06419033 is referenced by 169 patents and cites 5 patents.

The present invention provides apparatus and method for drilling a wellbore wherein a pilot wellbore section is drilled with a bit which section is enlarged by a trailing underreamer to the desired size. One or more steering sections between the underreamer and the drill bit are utilized for maintaining and changing the drilling direction. Each steering section includes a plurality of independently adjustable force application devices on a non-rotating sleeve. If an expandable liner is used, then an expansion device disposed above the underreamer expands the liner during retrieval of the drilling assembly to the surface.

Title
Apparatus and method for simultaneous drilling and casing wellbores
Application Number
9/733220
Publication Number
6419033 (B1)
Application Date
December 8, 2000
Publication Date
July 16, 2002
Inventor
Friedhelm Makohl
Hermannsburg
US
Detlef Hahn
Hannover
US
Agent
Madan Mossman & Sriram P C
US
Assignee
Baker Hughes Incorporated
TX, US
IPC
E21B 7/08
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