Patent Document

BACKGROUND 
       [0001]    Wellheads are used in oil and gas drilling to suspend casing strings, seal the annulus between casing strings, and provide an interface with the blowout preventer (“BOP”), for example. The design of a wellhead is generally dependent upon the location of the wellhead and the characteristics of the well being drilled or produced. 
         [0002]    In drilling the well, it is conventional to pass a number of concentric tubes (e.g., casing strings, tubing strings, etc.) down the well to support the borehole and/or segregate the borehole into annular zones. Typically, an outermost casing (i.e., conductor) is fixed in the ground, and the inner casings (e.g., casing, production casing, production tubing) are each supported from the next outer casing or by the wellhead. The wellhead is thus used to support a number of hangers that support the weight of the casing. In certain instances, it is desirable to apply torque to a downhole hanger or tool. Unfortunately, traditional torque-applying tools are typically bulky and difficult to position over the hanger, for instance. Moreover, traditional tools obstruct the borehole when installed, thus precluding full-bore access. 
         [0003]    Hangers also use seal assemblies to seal the annuli between the hangers and the wellhead. However, the seals as well as the casing itself are subject to forces throughout the life of the well that might cause the hanger to unseat and potentially compromise the seal between the casing hanger and the wellhead, for example. Thus, the seals used with hangers must be restrained from movement when subjected to force. The seal assemblies typically include robust bodies including both inner and outer seals that are set upon by applying actuation torque from a tool above the seal assembly. Typically, because the torque is applied from above the seal assembly, the actuator tool may only access one portion of the seal assembly to apply the actuation torque. Thus, usually both the inner and outer seals of the seal assembly are set simultaneously. In some situations, however, the inner and outer seals require different amounts of force to be set and thus simultaneous actuation constrains the ability to properly form a seal against the wellhead. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    For a more detailed description of the embodiments, reference will now be made to the following accompanying drawings: 
           [0005]      FIG. 1A  is a cross section of casing in a wellhead with an adjustable hanger being installed using an exemplary torque-provider assembly, wherein the left portion illustrates an over-pulled position and the right portion illustrates the installed position; 
           [0006]      FIG. 1B  is a view of the torque-provider assembly taken from plane A-A of  FIG. 1A ; 
           [0007]      FIG. 1C  is a view of an alternative and exemplary embodiment of a torque-provider assembly taken from plane A-A of  FIG. 1A  and showing a reverse orientation; 
           [0008]      FIG. 1D  is a view of another alternative torque-provider assembly taken from plane A-A of  FIG. 1A  and showing a combination of advancing and reverse-orientation pistons. 
           [0009]      FIG. 2A  is a view of the torque-provider assembly taken from plane A-A of  FIG. 2B ; 
           [0010]      FIG. 2B  is a cross section of an example seal assembly shown being installed on a plug casing hanger; 
           [0011]      FIG. 3A  is a view of the torque-provider assembly taken from plane B-B of  FIG. 3B ; 
           [0012]      FIG. 3B  is a cross section of an example seal assembly shown being uninstalled from the plug casing hanger and showing torque pistons configured for reverse rotation; and 
           [0013]      FIGS. 4A-4E  show an actuation sequence of the torque-provider assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]    In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. Any use of any form of the terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
         [0015]      FIGS. 1A-B  show a torque-provider assembly  10  used to install a casing string supported by a casing hanger  13  in a wellhead  14  that includes a wellhead bore. The torque-provider assembly  10  includes at least one set of torque-provider pistons  16  located in a BOP adapter  18  installed between the wellhead  14  and a BOP  20 . The torque-provider assembly  10  may be secured using the connectors as shown, and it is appreciated that any other suitable connector may also be used. It is also appreciated, however, that the piston set  16  may be located in other structural components, such as the wellhead or BOP flanges, for example. 
