that the assembly includes a drilling motor having a stator and a rotor, and with the shaft connected to the rotor. In an example, the second shaft member is a ring element further having a third engagement area, the shaft having a third shaft member with a fourth engagement area that is engaged with the third engagement area, and the one or more torsional locking elements are made of material that is harder than at least one of the first, the second, and the third shaft members. In an example, the first and second engagement areas are at a distance of less than 5 m to the drill bit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a partial side sectional elevational view of an example of excavating a wellbore. 
         FIG.  2 A  is a side view of an example of end portions of tubulars rotationally coupled together. 
         FIG.  2 B  is a perspective view of examples of contact surfaces of the tubulars of  FIG.  2 A . 
         FIG.  2 C  is a side sectional view of an example of end portions of tubulars of  FIG.  2 A  disposed in a housing. 
         FIG.  2 D  is a side view of an alternate example of tubulars of  FIG.  2 A  having a ring disposed between. 
         FIG.  3 A  is a side view of an alternate example of end portions of tubulars rotationally coupled together. 
         FIG.  3 B  is a perspective view of examples of contact surfaces of the tubulars of  FIG.  3 A . 
         FIG.  3 C  is a side sectional view of an example of end portions of tubulars of  FIG.  3 A  disposed in a housing. 
         FIG.  4 A  is a side perspective view of an alternate example of end portions of tubulars of  FIG.  2 A  and spaced away from another. 
         FIG.  4 B  is a side partial sectional view of a portion of the embodiment of the end portions of tubulars of  FIG.  4 A . 
         FIGS.  5 A and  5 B  are side views of alternate examples of end portions of the tubulars of  FIG.  2 A . 
         FIG.  6    is a side sectional view of an alternate example of the bottom-hole assembly of  FIG.  2 C . 
         FIG.  7    is a side sectional view of an alternate example of the bottom-hole assembly of  FIG.  2 C . 
         FIGS.  8 A and  8 B  are schematic representations of force transfers between members. 
     
    
    
     While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF INVENTION 
     The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. The use of the terms and similar references in this description (especially in the context of the following claims) “above”, “up”, “high” “upper”, and “upwards” are to be construed to mean between a referenced location and the surface of the Earth along the bottom-hole assembly or the drill pipes, and the terms and similar references “below”, “down”, “low”, “lower”, and “downwards” are construed to mean on a side opposite a referenced location and surface of the Earth along the bottom-hole assembly or the drill pipes. In an embodiment, usage of the term “about” includes +/−5% of a cited magnitude. In an embodiment, the term “substantially” includes +/−5% of a cited magnitude, comparison, or description. In an embodiment, usage of the term “generally” includes +/−10% of a cited magnitude. 
     It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
     As noted above, some connections between components that make up a drill string or a drilling tool include box and pin type connections, alternatives of which have shoulders adjacent the bases of their respective threaded portions and are referred to as Rotary Shouldered Thread Connections (“RSTC”). In an embodiment, the torsional load capacity of a RSTC depends on preloads at the shoulders (e.g. outer shoulders close to the outer diameter of pin and box) and at the threads, as well as friction on the preloaded surfaces of the shoulders and the threads that are in contact with one another. Another type of connection is referred to as a Double-Shouldered Connection (“DSC”) also has inner shoulders that increase the number of preloaded surfaces and the amount of total preload, that in turn increases frictional torque capacity. The ultimate torque capacity of the DSC is approximately the sum of frictional torque capacities at the shoulders and at the threads—each often being in the same order of magnitude (e.g. about 45%). The pitch of the thread usually has no more than a minor contribution to the torque capacity. 
     At high torque loads rotational sliding is possible between the outer shoulders of a pin and box connection. Relative movement between these members sometimes is in the range of about 0.01 mm to 0.1 mm or more. After assembly and make-up of the connection a portion of the operating torque is transmitted through the box outer shoulder; and which often is the major part of the total torque acting at the connection. This is thought to be the result of a higher torsional stiffness of the box compared to the pin. Because the frictional torque capacity of the outer shoulder is limited, sliding occurs at the outer shoulder above a certain torque value. However, this torque value causing the sliding is still below the ultimate limit of the connection (i.e. below the yield torque or below the break-out-torque depending on the direction of the torque). 
     Additional inner shoulders at pin and box (as in case of DSC) may increase the ultimate torque capacity. However, the torque load threshold value that causes sliding at the outer shoulders is the same for a connection without inner shoulders. In this scenario, values of other parameters are unchanged, such as stiffness, preload and coefficient of friction at the outer shoulders. Such sliding during drilling operations may cause significant problems, such as; wear, galling and heating at shoulders, loss of preload, leakage, metal fatigue, and fracture. This is particularly an issue during cyclic torque loading, such as torque oscillating between a minimum and a maximum value occurring during Torsional Oscillations, such as High Frequency Torsional Oscillations (“HFTO”, i.e. torsional oscillation with a frequency higher than approximately 10 Hz, such as higher than 30 Hz or 50 Hz) or stick/slip phenomena, which may cause a large number of such sliding events to occur back and forth and possibly at high frequencies. At loads above the sliding torque value sliding is possible along contact surfaces between threads and the inner shoulders, which can introduce additional undesirable effects of over-load, plastic deformations, fracture, or loosening. With regard to above described mechanism and challenges, a particular situation exists for example for Rotary Steerable Systems (“RSS”) and drilling motors. Such tools typically have a connection between components of a drive shaft which is mounted and rotating within a housing and transmits drilling torque to the drill bit. Borehole size limits the housing diameter that in turn limits the available diameter for this connection; which in turn reduces available cross sections and radii, and limits maximum preloads and the frictional torque capacity of connection designs such as those for the RSTC and DSC. Such a connection may not be as strong as the other connections in the drill string (not covered by a housing), it may therefore be particularly prone to above described failures and negatively affect reliability or performance of drilling operations. 
     Illustrated in  FIG.  1    is a side partial sectional view of a drilling assembly  10  forming a wellbore  12  from surface  14  and downward through a subterranean formation  16 . The drilling assembly  10  includes an elongated drill string  18  shown made up of individual drill pipes  20  that are connected at individual joints. A bottom-hole assembly  22  (also referred to as a downhole assembly) is depicted mounted on a lower end of drill string  18  and fitted with a drill bit  24  on its lower end. In an example, a fluid is pumped or circulated through an inner bore  25  of string  18  that extends through drill pipes  20  and through components of the bottom-hole assembly  22 . The fluid flows through the drill bit  24  to lubricate and cool drill bit  24  and to remove cuttings that may be created by rotating drill bit  24  at the bottom of wellbore  12 ; example fluids include wellbore fluid, drilling fluid, drilling mud, and combinations. In the example of  FIG.  1    the bottom-hole assembly  22  includes a housing  26 , a motor  28 , and connection assembly  30 . Motor  28  is schematically shown in dashed outline within housing  26 , and connection assembly  30  couples the drill bit  24  with an output from the motor  28 . Examples of the motor  28  include a displacement motor that provides a rotational force or torque in response to the wellbore fluid flowing through motor  28 . In the illustrated example motor  28  rotates connection assembly  30  and attached drill bit  24 . A rotational torque is delivered from motor  28  to drill bit  24  through connection assembly  30  for forming wellbore  12 . On surface  16  is a derrick  32  over an opening of wellbore  12 , and which provides support for devices and equipment used in wellbore operations. A surface means (not shown) is alternatively included for rotating drill string  20  and drill bit  24 . In one example surface means include a top drive with rotary table rotated by a prime mover such as an electric motor to rotate drill bit  24 , and are used together with motor  28  or for bottom-hole assemblies  22  that do not include a motor  28 . Alternatively, drill bit  24  is rotated by motor  28  alone and without surface means to rotate drill bit  24  or by only surface means to rotate drill bit  24  and without motor  28 . A wellhead assembly  34  is shown set over the opening of wellbore  12 , and which provides pressure control for wellbore  12 . In an example, downhole assembly  22  is a rotary steering system. 
