Abstract:
A locking swivel apparatus including an upper body portion having a counter bore about a cylindrical axis and a mandrel having an upper end receivable in the counter bore. The locking swivel also includes a lower cap member engaged with the upper body portion and disposed to secure the upper end of the mandrel in the counter bore. The locking swivel further includes an internal locking arrangement including a plurality of mating axial teeth configured to selectively couple and decouple the upper body portion and the mandrel. The selective coupling and decoupling disposed to correspondingly constrain and allow relative rotation of the upper body portion and the mandrel about the cylindrical axis. Methods are provided for fabricating embodiments of the present invention.

Description:
RELATED APPLICATIONS  
       [0001]    This application is a continuation of co-pending, commonly-assigned U.S. patent application Ser. No. 09/498,188 entitled MECHANICAL LOCKING SWIVEL APPARATUS, filed Feb. 4, 2000. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The apparatus of the present invention relates to locking swivels. More particularly, the present invention relates to an improved mechanical locking swivel positionable above the rig floor for allowing the reorientation of a bent sub during a directional drilling without having to withdraw a wireline that has been located within the drill string from above the rig floor.  
         BACKGROUND OF THE INVENTION  
         [0003]    In the drilling of oil wells, one of the more frequent types of wells that are drilled are directional wells. Rather than have to drill a well vertically, often times because of the location of the pocket of hydrocarbons, or for other reasons, the direction of the well has to be altered or done in a direction off of the vertical and is termed a directional well. This is accomplished with the use of a type of a bent sub, which is placed on the lower end of the drill string and the drill bit is rotated downhole via a motor known as a dynadrill. The bent sub, when it is oriented in a particular pre-determined orientation, will have the bit drill travel in that particular orientation as a directional well.  
           [0004]    Quite often in the drilling process, the direction of the drill bit has been mis-oriented and has to be adjusted slightly in order to reorient the bit in the proper direction. In most cases, this can easily be accomplished by setting the drill string via the slips, and rotating the rotary table slightly so that the entire drill string is re-oriented and then drilling can resume at that orientation. However, in the instance when there is a wireline which has been fed down into the drill string, because the wireline is usually fed through a side entry sub apparatus, the string cannot be rotated due to the fact that that would put stress on the wireline itself, which may result in the wireline being cut and the tool at the end of the wireline could be lost within the well bore, which would result in the tool having to be retrieved if possible. This is time consuming and expensive and requires that the well be shut down in order to do so. However, in the current state of the art, in order to reorient the drill bit while a wireline is downhole, the tool at the end of the wireline has to be retrieved from the well. Next, the drill string has to be reoriented in the proper direction and then the wireline would be re-fed down into the drill string for undertaking its work downhole. Again, this is time consuming and results in loss of rig time. There are also devices known in the industry, which attempt to provide a means by which the drill string can be oriented without having to orient the upper portion of the drill string above the rig floor where the wireline is being fed. These types of tools are known as swivels, and to some extent are successful to a certain point.  
           [0005]    There currently is issued U.S. Pat. No. 5,996,712, entitled “Mechanical Locking Swivel Apparatus,” which provided for a pair of pin members to engage the teeth of a second portion of the apparatus in order to lock the mandrel in place. Each of the pin members was set within a bore in the body of the tool, so that the pin could extend into the bore of the upper portion to engage the mandrel. It has been determined that this particular arrangement lends itself to a weakening of the upper tool body, and does not accomplish the task of the tool in the most favorable fashion. Therefore, applicant has attempted to solve this problem with the improved mechanical swivel apparatus as will be discuss and claimed in the present application.  
         SUMMARY OF THE INVENTION  
         [0006]    The apparatus of the present invention solves the shortcomings in the art in a simple and straightforward manner. What is provided is an improved mechanical swivel apparatus which has a first upper body portion threadably attached to the lower end of a side entry sub apparatus, and a second lower portion which is threadably attached to a section of drill pipe, the apparatus positionable above the rotary table on the rig floor, and having a continuous bore therethrough for running wireline or the like. The upper body portion includes a counterbore for receiving the upper end of a mandrel, so that the mandrel is able to move within the counterbore of the upper body portion. The lower portion comprises an open-ended cap member, which threadably engages the upper body portion, and has a shoulder portion, which engages a flange around the body of the mandrel so that the mandrel is allowed to move within the upper body portion but cannot be slidably removed therefrom. On its upper end, the mandrel portion further includes a plurality of outwardly extending teeth which define spaces there between, so that a plurality of teeth extending into the counterbore of the upper body portion, at a first position, lockingly engage between the teeth on the mandrel portion so that the mandrel portion is locked in place with the body portion. In a second position, the teeth on the mandrel are slidably moved out of engagement with the teeth on the upper body member, allowing the mandrel, and the drill string below the mandrel to move freely.  