         [0016]    Typically, a well is drilled by passing drill string through a wellhead and an attached BOP. Attached to the end of the drill string is a drill bit for creating the wellbore. As the wellbore is extended deeper, from time to time, the borehole must be supported from collapse or must be isolated from a fluid producing formation, for example. The drill string and drill bit are typically removed, and a tubular casing string (not shown) is run into the well to the desired depth. The weight of the casing is supported by a casing hanger  13 , which is secured to the upper end of the casing string and is supported by the wellhead  14 . In the example shown in  FIGS. 1A-B , the casing hanger  13  is an adjustable casing hanger that includes an adjustable landing ring  22 . The adjustable landing ring  22  rotates relative to the casing hanger  13  on threads to adjust the vertical position of the landing ring  22  relative to the casing hanger  13  body. As is shown, this threaded arrangement allows for relative vertical displacement between the casing hanger&#39;s body and the landing ring  22 . As a result, the tensioning of the casing string can be adjusted without changing the landing location of a landing shoulder, for example, on the wellhead  14 . In the illustrated embodiment, the adjustable casing hanger is run into an over-pulled position, at which time the torque-provider assembly  10  can be actuated to adjust the position of the landing ring  22  with respect to the casing hanger&#39;s body. Once adjusted, the casing hanger is lowered into its installed position, with the landing ring  22  engaging a landing shoulder  26  to support the casing hanger  13 . 
         [0017]      FIG. 1A  is a split view showing the casing hanger  13  and casing string being run into the wellhead  14  using a casing hanger running tool  24 , as described above. The illustrated casing hanger running tool  24  is secured to the casing hanger  13 , as would be appreciated by those of ordinary skill in the art. On the left,  FIG. 1A  shows the landing ring  22  before it is positioned for the wellhead landing shoulder  26 . On the right,  FIG. 1A  shows the landing ring  22  positioned and landed on the landing shoulder  26 . 
         [0018]    To position the landing ring  22 , the casing hanger running tool  24  includes a torque ring  28  and an energizing ring  30  that are used to transfer torque from the torque-provider piston set  16  to rotate the landing ring  22 . The torque-provider assembly  10  provides torque in a direction perpendicular to the longitudinal axis of the casing string  12 . As shown in  FIG. 1A , the torque-provider assembly  10  becomes essentially a horizontal torque-provider that provides torque to actuate and set the landing ring  22 . Thus, unlike some prior systems that require vertical access to the seal assembly, the torque-provider assembly  10  allows “horizontal” access to the landing ring  22  and does not require the positioning of a separate torque providing tool above the wellhead  14 . Moreover, the illustrated torque-provider assembly  10  provides full-bore access even when the torque-provider assembly  10  remains installed on the wellhead  14 . Thus, the torque-provider can mitigate expenses related to removal and reinstallation time, should the application of torque become later required. 
         [0019]    As shown in  FIGS. 1A-B , the torque-provider assembly  10  includes a single torque-provider piston set  16  that is hydraulically-powered to actuate pistons  32  and produce a rotational force on the landing ring  22 . The pistons  32  travel within cylinders  34  that are closed at their outer end with seal plugs  36 . Hydraulic lines (not shown) connect to the outside of the seal plugs  36  or to the BOP adapter  18  for providing hydraulic fluid pressure to the pistons  32  though seal plug ports  38  in the pistons  32  or the BOP adapter  18 . During actuation, the pistons  32  cycle between a retracted position to an extended position as hydraulic fluid pressure is applied and then retracted from the cylinders  34 . Also, as shown in  FIG. 1B , the pistons  32  are positioned around and are angled to engage the torque ring  28  at torque ring stops  40 . Thus, as each piston  32  extends, it engages a ring stop  40 , applying torque to the torque ring  28 . Unless restrained, the torque ring  28  rotates until the piston  32  is fully extended. The piston  32  then retracts and another piston  32  is extended to engage another ring stop  40  to further rotate the torque ring  28 . Depending on the application, the torque-provider  10  may also extend more than one piston  32  at the same time to engage ring stops  40  to apply higher amounts of torque or for possibly applying the final make-up torque for the torque ring  28 . 
