Patent Publication Number: US-7905492-B2

Title: Self-boosting wedge tubing-to-casing seal

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/991,936, filed Dec. 3, 2007, the entire contents of which are specifically incorporated herein by reference. 
    
    
     BACKGROUND 
     In the hydrocarbon recovery industry, there are many types of seals and anchoring arrangements due mostly to the many particular configurations of downhole tools that are needed for differing environmental conditions in different wells. While the great majority of prior art seals and anchoring arrangements work well for their intended purposes, there are consistently more conditions that are encountered due to advances in recovery technology as a whole and so additional sealing and anchoring arrangements are always welcomed by the art. 
     SUMMARY 
     A seal and/or anchoring arrangement includes a first perimetrically closed wedge, a second perimetrically closed wedge, an actuator in operable communication with one of the first and second wedges, and a frustoconical surface at an inside dimension of the inside more located surface of the first and second wedges. A method for creating a seal or anchor in a tubular structure includes urging at least a perimetrically closed first wedge and a perimetrically closed second wedge in a selected direction on a frustoconical surface at an inside most dimension of the at least first and second wedges, and expanding the at least first and second wedges until an outside most dimension of the at least first and second wedges contact an inside dimension of a separate structure whereby a seal of anchor is created. A seal and/or anchoring arrangement includes a first closed wedge exposed to annulus fluid, a second closed wedge exposed to annulus fluid, an actuator in operable communication with one of the first and second wedges, and a frustoconical surface at an inside dimension of the inside more located surface of the first and second wedges. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
         FIG. 1  is a schematic cross section view of an embodiment of a sealing and/or anchoring arrangement as disclosed herein in an unset position; 
         FIG. 2  is the view of  FIG. 1  illustrated in the set position; and 
         FIG. 3  is a schematic cross sectional vies of a wedge with a roughened surface thereon. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a seal and or anchor (hereinafter simply referred to as “seal” for brevity) configuration  10 . The seal  10  comprises three components that are interactive with each other to ultimately also interact with surfaces of separate components adjacent an inside dimension and an outside dimension of the seal  10 . These components include a first wedge  12 , a second wedge  14  in contact with one surface of the first wedge, and an actuator  16  in operable communication with one of the first wedge  12  and the second wedge  14 . In the  FIG. 1  illustration, the actuator  1  is in contact with first wedge  12  at a larger radially dimensioned end  20 . It is to be appreciated that in the event that the seal  10  is to be actuated by a pushing motion from actuator  16 , the actuator will be in contact with an end of one of the wedges that is of a larger radial dimension than the other end of the same wedge and the pushing direction will be the one tending to radially expand the seal  10 ; if alternatively the seal  10  is to be set using a pulling motion from the actuator  16 , it would be in contact with an end of one of the wedges that is of a smaller radial dimension than the other end of the same wedge with the pulling direction being the one tending to radially expand the seal  10 . In  FIG. 1 , as noted, the actuator contacts the larger radial end  20  and thus the arrangement illustrated uses a pushing motion from actuator  16 . At an opposite end of first wedge  12  is a radially smaller dimensioned end  22 . 
     Wedge  14  is complementarily positioned relative to wedge  12  with a radially larger end  24  most closely adjacent the smaller end  22  of wedge  12  while a smaller radial dimensioned end  26  of wedge  14  is most closely adjacent larger radial end  20  of wedge  12 . 
     As will be apparent from a brief review of the drawings, each wedge includes relatively broad angular surfaces; numerals  32  and  34  are associated with these surfaces on wedge  12  while numerals  36  and  38  are associated with these surfaces on wedge  14 . The angles of these surfaces are selected to ensure that when the seal  10  is set, they are substantially flush with the mating surfaces of a separate component radially outwardly located of the seal  10  and another separate component radially inwardly located of the seal  10 . In one embodiment of the seal  10 , the components radially outwardly and radially inwardly are as illustrated in the figures. A tubular component  40  may be a casing or other similar component having a surface  42  and the component radially inwardly of the seal is identified with numeral  44  and may be a tubular component or a solid component having a surface  46 . Component  44  does require that the surface  46  at least include a frustoconical surface at a portion of the surface for interaction with and setting of the seal  10 . The frustoconical surface  46  may be a part of component  44  or may be attached thereto without consequence to the operation of seal  10 . For example, the component  44  may simply be a tubular that is substantially straight and a frustoconical piece could be added thereto. 