           [0007]    In operation, the teeth of the upper body portion are engaged within the inner spaces between the teeth in the mandrel so that when the upper body portion is rotated, the mandrel is rotated, and in a second position the teeth of the upper body portion are disengaged from the teeth of the mandrel portion, so that the mandrel portion can remain stationary while the upper body portion is rotated. There is further included a plurality of seals and the like for sealing off the engagement of the surfaces between the moving parts of the body portions and the mandrel so that any fluid being flowed down through the bore in the tool is prevented from leaking out of the apparatus.  
           [0008]    Therefore, it is a principal object of the present invention to provide a mechanical swivel apparatus which provides an upper body portion engaged to a lower mandrel portion, through interlocking teeth formed on the outer face of the mandrel and the inner face of the upper body portion, so that the integrity of the walls of the body portion and the mandrel portion is not comprised through pins inserted into bores in the wall or the like.  
           [0009]    It is a further principal object of the present invention to provide an improved mechanical swivel apparatus, which mechanically engages and disengages so that the drill string below the apparatus can be rotated while the portion of the drill string above the apparatus remains stationary.  
           [0010]    It is a further principal object of the present invention to provide an improved mechanical swivel apparatus which provides for an upper body portion to mechanically engage a lower mandrel portion so that the drill string below the apparatus can be rotated while the portion of the drill string above the apparatus is rotated, the mechanical engagement allowing optimum strength in the body portion and the mandrel portion during engagement.  
           [0011]    It is a further object of the present invention to provide a mechanical swivel apparatus which is inserted along the drill string between an upper side entry sub through which wireline is fed, and the lower drill string, so that when the lower drill string must be rotated in order to properly orient the drill bit, the tool body can be placed in the disengaged position and the upper portion, including the side entry sub with the wireline, remains stationary, while the drill string is rotated to the proper orientation.  
           [0012]    It is a further object of the present invention to provide an apparatus positioned within the drill string above the rig floor which provides a mechanism to allow rotation of the drill string below the apparatus and to provide that the portion of the drill string above the apparatus remain stationary during wireline operations if orientation of the drill bit is necessary.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0014]    [0014]FIG. 1 illustrates an overall view of the preferred embodiment of the apparatus of the present invention within a drill string.  
         [0015]    [0015]FIG. 2 illustrates an exploded view of the lower mandrel portion including the lower cap and brass collar member of the preferred embodiment of the apparatus of the present invention.  
         [0016]    [0016]FIG. 3 illustrates an exploded view of the upper body portion of the preferred embodiment of the apparatus of the present invention.  
         [0017]    [0017]FIG. 4 provides a cross section view of the preferred embodiment of the apparatus of the present invention in the engaged position.  
         [0018]    [0018]FIG. 5 illustrates a cross section view of the apparatus of the present invention in the disengaged position.  
     
    
     DETAILED DESCRIPTION  
       [0019]    [0019]FIGS. 1 through 5 illustrate the preferred embodiment of the apparatus of the present invention by the number  10 . As illustrated in overall view in FIG. 1, there is illustrated the mechanical swivel apparatus  10  placed with in a drill string assembly  12 , the drill string as illustrated including an upper drive assembly  14 , a side entry sub apparatus  16 , of the type that is claimed and disclosed in U.S. Pat. Re 33,150, owned by Boyd&#39;s Bit Service, Inc., which, as illustrated includes a principal body portion  18 , and an angulated portion  20  having an upper fixture  22  for feeding a wireline  24 , as seen in partial view, down through a bore in the assembly  22  and principal body  18 , and down through the bore  25  in the drill string assembly  12  as illustrated. The assembly  10 , as illustrated, would be connected on its lowermost end to a section of drill pipe  26 , which is seen being moved into or out of the drill hole at the level of the rotary table  28 . In this particular embodiment, although not illustrated, on the lower end of the drill string there would be included a drill bit which would be operated by a dynadrill apparatus which is commonly known in the industry, and most likely there would be included a bent sub unit adjacent the dynadrill so that the drill bit would be drilling in a directional orientation.  
