Telescopic Conductor Casing for a Well Installation and a Method of Driving Same into the Underground

Abstract

A conductor casing device for establishing and lining a wellbore in unconsolidated sediments, the conductor casing being arranged to be driven into and to displace the unconsolidated sediments by axially directed impulses against an internal abutment in the lower portion of the conductor casing, where the conductor casing is telescopic. The invention also comprises a method of driving a telescopic conductor casing into unconsolidated sediments.

1 . A conductor casing device for establishing and lining a wellbore in unconsolidated sediments, the conductor casing being arranged to be driven into and to displace the unconsolidated sediments by axially directed impulses against an internal abutment in the lower portion of the conductor casing, wherein the conductor casing is telescopic. 
   
   
       2 . A device in accordance with  claim 1 , wherein an outer pipe is releasably coupled to an inner pipe by means of a coupling device. 
   
   
       3 . A device in accordance with  claim 1 , wherein an upper portion of the outer pipe is releasably coupled to an upper portion of the inner pipe. 
   
   
       4 . A device in accordance with  claim 1 , wherein one or more locking members abutting the outside wall of the inner pipe are arranged in a non-displaceable manner in the lower portion of the outer pipe. 
   
   
       5 . A device in accordance with  claim 1 , wherein the locking member(s) is/are arranged to allow an inner pipe released from the outer pipe to move axially away from the upper portion of the outer pipe. 
   
   
       6 . A device in accordance with  claim 1 , wherein that the locking member(s) is/are arranged to prevent an outer pipe released from the inner pipe to move axially towards the lower portion of the inner pipe. 
   
   
       7 . A device in accordance with  claim 1 , wherein the outer pipe is arranged to receive one or more externally placed stabilizers. 
   
   
       8 . A device in accordance with  claim 7 , wherein the outer pipe is provided with one or more stops arranged to abut an upper portion of the stabilizer(s). 
   
   
       9 . A device in accordance with  claim 1 , wherein the lower portion of the inner pipe is provided with a driving shoe arranged to receive axially directed driving impulses. 
   
   
       10 . A method of driving a conductor casing into unconsolidated sediments in order to establish and line a wellbore, the conductor casing being arranged to be driven into and to displace the unconsolidated sediments through axially directed impulses against an internal abutment in the lower portion of the conductor casing, wherein:
 an outer pipe is releasably coupled to the upper portion of an inner pipe;   the assembled telescopic conductor casing is driven into the unconsolidated sediments until the upper portion of the outer pipe assumes a prescribed height above the surface of the unconsolidated sediments;   the outer pipe is released from the inner pipe;   the inner pipe is driven further into the unconsolidated sediments until it stops against a preferably impenetrable structure, the inner pipe moving axially away from the upper portion of the outer pipe.   
   
   
       11 . A method in accordance with  claim 10 , wherein one or more stabilizers are mounted on the outer pipe prior to driving this into the unconsolidated sediments.