Apparatus and method for simultaneous drilling and casing wellbores
AssigneeBaker Hughes Incorporated
InventorsDetlef Hahn, Friedhelm Makohl
Life of this patent
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Abstract
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.
Claims12
An apparatus for drilling a wellbore, comprising:
- (a) a liner for casing the wellbore;
- (b) a drill bit at a first end of a drilling assembly for drilling a pilot wellbore;
- (c) at least one set of a plurality of force application devices on a nonrotating sleeve of the drilling assembly, each said force application device independently operable to exert force on the pilot wellbore for controlling direction of drilling of the wellbore;
- and
- (d) an underreamer disposed uphole of the at least one set of the force application devices adapted to enlarge the pilot wellbore to produce said wellbore when rotated.
A method of drilling a wellbore comprising:
- (a) conveying a drilling assembly on a drilling tubular into the borehole;
- (b) using a drill bit conveyed on a first end of the drilling assembly for drilling a pilot wellbore;
- (c) using a plurality of force application devices on a non-rotating sleeve of the drilling assembly for independently exerting a force on the pilot wellbore and controlling the direction thereof;
- (d) using an underreamer disposed near a second end of the drilling assembly and enlarging the pilot wellbore to produce said wellbore;
- and
- (e) using a liner coupled to the underreamer for lining said borehole.
Dependencies are inferred from the claim text.