     In an alternative, bottom-hole assembly  22  is modular, and optionally includes a plurality of subcomponents, such as a drill bit (the same or similar to drill bit  24 ), a steering assembly, a motor (the same or similar to motor  28 ), a bend motor, one or more measurement tools, one or more stabilizers, one or more reaming tools, one or more drive shafts, and the like. In an embodiment, the measurement tools measure characteristics of the formation, the wellbore trajectory, a drilling direction, or operational parameters of the drilling process (such as logging-while-drilling or measurement while drilling tools, also referred to as LWD or MWD tools. The one or more drive shafts convey torque from one subcomponent to another one, and may be optionally utilized if portions of a subcomponent rotate at different rotational velocities. In a non-limiting example, a steering assembly includes a drive shaft that rotates within a sleeve that is static or rotates at a rotational velocity slower than the drive shaft. Alternatively a motor, such as motor  28 , includes a rotor that selectively rotates within a stator that is static or rotating at a rotational velocity slower than or substantially different than the rotor. In an embodiment, drill pipes  20  or subcomponents of bottom-hole assembly  22  including parts of subcomponents, such as portions or members of drive shafts, are joined together by threaded connections, for example by threaded connections that are symmetric with respect to the longitudinal axis of the drill pipes  20  or subcomponents of bottom-hole assembly  22 . A detailed example of a connection assembly  30  is shown in a side view in  FIG.  2 A . As shown, connection assembly  30  includes an annular upper subcomponent  36  having an inner bore  37  shown extending along axis A X , and an annular lower subcomponent  38  also with an inner bore  39  shown extending along axis A X . In an alternative, bore  37  is in communication with bore  25  ( FIG.  1   ) and bore  39 , and fluid, such as wellbore fluid, drilling fluid, and/or drilling mud flows through bores  25 ,  37 ,  39  to drill bit  24 . In the example shown, a lower end of upper subcomponent  36  engages an upper end of lower subcomponent  38  along an example of a link  40 . In an embodiment, link  40  is part of a connection  41  that rotationally couples the subcomponents  36 ,  38 . Link  40  as illustrated is made up a series of raised members  42 ,  44  respectively formed on the opposing faces of upper subcomponent  36  and lower subcomponent  38 . In a non-limiting example, raised members  42 ,  44  are formed by knurling. The members  42 ,  44  are strategically profiled and complementarily fashioned so that when the upper and lower subcomponents  36 ,  38  are engaged as depicted in  FIG.  2 A , the members  42 ,  44  become intermeshed with one another. A flared portion  46  is formed on a section of upper subcomponent  36  proximate link  40 , and which has an outer diameter greater than a remaining section of upper subcomponent  36  shown. Referring to  FIG.  2 B , perspective views of the upper and lower subcomponents  36 ,  38  are shown, and which illustrate an elongated stinger  48  included with upper subcomponent  36  extends along axis A X  past link  40  into lower subcomponent  38 . Illustrated in  FIG.  2 B  and side sectional view in  FIG.  2 C , upper subcomponent  36  has an outer diameter less than an inner diameter of flared portion  46 . A shoulder  50  is defined on a radial surface of flared portion  46  that faces lower subcomponent  38  and makes up a part of link  40 . A corresponding shoulder  52  is shown on a radial surface of lower subcomponent  38  which faces upper subcomponent  36 . In the examples illustrated, raised members  42 ,  44  are respectively provided on shoulders  50 ,  52 ; and that project axially from shoulders  50 ,  52 . As illustrated in the examples of  FIGS.  2 A and  2 C , shoulders  50 ,  52  each lie in planes that are substantially perpendicular with axis A X , and raised members  42 ,  44  define projections that extend towards the opposing one of the shoulders  50 ,  52  and in a direction generally parallel with axis A X . The raised members  42  shown in the embodiment of  FIG.  2 B  are disposed adjacent one another and substantially covering the shoulder  50 . In an alternate embodiment spaces (not shown) are disposed between adjacent raised members  42 , and where the radial surface of the shoulder  50  in one or more of the spaces lies in a plane substantially perpendicular to axis A X . 
     Shown in detail in  FIG.  2 B  is one example of a portion of a row of raised members  42 . As shown, raised members  42  each have an end distal from shoulder  50  that defines a tip  53 , and facets  54 ,  55  on their lateral sides that project axially from shoulder  50  and converge to the tip  53 . In the example illustrated, tip  53  extends along a line that extends radially from axis A X . Facet  54  is oriented in a plane that is oblique with axis A X , whereas facet  55  is in a plane that is generally parallel with axis A X ; that in combination with facet  54  resembles a saw-tooth profile for the raised members  42  on shoulder  50 . A detail of raised members  44  also depicts members  44  having a tip  56  extending radially from axis A X , a facet  57  in a plane oblique with axis A X , and a facet  58  in a plane generally parallel with axis A X . An advantage of the profiling of raised members  42 ,  44  on shoulders  50 ,  52  is that at least a portion of the rotational torque t transmitted between the upper and lower subcomponents  36 ,  38  is transferred across link  40  and by the strategic profiling of the members  42 ,  44 . An additional advantage of the profiles on the raised members  42 ,  44  on shoulders  50 ,  52  is that the opposing facets  55 ,  58  define locking elements, for example rigid locking elements, at the shoulders  50 ,  52 ; in a non-limiting example the locking elements provide a means for increasing an amount of torque transmitted between shoulders  50 ,  52 , such as when subcomponents  36 ,  38  are rotationally engaged with one another. In an example, engaging the lateral surfaces of opposing facets  55 ,  58  transmits torque loads across shoulders  50 ,  52  that are greater than torque loads transmittable with a convention RSTC, thereby preventing rotational sliding between the upper and lower subcomponents  36 ,  38 . In an example adhesives are not used between shoulders  50 ,  52  (i.e. shoulders  50 ,  52  are purely mechanically connected) and the threaded connection are repeatedly opened and closed rendering the connection  41  being removable. In an example, the threaded connection are repeatedly mechanically opened and closed and without breaking or removing an adhesive. In an example, lateral sides of the raised members  42 ,  44  define those surfaces which are in planes that are either parallel with or oblique with axis A X . 
     Illustrated in  FIG.  2 C  is that stinger  48  is received within a bore  59  that extends axially through the lower subcomponent  38 . An end of bore  59  distal from upper subcomponent  36  tapers radially outward and is fitted with threads  60  to receive corresponding threads (not shown) of another subcomponent, such as drill bit  24  in  FIG.  1    a steering assembly, a motor (e.g. motor  28 ), a tool to measure characteristics of the formation, the wellbore trajectory, a drilling direction, operational parameters of the drilling process, a logging-while-drilling tool, a measurement while drilling tool, a stabilizer, a reaming tool, a drive shaft, or drive shaft member, and the like. In the example of  FIG.  2 C , an annular torque nut  62  is used to couple together upper and lower subcomponents  36 ,  38 . In an example torque nut  62  operates as a compression element. Torque nut  62  is set within an annular space  64  shown circumscribing a portion of bore  59  and stinger  48 . Annular space  64  is in the body of lower subcomponent  38 , an end of annular space  64  is defined where bore  59  abruptly increases in diameter to form a ledge  65  that faces away from shoulder  50 . Further in this example, torque nut  62  acts as a fastener to couple together upper and lower subcomponents  36 ,  38  and includes threads  66  on its inner radial surface that engage threads  68  formed on an end of stinger  48  along its outer surface. Engaging corresponding sets of threads  66 ,  68  and rotating torque nut  62  in a designated rotational direction draws stinger  48  towards threads  60 , that in turn urges shoulder  50  of the upper subcomponent  36  towards and into compressive contact with shoulder  52  of lower subcomponent  38 ; in this example shoulders  50 ,  52  are engaged without rotating either of shoulders  50 ,  52  about axis A X . The compressive contact between shoulders  50 ,  52  generates force Fi shown exerted axially along shoulder  50  and against shoulder  52 . The magnitude of force Fi is dependent upon a rotation of and torque applied to torque nut  62  when engaging threads  66 ,  68 , and increases with further rotation of torque nut  62  in a direction that applies tension to stinger  48 . Ledge  65  limits axial travel of torque nut  62 , and exerts a force to torque nut  62 , which is transferred via threads  66 ,  68  to result in force F 1 . Engaging threads  66 ,  68  with one another forms a threaded connection  69 , which in an example is included as part of connection  41 . 