     In one embodiment, where the angles of surfaces  32  and  46  and surfaces  34  and  36  are substantially the same, they will appear as in  FIGS. 1 and 2 . The angles of these surfaces together ensure that the angle of surface  38  will substantially match the angle of the surface  42 , which in the figures has no angle relative to an axis of the device (but could if desired). As in the illustrated embodiment, it is apparent that the angles of surfaces  46 ,  32 ,  34  and  36  cancel each other relative to the surface  38 . This is desirable and will ensure a good seal between surface  38  and surface  42 , whatever that angle may be. It will be appreciated, however, that the angles of the respective surfaces need not be exactly as shown but may be more steep or more shallow with the only result being a higher or lower setting force required from the actuator, respectively. Further, it is not critical that surface  46  be an identical angle with that of surface  32  or that surface  34  be identical to that of surface  36  or even that the angle of surface  38  be identical with that of surface  42  but rather it is merely important that these respective abutting surfaces be reasonably close to having the same angles for each interface. Ranges of angles for the respective surfaces  46 ,  32 ,  34 ,  36 ,  38  and  42  are about 0.13 to about 45 degrees with the illustrated embodiment being about 3 degrees for surfaces  46 ,  32 ,  34  and  36 . 
     Referring now to  FIGS. 1 and 2  simultaneously, actuation of the illustrated embodiment is discussed. Pursuant to a pushing motion imparted by actuator  16  upon wedge  12  in a direction associated with a growing radial dimension of component  44 , wedge  12  is expanded radially outwardly. It is to be noted that both wedge  12  and wedge  14  are perimetrically closed tubular shapes and so expansion is necessary to increase their respective outside dimensions. Beneficially, this means that there are no leak paths through the wedge structures themselves. Wedge  14  expands radially outwardly along with the wedge  12  until contact is made with surface  42  of component  40 . Wedge  14  does not move axially relative to wedge  12  during this expansion process although it is axially movable relative thereto. The purpose of facilitating such movement capability will be discussed hereunder. 
     Once the expansion of the wedges  12  and  14  causes contact between the seal  10  and the surfaces  46  and  42 , load on these surfaces is increased while the actuator  16  continues to push on the wedge  12  causing some deformation of the collective surfaces to match each other thereby ensuring a fluid tight seal. In addition, due to the shape of the wedges, annulus pressure from either side of the seal acts to tighten the seal rather than defeat it. Pressure differentials work to enhance the seal by tightening the wedges  12  and  14 . At the larger radial dimension of each wedge  12  and  14 , a surface  50  and  52  respectively is defined that has substantially larger surface area than a surface area of surfaces  54  and  56 , respectively. This arrangement provides a large surface area on only one side for each wedge for exposure to fluid pressure from the annulus thereby transmitting hydraulic force to the wedges (on one side thereof) unevenly. This biases the hydraulic pressure that might occur from each side of the seal to one wedge only, while the other wedge will be biased by pressure only from the opposite side of the seal. The surfaces  50  and  52  are intentionally exposed to the wellbore annulus so that the benefit of the arrangement is assured. This provides a great benefit to the art in that changing pressure differentials across the seal  10  will not undermine the seal  10 , as they tend to do with prior art seals. 
     The wedges of the seal  10  may be constructed of a number of possible materials. In some embodiments, the wedges may be of the same material as each other while in others they may be of different materials. Moreover, the wedges may be made of soft metals or other materials or may be constructed of harder materials such as steel, inconel, stainless steel, etc. used alone or that is coated in some way (plated, sputtered, etc.) with softer materials. Materials contemplated include but are not limited to relatively soft materials such as soft metal like copper, gold, silver, palladium, platinum, tin, lead, bismuth, etc, or alloys of these metals that can be applied to the seal by such methods as plating, brazing, thermal spray, sputtering, etc. or elastomers, or plastic materials such as Poltetrafluoroethylene, Polyetheretherketones (PEEK), etc. that can be applied and/or bonded by various industry recognized processes. Such materials enhance the sealing operation by deforming more easily into surface imperfections as noted above. 
     It is further to be understood that surfaces  32 ,  34 ,  36 , and  38  could have surface features such as a rib or a groove for an o-ring. Materials for such features may be any of the materials noted above. 
     Initially, in this detailed description, it was noted that the seal  10  could be in addition to a seal an anchor or could be alternatively an anchor. In such event where anchoring is desired and while it is possible for the seal itself with a smooth surface to provide for some anchoring, that function is enhanced by providing roughened surface features such as teeth  60  (illustrated in  FIG. 3 ) like a slip or a knurl, or otherwise to increase the relative generated friction against mating surfaces. 
     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.