         [0020]    Although described as hydraulic, it is appreciated that power may be provided by other means, even including providing power manually. It should also be appreciated that the piston set  16  may be any suitable configuration for providing torque to the landing ring  22  and may be actuated by a number of suitable means, including manual actuation or motorized actuation. Also, although shown with only one torque-provider piston set  16 , the torque-provider assembly  10  may also include more than one offset torque-provider piston set  16 . The piston set  16  may also include pistons  32  oriented for reverse rotation as shown in  FIG. 1C . Alternatively, the reverse pistons  32  may be combined with the advancing pistons  32  as shown in  FIG. 1D . Also, the reverse orientation pistons  32  may be a second, offset piston set  16  such as shown in  FIG. 2B  and described further below. With the reverse orientation, the pistons  32  may be used to both land and unseat the landing ring  22 . Additionally, the reverse orientation piston set  16  may be obtained by uninstalling the torque-provider assembly  10 , turning the assembly  10  over, and then reinstalling the torque-provider assembly  10 . 
         [0021]    Referring again to  FIG. 1A , the torque ring  28  is supported for rotation around the hanger running tool  24  but does not move axially when rotated. The torque ring  28  engages the energizing ring  30  in a key-in-groove arrangement such that rotating the torque ring  28  rotates the energizing ring  30  while allowing the energizing ring  30  to move axially. In addition, the energizing ring  30  engages the landing ring  22  in a tongue-and-groove arrangement such that rotation is transferred from the energizing ring  30  to the landing ring  22 . The torque-provider assembly  10  may thus be used to rotate the landing ring  22 . Rotation of the landing ring  22  moves the landing ring  22  in the direction of the landing shoulder  26  until the landing ring  22  is properly positioned, at which point the landing ring  22  lands on the shoulder  26  as shown on the right side of  FIG. 1A . The casing hanger  13  may now be supported by the wellhead  14  and the casing hanger running tool  24 , including the torque ring  28  and energizing ring  30 , may be removed from the wellhead  14  with the casing  12  and casing hanger  13  remaining installed in the wellhead  14 . The casing hanger running tool  24  may detach from the casing hanger  13  by any suitable method, such as rotating the casing hanger running tool  24  relative to the casing hanger  13  to release pins from a groove in the casing hanger  13 . It is appreciated that other connections between the casing hanger running tool  24  and the casing hanger  13  may also be used. With the casing and casing hanger  13  installed and the casing hanger running tool  24  removed, a seal assembly may be installed or other drilling operations may commence. 
         [0022]    Casing hangers typically use seal assemblies to form a seal between the outside of the casing hanger and the wellhead. As a further example of how the torque-provider assembly  10  may be used,  FIGS. 2A and 2B  show a seal assembly  42  that may be used to provide a metal-to-metal seal between the wellhead  14  and a plug casing hanger  13 . It is appreciated though that the seal assembly  42  may be used to seal off an actual casing hanger  13  and that seals other than a metal-to-metal seal may also be used under appropriate conditions. 
         [0023]      FIGS. 2A and 2B  show a torque-provider assembly  10  used to set the seal assembly  42  that is run into the wellhead  14  using a seal assembly running tool  46 . The torque-provider assembly  10  includes a BOP adapter  18  and torque-provider piston sets  16  that are secured onto the wellhead  14 . 
         [0024]    The torque-provider assembly  10  provides torque in a direction perpendicular to the longitudinal axis of the seal assembly running tool  46 . Thus, similarly to  FIGS. 1A-C , the torque-provider assembly  10  becomes essentially a horizontal torque-provider that provides torque to actuate and set the seal assembly  42 . Thus, unlike some prior systems that require vertical access to the seal assembly, the torque-provider assembly  10  allows “horizontal” access to the seal assembly  42 . The torque-provider assembly  10  may thus provide torque to the seal assembly  42  in different locations, in different amounts, and at different times if desired, which would not be possible with typical previous “vertical” access torque-providers. 
         [0025]    In the example shown in  FIGS. 2A and 2B , the torque-provider assembly  10  includes two piston sets  16 . For convenience, the piston sets  16  are described as a first, or “upper,” piston set  16  and a second, or “lower,” piston set  16 . It is appreciated that upper and lower piston sets  16  may be any suitable configuration for providing torque to the seal assembly  42 . For example, as shown and as previously described, the piston sets  16  are hydraulically-powered to actuate pistons  32  and produce a rotational force on the seal assembly  42 . However, torque may be provided by other means, even including providing torque manually. Also, although shown with two piston sets  16 , the torque-provider assembly  10  may include any number of piston sets  16  depending on the design of the seal assembly  42 . 