     Still referring to  FIG.  2 C , as illustrated the outer diameter D 48  of stinger  48  and that of threads  66 ,  68  are less than the outer diameter D 36  of upper subcomponent  36 . The threshold value of the force F 1  to rotationally affix the upper and lower subcomponents  36 ,  38  is lower when torque is transferred across the link  40  than when known tubular couplings are employed; such as a standard box and pin connection. One of the advantages provided by the lower torque requirement is that the dimensions (such as diameter and length) of the torque nut  62  are also lowered, which results in less weight and cost. The raised members  42 ,  44  utilize existing contact surfaces between the upper and lower subcomponents  36 ,  38  to increase an area of the interface of force transfer between the upper and lower subcomponents  36 ,  38 ; and also magnitudes of resultant forces transferred between the subcomponents  36 ,  38 . By expanding the force transfer interface to include force transfer across the raised members  42 ,  44 , in turn increases the rotational force and torque that is transferred between the upper and lower subcomponents  36 ,  38 . The addition of the corresponding raised members  42 ,  44  thereby increase the size and capabilities of the interface of force transfer, and thereby provide the advantage of reducing the chances or amount of sliding, and avoiding a connection that is loose. Included in the example of  FIG.  2 C  is a groove  70  shown formed along an inner surface of lower subcomponent  38  at an end adjacent the shoulder  52 , as illustrated groove  70  limits an engagement area of shoulders  50 ,  52  and reduces the maximum stress level at and around link  40 . In embodiments with the groove  70  that reduces engagement area of shoulders  50 ,  52  the pre-compression applied to link  40  without exceeding stress limits at engagement areas. The presence of groove  70  also increases an average diameter of where shoulders  50 ,  52  are engaged, which in turn increases a maximum magnitude of torque transmitted between subcomponents  36 ,  38  across link  40  and without relative movement between shoulders  50 ,  52 . The size of groove  70  has to be defined by carefully balancing the various effects which may be calculated by an optimization algorithm to determine a size or range of sizes of groove  70  for particular applications, example sizes of a radius of groove  70  include up to about 3 mm, up to about 5 mm, and up to about 7 mm. 
     Further depicted in the example of  FIG.  2 C  is the housing  26  circumscribing the upper and lower subcomponents  36 ,  38 . As shown, housing  26  is a generally annular member and which bearings  71  are housed within an inner radius of housing  26  to facilitate for the rotation of upper and lower subcomponents  36 ,  38  with respect to housing  26 , example embodiments of bearings  71  include radial and axial type bearings. In the example of  FIG.  2 C  subcomponents  36 ,  38  are respectively shown as upper and lower portions of a drive shaft, which in an example rotate within housing  26  and transmit torque to for rotating drill bit  24  ( FIG.  1   ). In alternatives housing  26  is rotationally static, or rotating at a lower rotational velocity than subcomponents  36 ,  38 . Further, seals  72  are optionally illustrated that provide a pressure barrier to fluids ambient to the bottom-hole assembly  22 , such as drilling or other wellbore fluids within a wellbore. Embodiments exist without a seal between housing  26  and subcomponents  36 ,  38  to allow fluid, e.g. wellbore fluid or drilling fluid, to flow around subcomponents  36 ,  38  in addition to or as an alternative to fluid flowing through bores  37 ,  39  in subcomponents  36 ,  38 . In an alternate embodiment (not shown), housing  26  terminates above lower subcomponent  38 ; and optionally the respective outer diameters of housing  26  and lower subcomponent  38  are substantially the same. This alternative embodiment allows for a larger outer diameter of torque nut  62 , and/or increased cross sections and axial loads (like a preload) acting at locking elements (at respectively engaged surfaces). Advantages exist for a high axial (pre-) load to transfer high torque or torsional loads as well as bending without sliding or losing contact. Optionally, with larger diameters at the lower end of the lower subcomponent  38  additional advantages are realized of greater strength of the drill bit connection or “bit box”, and alternatively disposed at threads  60  to receive corresponding threads (not shown) of another component. 
     An alternate embodiment of connection assembly  30 A and bottom-hole assembly  22 A is shown in  FIGS.  3 A,  3 B, and  3 C . Shown in side view in  FIG.  3 A , and similar to the embodiment of  FIG.  2 A , raised members  42 A,  44 A respectively located on the upper and lower subcomponents  36 A,  38 A are intermeshed with one another to form a link  40 A across which a rotational torque is transferred between upper and lower subcomponents  36 A,  38 A. Referring to  FIG.  3 B , a perspective view of connection assembly  30 A is provided in a perspective view. Details of the raised members  42 A,  44 A are shown in  FIG.  3 B  illustrating that planar surfaces on the members  42 A, define facets  54 A,  55 A, and that planar surfaces on members  44 A define facets  57 A,  58 A. In the example shown, facets  54 A,  55 A are angularly offset from and generally oblique to axis A X , and the angular offset between axis A X  and facets  54 A is substantially the same as the angular offset between axis A X  and facets  55 A. As shown, axis A X  extends longitudinally along connection assembly  30 A and in examples of operation connection assembly  30 A rotates about axis A X . Further in this example, facets  57 A,  58 A are also angularly offset from and generally oblique to axis A X , and with angular offsets that are substantially the same. Tips  53 A are formed where facets  54 A,  55 A join, and tips  56 A are formed where facets  57 A,  58 A join, tips  53 A,  56 A are shown extending generally radially from axis A X . In an example, raised members  42 A,  44 A are in a configuration commonly referred to as Hirth teeth. In similar fashion, rotation of one of the upper or lower subcomponents  36 A,  38 A transmits a rotational torque across link  40 A from interaction of the facets  54 A,  55 A on shoulder  50 A and facets  57 A,  58 A of raised members  56 A on shoulder  52 A. 
     Referring now to  FIG.  3 C , shown in side sectional view is an alternate example of bottom-hole assembly  22 A in which upper and lower subcomponents  36 A,  38 A are joined together by torque nut  62 A; and between subcomponent  38 A and housing  26 A are optional bearings  71 A and a seal  72 A. In this embodiment, torque nut  62 A is an annular elongated member having a base  74 A formed on a lower terminal end and defined where a length of torque nut  62 A has an enlarged outer diameter. In an alternative, torque nut  62 A operates as a compression element. The diameter increase of torque nut  62 A is abrupt and defines a ledge  76 A shown facing upper subcomponent  36 A and in a plane substantially perpendicular with axis A X . Ledge  76 A is illustrated in interfering contact with shoulder or ledge  65 A formed on the upper end of annular space  64 A. In the example of  FIG.  3 C , the threads  66 A are on an outer surface of a portion of torque nut  62 A that is distal from the base  74 A. Threads  66 A are shown engaged with threads  68 A formed on an inner surface of a bore  80 A that extends along axis A X  and through upper subcomponent  36 A. In an embodiment subcomponents  36 A,  38 A are upper and lower portions of a drive shaft that are engaged by link  40 A and threaded connection  69 A, the combination of the link  40 A and threaded connection  69 A define connection  41 A. Threaded connection  69 A is formed by engaging threads  66 A,  68 A, and link  41 A is formed by intermeshing raised members  42 A,  44 A. In a non-limiting example of operation, the drive shaft selectively rotates relative to and within housing  26 A with a rotational speed that is substantially higher than the rotational speed of housing  26 A. Also in this example, the diameter of bore  80 A transitions abruptly outward proximate link  40 A to define an annular space  82 A, and an outer diameter D 62A  of torque nut  62 A is less than an outer diameter D 36A  of upper subcomponent  36 A. An optional gap  83 A is shown between subcomponents  36 A,  38 A when raised members  42 A,  44 A ( FIG.  3 A ) are intermeshed and fully engaged to form link  40 A, and that provides clearance in a position where respective shoulders of link  40 A are not fully engaged so that raised members  42 A,  44 A become fully engaged. As discussed above, a maximum magnitude of the force F A  exerted onto upper subcomponent  36 A by threaded engagement shown is limited by diameter D 62A , which also limits torque transfer capabilities of standard box and pin connections. An advantage provided by the present disclosure is that engagement between raised members  42 A and raised members  44 A introduces an additional mode or path of transferring torque or rotational force between upper subcomponent  36 A and lower subcomponent  38 A; and which greatly increases the maximum amount of torque or rotational force transferred between upper and lower subcomponents  36 A,  38 A, and conversely reduces the possibility of rotational slippage between upper and lower subcomponents  36 A,  38 A during operations that experience expected loads. Examples exist where spaces (not shown) exist between adjacent members  42 A and members  44 A, in this alternative the radial surface of the shoulder  50 A in one or more of the spaces lies in a plane substantially perpendicular to axis A X . In another alternative, portions of members  42 A are out of contact with opposing portions of members  44 A. 
