Abstract:
A resettable antiextrusion system including a backup ring, a ramp in operable communication with the backup ring, and a gauge ring attached to the ramp. A method for sealing a tubular.

Description:
BACKGROUND 
       [0001]    Annular seals are a common part of virtually all hydrocarbon recovery systems. Such seals come in many different configurations and ratings. Such seals are a necessary and important part of hydrocarbon recovery efforts and generally function well for their intended purposes. In situation where there is a high differential pressure across the seal however extrusion of the seal becomes a concern. Extrusion occurs axially when the seal is extruded through a small gap between the tubular at an inside surface of the seal and the tubular at the outside surface of the seal. The gap is there because in order to run a tubular into a casing, clearance is necessary. This is also the reason that a seal is needed in the first place. While many configurations have been created to limit the gap and improve extrusion resistance, the art is always receptive to alternative methods and particularly to configurations capable of accommodating higher pressure differentials. 
       SUMMARY 
       [0002]    A resettable antiextrusion system including a backup ring, a ramp in operable communication with the backup ring, and a gauge ring attached to the ramp. 
         [0003]    A method for sealing a tubular including compressing a resettable antiextrusion system including a backup ring, a ramp in operable communication with the backup ring, a gauge ring attached to the ramp, urging the backup ring along the ramp to gain a greater radial dimension than the gauge ring, deforming an element at the system into contact with the tubular adjacent the backup ring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
           [0005]      FIG. 1  is a cross section view of a resettable antiextrusion backup system in an unsealed condition; 
           [0006]      FIG. 2  is a cross section view of a resettable antiextrusion backup system in a sealed condition; 
           [0007]      FIG. 3  is a perspective view of a backup ring as disclosed herein; 
           [0008]      FIG. 4  is a perspective view of a ramp as disclosed herein; 
           [0009]      FIG. 5  is a perspective view of a gauge ring as disclosed herein; 
           [0010]      FIG. 6  is a perspective view of an assembly of  FIGS. 3 and 4 ; 
           [0011]      FIG. 7  is a perspective view of an assembly of  FIGS. 3 ,  4  and  5 ; 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIGS. 1 and 2  a cross section of a resettable antiextrusion backup system  10  is illustrated in an unset ( FIG. 1 ) and set ( FIG. 2 ) condition respectively. Focusing upon  FIG. 1 , the system  10  is illustrated in cross section within another tubular structure  12  such as a casing segment. It will be apparent that there is a clearance  14  between a gauge ring  16  and an inside surface  18  of the casing  12 . This clearance is taken up by an element  20  when the system  10  is compressed. This is similar to prior art devices in that those devices cause an element to expand into contact with an inside surface of a tubular in which they are set but due to the size of the clearance, extrusion of such elements is possible. In the system disclosed herein, extrusion is prevented by a backup ring  22  that is displaceable to occupy the clearance space entirely. With the backup ring  22  in place, it is impossible for the element  20  to extrude in the direction of the backup ring  22 . Advantageously, in the system disclosed, it is also possible to retract the backup ring  22  to an outside dimension less than that of the gauge ring  16 . Moreover, setting and unsetting of the system  10  is possible for a great number of cycles. 
         [0013]    In order to actuate the backup ring  22 , a number of other components of the system  10  are utilized. A ramp  24  exhibits a frustoconical surface  26  that interacts with the backup ring  22  during axial compression of system  10  to cause the backup ring  22  to gain in radial dimension resulting in the backup ring spanning the entirety, in one embodiment, or at least a substantial portion of, in other embodiments, the clearance  14 . In one embodiment the frustoconical surface  26  has an angle of about 40 to about 60 degrees and in a specific embodiment has an angle of about 50 degrees. In this position, the backup ring  22  effectively prevents extrusion of the element  20  due to differential pressure thereacross. 
         [0014]    The ramp  24  is fixedly connected at one or more connections  28  to the gauge ring  16  such that the ramp  24  and the gauge ring  16  always move together in an assembled system  10 . In order to provide a greater understanding of the backup ring  22 , ramp  24  and gauge ring  16 , reference is made to  FIGS. 3-7  in which is illustrated each one of these components in perspective view in  FIGS. 3 ,  4 , and  5  and then combinations of these components in  FIGS. 6 and 7 . The backup ring  22  includes one or more openings  30  that allow for the fixed connections  28  between the ramp  24  and the gauge ring  16 . The fixed connections  28 , in one embodiment hereof comprise a thread  32  at an inside surface  34  of the gauge ring  16  and a thread  36  at an outside surface  38  of the ramp  24 . The two threads are complementary and engage one another through the openings  30  when the backup ring  22 , ramp  24  and gauge ring  16  are assembled. It will be noted by the astute reader that the openings  30  are larger in the axial direction that the thread  36  is in the axial direction. This is to allow for axial movement of the backup ring  22  relative to the fixedly connected ramp  24  and gauge ring  16 . Axial movement is provided to allow for the backup ring  22  movement up the frustoconical surface  26  of the ramp  24  which in turn causes the backup ring  22  to gain in radial dimension and fill the clearance  14 . A review of  FIGS. 6 and 7  will make the assembly clear to one of ordinary skill in the art. 
         [0015]    Referring back to  FIG. 1 , the ramp is slidably in contact with a booster sleeve  40  that in turn is supported by more downhole components not germane to this disclosure but represented schematically by the structure identified with numeral  42 . At an opposite end of the system  10  is another schematically represented structure  44  representing components more uphole of the system  10  which again are not germane to the disclosure. These two illustrated structures are only illustrated to show a structure to which certain components of the system  10  are attached. Booster Sleeve  40  is one such component of the system  10  and is attached to structure  42  via a thread  46 . A spacer  48  is supported by the structure  42  in some embodiments to limit overall stroke of the system  10  to prevent damaging the element  20 . Spacer  48  is sized to be contacted by a connector sleeve  50  that is itself fixedly connected to structure  44 . This connection is via a thread  52  in one embodiment though any fixed connection could be substituted. Structure  44  is also fixedly connected to backup ring  22  at thread  54 . Finally a retraction dog  56  is disposed in a slot  58  in ramp  24  to ensure that with a tensile load placed on system  10 ,the load is transferred to the Booster Sleeve  40  and subsequently reduces the radial dimension of the Back Up Ring  22  to an outside dimension less than the outside dimension of the Gage Ring  16 . 
         [0016]    In operation, the system  10  provides, as above noted, up to a full clearance  14  obstruction and upon unsetting, the backup ring  22  can be brought back to a sub gauge dimension. This is exceedingly beneficial to the art because it means that extrusion of seals can be reliably and effectively prevented while the system  10  can be repositioned in the wellbore without concern for becoming stuck or doing damage to other wellbore tools due to an antiextrusion configuration having an outside dimension greater that gauge size. 
         [0017]    While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.