System and method for sealing a tubing string

Abstract

A sealing tool for sealing a tubing string at a predetermined location, the sealing tool having a prong assembly and a plug assembly, each of which includes a cavity configured to capture and retain debris, and the plug assembly including at least one equalization hole for fluid communication through the plug when unobstructed by the prong.

What is claimed is: 
     
         1 . A sealing tool for a subsurface tubing string, comprising:
 a prong comprising an upper section having a cavity in communication with a substantially open top, a lower extension, and an external shoulder disposed therebetween,   a locking mandrel plug (LMP) comprising an open upper section configured to reversibly connect to a tubing string and receive a portion of a longitudinal extension of the prong, and a lower section comprising a cavity in fluid communication with the open upper section;   at least one equalization hole disposed through a wall of the LMP above the LMP cavity and providing fluid communication between an interior of the plug, and an exterior thereof; and   wherein an outer diameter of at least a bottom portion of the lower extension of the prong is selected to substantially correspond to an inner diameter of the LMP proximal the at least one equalization hole, such that a close mating relationship may be formed between the LMP and prong.   
     
     
         2 . The sealing tool of  claim 1 , wherein the bottom portion of the lower extension of the prong comprises a nose and at least one seal. 
     
     
         3 . The sealing tool of  claim 2 , further comprising at least one spacer disposed between a pair of seals. 
     
     
         4 . The sealing tool of  claim 2 , wherein a distance between the at least one seal and the external shoulder of the prong is substantially identical to a distance between the at least one equalization hole and an internal shoulder of the upper section of the LMP. 
     
     
         5 . The sealing tool of  claim 1 , wherein the LMP comprises a sealing stack disposed on an outer surface thereof. 
     
     
         6 . The sealing tool of  claim 5 , wherein the sealing stack is retained by a removable locking ring. 
     
     
         7 . The sealing tool of  claim 1 , wherein the at least one equalization hole comprises a plurality of equalization holes disposed equidistantly along a circumference of the LMP. 
     
     
         8 . The sealing tool of  claim 1 , wherein the at least one equalization hole comprises internal threads. 
     
     
         9 . The sealing tool of  claim 1 , further comprising a removable cap disposed at the bottom of the cavity of the LMP. 
     
     
         10 . The sealing tool of  claim 1 , wherein the cavity of the prong comprises at least 50% of the volume the upper section of the prong. 
     
     
         11 . The sealing tool of  claim 1 , wherein the cavity of the LMP comprises at least 50% of the volume of the LMP. 
     
     
         12 . A method of manufacturing a locking mandrel plug for a tubing string, comprising:
 forming a generally tubular body having an outwardly-tapered top;   forming a mating interface in an inner surface of the outwardly-tapered top, configured to operatively connect to a predetermined conveyance;   forming a cavity within a lower portion of the generally tubular body, the cavity comprising the majority of the interior volume of the lower portion, and fluidly-connected to the interior of the outwardly-tapered top; and   forming at least one equalization hole through an exterior wall of the generally tubular body, between the cavity and the outwardly-tapered top.   
     
     
         13 . The method of  claim 12 , further comprising forming an internal shoulder between the outwardly-tapered top and the at least one equalization hole. 
     
     
         14 . The method of  claim 13 , wherein forming the internal shoulder further comprises configuring the internal shoulder to correspond to an outer shoulder of a predetermined prong. 
     
     
         15 . The method of  claim 12 , wherein forming the cavity includes occupying at least 50% of the volume of the lower portion of the generally tubular body. 
     
     
         16 . The method of  claim 12 , further comprising disposing a sealing stack on an outer circumference of the generally tubular body. 
     
     
         17 . The method of  claim 16 , further comprising retaining the sealing stack by operatively connecting a locking ring to the outer circumference of the generally tubular body. 
     
     
         18 . The method of  claim 17 , wherein the location of the locking ring is adjustable to accommodate differing configurations of the sealing stack. 
     
     
         19 . The method of  claim 17 , further comprising retaining the locking ring by operatively connecting a set screw to both the locking ring and the generally tubular body.