     An alternate example of a portion of the connection assembly  30 B is shown in perspective view in  FIG.  4 A . In this example, connection assembly  30 B is shown to be substantially the same as the connection assembly  30  of  FIGS.  2 A- 2 C ; and which further includes particles  84 B, such as rigid particles, formed on and adhered or otherwise attached to the surface of shoulder  52 B of lower subcomponent  38 B; or shoulder  50 B of upper subcomponent  36 B; particles  84 B optionally embed into the surface of shoulder  50 B. The particles  84 B on one or both of shoulders  50 B,  52 B increases rotational torque transfer between the shoulders  50 B,  52 B. In an embodiment, particles  84 B are embedded into one or each of shoulders  50 B,  52 B; alternatively the particles  84 B are embedded by application of an axial force, such as that created during forming the connection, e.g. forming the connection by threads, for example by threads of torque nuts similar to those shown in  FIGS.  2 C and  3 C . Example materials of the particle  84 B include diamonds, tungsten, carbides, and any other material having a hardness that is at least about that of the material making up shoulders  50 B,  52 B. Example sizes of the particles  84 B include up to about 2 mm, up to about 1 mm, up to about 500 μm, up to about 200 μm, and up to about 100 μm. Particles  84 B are another form of projections that extend out axially from one or both of shoulders  50 B,  52 B for engagement with an opposing one of the shoulders  50 B,  52 B. Other examples of projections include but are not limited to keys, teeth, rings, balls, cylinders, or particles with irregular surfaces. In an example, particles  84 B are optionally included with or attached to friction shims. An example of friction shims suitable for an embodiment disclosed herein are available from 3M Advanced Materials Division, 3M Center St. Paul, Minn. 55144 USA, and described in the following website http://multimedia.3m.com/mws/media/1001697O/3m-friction-shims.pdf, the entire contents of which are incorporated by reference herein, and for all purposes. A portion of the connection assembly  30 B of  FIG.  4 A  is shown in an enlarged and partial sectional view in  FIG.  4 B . In  FIG.  4 B  example particles  84 B 1-5  are illustrated spanning between opposing faces of shoulders  50 B,  52 B. Embodiments exist where torque t is transferred from one of the shoulders  50 B,  52 B to the other and through or across particles  84 B 1-5  that are between the shoulders  50 B,  52 B. As shown, some particles  84 B 1-5  have diamond like shapes where portions of their outer surfaces are planar, and others have conical portions or are irregularly shaped. Shapes of the particles  84 B 1-5  are not limited to the examples shown in  FIG.  4 B , but include any shape or configuration. Further in this example, particles  84 B 1-3  have portions embedded in each of shoulders  50 B,  52 B; whereas particle  84 B 4  has a portion embedded only in shoulder  52 B, and no portion of particle  84 B 5  is embedded in either of the shoulders  50 B,  52 B. Instead particle  84 B 5  is illustrated wedged between shoulders  50 B,  52 B. Although particle  84 B 4  is embedded in a single one of the shoulders  50 B,  52 B, and particle  84 B 5  is not embedded in either of the shoulders  50 B,  52 B, in an example all or a portion of torque t, torsional load, or rotational force transfers between shoulders  50 B,  52 B through one or both of particles  84 B 4,5 . In an alternate embodiment, locking elements are forced into at least one of the engaged surface by applying a pre-compression by a pre-load force; pre-compressing shoulders  50 B,  52 B with locking elements between the shoulders  50 B,  52 B elastically or inelastically deforms at least one of shoulders  50 B,  52 B in a way that locking elements will be forced into one or both of the shoulders  50 B,  52 B. Optionally, one or more of a washer like ring, shim ring, bearing ring, or bearing race (not shown) are disposed on any of the above described shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B), and which optionally is equipped with raised profiles and/or particles in addition to or as an alternative to raised profiles and/or particles on one or more of described shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B). In a non-limiting example, the washer like ring, shim ring, bearing ring, or bearing race has raised profiles and/or particles that are made of a material that is harder than the opposing shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B). In an example, the washer like ring, shim ring, bearing ring, or bearing race is made of a material that is harder than opposing shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B) of upper/lower subcomponents  36 B,  38 B and profiles or particles are optionally made of the material of washer like ring, shim ring, bearing ring, or bearing race. In an embodiment, raised profiles and/or particles are on both sides of the washer like ring, shim ring, bearing ring, or bearing race, and alternatively the respective corresponding shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B) of upper/lower subcomponents  36 B,  38 B have no locking elements (e.g. raised profiles/particles). In this embodiment, locking elements on washer like ring, shim ring, bearing ring, or bearing race are forced into at least one of the engaged surface of corresponding shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B) of upper/lower subcomponents  36 B,  38 B by applying a pre-compression by a pre-load force; pre-compressing shoulders  50 B,  52 B with washer like ring, shim ring, bearing ring, or bearing race between the shoulders  50 B,  52 B elastically or in-elastically deforms at least one of shoulders  50 B,  52 B in a way that locking elements of washer like ring, shim ring, bearing ring, or bearing race is forced into one or both of the shoulders  50 B,  52 B. In this embodiment, locking elements on washer like ring, shim ring, bearing ring, or bearing race found to be worn after upper/lower subcomponents  36 B,  38 B are replaceable with replacement or refurbishment of the washer like ring, shim ring, bearing ring, or bearing race; which provides an advantage of time and cost efficiencies and savings over that of rework and/or replacement one or both of upper/lower subcomponents  36 B,  38 B. Further optionally, a material layer, such as a metal inlay or coating (e.g. nickel coating), is provided on any of the above described shoulders (i.e.  50 ,  50 A,  50 B,  52 ,  52 A,  52 B) and in which particles are embedded. Advantages provided by the locking elements prevent relative movement between opposing shoulders when drilling torque is provided through the threaded connection to the drill bit while at the same time rotation of the drill bit is generating torsional oscillations, for example high-frequency torsional oscillations at the threaded connection. An example of replaceable rings  85 B,  87 B are optionally included with shoulders  50 B,  52 B. 