         [0020]    In discussing the particulars of apparatus  10  as illustrated in FIG. 1, reference is made to FIGS.  2 - 5 . As illustrated, apparatus  10 , as was discussed earlier, would be connectedly engaged on its upper portion to perhaps a sub  27 , which may be a wear sub, which would be utilized in conjunction with the side entry sub apparatus  16 . The sub  27  would be threadably engaged via threads  30  to the upper body portion  32  of the apparatus, through a pin and box connection (as illustrated on FIGS. 3, 4 and  5 ). With reference to FIG. 3, the upper body portion  32  would include a bore portion  34  which would be substantially the same size bore as the drill pipe  26  and the sub  27 . The bore  34  of the upper body portion  32  would form an expanded counter bore area  36  for receiving the upper end  38  of a mandrel  40  (illustrated generally on FIG. 2), the purpose of which will be described further. As further illustrated on FIGS. 2 through 5, the lower end of the body portion  32  would form a pin and box threaded connection  42  to a lower cap member  44 . Lower cap member  44 , when threaded to the lower end of the body portion  32 , provides a bore in which the mandrel travels, and includes a lower shoulder  45 , the function of which will be described below.  
         [0021]    As further illustrated in FIG. 2, reference is made to mandrel  40 , which as was stated earlier, includes the upper end  38  and the lower pin end  39 , which would be threadably engaged to the box end  41  of drill pipe  26 , as seen in FIGS. 4 and 5. Like body portion  32 , mandrel  40  would also include a continuous bore  34  that would be basically continuous with the bore of the upper body portion  32  and cap  44 . Mandrel  40  would include a continuous side wall  46  which would be of a diameter slightly less than the internal diameter  47  of the shoulder  45  formed by the lower end of cap portion  44 , and including an angular flange  50  around its wall  46 . As illustrated, after mandrel  40  has been inserted into the counter bore  36  of the upper body portion  32 , the cap member  44  is threadably engaged to the lower end  42  of upper body portion  32  illustrated generally on FIG. 3. The threadable engagement between cap  44  and lower end  42  would be through a left hand thread rather than the normal right hand thread when threaded connections are made up. It should be noted that once cap member  44  is threaded in place, the annular flange  50  formed around the wall  46  of mandrel extends outward further than the opening  47  of the cap member  44 , thus the mandrel  40  cannot become disengaged from within the counter bore  36  for the reasons as will be described further. As illustrated, mandrel  40 , as was stated earlier, has a continuous wall  46  and a continuous bore  34  therethrough which would coincide with the continuous bore of body portion  32  for continuous flow of fluid down the drill string and allows the continuous movement of wireline a indicated by arrow  76  in FIG. 5. Further as illustrated on FIGS. 2 and 5, and was stated earlier, mandrel  40  includes the continuous annular flange  50 , the upper surface of which  51  which rests against a Teflon® (E. I. DuPont de Nemour, Wilmington, Del.) member  68 . Further, the mandrel includes a lower point end  39 , which would threadably engage into a length of drill pipe  26 . With reference now to FIG. 2, on the upper end of mandrel  40 , there is included an engagement means  80 . This engagement means  80  includes a plurality of spaced apart teeth members  82  defining spaces  84  therebetween. The spaces  84  would be slightly larger that the width of the teeth members  54  formed in the upper body portion  32  on FIG. 3, for the reasons as will be discussed further. As further illustrated in FIG. 2, the lower cap  44  is illustrated with its inwardly extending shoulder  45  from its continuous wall portion  48 . The cap as was stated earlier includes a series of upper threads  49  which threadably engage to the lower end  42  of body  32 , for the reasons as stated earlier. As further illustrated in FIGS. 2 and 5, there is a brass collar  75 . Brass collar  75  would be slidably engaged within cap member  44  and would loosely fit against the wall  48  of cap member  44  so as to serve as a protective barrier between the mandrel  40  and the cap member  44  while the tool is at rest so as to help to prevent rust or the like from forming.  
