Rotating backup system for packer elements used in non-retrievable applications

Abstract

A packer element assembly includes an annular sealing element having inner and outer sides, wherein the sealing element is axially compressible from a first position to a set position, and first and second backup rings located on opposite ends of the sealing element. When the sealing element is axially compressed to the set position, the sealing element expands radially, and the backup rings rotate relative to the sealing element. A setting method may include locating the packer element assembly within a well casing bore, and axially compressing the packer element assembly to the set position. The sealing element expands radially such that the outer side of the sealing element expands against the well casing bore and the backup rings are rotated relative to the sealing element to eliminate a gap between a mandrel and the sealing element, thereby preventing extrusion of the sealing element along both inner and outer sides.

1 . A packer element assembly comprising:
 an annular sealing element having an inner side and an outer side, and the sealing element is axially compressible from a first position to a set position; and   first and second backup rings located on opposite ends of the sealing element;   wherein, when the sealing element is axially compressed from the first position to the set position, the sealing element expands radially, and the backup rings rotate relative to the sealing element to prevent axial extrusion of the sealing element at both the inner side and the outer side in the set position.   
     
     
         2 . The packer element assembly of  claim 1 , wherein each backup ring has a cross-sectional face such that when the first and second backup rings rotate to the set position, the cross-sectional face is configured to prevent axial extrusion of the sealing element at both the inner side and the outer side. 
     
     
         3 . The packer element assembly of  claim 2 , wherein the cross-sectional face comprises an upper side, a first slope that is sloped with a first angle relative to the upper side, a second slope that is sloped with a second angle relative to the upper side, and a chamfered end opposite the upper side. 
     
     
         4 . The packer element assembly of  claim 3 , wherein the first angle of the first slope is greater than the second angle of the second slope. 
     
     
         5 . The packer element assembly of  claim 3 , wherein in the set position, a chamfer of each chamfered end compresses against the sealing element adjacent the inner side of the sealing element. 
     
     
         6 . The packer element assembly of  claim 1 , wherein the backup rings are made of a thermoplastic material. 
     
     
         7 . The packer element assembly of  claim 6 , wherein the backup rings are made of one of a polyaryletherketone, polytetrafluoroethylne, or polyamide-imide material. 
     
     
         8 . The packer element assembly of  claim 1 , wherein the backup rings are made of one of brass, bronze, or aluminum. 
     
     
         9 . The packer element assembly of  claim 1 , wherein the sealing element is made of an elastomeric material. 
     
     
         10 . The packer element assembly of  claim 1 , further comprising a mandrel positioned on the inner side of the sealing element. 
     
     
         11 . The packer element assembly of  claims 10 , further comprising a first setting cone located around the mandrel on a down hole side of the sealing element, and a second setting cone located around the mandrel on an up hole side of the setting element, wherein the second setting cone is moveable from the up hole side toward the down hole side to axially compress the sealing element from the first position to the set position. 
     
     
         12 . A method of setting a packer element assembly comprising the steps of:
 locating a packer element assembly at a desired position within a well casing bore, the packer element assembly comprising an annular sealing element having an inner side and an outer side, and first and second backup rings located on opposite ends of the sealing element;   axially compressing the packer element assembly to a set position, wherein the sealing element expands radially such that the outer side of the sealing element expands against the well casing bore; and   wherein upon axially compressing the sealing element to the set position, the backup rings rotate relative to the sealing element to eliminate a first gap between the well casing and the outer side of the sealing element, thereby preventing extrusion of the sealing element along the well casing.   
     
     
         13 . The setting method of  claim 12 , wherein the packer element assembly further comprises a mandrel positioned on the inner side of the sealing element,
 wherein upon axially compressing the sealing element, the rotating of the backup rings relative to the sealing element further eliminates a second gap between the mandrel and the inner side of the sealing element, thereby preventing extrusion of the sealing element along the mandrel.   
     
     
         14 . The setting method of  claim 13 , wherein the packer element assembly further comprises a first setting cone located around the mandrel on a down hole side of the sealing element, and a second setting cone located around the mandrel on an up hole side of the setting element; and
 the setting method further comprising moving the second setting cone from the up hole side toward the down hole side to axially compress the sealing element from the first position to the set position.   
     
     
         15 . The setting method of  claim 12 , wherein the packer element assembly is compressed from an up hole side of the well casing toward a down hole side of the well casing. 
     
     
         16 . The setting method of  claim 12 , wherein the backup rings each has a chamfered end, and when the backup rings rotate a chamfer of each chamfered end compresses against the sealing element adjacent the inner side of sealing element.