     Provided in a side view in  FIG.  5 A  is an example of a portion of the connection assembly  30 C where the raised members  42 C have a frusto-conical shape. As shown, the larger diameter portion of raised members  42 C mounts on the shoulder  50 C of upper subcomponent  36 C and mesh with raised members  44 C of lower subcomponent  38 C. Example lengths of raised members  42 C,  44 C (i.e. from shoulders  50 C,  52 C to their free ends) include up to about 5 mm, up to about 3 mm, up to about 1 mm, up to about 800 μm, up to about 500 μm, and up to about 100 μm. Raised members  44 C also have a frusto-conical configuration and with the larger diameter portion mounted to the shoulder  52 C of lower subcomponent  38 C. Raised members  42 C are illustrated meshed with raised members  44 C and positioned so that rotation of one of the upper and lower subcomponents  36 C,  38 C exerts a torque t of rotational force onto the other one of the upper and lower subcomponents  36 C,  38 C across the interface of members  42 C,  44 C. The tips  56 C of members  44 C terminate short of shoulder  50 C and define spaces  86 C between tips  56 C and shoulder  50 C. Similar spaces  88 C are defined between tips  53 C and shoulder  52 C. In this example raised members  44 C are not in contact with opposing shoulder  50 C and raised members  42 C are not in contact with opposing shoulder  52 C when pre-compressed (i.e. when compressively preloaded); which allows for sufficient space during pre-compression, and positions shoulder  50 C away from and not in contact with shoulder  52 C when pre-compressed. Alternatives exist with one or more of tips  56 C,  53 C in contact with shoulders  50 C,  52 C. Shown in side view in  FIG.  5 B  are alternate examples of raised members  42 D,  44 D that project respectfully from shoulders  50 D,  52 D. The tips  53 D,  56 D of raised members  42 D,  44 D are generally rounded and shown inserted into complementary shaped recesses between adjacent members  42 D,  44 D. Example lengths of raised members  42 D,  44 D (i.e. from shoulders  50 D,  52 D to their free ends) include up to about 5 mm or smaller, up to about 3 mm, up to about 1 mm, up to about 800 μm, up to about 500 μm, and up to about 100 μm. Similar to the configuration of  FIG.  5 A , meshing of the members  42 D,  44 D rotationally couples upper and lower subcomponents  36 D,  38 D. Also illustrated in the example of  FIG.  5 B  are spaces  90 D between tips  56 C and shoulder  50 D and spaces  92 D between tips  53 C and shoulder  52 D. Optionally the tips or free ends of raised members  42 D are spaced away from shoulder  52 D, the tips or free ends of raised members  44 D are spaced away from shoulder  50 D so that raised members  44 D are not in contact with opposing shoulder  50 D and raised members  42 D are not in contact with opposing shoulder  52 D when pre-compressed to allow for sufficient space during pre-compression; also in this example shoulder  50 D and shoulder  52 D are not in contact, e.g. in direct contact, when pre-compressed. In an alternative, one or more of tips  53 D,  56 D is in contact with shoulders  50 D,  52 D. While  FIGS.  2 A and  2 B  were mainly discussed in relation to  FIG.  2 C  and  FIGS.  3 A,  3 B  were mainly discussed in relation to  FIG.  3 C , this is not to be meant as a limitation of anything described herein; similarly, all embodiments discussed with respect to  FIGS.  2 A,  2 B,  3 A,  3 B,  4 A,  4 B,  5 A, and  5 B  can be advantageously used as shown and discussed with respect to  FIGS.  2 C,  3 C,  6 , and  7    (as will be discussed below). 
     Referring now to  FIG.  6   , shown in a side sectional view is an alternate example of a bottom-hole assembly  22 E forming a wellbore  12 E through a formation  16 E. In this example, an end of tubular  20 E attaches to a connection assembly  30 E which includes an upper subcomponent  36 E and a lower subcomponent  38 E that are coupled together. Examples of tubular  20 E include a drill pipe or subcomponent of bottom-hole assembly  22 E. More specifically, in the example shown upper subcomponent  36 E directly couples to tubular  20 E, and on an end opposite upper subcomponent  36 E lower subcomponent  38 E is coupled to drill bit  24 E. Options exist that instead of drill bit  24 E, another subcomponent of bottom-hole assembly  22 E is attached to the lower end of lower subcomponent  38 E. In the illustrated example, upper and lower subcomponents  36 E,  38 E are disposed around and along common rotational or longitudinal axis A X  of bottom-hole assembly  22 E, and drill bit  24 E is shown in direct contact with lower subcomponent  38 E. Alternatively, subcomponents (not shown) are disposed between lower subcomponent  38 E and drill bit  24 E so that drill bit  24 E is in indirect contact with lower subcomponent  38 E rather than in direct contact. In a non-limiting example, tubular  20 E, subcomponents  36 E,  38 E, and drill bit  24 E rotate at the same speed about rotational or longitudinal axis A X  at the same time while drill bit  24 E is in direct contact with formation  16 E thereby penetrating formation  16 E and creating wellbore  12 E. Rotation of tubular  20 E, subcomponents  36 E,  38 E as well as drill bit  24 E about rotational or longitudinal axis A X  is optionally powered by surface means, or by a downhole motor such as motor  28 . In a non-limiting example of operation, by rotating drill bit  24 E in direct contact with formation  16 E torsional oscillations (e.g. high-frequency torsional oscillations) within drill bit  24 E, subcomponents  36 E,  38 E as well as tubular  20 E are created that overlay the rotation of tubular  20 E, upper and lower subcomponents  36 E,  38 E, and drill bit  24 E about rotational or longitudinal axis A X  that is generated by the surface means or downhole motor. In some instances torsional oscillations (also known as torsional vibrations) generate accelerations, for example periodic oscillations, some of which are at a magnitude to damage downhole components, such as parts, couplings, or connections. A sleeve  26 E at least partially disposed around drive shaft is shown partially circumscribing adjacent portions of upper and lower subcomponents  36 E,  38 E. Sleeve  26 E is selectively rotatably coupled to subcomponents  36 E,  38 E by radial and/or axial bearings  71 E; by means of bearings  71 E sleeve  26 E is able to rotate at a different speed than subcomponents  36 E and  38 E. In alternatives sleeve  26 E is static, or rotates relative to formation  16 E at an angular velocity slower than that of subcomponents  36 E,  38 E. Optionally, one or more actuators  93 E is schematically shown included with sleeve  26 E that in an example, when actuated engage the wall of borehole  12 E in order to steer bottom-hole assembly  22 E and adjust or change the drilling direction. In the example shown, sleeve  26 E has a maximum outer diameter that is smaller than the diameter of drill bit  24 E which defines the diameter of borehole  12 E. Sleeve  26 E also has a minimum inner diameter depending on the required wall thickness of sleeve  26 E. Similar to the example of  FIG.  2 C , upper and lower subcomponents  36 E,  38 E are coupled together with a fastener; such as a threaded fastener, the fastener shown in the example includes a torque nut  62 E and a stinger  48 E; in another example the fastener includes an elongated torque member  62 A (e.g. a bolt with a head) as previously shown in  FIG.  3 C . In a non-limiting example of drilling with the downhole assembly  22 E an operational torque is acting on upper subcomponent  36 E and is transmitted by this coupling to lower subcomponent  38 E and further to a drill bit  24 E shown attached to an end of lower subcomponent  38 E opposite its connection to upper subcomponent  36 E. In an example, torque nut  62 E (or likewise elongated torque member  62 A (e.g. a bolt with a head)—as previously shown in  FIG.  3 C ) does not transmit torque from upper subcomponent  36 E to lower subcomponent  38 E or from upper subcomponent  36 E and/or lower subcomponent  38 E to drill bit  24 E. Instead, a gap  83 E is defined between torque nut  62 E and drill bit  24 E as well as between stinger  48 E and drill bit  24 E to allow for full pre-compression when threading drill bit  24 E to lower subcomponent  38 E of the drive shaft. Optionally, upper and lower subcomponents  36 E,  38 E are rotating within and relative to sleeve  22 E and both are transmitting the complete drilling torque (except losses due to contact between outer diameters of drive shaft members and housing or borehole). A portion of upper subcomponent  36 E proximate its lower terminal end has a reduced diameter to define a stinger  48 E. The outer diameter of upper subcomponent  36 E abruptly transitions where the stinger  48 E initiates to form a downward facing shoulder  50 E. Stinger  48 E is shown inserted into and circumscribed by lower subcomponent  36 E and where shoulder  50 E abuts shoulder  52 E formed on an upper terminal end of lower subcomponent  38 E. Engagement of shoulders  50 E,  52 E forms link  40 E, and similar to link  40 ,  40 A described above provides for the transfer of forces. In an example, a major portion of the drilling torque transferred between upper and lower subcomponents  36 E,  38 E occurs across link  40 E, and a minor portion of the drilling torque is transmitted across the fastener (e.g. torque nut  62 E and stinger  48 E). Force transfer across fastener typically occurs by static friction or adhesion at mating contact faces and without further locking element. Example percentages of total torque transfer between upper and lower subcomponents  36 E,  38 E across the links  40 A- 40 E range from about 50% to about 90% and all values between; and across the fastener range from about 10% to about 50% and all values between; in a specific non-limiting example the percentage of torque transfer across the links  40 A- 40 E is about 75% and the percentage of torque transfer across the above described fasteners is about 25%. For manufacturing reasons, the outer diameter of link  40 E and the engagement area of shoulders  50 E and  52 E is limited by the minimum inner diameter of sleeve  26 E, and in examples is smaller than other RSTC within the bottom-hole assembly  22 E, such as the connection between tubular  20 E and upper subcomponent  36 E of the drive shaft or lower subcomponent  38 E and drill bit  24 E. In examples, the minimum inner diameter of upper and lower subcomponents  36 E and  38 E of connection assembly  30 E is limited to provide sufficient space for fluid flowing through inner bore  37 E to drill bit  24 E to cool and lubricate drill bit  24 E. In this situation, the engagement area where shoulders  50 E and  52 E are engaged is limited and reduced compared to RSTC within the bottom-hole assembly  22 E; such as the connection between tubular  20 E and upper subcomponent  36 E, or lower subcomponent  38 E and drill bit  24 E due to the maximum inner diameter of upper and lower subcomponents  36 E and  38 E and minimum inner diameter of sleeve  26 E. The reduced engagement area does not allow the same amount of pre-compression at link  40 E as at other RSTC within the bottom-hole assembly  22 E, such as the connection between tubular  20 E and upper subcomponent  36 E of the drive shaft or lower subcomponent  38 E and drill bit  24 E. In addition, the ability to transmit torque t across link  40 E is reduced by its lowered diameter, such as the torque that is needed to rotate upper and lower subcomponents  36 E and  38 E of the connection assembly  30 E and drill bit  24 E in contact with formation  16 E plus torque created by torsional oscillations due to the rotation of drill bit  24 E in contact with formation  16 E, as other RSTC with larger diameters within the bottom-hole assembly  22 E, such as the connection between tubular  20 E and upper subcomponent  36 E of the drive shaft or lower subcomponent  38 E and drill bit  24 E. In the special situation where link  40 E between upper subcomponent  36 E and lower subcomponent  38 E of the drive shaft is limited between the maximum inner diameter of the drive shaft and the minimum inner diameter of sleeve  26 E, one or both of shoulders  50 E and  52 E may be advantageously provided with torsional locking elements such as shown and described in more detail above and below. As several modes of torsional oscillations may exist within drilling assembly  22 E, one or both of shoulders  50 E and  52 E may be advantageously provided with torsional locking elements  110 E such as shown and described in more detail above and below when the link  40 E is relatively close to drill bit  24 E, for example when a distance between link  40 E and drill bit  24 E is not more than 5 m or not more than 3 m. 
