Method and Device for a Running Tool

Abstract

A method and device for drilling or cleaning an underground borehole. The device includes a drilling tool, a drill string with two pipe conduits extending up to the surface and an arrangement for providing one drilling fluid for circulation in a drill string and a second arrangement for providing a second fluid in an annulus formed between the drill string and the wall of a borehole making the drill string approximately weightless.

1 . A method for establishing an underground borehole, said method comprising the steps of:
 placing a running tool including a drilling tool, a drill string, having a first conduit and a second conduit extending up toward a surface and a packer which is arranged to seal against the wall of a casing at the bottom of the borehole, the drill string made from a material less dense than steel and   circulating a first liquid in the drill string using only the first conduit and the second conduit, the first liquid having a selected density less than a selected density of a second liquid disposed between the outside of the drill string and a wall of the borehole.   
     
     
         2 . The method in accordance with  claim 1  further comprising, moving the running tool forward to the bottom of the borehole by means of fluid pressure in the borehole above the running tool. 
     
     
         3 . The method in accordance with  claim 2  further comprising, draining fluid in the borehole below the running tool to the surface by means of the second conduit. 
     
     
         4 . The method in accordance with  claim 3  further comprising, draining fluid in the borehole below the running tool to the surface by means of the second conduit assisted by a downhole pump. 
     
     
         5 . The method in accordance with  claim 1  further comprising, drilling a cylindrical drill core and transporting the cylindrical core out of the borehole during drilling by the liquid flow through the running tool up through the second conduit in the drill string. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . A method for establishing an underground borehole, comprising:
 placing a running tool including a drilling tool, a drill string with two pipe conduits extending out of the borehole in the borehole, and wherein the drill string is made approximately weightless by circulating a liquid in the drill string, the liquid having a lower density than a liquid on the outside of the drill string and wherein the drill string is made from a material less dense than steel.   
     
     
         15 . (canceled) 
     
     
         16 . The method of  claim 1  wherein the material comprises aluminum. 
     
     
         17 . The method of  claim 14  wherein the material comprises aluminum.