Downhole tool string

Abstract

The invention relates to a relates to a downhole tool string wherein the upper part of the string includes a release tool for releasably coupling with a pipe-severing tool.

What is claimed: 
     
         1 . A downhole tool string ( 100 ), said tool string comprising:
 a pipe-severing tool ( 5 ); and   an upper part ( 7 ) of the downhole string ( 100 ) comprises a release tool for releasably coupling with the pipe-severing tool ( 5 ).   
     
     
         2 . The downhole tool string ( 100 ) according to  claim 1 , wherein the pipe-severing tool ( 5 ) is configured to sever after release from the upper part ( 7 ). 
     
     
         3 . The downhole tool string ( 100 ) according to  claim 1 , wherein the pipe-severing tool ( 5 ) comprises an anchor tool ( 20 ) connected in series with a pipe-severing unit ( 10 ). 
     
     
         4 . The downhole tool string ( 100 ) according to  claim 3 , wherein the pipe-severing unit ( 10 ) is selected from a group consisting of: a chemical cutter tool, a jet cutter tool, a radial cutting torch, a drill collar-severing tool, and a string-shot back-off tool. 
     
     
         5 . The downhole tool string ( 100 ) according to  claim 1 , wherein the upper part ( 7 ) of the downhole tool string ( 100 ) includes a wireline tractor ( 60 ) configured for conveying the downhole tool string ( 100 ) to a depth in a well ( 1 ). 
     
     
         6 . A downhole tool string ( 100 ), said tool string comprising:
 a pipe-severing tool ( 5 );   an upper part ( 7 ) of the downhole string ( 100 ) comprises a release tool releasably coupled with the pipe-severing tool ( 5 ); and   the pipe-severing tool configured to sever after release from the upper part ( 7 ).   
     
     
         7 . The downhole tool string ( 100 ) according to  claim 6 , wherein the pipe-severing tool ( 5 ) comprises an anchor tool ( 20 ) connected in series with a pipe-severing unit ( 10 ). 
     
     
         8 . The downhole tool string ( 100 ) according to  claim 7 , wherein the pipe-severing unit ( 10 ) is selected from a group consisting of: a chemical cutter tool, a jet cutter tool, a radial cutting torch, a drill collar-severing tool, and a string-shot back-off tool. 
     
     
         9 . The downhole tool string ( 100 ) according to  claim 6 , wherein the upper part ( 7 ) of the downhole tool string ( 100 ) includes a wireline tractor ( 60 ) configured for conveying the downhole tool string ( 100 ) to a depth in a well ( 1 ).