     Still referring to  FIG.  6   , the torque nut  62 E shown is a substantially annular member having threads  66 E on an inner circumference that selectively engage threads  68 E on a portion of the outer circumference of upper subcomponent  36 E. Threads  68 E are illustrated proximate a lower terminal end of upper subcomponent  36 E. In this example, a ledge  65 E is depicted on an inner surface of lower subcomponent  38 E, and positioned in a mid-portion of lower subcomponent  38 E. Ledge  65 E is a radial surface shown facing towards drill bit  24 E, and formed where a diameter of an axial bore through lower subcomponent  38 E changes abruptly. A lateral end of torque nut  62 E facing away from drill bit  24 E abuts ledge  65 E along a generally radial interface. In a non-limiting example of operation and similar to that described above, engaging threads  66 E,  68 E respectively on torque nut  62 E and lower subcomponent  38 E results in a compressive preload force for continued engagement of shoulders  50 E,  52 E, and link  40 E provides a rotational coupling between upper and lower subcomponents  36 E,  38 E that restricts relative rotational movement or sliding between upper and lower subcomponents  36 E,  38 E. In an example relative rotational movement or sliding is due to torsional oscillations, such as high frequency torsional oscillations that are created by rotating drill bit  24 E in contact with formation  16 E. Link  40 E further optionally includes a locking element  42 E positioned between mating shoulders  50 E,  52 E. Further shown in  FIG.  6    are radial and/or axial bearings disposed between upper subcomponent  36 E and sleeve  26 E, and also between lower subcomponent  38 E and sleeve  26 E. 
     Another alternative of a bottom-hole assembly  22 F is illustrated in a side sectional view in  FIG.  7   , and which is in use for forming a wellbore  12 F. Similar to that of  FIG.  6   , bottom-hole assembly  22 F of  FIG.  7    includes upper and lower subcomponents  36 F,  38 F with opposing shoulders  50 F,  52 F including a locking element between that form a link  40 F for transferring forces and/or torque, for example more than 50% of the drilling torque between the upper and lower subcomponents  36 F,  38 F while being compressively preloaded by a fastener. In this example, bottom-hole assembly  22 F includes an elongated flex shaft  94 F shown mounted to an end of upper subcomponent  36 F opposite lower subcomponent  38 F which in turn is connected to drill bit  24 F. As shown, upper and lower subcomponents  36 F and  38 F are disposed around and along common rotational or longitudinal axis A X  of bottom-hole assembly  22 F. In  FIG.  7    drill bit  24 F is shown in direct contact with lower subcomponent  38 F, alternatively other subcomponents (not shown) are disposed between lower subcomponent  38 F and drill bit  24 F; so that drill bit  24 F is indirect contact rather than in direct contact with lower subcomponent  38 F. In a non-limiting example, subcomponents  36 F and  38 F, flex shaft  94 F, as well as drill bit  24 F rotate about rotational or longitudinal axis A X  while drill bit  24 F is in direct contact with formation  16 F thereby penetrating formation  16 F and creating wellbore  12 F. Optionally, rotation of subcomponents  36 F and  38 F, flex shaft  94 F, as well as drill bit  24 F about rotational or longitudinal axis A X  is powered by surface means or by a downhole motor such as motor  28 . In alternatives, rotating drill bit  24 F in direct contact with formation  16 F creates torsional oscillations (e.g. high-frequency torsional oscillations) within drill bit  24 F, subcomponents  36 F and  38 F, and flex shaft  94 F that overlay the rotation of tubular  20 F, upper and lower subcomponents  36 F and  38 F and drill bit  24 F about rotational or longitudinal axis A X  that is generated by the surface means or downhole motor. Torsional oscillations (also known as torsional vibrations) alternatively cause repeated high accelerations that damage downhole components such as parts or couplings/connections. A housing  26 F is disposed at least partially around the drive shaft and flex shaft  94 F that is rotatably connected to subcomponents  36 F and/or  38 F, e.g. by radial and/or bearings  71 F. By means of bearings  71 F housing  26 F is selectively rotated at a different speed than subcomponents  36 F,  38 F and flex shaft  94 F. In examples housing  26 F is static or rotates at an angular velocity less than that of subcomponents  36 F and  38 F. Examples of rotation are about axis A X  and with respect to formation  16 F. Housing  26 F has a maximum outer diameter that is smaller than the diameter of drill bit  24 F which defines the diameter of borehole  12 F. Housing  26 F also has a minimum inner diameter depending on the required wall thickness of housing  26 F. A rotor  96 F on an end of flex shaft  94 F opposite upper subcomponent  36 F inserts into a stator  98 F. Rotor  96 F and stator  98 F engage one another along complementary undulations formed on their respective outer and inner surfaces. Rotor  96 F and stator  98 F together form an example of a motor, such as motor  28  of  FIG.  1   . Stator  98 F is shown mounted between an upper end of housing  26 F and a lower end of a tubular  20 F, which in an example is a drill pipe or another component of bottom-hole assembly  22 F. In an embodiment, housing  26 F includes one or more housing members, and optionally includes other subcomponents of a bottom-hole assembly  22 F (not shown). In an example, bearings  71 F facilitate transfer of an axial load from tubular  20 F to drill bit  24 F via stator  98 F, housing  26 F, and at least one of subcomponents  36 F,  38 F, and torque is transferred from rotor  96 F via flex shaft  94 F, and one or more subcomponents  36 F,  38 F to drill bit  24 F. Wellbore fluid, such as drilling fluid, is optionally pumped through inner bore of tubular  20 F, and which flows into the annular space between rotor  96 F and stator  98 F, the annular space between flex shaft  94 F and housing  26 F, the annular space between subcomponents  36 F,  38 F and housing, and the inner bore of subcomponents  36 F and  38 F to the inner bore of drill bit  24 F for lubrication and cooling drill bit  24 F. An example material of flex shaft  94 F is a soft and relatively flexible material (e.g. titanium), in the example shown flex shaft  94 F does not include an inner bore or other passage for the flow of drilling fluid. In this example, transfer of drilling fluid from the annular space between flex shaft  94 F and housing  26 F and inner bore of subcomponents  36 F and  38 F takes place through openings in upper subcomponents  36 F or openings in an optional bonnet sub (not shown) between upper subcomponent  36 F and flex shaft  94 F. In an example of operation, rotor  96 F rotates within stator  98 F by flowing wellbore fluid, such as drilling fluid, through tubular  20 F and into stator  98 F. Rotation of rotor  96 F in turn rotates flex shaft  94 F, upper and lower drive upper and lower subcomponents  36 F,  38 F, and in one embodiment drill bit  24 F. Similar to the example of  FIG.  2 C , upper and lower subcomponents  36 F,  38 F are coupled together with a fastener, such as a threaded fastener; the fastener shown in the example includes a torque nut  62 F and a stinger  48 F; in another example the fastener includes an elongated torque member  62 F (e.g. a bolt with a head) as previously shown in  FIG.  3 C . In an example, when drilling an operational torque is acting on upper subcomponent  36 F and is transmitted by this coupling to lower subcomponent  38 F and further to a drill bit  24 F shown attached to an end of lower subcomponent  38 F opposite its connection to upper subcomponent  36 F. In an example, torque