High integrity hanger and seal for casing

Abstract

Casing segments and an expansion cone are positioned and cemented within a new section of a wellbore with a lower casing segment in an overlapping relationship with an upper casing segment. The lower casing segment is radially expanded such that an upper end of the lower casing segment comes into contact with the interior wall of the upper casing segment at the overlap region. The upper casing segment has an inward facing profile at the overlap region that includes a set of wickers that are driven into the lower casing exterior when it is expanded. This forms a metal-to-metal seal between the upper and lower casing segments at the overlap region.

1 . An apparatus for forming a wellbore casing in a well, comprising:
 an upper casing segment cemented within the well;   a wicker profile formed at an interior end of the upper casing segment;   a lower casing segment installed within the well; and   an upper end on the lower casing segment that overlaps with and is radially deformed into the wicker profile on the upper casing segment, to create a metal-to-metal seal.   
     
     
         2 . The apparatus of  claim 1 , further comprising a circumferential recess formed adjacent to wicker profile on the interior of the initial casing segment, and a portion of the upper end of the lower casing segment is radially deformed into the recess. 
     
     
         3 . The apparatus of  claim 2 , wherein the wicker profile comprises a plurality of parallel, circumferential grooves, each of the grooves being triangular in configuration. 
     
     
         4 . The apparatus of  claim 1 , wherein after being radially deformed, the upper end of the lower casing segment has an inner diameter substantially equal to a nominal inner diameter of the upper casing segment. 
     
     
         5 . The apparatus of  claim 1 , further comprising an upper and a lower circumferential recess formed above and below the wicker profile on the interior of the initial casing segment, and a portion of the upper end of the lower casing segment is radially deformed into the recesses. 
     
     
         6 . The apparatus of  claim 1 , wherein a full length of the lower casing segment is radially expanded to a nominal inner diameter equal to a nominal inner diameter of the upper casing segment. 
     
     
         7 . The apparatus of  claim 1 , wherein an outer surface on the end of the lower casing segment is fabricated from a metal that is softer than the wicker profile. 
     
     
         8 . The apparatus of  claim 1 , wherein the wicker profile comprises a plurality of parallel, triangular shaped grooves, the grooves being fabricated of a harder metal than that of the upper casing segment, the wicker profile being joined to the upper casing segment. 
     
     
         9 . The apparatus of  claim 1 , wherein the upper casing segment is cemented within the well at the approximate location where the end on the subsequent casing segment overlaps with the wicker profile. 
     
     
         10 . An apparatus for forming a wellbore casing in a well, comprising:
 an upper casing segment cemented within the well;   a wicker profile formed at an interior end of the upper casing segment, wherein the wicker profile comprises a plurality of parallel, circumferential grooves, each of the grooves being triangular in configuration, and wherein the grooves are fabricated of a harder metal than that of the upper casing segment, the wicker profile being joined to the upper casing segment;   a lower casing segment installed within the well, wherein an outer surface on the end of the lower casing segment is fabricated from a metal that is softer than the wicker profile; and   an upper end on the lower casing segment that overlaps with and is radially deformed into the wicker profile on the upper casing segment, to create a metal-to-metal seal.   
     
     
         11 . The seal assembly of  claim 10 , further comprising a circumferential recess formed adjacent to wicker profile on the interior of the initial casing segment, and a portion of the upper end of the lower casing segment is radially deformed into the recess. 
     
     
         12 . The apparatus of  claim 10 , wherein after being radially deformed, the upper end of the lower casing segment has an inner diameter substantially equal to a nominal inner diameter of the upper casing segment. 
     
     
         13 . The apparatus according to  claim 10 , further comprising an upper and a lower circumferential recess formed above and below the wicker profile on the interior of the initial casing segment, and a portion of the upper end of the lower casing segment is radially deformed into the recesses. 
     
     
         14 . The apparatus of  claim 10 , wherein a full length of the lower casing segment is radially expanded to a nominal inner diameter equal to a nominal inner diameter of the upper casing segment. 
     
     
         15 . The apparatus of  claim 10 , wherein the lower casing segment is cemented within the well at the approximate location where the end on the lower casing segment overlaps with the wicker profile. 
     
     
         16 . A method of creating a wellbore casing in a well, comprising:
 forming a wicker profile at an interior end of an upper casing segment;   installing and cementing the upper casing segment in the wellbore;   installing a lower casing segment at a lower depth than the upper casing segment so that an end of the lower casing segment overlaps with the wicker profile on the upper casing segment; and   radially expanding at least a portion of the subsequent casing segment to create a metal-to-metal seal between the upper and lower casing segments at the point where the upper and lower casing segments overlap.   
     
     
         17 . The method of  claim 16 , further comprising the steps of:
 drilling a predetermined depth below the end of the upper casing to create an open hole that accommodates the lower casing segment;   cementing the lowert casing segment prior to radially expanding the lower casing segment; and   pressurizing the bore of the casing to test for leakage at the metal-to-metal seal.   
     
     
         18 . The method of  claim 16 , wherein radially expanding at least a portion of the lower casing segment is by an expansion tool. 
     
     
         19 . The method of claim of  16 , wherein forming a wicker profile comprises forming the wicker profile of a harder metal than a metal of the upper end of the lower casing segment.