Method and Device for Subsea Wire Line Drilling

Abstract

A method and a device for subsea wire line drilling permit the recovery of a full core barrel with a coiled tubing, without pulling up a drill string.

1 . A method for subsea wire line drilling, the method comprising the following steps:
 drilling a hole in a seafloor with a drill string;   running coiled tubing down the drill string to a full core barrel having a core and latching the coiled tubing onto the full core barrel;   recovering the full core barrel with the coiled tubing without pulling up the drill string;   inserting the full core barrel into a tool carousel;   retrieving an empty core barrel from the tool carousel;   attaching the coiled tubing to the empty core barrel;   lowering the empty core barrel into the drill string;   unlatching the coiled tubing from the empty core barrel; and   restarting drilling to recover another core.   
   
   
       2 . A device for subsea wire line drilling, the device comprising:
 a drilling head to be disposed under water; and   a wire line coiled tubing system associated with said drilling head under water, said coiled tubing system including a reel, coiled tubing wound on said reel, a drill string with a drill rod and a drill bit, and a core barrel to be latched to said coiled tubing for recovering cores without pulling up said drill string.   
   
   
       3 . The device according to  claim 2 , which further comprises instrumentation associated with said reel for sending telemetry to the surface. 
   
   
       4 . The device according to  claim 2 , which further comprises a tube straightener downstream of said reel in tube travel direction into a hole, and an injector downstream of said tube straightener for injecting said coiled tubing into the hole. 
   
   
       5 . The device according to  claim 2 , which further comprises a tool carousel, and tool arms for inserting said core barrel into and removing said core barrel from said tool carousel.