nut  62 F (or likewise elongated torque member  62 F (e.g. a bolt with a head)—as previously shown in  FIG.  3 C ) does not transmit torque from upper subcomponent  36 F to lower subcomponent  38 F or from upper subcomponent  36 F and/or lower subcomponent  38 F to drill bit  24 F. Instead, a gap  83 F is defined between torque nut  62 F and drill bit  24 E as well as between a stinger  48 F and drill bit  24 F to allow for full pre-compression when threading drill bit  24 F to lower subcomponent  38 F. Optionally, upper and lower subcomponents  36 F,  38 F are rotating within and relative to a housing  26 F and both are transmitting the complete drilling torque (except losses due to contact between outer diameters of drive shaft members and housing  26 F or borehole  12 F). A portion of upper subcomponent  36 F proximate its lower terminal end has a reduced diameter to define stinger  48 F. The outer diameter of upper subcomponent  36 F abruptly transitions where the stinger  48 F initiates and which forms a downward facing shoulder  50 F. Stinger  48 F is shown inserted into and circumscribed by lower subcomponent  38 F, and where shoulder  50 F abuts shoulder  52 F formed on an upper terminal end of lower subcomponent  38 F. In an embodiment, engagement of shoulders  50 F,  52 F forms link  40 F, and similar to links described above provides for the transfer of forces respectively a major portion of the drilling torque (such as about 75%) further across upper and lower subcomponents  36 F,  38 F. Also in this embodiment a minor remaining portion of the drilling torque (such as about 25%) is transmitted across the compression element or fastener (torque nut  62 F and stinger  48 F), by static friction or adhesion at mating contact faces and without further locking element. In an example, link  40 F has an outer diameter that is smaller than bearing  71 F, in this example link  40 F includes parts of bearing  71 F such as one or more bearing races between shoulders  50 F and  52 F. The one or more bearing races optionally have complementary shoulders to shoulders  50 F and/or  52 F of link  40 F, and also optionally include shoulders that are complementary to shoulders of other subcomponents that are abutted by the shoulders such as other bearing races. In one example, a stack of bearing rings or races are pre-compressed between shoulders  50 F and  52 F of upper and lower subcomponents  36 F and  38 F to form link  40 F. Optionally included with shoulders of bearing rings or races are torsional locking elements in a same way as discussed throughout this disclosure with respect to other subcomponents of threaded connections. In this case, the outer diameter of link  40 F and the engagement area of shoulders  50 F and  52 F is limited by the maximum outer diameter of bearing  71 F and smaller than other RSTC within the bottom-hole assembly  22 E, such as the connection between tubular  20 F and upper subcomponent  36 F of the drive shaft or lower subcomponent  38 F of the drive shaft and drill bit  24 F. In addition, the minimum inner diameter of upper and lower subcomponents  36 F and  38 F of the drive shaft is limited to provide sufficient space for fluid flowing through inner bore  99 F to drill bit  24 F to cool and lubricate drill bit  24 F. In this situation, the engagement area where shoulders  50 F and  52 F are engaged is limited and reduced compared to other RSTC within the bottom-hole assembly  22 F, such as the connection between stator  94 F and housing  26 F or lower subcomponent  38 F and drill bit  24 F due to the maximum inner diameter of upper and lower subcomponents  36 F and  38 F of the drive shaft and maximum outer diameter of bearing  71 F. The reduced engagement area does not allow the same amount of pre-compression at link  40 F as at other RSTC within the bottom-hole assembly  22 F, such as the connection between tubular  20 F and upper subcomponent  36 F of the drive shaft or lower subcomponent  38 F and drill bit  24 F. In addition, the reduced diameter of link  40 F in turn limits a maximum torque t transferred across link  40 F, such as the torque t that is needed to rotate upper and lower subcomponents  36 F and  38 F of the drive shaft and drill bit  24 F in contact with formation  16 F, plus torque created by torsional oscillations due to the rotation of drill bit  24 F in contact with formation  16 F. In some instances the maximum torque t transferred across link  40 F is less than that of a RSTC with larger diameters within the bottom-hole assembly  22 F, such as the connection between tubular  20 F and upper subcomponent  36 F of the drive shaft or lower subcomponent  38 F and drill bit  24 F. In the special situation where link  40 F between upper subcomponent  36 F and lower subcomponent  38 F of the drive shaft is limited between the maximum inner diameter of the drive shaft and maximum outer diameter of bearing  71 F, one or both of shoulders  50 F and  52 F (and complementary shoulders of subcomponents between shoulders  50 F and  52 F, e.g. bearing traces) are advantageously provided with torsional locking elements, such as shown and described in more detail above and below. In examples in which several modes of torsional oscillations exist within drilling assembly  22 F, torsional locking elements are provided on one or both of shoulders  50 F and  52 F as shown and described in more detail above and below. Optionally, torsional locking elements are included when a distance between link  40 F and drill bit  24 F, is up to about 8 m, is up to about 5 m, or up to about 3 m. In an example of operation, rotor  96 F rotates within stator  98 F by flowing fluid through drill pipe  20 F and into stator  98 F. Rotation of rotor  96 F causes flex shaft  94 F,  96 F to rotate, that in turn rotates upper and lower subcomponents  36 F,  38 F. In one embodiment a distance between bit  24 F and link  40 F ranges up to about three meters. An axis A 94F  of flex shaft  94 F precesses about axis A X  with rotation of flex shaft  94 F. 
     Schematically represented in  FIG.  8 A  is a first subcomponent  101  which has a first longitudinal axis A 101  and first end  102  with a shoulder  103  similar to shoulders  50 - 50 E described above. A second subcomponent  104  is shown spaced axially away from first subcomponent  101  and having a second longitudinal axis A 104 . Second subcomponent  104  as shown further includes a second end  105  and shoulder  106  similar to shoulders  52 - 52 E described above. A preload force F 107  is schematically shown directed axially from first subcomponent  101  and towards second subcomponent  104 . An example of a locking element  108  is shown within a dashed outline, and that rotationally interlocks (micro or macro scale) mating ends  104 ,  105 . The example locking element  108  includes a raised member  109  shown projecting axially from shoulder  103  and intermeshed between raised members  110  and raised member  111  that each project from shoulder  106 . In an example, locking element  108  makes up the torsional locking element referred to above. A first surface  112  of raised member  109  is in contact with a first surface  113  of raised member  110 , and a second surface  114  of raised member  109  is in contact with a second surface  115  of raised member  111 . Surfaces  112 ,  113 ,  114 ,  115  are shown as being planar and oriented generally oblique with axis A 104 . A first surface vector V 112  and a second surface vector V 114  are schematically represented as arrows extending in a direction generally perpendicular with first and second surfaces  112 ,  114  respectively. Also schematically shown is surface vector V 113  that is directionally opposite first surface vector V 112 , and torque t 101  representing rotational torque of section  101  and about axis A 101 . 