         [0026]    As shown in  FIGS. 2A and 2B , the seal assembly  42  is designed to form a seal in the annulus between the casing hanger  13  and the wellhead  14 . To do so, the seal assembly  42  includes a seal that forms an inner and outer seal contemporaneously by applying axial compression to expand the seal radially. However, it is appreciated that the seal may also be configured to set an inner seal and outer seal at different times. 
         [0027]    The seal assembly  42  includes nested sleeves, or rings, that rotate on threads to provide the axial compression for setting the seal. As shown in  FIG. 2B , the torque-provider assembly transfers torque to the seal assembly  42  through the seal assembly running tool  46  that includes an upper torque ring  52  supported for rotation on the seal assembly running tool  46  without relative axial movement. As shown, the upper piston set  16  provides torque to the upper torque ring  52 , which in turn rotates another ring that rotates on threads to compress and set the seal between the plug casing hanger  13  and the wellhead  14 . 
         [0028]    Once the seal is set, the upper piston set  16  may be deactivated to stop applying torque to the upper torque ring  52 . The lower piston set  16  may then be activated to lock the seal as well as lock the seal assembly  42  to the wellhead  14 . As shown, the seal assembly running tool  46  further includes a lower torque ring  58 . Similarly to the upper piston set  16 , the lower piston set  16  rotates the lower torque ring  58  without relative axial movement to the tool  46 . The lower torque ring  58  is likewise similar to the upper torque ring in that it is engaged with and thus is able to rotate additional rings on threads for axial movement. For example, the lower torque ring  58  drives rings to engage a securing mechanism for locking the seal assembly  42  in place in the wellhead  14 . The lower torque ring  58  also uses reverse thread mechanisms to lock the securing mechanism and the seal in place. 
         [0029]    With the inner and outer seals  48 ,  50  set and the seal assembly  42  locked to the wellhead  14 , the seal assembly running tool  46  may be removed. As shown in  FIGS. 3A and 3B , should the seal assembly  42  need to be removed, the torque-provider assembly  10  may include, or be replaced with piston sets  16  with pistons  32  oriented to rotate the upper and lower torque rings  52 ,  58  in the opposite direction, thus disengaging the seal assembly  42  to unset the seal. The seal assembly  42  may then be removed from the wellhead  14 . Although shown as separate from the piston sets  16  in  FIGS. 2A-B , it is appreciated that the reverse orientation pistons  32  may be included with the advancing pistons  32  in the same piston sets  16 . As previously mentioned, torque-provider assembly  10  may also be turned upside down to reverse the orientation of the pistons  32  to create reverse rotation torque. 
         [0030]    As described above and shown in  FIGS. 4A-4F , the torque-provider assembly  10  includes piston sets  16  that include more than one piston  32  acting on a torque ring  70 .  FIGS. 4A-4F  illustrate the actuation process of the pistons  32  on a unidirectional torque ring  70 . As shown, the pistons  32  are operated in alternating fashion to engage ring stops  72 . After one piston  32  is extended, it is retracted to provide clearance for another piston  32  to extend and thus further rotated the torque ring  70 . The process is repeated until the torque ring  70  is rotated to its desired position. However, more than one piston may be extended simultaneously for applying an increased amount of torque such as for applying the final make-up torque for a desired application. Although shown with only two pistons  32 , each piston set  16  may include more than two pistons  32  oriented to rotated the torque ring  70  in the same direction. Also, as described previously, the torque ring  70  may instead be a bi-direction torque ring with bi-directional torque ring stops as shown in  FIGS. 2A and 3A . In such an embodiment, there may be more than one offset piston set  16  with the piston sets acting to rotate the torque ring in different directions. Alternatively, a single piston set  16  may include pistons  32  in the same set that are oriented to rotate the torque ring in opposite directions. It is appreciated that these embodiments of piston sets  16  and torque rings are also applicable to each of the embodiments shown in  FIGS. 1A-3B . 
         [0031]    While specific embodiments have been shown and described, modifications can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments as described are exemplary only and are not limiting. Many variations and modifications are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.

Technology Category: 0