Releasing mechanism for downhole sealing tool

Abstract

A releasing mechanism for releasing a hydraulically actuated setting tool from a downhole tool is provided. Preferably, the downhole tool to be released is a wellbore sealing tool such as a bridge plug, packer or inflatable packer. The releasing mechanism comprises an adapter having a body, a connector above the body connected to the setting tool, and a lower portion. The releasing mechanism further comprises a releasable connection which releasably connects the lower portion of the adapter to a mandrel within the bridge plug or other sealing tool. In one embodiment, the releasable connection defines a frangible body disposed within the plane of the circumferential bore of the bridge plug mandrel. In another arrangement, the releasable connection defines both a frangible body and threaded collet fingers which releasably engage matching threads on the outer surface of the mandrel of the bridge plug or other wellbore sealing tool.

1 . A releasing mechanism for releasing a setting tool from a plugging tool within a wellbore, the releasing mechanism supporting a mandrel on the plugging tool while the plugging tool is being set, the mandrel having an essentially circumferential bore therein, the releasing mechanism comprising: 
 an adapter having a top end connected to the setting tool; and    a releasable connector connecting the adapter and the mandrel, the releasable connector being disposed within a longitudinal plane of the circumferential bore of the mandrel.    
     
     
         2 . The releasing mechanism of  claim 1 , wherein the releasable connector defines a nose frictionally disposed within the bore of the mandrel, the nose having a shear plane which fails under tensile forces applied by the setting tool.  
     
     
         3 . The releasing mechanism of  claim 2 , wherein the adapter comprises: 
 a body;    a connector above the body for connecting the adapter with the setting tool; and    a lower tubular portion having a bore therein, the tubular portion having a bottom end which is landed at a top end of the mandrel.    
     
     
         4 . The releasing mechanism of  claim 3 , wherein the plugging tool is a bridge plug.  
     
     
         5 . The releasing mechanism of  claim 4 , further comprising a tubular rod having a top end and a bottom end, the top end being threadedly connected to the lower tubular portion within the bore of the adapter, and the bottom end being threadedly connected to the shear nose above its shear plane.  
     
     
         6 . The releasing mechanism of  claim 5 , further comprising: 
 a collet disposed circumferentially around the tubular rod and below the tubular portion of the adapter, the collet having a plurality of radially spaced apart fingers which extend downward towards the nose so as to frictionally reside between the nose below the shear plane, and the inner surface of the mandrel; and    a retrieving rod having a top end and a bottom end, the top end having an enlarged outer diameter portion defining a shoulder, and a lower ended threadedly connected to a portion of the nose below the shear plane.    
     
     
         7 . The releasing mechanism of  claim 6 , wherein the threaded rod further comprises: 
 an enlarged wall thickness portion defining an inner shoulder which catches the shoulder of the retrieval rod when the nose has failed due to tensile forces, and when the adapter is being raised within the wellbore; and    an outer shoulder to retrieve the collet from the wellbore when the adapter is being raised within the wellbore.    
     
     
         8 . The releasing mechanism of  claim 5 , further comprising a metallic sleeve disposed along an inner surface of the mandrel proximate to the top end of the mandrel.  
     
     
         9 . The releasing mechanism of  claim 8 , further comprising: 
 a collet disposed circumferentially around the tubular rod and below the tubular portion of the adapter, the collet having a plurality of radially spaced apart fingers which extend downward towards the nose so as to frictionally reside between the nose below the shear plane, and the inner surface of the mandrel; and    a retrieving rod having a top end and a bottom end, the top end having an enlarged outer diameter portion defining a shoulder, and a lower ended threadedly connected to a portion of the nose below the shear plane.    
     
     
         10 . The releasing mechanism of  claim 9 , wherein the threaded rod further comprises: 
 an enlarged wall thickness portion defining an inner shoulder which catches the shoulder of the retrieval rod when the nose has failed due to tensile forces, and when the adapter is being raised within the wellbore; and    an outer shoulder to retrieve the collet from the wellbore when the adapter is being raised within the wellbore.    
     
