Expandable packer

Abstract

An expandable packer tool comprising a mandrel tool body; a sleeve-like packer element mounted on the tool body; and a setting mechanism that is operable to axially compress the packer element such that the diameter of the packer element in its compressed state is increased compared to it uncompressed state. An extrusion barrier can comprise a ring of seal elements disposed around the tool body on either side of the packer element, and arranged to engage the packer element so that expansion of the packer element causes the ring of seal elements to expand in a corresponding manner so as to form an extrusion barrier; wherein the ring of seal elements comprises wedge-shaped seal members comprising first seal members having a inner base wider than an outer surface, and second seal members having an inner base narrower than an outer surface, the ring comprising alternating first and second members, the inclined faces of each wedge-shaped member engaging the corresponding faces of adjacent members. A retraction mechanism for the packer element comprises a cut-out in its inner surface near at least one end; and the setting mechanism comprises an inner mandrel that has an outward projection that engages in the cut-out so that the inner mandrel can exert a pulling force on the packer element.

1 - 13 . (canceled) 
     
     
         14 . An expandable packer tool comprising:
 a mandrel tool body;   a sleeve-like packer element mounted on the tool body;   a setting mechanism that is operable to axially compress the packer element such that the diameter of the packer element in its compressed state is increased compared to its uncompressed state; and   a ring of seal elements disposed around the tool body on either side of the packer element, and arranged to engage the packer element so that expansion of the packer element causes the ring of seal elements to expand in a corresponding manner so as to form an extrusion barrier;   wherein   the ring of seal elements comprises wedge-shaped seal members comprising first seal members having an inner base wider than an outer surface, and second seal members having an inner base narrower than an outer surface, the ring comprising alternating first and second members, the inclined faces of each wedge-shaped member engaging the corresponding faces of adjacent members.   
     
     
         15 . A tool as claimed in  claim 14 , wherein the first and second seal members have curved outer surfaces such that when the ring is in its expanded condition, the ring has a substantially circular outer surface. 
     
     
         16 . A tool as claimed in  claim 14 , wherein the first and second seal members have substantially flat axial faces. 
     
     
         17 . A tool as claimed in  claim 14 , wherein each seal member is located at one end of a mounting arm that is pivotally connected to the tool body at its other end. 
     
     
         18 . A tool as claimed in  claim 17 , wherein a sleeve is provided around the outside of the mounting arms. 
     
     
         19 . A tool as claimed in  claim 14 , wherein the inclined surfaces of the first seal members act on the corresponding surfaces of the second seal members to urge them outwards when the packer element is compressed. 
     
     
         20 . A tool as claimed in  claim 14 , wherein the inclined surfaces of the second seal members act on the corresponding surfaces of the first seal members to urge them inwards when the packer element is uncompressed. 
     
     
         21 . A tool as claimed in  claim 20 , wherein the second seal members are normally biased radially inwardly. 
     
     
         22 . A tool as claimed in  claim 14 , wherein the packer element has a conical end surface and the seal members are provided with an inclined inner face that engages on the conical end surface such that urging the seal members and the packer element together causes the seal members to be urged radially outwardly. 
     
     
         23 . A tool as claimed in  claim 14 , wherein the packer element comprises a cut-out in its inner surface near at least one end; and the setting mechanism comprises an inner mandrel that has an outward projection that engages in the cut-out so that the inner mandrel can exert a pulling force on the packer element. 
     
     
         24 . A tool as claimed in  claim 23 , wherein the cut-out is in the form of a circumferential groove and the outward projection is in the form of a circumferential rim. 
     
     
         25 . An expandable packer tool comprising:
 a mandrel tool body;   a sleeve-like packer element mounted on the tool body; and   a setting mechanism that is operable to axially compress the packer element such that the diameter of the packer element in its compressed state is increased compared to it uncompressed state;   wherein   the packer element comprises a cut-out in its inner surface near at least one end; and   the setting mechanism comprises an inner mandrel that has an outward projection that engages in the cut-out so that the inner mandrel can exert a pulling force on the packer element.   
     
     
         26 . A tool as claimed in  claim 25 , wherein the cut-out is in the form of a circumferential groove and the outward projection is in the form of a circumferential rim. 
     
     
         27 . An expandable packer tool comprising:
 a mandrel tool body;   a sleeve packer element mounted on the tool body;   a setting mechanism that is operable to axially compress the packer element such that the diameter of the packer element in its compressed state is increased compared to its uncompressed state; and   a ring of seal elements disposed around the tool body on either side of the packer element, and arranged to engage the packer element so that expansion of the packer element causes the ring of seal elements to expand in a corresponding manner so as to form an extrusion barrier;   wherein   the ring of seal elements comprises wedge-shaped seal members comprising first seal members having a inner base wider than an outer surface, and second seal members having an inner base narrower than an outer surface, the ring comprising alternating first and second members, the inclined faces of each wedge-shaped member engaging the corresponding faces of adjacent members; and   wherein each seal member is located at one end of a mounting arm that is pivotally connected to the tool body at its other end and a sleeve is provided around the outside of the mounting arms.