Sealing element for downhole tool

Abstract

Expansion sealing elements used to prevent fluid, flow through an annul us formed by tubing within the well and the wall of the wellbore or casing are provided. The expansion sealing elements are useful on downhole tools including those that need to be lowered through a first casing to be set in a second casing, which, has a larger diameter than the first casing.

1 . A downhole tool for use in a well having a casing, the downhole tool comprising:
 a mandrel;   a slip ring disposed about said mandrel, wherein said slip ring has an unset position in which the slip ring does not engage the casing and a set position in which said slip ring grippingly engages the casing;   a wedge disposed about said mandrel, wherein said wedge engages said slip ring such that relative longitudinal movement of said wedge and said slip ring drives said slip ring radially outward to the set position; and   a sealing element comprising;
 a first sealing member; 
 a second sealing member wherein said first sealing member engages said second sealing member such that said sealing element has a first position and a second position, and wherein said first sealing member stretches over said second sealing member when said sealing element is in said second position such that said stretching places the first sealing member in sealing engagement with said casing, and wherein said first sealing member and said second sealing member are in operable relation with said wedge such that said relative longitudinal movement of said wedge and said slip ring moves the sealing element from said first position to said second position. 
   
     
     
         2 . The downhole tool of  claim 1 , wherein said first sealing member is radially outward from said second sealing member when said sealing element is in said second position. 
     
     
         3 . The downhole tool of  claim 1 , wherein said sealing element moves from said first position to said second position under compression or tension. 
     
     
         4 . The downhole tool of  claim 3 , wherein said first sealing member has an inner surface with an inclined inner wall and said second sealing member has an outer surface with an inclined outer wall, and wherein said inclined inner wall matches said inclined outer wall so as to facilitate said stretching of said first sealing member. 
     
     
         5 . The downhole tool of  claim 4 , wherein when said sealing element is in said second position:
 said outer surface of said first sealing member is in sealing engagement with a wall of a wellbore:   said inner surface of said first sealing member is in sealing engagement with said outer surface of said second sealing member; and   said inner surface of said second member is in sealing engagement with a mandrel of said downhole tool.   
     
     
         6 . The downhole tool of  claim 4 , wherein said first sealing member is radially outward from said second sealing member when said sealing element is in said second position. 
     
     
         7 . A downhole tool for use in a wellbore comprising:
 a mandrel   a first sealing member disposed about said mandrel;   a second sealing member disposed about said mandrel, wherein when said downhole tool moves from an unset position to a set position, said first sealing member moves in relation to said second sealing member such that during the thus resulting relative movement said first sealing member slides over said second sealing member so that said relative movement causes said first sealing member to come into sealing engagement with said wellbore.   
     
     
         8 . The downhole tool of  claim 7 , wherein when said downhole tool moves from an unset position to a set position, said first sealing member sealingly engages said second sealing member and said second sealing member sealingly engages said mandrel. 
     
     
         9 . The downhole tool of  claim 7 , wherein said first sealing member is longitudinally separated from said second sealing member when said downhole tool is in said unset position and wherein said first sealing member is radially outward from said second sealing member when said downhole tool is in said second position. 
     
     
         10 . The downhole tool of  claim 7 , wherein said first sealing member stretches over said second sealing member when said downhole tool moves from said unset position to said set position. 
     
     
         11 . The downhole tool of  claim 10 , wherein said first sealing member has an inner surface with an inclined inner wall and said second sealing member has an outer surface with inclined outer wall, and wherein said inclined inner wall matches said inclined outer wall so as to facilitate said stretching of said first sealing member. 
     
     
         12 . The downhole tool of  claim 11 , wherein when said downhole tool moves from said unset position to said set position, compressive forces are applied to said first sealing member and to said second sealing member thus moving said first sealing member from being longitudinally separated from said second sealing member to being radially outward from said second sealing member. 
     
     
         13 . The downhole tool of  claim 12  wherein, when said downhole tool moves from an unset position to a set position, said first sealing member sealingly engages said second sealing member and said second sealing member sealingly engages said mandrel. 
     
     
         14 . A method of operating a servicing tool in a wellbore comprising:
 longitudinally compressing a sealing element along a central axis, wherein said sealing element has a first sealing member and a second sealing member and said compressing results in relative axial movement of said first sealing member and said second sealing member;   upon sufficient compression, expanding said first sealing member such that it stretches over said second sealing member and sealingly engages said wellbore.   
     
     
         15 . The method of  claim 14 , wherein during said relative axial movement said first sealing member moves from being longitudinally separated from said second sealing member to being radially outward from said second sealing member. 
     
     
         16 . The method of  claim 14 , wherein, after said first sealing member stretches over said second sealing member, said first sealing member sealingly engages said second sealing member. 
     
     
         17 . The method of  claim 16 , wherein said first sealing member has an inner surface with an inclined inner wall and said second sealing member has an outer surface with an inclined outer wall, and wherein said inclined inner wall matches said inclined outer wall so that said first sealing member stretches over said second sealing member by said inclined inner wall moving along said inclined outer wall. 
     
     
         18 . The downhole tool of  claim 14 , wherein said longitudinal compressing results from relative longitudinal movement of a slip ring and a wedge, which drives said slip ring from an unset position in which said slip ring does not engage the wellbore to a set position in which said slip ring grippingly engages the wellbore. 
     
     
         19 . The downhole tool of  claim 7 , further comprising:
 a slip ring disposed about said mandrel, wherein said slip ring has an unset position in which the slip ring does not engage the wellbore and a set position in which said slip ring grippingly engages the wellbore;   a wedge disposed about said mandrel, wherein said wedge engages said slip ring such that relative longitudinal movement of said wedge and said slip ring drives said slip ring radially outward to said set position, and wherein said first sealing member and said second sealing member are in operable relation with said wedge such that said relative longitudinal movement of said wedge and said slip ring results in said relative movement of said first sealing member and second sealing member.