Expanding and collapsing apparatus and methods of use

Abstract

The invention provides an expanding and collapsing ring apparatus (171) and method of use. The expanding and collapsing ring comprises a plurality of elements (177) assembled together to form a ring structure (172, 173a, 173b) oriented in a plane around a longitudinal axis. The ring structure is operable to be moved between a collapsed condition and a first expanded condition by movement of the plurality of elements on actuation by an axial force. The apparatus further comprises a secondary expanding and collapsing mechanism operable to move the ring structure between its collapsed condition or its first expanded conditions to a second expanded condition on actuation by an axial force. Applications of the invention include oilfield devices, including anti-extrusion rings, plugs, packers, locks, patching tools, connection systems, and variable diameter tools run in a wellbore.

1 . An expanding and collapsing ring apparatus comprising:
 a plurality of elements assembled together to form a ring structure oriented in a plane around a longitudinal axis;   wherein the ring structure is operable to be moved between a collapsed condition and a first expanded condition by movement of the plurality of elements on actuation by an axial force;   and wherein the apparatus further comprises a secondary expanding and collapsing mechanism operable to move the ring structure between its collapsed condition or its first expanded condition to a second expanded condition on actuation by an axial force.   
     
     
         2 . The apparatus according to  claim 1 , wherein the plurality of elements is operable to be moved relative to one another between the expanded and collapsed conditions by sliding the elements with respect to one another in the plane of the ring structure. 
     
     
         3 . The apparatus according to  claim 1 , wherein the ring structure comprises one or more ring surfaces configured to be presented to an auxiliary surface when actuated to an expanded condition or a collapsed condition. 
     
     
         4 . The apparatus according to  claim 3 , wherein the one or more ring surfaces comprises a substantially cylindrical surface arranged to contact or otherwise interact with an inner surface of a tubular or bore. 
     
     
         5 . The apparatus according to  claim 3 , wherein the ring surface is substantially smooth. 
     
     
         6 . The apparatus according to  claim 3 , wherein the ring surface is provided with one or more functional formations thereon, for interacting with an auxiliary surface. 
     
     
         7 . The apparatus according to  claim 1 , wherein the elements are configured to move between their expanded and collapsed radial positions in a path which is tangential to a circle described around and concentric with the longitudinal axis. 
     
     
         8 . The apparatus according to  claim 1 , wherein each element of the ring structure comprises a first contact surface and second contact surface respectively in abutment with first and second adjacent elements, and wherein the elements are configured to slide relative to one another along their respective contact surfaces. 
     
     
         9 . The apparatus according to  claim 8 , wherein the first contact surface and/or the second contact surface are oriented tangentially to a circle described around and concentric with the longitudinal axis. 
     
     
         10 . The apparatus according to  claim 8 , wherein the first contact surface and the second contact surface converge towards one another in a direction towards an inner surface of the ring structure. 
     
     
         11 . (canceled) 
     
     
         12 . The apparatus according to  claim 1 , wherein the elements are provided with interlocking profiles for interlocking with an adjacent element. 
     
     
         13 . The apparatus according to  claim 1 , comprising a biasing means configured to bias the ring structure to one of its expanded or collapsed conditions. 
     
     
         14 - 15 . (canceled) 
     
     
         16 . The apparatus according to  claim 1 , wherein the ring structure is a first ring structure, and the secondary expanding and collapsing mechanism comprises a second ring structure, wherein the second ring structure is operable to move the first ring structure from an intermediate expanded condition to a fully expanded condition. 
     
     
         17 . The apparatus according to  claim 16 , wherein the second ring structure is one of a second pair of ring structures, operable to move the first ring structure from an intermediate expanded condition to a fully expanded condition. 
     
     
         18 . The apparatus according to  claim 17 , wherein each of the second pair of ring structures are disposed on opposing sides of the first ring structure. 
     
     
         19 . The apparatus according to  claim 17 , wherein each of the second pair of ring structures comprises a plurality of second elements assembled together to form the second ring structure oriented in a plane around the longitudinal axis. 
     
     
         20 . The apparatus according to  claim 19 , wherein the plurality of second elements is operable to be moved relative to one another between expanded and collapsed conditions of the respective second ring structures by sliding the second elements with respect to one another in the planes of the second ring structures. 
     
     
         21 . The apparatus according to  claim 16 , wherein each of the second ring structures defines a respective outer surface, which is inclined with respect to a surface parallel to the longitudinal axis. 
     
     
         22 . The apparatus according to  claim 21 , wherein the respective outer surfaces are conical wedge surfaces which face the first ring structure. 
     
     
         23 . The apparatus according to  claim 19 , wherein the plurality of elements of the second ring structures are operable to be moved between their expanded and collapsed conditions by sliding with respect to one another in the plane of the second ring structure, in a direction tangential to a circle concentric with the second ring structure. 
     
     
         24 . The apparatus according to  claim 1 , wherein the apparatus comprises a plurality of additional ring structures arranged in functional pairs, and operable to move the first ring structure from an intermediate expanded condition to a subsequent intermediate expanded condition, or a fully expanded condition. 
     
     
         25 . The apparatus according to  claim 24 , wherein each additional ring structure comprises a biasing means configured to bias the first ring structure to one of its expanded or collapsed conditions, and wherein biasing means of the first and second or additional ring structures are selected to define a sequence of expanding and collapsing of the apparatus. 
     
     
         26 - 29 . (canceled) 
     
     
         30 . The apparatus according  claim 1 , wherein each of a functional pair of additional ring structures and/or the elements thereof are configured to limit the travel of a corresponding additional ring structures and/or the elements thereof. 
     
     
         31 . An oilfield tool comprising the apparatus of  claim 1 . 
     
     
         32 . The oilfield tool according to  claim 31 , configured as a downhole tool selected from the group consisting of: a plug, a packer, an anchor, a tubing hanger, or a downhole locking tool. 
     
     
         33 - 34 . (canceled) 
     
     
         35 . A variable diameter downhole tool comprising an apparatus according to  claim 1 . 
     
     
         36 . (canceled) 
     
     
         37 . A connector system comprising a first connector and a second connector, wherein one of the first and second connectors comprises the apparatus of  claim 1 . 
     
     
         38 . A patch apparatus for a fluid conduit or tubular, the patch apparatus comprising the apparatus of  claim 1 . 
     
     
         39 . A method of expanding an apparatus, the method comprising:
 providing an apparatus comprising: a plurality of elements assembled together to form a ring structure oriented in a plane around a longitudinal axis; and a secondary expanding and collapsing mechanism;   imparting an axial force to the ring structure to move the plurality of elements from a collapsed condition to a first expanded condition; and   imparting an axial force to the secondary expanding and collapsing mechanism to move the first ring structure from its first expanded condition to a second expanded condition.   
     
     
         40 . A method of collapsing an apparatus, the method comprising:
 providing an apparatus comprising: a plurality of elements assembled together to form a ring structure oriented in a plane around a longitudinal axis; and a secondary expanding and collapsing mechanism;   releasing or reducing an axial force from the secondary expanding and collapsing mechanism to move the ring structure from a second expanded condition to a first expanded condition; and   releasing or reducing an axial force from the ring structure to move the plurality of elements, thereby moving the ring structure from the first expanded condition to a collapsed condition.