Elastically deformable support for an expandable seal element of a downhole tool

Abstract

An elastically deformable support for an expandable seal element of a downhole tool, an expandable seal assembly incorporating such a seal element and support, and a downhole tool, such as a packer, incorporating the expandable seal assembly are disclosed. The elastically deformable support may be one-piece. The support is deformable between an unexpanded configuration and a radially expanded configuration and includes a plurality of base portions, each base portion having a surface which, in use, faces towards the seal element; and a plurality of overlap portions, each overlap portion extending from a respective base portion so that it overlaps the surface of an adjacent base portion and having a surface which, in use, faces towards the seal element. The base portions and the overlap portions are arranged to define a generally ring-shaped seal support structure which forms a continuous circumferentially extending support surface for abutting and supporting the seal element.

1 . A one-piece elastically deformable support for an expandable seal element of a downhole tool, in which the support is deformable between an unexpanded configuration and a radially expanded configuration and comprises:
 a plurality of base portions, each base portion having a surface which, in use, faces towards the seal element; and   a plurality of overlap portions, each overlap portion extending from a respective base portion so that it overlaps the surface of an adjacent base portion and having a surface which, in use, faces towards the seal element;   in which the base portions and the overlap portions are arranged to define a generally ring-shaped seal support structure which forms a continuous circumferentially extending support surface for abutting and supporting the seal element.   
     
     
         2 . A support as claimed in  claim 1 , in which:
 the base portions are arranged so that they can separate to facilitate expansion of the support;   the overlap portions are arranged so that they can slide over the surface of the adjacent base portion during expansion of the support; and   in the expanded configuration of the support, the continuous circumferentially extending support surface comprise the surfaces of the overlap portions and at least part of the surfaces of at least some of the base portions.   
     
     
         3 . A support as claimed in  claim 1  in which, in the unexpanded configuration of the support, the continuous circumferentially extending support surface is defined by the surfaces of the overlap portions. 
     
     
         4 . A support as claimed in  claim 1  in which, in the unexpanded configuration of the support, the continuous circumferentially extending support surface is defined by the surfaces of the overlap portions and at least part of the surfaces of at least some of the base portions. 
     
     
         5 . A support as claimed in  claim 1  in which, the expanded configuration, the continuous circumferentially extending support surface comprises the surfaces of the overlap portions and at least part of the surfaces of the base portions. 
     
     
         6 . A support as claimed in  claim 1 , in which each overlap portion extends in a generally circumferential direction from the respective base portion over the surface of the adjacent base portion. 
     
     
         7 . A support as claimed in  claim 1 , in which the generally ring-shaped support structure comprise a radially outer extent and a radially inner extent, and in which the base portions each extend across a full radial width of the support structure, and so from the inner extent to the outer extent. 
     
     
         8 . A support as claimed in  claim 1 , in which the generally ring-shaped support structure comprise a radially outer extent and a radially inner extent, and in which the overlap portions each extend across a full radial width of the support structure, and so from the inner extent to the outer extent. 
     
     
         9 . A support as claimed in  claim 1 , in which the base portions form a ring-shaped base section of the generally ring-shaped seal support structure, when the support is in the unexpanded configuration. 
     
     
         10 . A support as claimed in  claim 1 , in which the overlap portions form a ring-shaped overlap section of the generally ring-shaped seal support structure, when the support is in the unexpanded configuration. 
     
     
         11 . A support as claimed in  claim 1 , in which the support surface is for abutting and supporting an axial end of the seal element, the generally ring-shaped seal support structure defining an axial end of the support. 
     
     
         12 . A support as claimed in  claim 1 , in which the base portions are spaced axially from the overlap portions so that, in use, the overlap portions are located closer to the seal element than the base portions. 
     
     
         13 . A support as claimed in  claim 1 , in which the base portions are arranged so that they are generally in a first plane which is perpendicular to a main axis of the support, and in which the overlap portions each extend out of the first plane to overlap the surface of the adjacent base portion. 
     
     
         14 . A support as claimed in  claim 13 , in which the overlap portions are arranged so that they are generally in a second plane which is parallel to the first plane, and spaced axially along the support from the first plane. 
     
     
         15 . A support as claimed in  claim 1 , in which the overlap portions have first and second circumferential edges, and in which the overlap portions are arranged to taper in axial thickness towards the edges. 
     