     
         11 . The releasing mechanism of  claim 1 , wherein the adapter comprises: 
 a body;    a connector above the body for connecting the adapter with the setting tool; and    a lower tubular portion having a bore therein, the tubular portion having a bottom end which is landed at a top end of the mandrel.    
     
     
         12 . The releasing mechanism of  claim 11 , wherein the plugging tool is a bridge plug.  
     
     
         13 . The releasing mechanism of  claim 12 , further comprising a tubular shear rod, the shear rod having a top end and a bottom end, the top end being threadedly connected to the tubular portion of the adapter within the bore, and the lower portion being threadedly connected to the inner surface of the mandrel.  
     
     
         14 . The releasing mechanism of  claim 13 , wherein the releasable connection defines a shear plane fabricated between the top end and the bottom end of the tubular shear rod such that the shear rod fails due to tensile forces applied on the shear rod when the hydraulic setting tool is actuated.  
     
     
         15 . The releasing mechanism of  claim 1 , wherein the adapter comprises: 
 a body;    a connector above the body for connecting the adapter with the setting tool; and    a bottom end defining a male portion which extends into the bore of the mandrel.    
     
     
         16 . The releasing mechanism of  claim 15 , wherein the releasable connection defines a plurality of shear screws releasably connecting the male portion of the adapter with the mandrel.  
     
     
         17 . The releasing mechanism of  claim 16 , further comprising an inner sleeve, the inner sleeve defining a tubular metal body disposed concentrically within the inner surface of the mandrel at the location of the plurality of shear screws.  
     
     
         18 . The releasing mechanism of  claim 17 , wherein the inner sleeve further comprises barbs disposed about the outer surface of the metal sleeve which frictionally engages the mandrel.  
     
     
         19 . The releasing mechanism of  claim 4 , wherein the releasable connector comprises an elongated rod having a top end and a bottom end, the top end being threadedly connected to the bore of the tubular portion of the adapter, and the lower end being disposed adjacent to the reinforcing insert within the bore of the mandrel.  
     
     
         20 . The releasing mechanism of  claim 19 , further comprising a generally tubular reinforcing insert fabricated into the inner surface of the mandrel proximate to a top end of the mandrel.  
     
     
         21 . The releasing mechanism of  claim 1 , wherein the releasable connector defines a shear ring.  
     
     
         22 . The releasing mechanism of  claim 21 , wherein the shear ring and the reinforcing insert are each fabricated from a metallic substance.  
     
     
         23 . The releasing mechanism of  claim 22 , wherein the plugging tool is a bridge plug.  
     
     
         24 . The releasing mechanism of  claim 23 , wherein the shear ring is disposed intermediate to the lower portion of the elongated rod and the reinforcing insert, and wherein the shear ring includes a shoulder extending into a profile within the reinforcing insert.  
     
     
         25 . A releasing mechanism for releasing a hydraulic setting tool from a bridge plug within a wellbore, the releasing mechanism supporting a mandrel on the bridge plug while the bridge plug is being set, the mandrel having an essentially circumferential bore therein, the releasing mechanism comprising: 
 an adapter having a body, a top end above the body connected to the setting tool, and a shoulder disposed within the body;    a tubular retaining sleeve disposed around a lower portion of the body and connected the shoulder of the adapter at a top end of the retaining sleeve, the retaining sleeve further having a bottom end and a dog intermediate the top end and the bottom end of the retaining sleeve;    a collet defining a tubular member disposed essentially concentrically within the retaining sleeve below the adapter, the collet having a plurality of radially spaced-apart collet fingers, the collet fingers being held closely to the mandrel by the lower end of the retaining sleeve; and    a frangible body having a top end threadedly connected within the bore of the tubular portion of the adapter, and a lower end threadedly connected to the collet, and having a shear plane fabricated between the top end and the lower end, the shear body failing long the shear plane in response to tensile forces when the hydraulic setting tool is actuated.