Method and Apparatus Suitable For Hole Cleaning During Operations

Abstract

Apparatus for drilling operations in underground boreholes, comprises: a drilling assembly that can be located in a borehole and is moved along the borehole during the drilling operation; a flexible fluid supply line connected to and in fluid communication with the drilling assembly and extending from the drilling assembly to the surface when the drilling assembly is in the borehole; and an electric cable for providing electric power to the drilling assembly and extending from the drilling assembly to the surface when the drilling assembly is in the borehole; the fluid line and the electric cable are separate, and the electric cable being outside the fluid line. A method for conducting drilling operations using an apparatus as defined above, comprises operating the drilling assembly and directing fluid between the surface and the drilling assembly via the flexible fluid line.

1 . Apparatus for drilling operations in underground boreholes, comprising:
 a drilling assembly that can be located in a borehole and is moved along the borehole during the drilling operation;   a flexible fluid supply line connected to and in fluid communication with the drilling assembly and extending from the drilling assembly to the surface when the drilling assembly is in the borehole; and   an electric cable for providing electric power to the drilling assembly and extending from the drilling assembly to the surface when the drilling assembly is in the borehole; wherein   the fluid line and the electric cable are separate, the electric cable being outside the fluid line.   
   
   
       2 . Apparatus as claimed in  claim 1 , wherein the fluid line and the electric cable are connected to each other in at least one location between the drilling assembly and the surface. 
   
   
       3 . Apparatus as claimed in  claim 1  or  2 , further comprising at least one drum for storing and delivering the fluid line and/or cable to the well. 
   
   
       4 . Apparatus as claimed in  claim 3 , wherein a separate drum is provided for the fluid line. 
   
   
       5 . Apparatus as claimed in  claim 1 , wherein the fluid line and/or the electric cable is formed from segments joined end-to-end by connectors. 
   
   
       6 . Apparatus as claimed in  claim 5 , further comprising a secondary fluid line connected to the fluid line in an upper region thereof. 
   
   
       7 . Apparatus as claimed in  claim 6 , wherein the secondary fluid line is connected to the fluid line at the connector between the uppermost segment and the adjacent segment. 
   
   
       8 . Apparatus as claimed in  claim 4  or  7 , further comprising a pressure-controlled housing, the drum of the fluid line or the secondary fluid line being located inside the housing. 
   
   
       9 . Apparatus as claimed in  claim 8 , further comprising a port in the housing to allow fluid to be introduced to or withdrawn from the fluid line or secondary fluid line. 
   
   
       10 . A method for conducting drilling operations using an apparatus as claimed in  claim 1 , the method comprising operating the drilling assembly and directing fluid between the surface and the drilling assembly via the flexible fluid line. 
   
   
       11 . A method as claimed in  claim 10 , wherein the fluid is a drilling fluid which is introduced to the borehole at the surface and circulates from the bottom of the borehole back to the surface via the fluid line so as to carry drilled cuttings away from the drilling assembly. 
   
   
       12 . A method as claimed in  claim 10  or  11 , wherein the fluid line and the electric cable are fed into or withdrawn from the borehole as the drilling assembly moves along the borehole. 
   
   
       13 . A method as claimed in  claim 10 , comprising connecting the fluid line and electric cable can together in at least one point along as they are fed into the borehole. 
   
   
       14 . A method as claimed in  claim 10 , wherein the fluid line and/or electric cable are formed from segments, the method comprising joining the segments with connectors as the fluid line and/or electric cable are fed into the well, or disconnecting the segments at the connectors as the fluid line and/or electric cable are withdrawn from the well. 
   
   
       15 . A method as claimed in  claim 14 , further comprising connecting a secondary fluid line to the fluid line in an upper region thereof. 
   
   
       16 . A method as claimed in  claim 15 , comprising connecting the secondary fluid line between the uppermost segment and the adjacent segment. 
   
   
       17 . A method as claimed in  claim 15  or  16 , wherein the secondary fluid line is used to introduce or withdraw fluid from the fluid line. 
   
   
       18 . A method as claimed in  claim 15 , wherein secondary fluid line is typically shorter than the fluid line, the method comprising periodically disconnecting the secondary fluid line is periodically from the fluid line and reconnecting it at another location as the fluid line is fed into or withdrawn from the borehole. 
   
   
       19 . A method as claimed in  claim 10 , further comprising storing the fluid line and/or secondary fluid line can in a pressure-controlled housing. 
   
   
       20 . A method as claimed in  claim 19 , wherein the housing is maintained at or near borehole pressure, the method comprising feeding the fluid line and/or secondary line between the housing and the borehole while being maintained at or near borehole pressure.