     
         16 . A support as claimed in  claim 1 , in which the base portions and the overlap portions have radially outer and radially inner extents, and have a greater width at their outer extents than at their inner extents. 
     
     
         17 . A support as claimed in  claim 1 , comprising:
 first and second axially opposed ends;   a first generally ring-shaped seal support structure provided on the first axial end; and   a second generally ring-shaped seal support structure provided on the second axial end;   in which the first generally ring-shaped seal support structure is arranged to abut and support a first seal element at the first axial end of the support, and the second generally ring-shaped seal support structure is arranged to abut and support a second seal element at the second axial end of the support.   
     
     
         18 . A support as claimed in  claim 17 , in which the base portions each comprise a plurality of legs extending in an axial direction of the support, each leg of each base portion extending to a different base portion on the other seal support structure. 
     
     
         19 . A support as claimed in  claim 1 , in which the support comprises a plurality of slots extending between an inner surface of the support and an outer surface of the support and in an axial direction along the support, the slots being expandable to facilitate expansion of the support. 
     
     
         20 . A support as claimed in  claim 19 , in which the seal support structure covers ends of the slots, to prevent extrusion of the seal element into the slots following expansion. 
     
     
         21 . A support as claimed in  claim 19 , in which the support comprises first and second sets of slots, each set comprising a plurality of slots, said slots of the first set extending inwardly from a first axial end of the support, and said slots of the second set extending inwardly from a second axial end of the support opposite to the first end. 
     
     
         22 . A support as claimed in  claim 1 , comprising a seal component extending around at least part of a radially outer surface of the support. 
     
     
         23 . A support as claimed in  claim 1 , in which the support has an integral seal element. 
     
     
         24 . A support as claimed in  claim 23 , in which the seal element is an annular seal element located in a seat defined in the support surface. 
     
     
         25 . A support as claimed in  claim 1 , in which the support is a high expansion support, capable of elastically deforming so that a ratio of an outer diameter of the support in the unexpanded configuration relative to an outer diameter in the expanded configuration is at least about 1:1.20. 
     
     
         26 . An expandable seal assembly for a downhole tool, the seal assembly comprising:
 an expandable seal element which is radially expandable between an unexpanded configuration where the seal element is out of contact with a downhole surface, and an expanded configuration where the seal element can sealingly abut the downhole surface; and   a one-piece elastically deformable support, in which the support is deformable between an unexpanded configuration and a radially expanded configuration and comprises:   a plurality of base portions, each base portion having a surface which, in use, faces towards the seal element; and   a plurality of overlap portions, each overlap portion extending from a respective base portion such that it overlaps the surface of an adjacent base portion and having a surface which, in use, faces towards the seal element;   in which the base portions and the overlap portions are arranged to define a generally ring-shaped seal support structure which forms a continuous circumferentially extending support surface for abutting and supporting the seal element.   
     
     
         27 . An assembly as claimed in  claim 26 , comprising first and second expandable seal elements, and in which the support comprises first and second axially opposed ends, a first generally ring-shaped seal support structure provided on the first axial end and arranged to abut and support the first seal element, and a second generally ring-shaped seal support structure provided on the second axial end and arranged to abut and support the second seal element. 
     
     
         28 . An assembly as claimed in  claim 26 , comprising first and second such one-piece elastically deformable supports, the seal element disposed between the supports so that the first support abuts and supports a first surface of the seal element, and the second support abuts and supports a second, opposite surface of the seal element. 
     
     
         29 . A downhole tool comprising at least one expandable seal assembly according to  claim 26 . 
     
     
         30 . An elastically deformable support for an expandable seal element of a downhole tool, in which the support is deformable between an unexpanded configuration and a radially expanded configuration and comprises:
 a plurality of base portions, each base portion having a surface which, in use, faces towards the seal element; and   a plurality of overlap portions, each overlap portion extending from a respective base portion so that it overlaps the surface of an adjacent base portion and having a surface which, in use, faces towards the seal element;   in which the base portions and the overlap portions are arranged to define a generally ring-shaped seal support structure which forms a continuous circumferentially extending support surface for abutting and supporting the seal element;   in which the base portions are arranged so that they can separate to facilitate expansion of the support;   in which the overlap portions are arranged so that they can slide over the surface of the adjacent base portion during expansion of the support;   and in which, in the expanded configuration of the support, the continuous circumferentially extending support surface comprises the surfaces of the overlap portions and at least part of the surfaces of at least some of the base portions.