Refrac liner with isolation collar

Abstract

A collar for a refracturing liner includes a body having a first end and a second end, the first end being configured to connect to a first liner segment, and the second end being configured to connect to a second liner segment. The body defines an inner diameter surface extending between the first and second ends. The collar also includes at least one radial expansion feature formed in the body, wherein the at least one radial expansion feature is configured to deform radially outward when the body is axially compressed, and wherein the at least one radial expansion feature is configured to engage a surrounding tubular and form a fluid flow barrier therewith.

What is claimed is: 
     
         1 . A collar for a refracturing liner, comprising:
 a body having a first end and a second end, the first end being configured to connect to a first liner segment, and the second end being configured to connect to a second liner segment, wherein the body defines an inner diameter surface extending between the first and second ends; and   at least one radial expansion feature formed in the body, wherein the at least one radial expansion feature is configured to deform radially outward when the body is axially compressed, and wherein the at least one radial expansion feature is configured to engage a surrounding tubular and form a fluid flow barrier therewith.   
     
     
         2 . The collar of  claim 1 , wherein the at least one radial expansion feature comprises a recess formed in the inner diameter surface of the body. 
     
     
         3 . The collar of  claim 2 , wherein the recess is arcuate in cross-section. 
     
     
         4 . The collar of  claim 2 , wherein the body has a reduced radial thickness where the recess is formed in comparison to a radial thickness of the body adjacent to the recess. 
     
     
         5 . The collar of  claim 1 , wherein the body is configured to deform radially outward at the at least one radial expansion feature to a greater extent the body deforms radially outward away from the at least one radial expansion feature. 
     
     
         6 . The collar of  claim 1 , wherein at the at least one radial expansion feature comprises a first recess formed in the inner diameter surface of the body and a second recess formed in the inner diameter surface of the body, the first and second recesses being spaced axially apart along the body. 
     
     
         7 . A method for refracturing a well, comprising:
 positioning a liner within a perforated casing of a well that extends through a formation, such that an annulus is formed between the liner and the perforated casing, wherein the liner comprises a plurality of liner segments connected together by a plurality of isolation collars;   axially compressing the liner, wherein axially compressing the liner causes at least some of the plurality of isolation collars to deform radially outwards and at least partially block fluid flow in the annulus;   perforating the liner so as to create new perforations axially between two of the plurality of isolation collars; and   pumping fracturing fluid into the formation through the new perforations.   
     
     
         8 . The method of  claim 7 , wherein positioning the liner comprises positioning the plurality of isolation collars axially between existing perforations in the perforated casing, such that the existing perforations are covered by at least some of the plurality of liner segments. 
     
     
         9 . The method of  claim 7 , wherein positioning the liner comprises anchoring an uphole end of the liner above an uphole-most perforation formed in the perforated casing. 
     
     
         10 . The method of  claim 7 , wherein axially compressing the liner comprises:
 positioning a work string inside the liner; and   pulling the work string uphole in the liner.   
     
     
         11 . The method of  claim 7 , wherein axially compressing the liner comprises increasing a pressure on an uphole end of the liner, such that the liner is pushed downhole. 
     
     
         12 . The method of  claim 11 , further comprising landing a packer on the uphole end of the liner, such that the pressure on the uphole end of the liner is applied to the liner via the packer. 
     
     
         13 . The method of  claim 7 , further comprising positioning a plug in the liner between two of the isolation collars, wherein the plug is positioned downhole of the new perforations, and wherein the plug prevents the fracturing fluid from flowing through the liner and thereby directs the fracturing fluid into the formation through the new perforations. 
     
     
         14 . A refracturing system, comprising:
 a first liner segment;   a second liner segment; and   an isolation collar connecting together the first and second liner segments, wherein the isolation collar is configured to be deformed radially outward by pressing the first and second liner segments together, so as to form at least a partial barrier to fluid flow through an annulus formed between the first and second liner segments and a surrounding tubular.   
     
     
         15 . The system of  claim 14 , wherein the surrounding tubular comprises a perforated casing. 
     
     
         16 . The system of  claim 14 , further comprising an anchor coupled to the first liner segment and configured to hang the refrac system from the surrounding tubular, wherein the isolation collar and the first and second liner segments are configured to receive a work string therethrough, such that the work string applies an uphole force on the second liner segment and presses the second liner segment towards the first liner segment, thereby pressing the first and second liner segments together and radially deforming the isolation collar. 
     
     
         17 . The system of  claim 14 , further comprising a packer engaging an uphole end of the first liner segment, wherein a pressure applied to the uphole end of the first liner segment causes the first liner segment to be pressed toward the second liner segment, thereby pressing the first and second liner segments together and radially deforming the isolation collar. 
     
     
         18 . The system of  claim 14 , wherein the isolation collar comprises:
 a body having a first end and a second end, the first and second ends being configured to connect to the first and second liner segments, respectively, wherein the body defines an inner diameter surface extending between the first and second ends; and   at least one radially expansion feature formed in the body, wherein the at least one radial expansion feature is configured to deform radially outward when the body is axially compressed, wherein the body is configured to deform radially outward by a greater extent at the at least one radial expansion feature than the body deforms away from the at least one radial expansion feature, and wherein the at least one radial expansion feature is configured to engage the surrounding tubular and form the at least partial barrier.   
     
     
         19 . The system of  claim 18 , wherein the at least one radial expansion feature comprises a recess formed in the inner diameter surface of the body. 
     
     
         20 . The system of  claim 18 , wherein at the at least one radial expansion feature comprises a first recess formed in the inner diameter surface of the body and a second recess formed in the inner diameter surface of the body, the first and second recesses being spaced axially apart along the body.