     Similarly, schematically represented in  FIG.  8 B  is a first subcomponent  101 A which has a first longitudinal axis A 101  and a first end  102 A having a shoulder  103 A similar to shoulder  103  of  FIG.  8 A . A second subcomponent  104 A is spaced away from first subcomponent  101 A and has a second longitudinal axis A 104A , a second end  105 A of second subcomponent  104 A faces second end  103 A and includes a shoulder  106 A similar to shoulder  106  of  FIG.  8 A . A preload force F 107A  is schematically represented directed axially from first subcomponent  101 A to second subcomponent  104 A. A locking element  108 A is represented within a dashed outline, and which includes an irregularly shaped member  109 A in contact with shoulder  103 A and partially embedded in shoulder  106 A. A first surface  112 A of member  109 A engages a second surface  113 A that is within shoulder  106 A, and a second surface  114 A of member  109 A shown facing away from first surface  112 A is in contact with a second surface  115 A also within shoulder  106 A. A first surface vector V 112A  and a second surface vector V 114A  are schematically represented as arrows extending in a direction generally perpendicular with first and second surfaces  112 A,  114 A respectively. Also schematically shown is surface vector V 113A  that is directionally opposite first surface vector V 112A , and torque t 101A  representing rotational torque of section  101 A and about axis A 101A . 
     An advantage realized with the present disclosure is the hindrance or prevention of sliding (cyclic or otherwise), e.g. torsional or rotational sliding, between opposing surfaces of a connection, such as a connection between a pair of tubulars and one of the tubulars is rotating in response to rotation of the other tubular. An example of opposing surfaces include the shoulders in connections in a RSTC that are otherwise subject to sliding when subjected to cyclic torsional loading like HFTO. In  FIG.  2 D  a ring  116 - 116 F (e.g. a washer ring, a shim ring, a bearing ring, or race, or any other component) with surfaces  118 - 118 F and  120 - 120 F is shown optionally inserted between shoulder  50 - 50 F of lower subcomponenet  36 - 36 F and with torsional locking elements  42 - 42 F and shoulder  52 - 52 F of lower subcompenent  38 - 38 F with torsional locking elements  44 - 44 F, and being as well compressively preloaded by the fastener. In an alternative, ring  116 - 116 F is part of the locking element, as described above in detail and optionally disposed between at least one or any mating shoulders to prevent rotational sliding; in a specific examples such as between upper drive shaft shoulder  50 F and a ring shoulder; or between mating ring shoulders (in case of multiple rings). Similar modifications to presently known driveshaft connections of a downhole motor or rotary steering system also present significant advantages. As such, the damage to shoulders and cracks of currently known connections is avoided with implementation of techniques described herein. 
     The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims. 
     Set forth below are some embodiments of the foregoing disclosure: 
     Embodiment 1. A downhole assembly comprising: an axis; a first tubular member; a second tubular member; a fastener in selective simultaneous engagement with the first and second tubular members, the fastener, having a diameter less than diameters of the first and second tubulars, that is in interfering contact with the second tubular member, and selectively configured to be in axial compression; a first contact surface on the first tubular member; a second contact surface on the second tubular member that is engaged with the first contact surface when the fastener is in axial compression; a first profile on the first contact surface comprising facets; and a second profile on the second contact surface comprising facets that are complementary to the facets of the first profile and abut the facets of the first profile. 
     Embodiment 2. The downhole assembly of Embodiment 1, wherein the first and second profiles comprise raised members on the first and second contact surfaces, and wherein the facets comprise lateral sides of the raised members. 
     Embodiment 3. The downhole assembly of any prior embodiment, wherein an elongated stinger extends axially from the first tubular member and inserts into a bore in the second tubular member, and wherein the fastener threadingly engages an end of the stinger distal from the first tubular member. 
     Embodiment 4. The downhole assembly of any prior embodiment, wherein the fastener is disposed in an annular space defined where a radius of the bore is increased along a portion of the second tubular member, and where the fastener is in interfering contact with a shoulder that is formed at an end of the annular space. 
     Embodiment 5. The downhole assembly of any prior embodiment, wherein the fastener comprises an annular member disposed in a bore in the second tubular member, and wherein the fastener is in selective engagement with an inner diameter of the first tubular member. 
     Embodiment 6. The downhole assembly of any prior embodiment, wherein an outer diameter of the fastener is increased along a portion of the fastener distal from the first tubular member to define a raised collar, and wherein the raised collar is disposed in an annular space that circumscribes a portion of the bore. 
     Embodiment 7. The downhole assembly of any prior embodiment, wherein a lateral side of the raised collar facing the first tubular member is in interfering contact with a shoulder defined at an end of the annular space. 
     Embodiment 8. The downhole assembly of any prior embodiment, wherein the assembly comprises a drilling motor and is attached to a drill bit that is selectively disposed in a wellbore. 
     Embodiment 9. The downhole assembly of any prior embodiment, wherein the first tubular member comprises an upper drive shaft, and wherein the second tubular member comprises a lower drive shaft. 
     Embodiment 10. The downhole assembly of any prior embodiment, wherein the first and second contact surfaces are each in planes that are substantially perpendicular with the axis. 
     Embodiment 11. A downhole assembly comprising: a first tubular member; a second tubular member selectively engaged with the first tubular member with a coupling having an outer radius that is less than an outer radius of the first tubular member and an outer radius of the second tubular member; an interface between the first and second tubular members, and across which a rotational torque between the first and second tubular members is transmitted; first and second shoulders respectively provided on the first and second tubular members, the first and second shoulders in selective engagement with one another when the interface is formed; and projections on at least one of the first and second shoulders, and through which a portion of rotational torque between the first and second tubular members is transmitted. 
     Embodiment 12. The downhole assembly of any prior embodiment, wherein the projections comprise a first set of raised members that project axially from the first shoulder, and have lateral sides that are oriented oblique with an axis of the first tubular member. 
     Embodiment 13. The downhole assembly of any prior embodiment, wherein the projections further comprise a second set of raised members that project axially from the second shoulder, and have lateral sides that are complementary to the lateral sides on the first set of raised members. 
     Embodiment 14. The downhole assembly of any prior embodiment, wherein the coupling comprises an annular fastener having a portion threaded to the first tubular member, and a distal portion in compressive engagement with the second tubular member. 
     Embodiment 15. The downhole assembly of any prior embodiment, wherein the annular fastener is in compression when the first and second tubular members are engaged. 
     Embodiment 16. The downhole assembly of any prior embodiment, wherein the projections comprise particles on a first surface of the first shoulder, and that press into a second surface on the second shoulder when the first and second tubular members are engaged. 
     Embodiment 17. The downhole assembly of any prior embodiment, wherein the particles are embedded in the first surface. 
     Embodiment 18. The downhole assembly of any prior embodiment, wherein the interface comprises the coupling and the first and second shoulders. 
     Embodiment 19. The downhole assembly of any prior embodiment, wherein the shoulders are annular and circumscribe the coupling. 
     Embodiment 20. A downhole drilling assembly comprising: a first shaft member section having a first longitudinal axis; a second shaft member section having a second longitudinal axis; a drill bit at an end; one of the first and second shaft member sections torsionally fixedly connected to the drill bit; a housing; at least one of the first and the second shaft member sections disposed within the housing; the first and the second shaft member sections connected to transmit torque to the drill bit through a connection; the connection comprising a first end of first shaft member section and a second end of second shaft member section engaged with each other by a preload force that has a component that is parallel to one of the first and the second longitudinal axis; the engagement obtained by relative movement of both ends parallel to one of first and second longitudinal axis towards each other and without rotation against each other; a locking element creating a rotational interlock with at least a part of at least one of the two ends; the locking element comprising a first and a second surface at the first end each defined by at least one surface vector, each of the at least two surface vectors having a component that is perpendicular to the first longitudinal axis; a third and a forth surface at the second end each defined by at least one surface vector, each of the at least two surface vectors having a component that is perpendicular to the second longitudinal axis; the first and the third surface engaged with each other, defining a first pair of engaged surfaces and a first continuous contact area at which a first impact force is transmitted under torque; the second and the forth surface engaged with each other, defining a second pair of engaged surfaces and a second continuous contact area at which a second impact force is transmitted under torque; each center of first and second continuous contact areas being eccentrically to first and second longitudinal axis; each of the first and the second impact forces having a component that is perpendicular to one of first and second longitudinal axis.