Securing a composite bridge plug

Abstract

A filament wound composite tube is inserted into a non-metallic mandrel below the core to support the core when holding pressure in the top annulus. The tube has a close-fit tolerance to the inner surface of the mandrel. The tube is secured in place with pins through a mule shoe, such that the bore of the tube is not impeded. Alternately, a retainer with wickers is disposed in the mandrel below the core to support the core when holding pressure in the top annulus. The wickers are biased to engage with an inner surface of the mandrel, holding the insert in place under pressure. Axial movement of the core downward further engages the wickers with the mandrel, helping to support the load.

1 . A plug system for a mandrel having a bore, comprising:
 a non-metallic plug comprising:
 a non-metallic core configured for disposal within the bore of the mandrel; and 
 a seal disposed about the non-metallic core for sealingly engaging the non-metallic core with the inner diameter of the mandrel; 
   a support element, configured for disposal within the bore of the mandrel axially adjacent to the non-metallic plug and affixed to the mandrel.   
     
     
         2 . The plug system of  claim 1 , wherein the support element comprises a non-metallic tube disposed in the bore of the mandrel, abutting the non-metallic core and pinned to the mandrel. 
     
     
         3 . The plug system of  claim 1 , wherein the support element comprises a retainer, comprising:
 a plurality of wickers, configured to engage an inner surface of the mandrel, preventing downhole movement of the retainer.   
     
     
         4 . The plug system of  claim 3 , wherein the retainer is radially compressible for insertion into the mandrel. 
     
     
         5 . The plug system of  claim 1 , further comprising:
 a plurality of pins, inserted radially through a wall of the mandrel into the support element, affixing the support element to the mandrel.   
     
     
         6 . The plug system of  claim 1 , wherein the support element has an outer diameter in close tolerance with an inner diameter of the mandrel. 
     
     
         7 . A downhole tool, comprising:
 a non-metallic mandrel, having a bore;   a non-metallic element system disposed about the mandrel, comprising:
 a sealing element, configured for radial expansion; 
   a non-metallic core, comprising:
 a non-metallic member configured for disposal within the bore of the mandrel; and 
 a seal disposed with the non-metallic member for sealingly engaging the non-metallic core with an inner surface of the mandrel; 
   a support element, configured for disposal within the bore of the mandrel axially adjacent to the non-metallic plug and affixed to the mandrel.   
     
     
         8 . The downhole tool of  claim 7 , wherein the support element comprises a non-metallic tube disposed in the bore of the mandrel, abutting the non-metallic core, and pinned to the mandrel. 
     
     
         9 . The downhole tool of  claim 7 , wherein the support element comprises a retainer, comprising:
 a plurality of wickers, configured to engage the inner surface of the mandrel, preventing downhole movement of the retainer.   
     
     
         10 . The downhole tool of  claim 9 ,
 wherein the retainer is radially expandable for engagement with the inner surface of the mandrel, and   wherein the core further comprises an expander portion, configured to engage the retainer and radially expand the retainer.   
     
     
         11 . The downhole tool of  claim 7 , further comprising:
 a plurality of pins, inserted radially through a wall of the mandrel into the support element, affixing the support element to the mandrel.   
     
     
         12 . The downhole tool of  claim 7 , wherein the support element has an outer diameter in close tolerance with the inner diameter of the mandrel. 
     
     
         13 . A method of sealing a bore of a mandrel, comprising:
 disposing a core in the bore of the mandrel;   sealing the core to an inner surface of the mandrel;   affixing the core to the mandrel;   disposing a support element axially adjacent to the core in the bore of the mandrel;   affixing the support element to the mandrel.   
     
     
         14 . The method of  claim 13 , wherein affixing the support element to the mandrel comprises pinning the support element to a mule shoe of the mandrel. 
     
     
         15 . The method of  claim 13 , wherein affixing the support element to the mandrel comprises engaging a wicker of the support element with the inner surface of the mandrel. 
     
     
         16 . The method of  claim 13 , wherein disposing a support element comprises:
 disposing the support element on an installation tool, positioning the support element in the bore of the mandrel with the installation tool;   radially expanding the support element with an expander portion of the core to engage the inner surface of the mandrel; and   removing the installation tool.   
     
     
         17 . The method of  claim 13 , wherein the support element is a non-metallic tube. 
     
     
         18 . The method of  claim 13 , wherein the core is non-metallic and the support element is metallic. 
     
     
         19 . A method of sealing a bore of a mandrel, comprising:
 disposing a support element in the bore of the mandrel;   disposing a core in the bore of the mandrel, comprising:
 inserting an expander portion of the core into the support element; 
 radially expanding the support element with the expander portion; and 
 engaging the support element with an inner surface of the mandrel to prevent axial movement of the support element and the core; and 
   affixing the core to the mandrel.