Device for a Borehole Arrangement

Abstract

A device for a borehole arrangement, in which a casing for a borehole is formed of at least one casing section, and in which there is placed at a downhole end portion of the casing at least one downhole tool, for example a drilling tool, wherein the casing is provided with two or more pipe bores, each separately extending continuously through a substantial part of the length of the casing and being separated in a fluid-tight manner from adjacent pipe bores and from an external annulus defined by the external mantle surface of the pipe and a borehole wall.

1 . A device for a borehole arrangement, in which a casing for a borehole is formed of at least one casing section, and in which there is placed at a downhole end portion of the casing at least one downhole tool, for example a drilling tool, wherein the casing is provided with two or more pipe bores, each separately extending continuously over a substantial part of the length of the casing and being separated in a fluid-tight manner from adjacent pipe bores and from an external annulus defined by the external mantle surface of the pipe and a borehole wall. 
   
   
       2 . The device in accordance with  claim 1 , wherein at least one pipe bore is arranged in the wall of the casing. 
   
   
       3 . The device in accordance with  claim 1 , wherein at least one pipe bore is arranged on or at the external mantle surface of the casing. 
   
   
       4 . The device in accordance with  claim 1 , wherein the casing includes one or more channels extending in the axial direction in the external mantle surface of the casing and being arranged to receive one or more lines for fluid conveyance or for the transfer of control and/or monitoring signals between a surface installation and downhole installations disposed along the casing or at the downhole end portion of the casing. 
   
   
       5 . The device in accordance with  claim 1 , wherein the casing is provided with one or more annular packers surrounding the casing and being arranged to define selectively and fluid-communicatingly a portion of the external annulus, the packer being releasably set against the wall of the borehole. 
   
   
       6 . The device in accordance with  claim 5 , wherein a plurality of the packers are placed on the casing adjacent to the downhole end portion of the casing, the packers including means for the selective release and fixing relative to the external mantle surface of the casing and selective fixing against the borehole wall at a random point in the axial extent of the casing. 
   
   
       7 . The device in accordance with  claim 5 , wherein the packers are provided with one or more closable packer fluid passages. 
   
   
       8 . The device in accordance with  claim 7 , wherein the packer fluid passages are arranged to close to fluid passage in a chosen direction and at the same time stay open to fluid passage in the opposite direction. 
   
   
       9 . The device in accordance with  claim 7 , wherein the packer fluid passages are formed as check valves. 
   
   
       10 . The device in accordance with  claim 5 , wherein the packer is provided with means for the controlled fixing and release of the packer relative to the borehole wall. 
   
   
       11 . The device in accordance with  claim 1 , wherein an end cover is placed fluid-sealingly on the downhole end portion of the casing. 
   
   
       12 . The device in accordance with  claim 11 , wherein the end cover is provided with one or more closable end cover fluid passages. 
   
   
       13 . The device in accordance with  claim 12 , wherein the end cover fluid passages are arranged to close to fluid passage in a chosen direction and at the same time stay open to fluid passage in the opposite direction. 
   
   
       14 . The device in accordance with  claim 12 , wherein the end cover fluid passages are formed as check valves. 
   
   
       15 . The device in accordance with  claim 11 , wherein the end cover is provided with one or more fluid-sealingly closable passages for downhole tools. 
   
   
       16 . The device in accordance with  claim 1 , wherein the downhole tool is a downhole tractor which is arranged to move in an open, uncased portion of the borehole at the downhole end portion of the casing and to carry means for working the borehole. 
   
   
       17 . The device in accordance with  claim 16 , wherein the downhole tool is connected in a fluid-communicating manner to at least one of the pipe bores of the casing for the circulation of one or more fluids between a surface installation and the downhole tool with return to the surface installation, possibly between the surface installation, the downhole tool and the open borehole with return to the surface installation. 
   
   
       18 . The device in accordance with  claim 16 , wherein the downhole tool is mechanically connected to the downhole end portion of the casing and is arranged to pull the casing into the open portion of the borehole. 
   
   
       19 . The device in accordance with  claim 18 , wherein the downhole end portion of the casing is mechanically connected to a pulling device on the downhole tool. 
   
   
       20 . The device in accordance with  claim 19 , wherein the pulling device is a winch. 
   
   
       21 . The device in accordance with  claim 1 , wherein at least one of said two or more pipe bores is provided with selectively closable openings in said downhole end portion of the casing.