         [0022]    Reference is now made to FIG. 3, which illustrates the particular construction of the upper body portion  32 . As was stated earlier, upper body portion  32  includes an upper neck portion  33 , which is threadably engaged at threads  30  to a sub  27  as was seen in FIGS. 4 and 5. There is again as illustrated in FIG. 3, a continuous bore  34  through the body portion, which expands into an enlarged counter bore  36 . As illustrated, the neck portion  33  then forms a thickened lower body portion  35  in which the counter bore  36  is formed, which then results in the lower threaded end  42  of the body portion  32 , which would then threadably engage with cap member  44 , which is illustrated in composite view in FIGS. 4 and 5. Continuing with FIG. 3, there is included a plurality of teeth  54  formed in the inner wall  55  of the lower body portion  32 . There is further included a ring  68  formed of Teflon® or the like which would rest around a lower shoulder  70  of the lower body portion  35  so as to form a smooth mating surface between the ring  68  and the flange  50  of mandrel  40  during operation.  
         [0023]    Reference now is made to FIGS. 4 and 5 for a discussion of the overall operation of the tool. As seen in FIG. 4, the mandrel  40  is in position within the counter bore  36  of body portion  32  and the mandrel is maintained within the opening  36  of body portion  32  via the cap portion  44  that has been engaged thereto. It is seen that the teeth  54  in the body portion  32  project into the counter bore  36 , and are engaged within the spaces  84  formed between the teeth members  82  of the mandrel  40 . In this position, the teeth  54  of body  32  are interlocked with teeth  82  of the mandrel  40 , and the mandrel therefore, is locked in place with body portion  32  and cap  44 , for example, while the drilling is taking place by the directional drill bit, and both the body portion  32  and mandrel  40  are rotating in unison as seen by arrows  90 .  
         [0024]    In the event that the drill bit needs to be reoriented, reference is made to FIG. 5, where the upper body portion  32  again is illustrated threadably engaged to the cap member  44  with the mandrel  40  secured within counter bore  36 . However, in this position the teeth  82  of mandrel  40  have been moved out of alignment with the teeth  54  of the body portion  32 , so that the mandrel  40  is free to rotate freely in the direction for example of arrow  92 , without the upper body portion  32  and cap  44  rotating. This is accomplished by securing the section of drill pipe  26 , which is projecting into the rotary table by the slips on the rotary table. Since the mandrel  40  is threadably secured to the now stationary drill pipe  26 , as the upper portion of the tool is moved slightly downward in the direction of arrow  93  on FIG. 4, the teeth members  54  of the body  32  move out of alignment with teeth members  82  of the mandrel  40 . When this is accomplished, the mandrel  40 , together with the drill pipe  26  below the mandrel, is free to rotate while the upper body portion  32 , and the assembly above it, remaining stationary. Referring momentarily to FIG. 1, the rotary table  28  can then be rotated the number of degrees necessary to properly align the drill bit without the upper portion of the tool  10  and anything above it, including the side entry sub  16 , having to move. After the drill bit has been properly oriented, the upper portion of the drill string  26  (as seen on FIG. 5) is moved slightly upward in the direction of arrow  94  until the teeth  54  of body portion  32  are slidably re-engaged within the inner spaces  84  between teeth  82  of mandrel  40 , so that the entire drill string now becomes stationary as one fixed string.  
         [0025]    This improved mechanical locking swivel, which utilizes interlocking teeth between the mandrel  40  and body  32  results in a substantially stronger engagement between the two members, and by having the teeth formed on the inner wall of the body  32  and the outer wall of the mandrel  40 , the walls of the two members are not compromised by through bores or the like, and are stronger in order to drive the drill string when the two members are engaged through the interlocking of the teeth.  
         [0026]    Furthermore, this improved mechanical swivel apparatus, by allowing engagement and disengagement between portions of the apparatus through interlocking teeth, has allowed one portion of the apparatus to remain stationary while a second portion of the apparatus is movable. This gives the driller the ability to rotate that portion of the drill string below the upper portion of the apparatus without having to rotate the upper portion of the apparatus and anything above it at all. By doing this, this eliminates any potential problem that would arise should the side entry sub have to be rotated with the wireline engaged through it, which would put unneeded stress on the wireline and perhaps rupture it.