Method and tool for unblocking a control line

Abstract

A method to release a control line for a safety valve removably disposed in a nipple ( 9 ) of a wellbore production tubing, comprises the steps of: —removing the safety valve from the nipple; —setting into the nipple a sealing tool ( 41 ) which sealingly connects the control line ( 10 ) and a mini tubing ( 42 ) running down into the production tubing; —increasing the pressure of a fluid into the mini tubing to cause fluid to flow into the control line through the sealing tool.

1 . A method to release a control line ( 10 ) for a safety valve ( 8 ) removably disposed in a nipple ( 9 ) of a wellbore production tubing ( 3 ), comprising the steps of:
 removing the safety valve from the nipple;   setting into the nipple a sealing tool ( 41 ) which sealingly connects the control line ( 10 ) and a mini tubing ( 42 ) running down into the production tubing;   increasing the pressure of a fluid into the mini tubing to cause fluid to flow into the control line through the sealing tool.   
   
   
       2 . The method according to  claim 1 , further comprising the step of increasing the pressure of a fluid alternatively into the mini tubing and into the control line. 
   
   
       3 . The method according to  claim 1 , further comprising the step of increasing the pressure of a fluid intermittently into the mini tubing. 
   
   
       4 . The method according to  claim 1 , further comprising the step of increasing the pressure of a fluid intermittently into the control line. 
   
   
       5 . The method according to any of  claims 1  to  4 , comprising the step of moving a piston ( 48 ) into the sealing tool to provide a multiplicator effect on the pressure increasing. 
   
   
       6 . The method according any of  claims 1  to  5 , wherein the fluid is a solvent liquid. 
   
   
       7 . The method according any of  claims 1  to  5 , wherein the fluid is an incompressible liquid. 
   
   
       8 . The method according to  claim 6 , wherein the fluid is diesel oil. 
   
   
       9 . A wellbore installation ( 1 ) comprising a production tubing ( 3 ) with a nipple ( 9 ) for receiving a working device ( 40 ), characterized in that the working device comprises
 a sealing tool ( 41 ) having a sealed chamber ( 45 , 56 , 52 , 54 , 51 ) defined with an inside cylindrical wall of the nipple ( 9 ) and two seals ( 46 ) spaced apart from each other according to an axial direction (A) of the production tubing; and   a mini tubing ( 42 ) running down said production tubing ( 3 ) and connected to said sealed chamber for flowing a fluid against the inside cylindrical wall of the nipple ( 9 ).   
   
   
       10 . The wellbore installation of  claim 9 , wherein said nipple is fitted for receiving a safety valve ( 8 ) actuated by a control line ( 10 ) issuing into said sealed chamber. 
   
   
       11 . The wellbore installation of  claim 9 , wherein the inside cylindrical wall of the nipple against which flows the fluid comprises a weak area. 
   
   
       12 . The wellbore installation according to any of  claims 9  to  11 , wherein the sealing tool further comprises a pressure intensifier means. 
   
   
       13 . The wellbore installation according to any of  claims 9  to  11 , wherein the sealing tool comprises a movable piston ( 48 ). 
   
   
       14 . The wellbore installation according to  claim 13 , wherein the piston comprises two end sides ( 49 , 50 ) having different surface areas. 
   
   
       15 . The wellbore installation according to  claim 14 , wherein the piston is bored with a check valve ( 55 ) disposed in a bore ( 54 ). 
   
   
       16 . The wellbore installation according to  claim 15 , wherein the bore ( 54 ) in the piston ( 48 ) is obstructed with a ball ( 57 ) dropped into the mini tubing ( 42 ). 
   
   
       17 . The wellbore installation according to  claim 16 , wherein a dart ( 60 ) running down into the mini tubing holds the ball out of the bore. 
   
   
       18 . The wellbore installation according to any of  claims 9  to  17 , wherein the two seals ( 46 ) are O-ring packings arranged in the sealing tool ( 41 ) and bearing against the inside cylindrical wall of the nipple ( 9 ). 
   
   
       19 . The wellbore installation according to any of  claims 9  to  18 , wherein the mini tubing is connected to a pressure-supplying pump.