1
Detlef Hahn, Friedhelm Makohl: Apparatus and method for simultaneous drilling and casing wellbores. Baker Hughes Incorporated, Madan Mossman & Sriram P C, July 16, 2002: US06419033 (169 worldwide citation)

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 maintai ...


2
Detlef Hahn, Friedhelm Makohl: Apparatus and method for simultaneous drilling and casing wellbores. Baker Hughes Incorporated, Paul S Madan, Madan Mossman & Sriram PC, March 27, 2003: US20030056991-A1 (7 worldwide citation)

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 maintai ...


3
Hahn Detlef, Makohl Friedhelm: Appareil et methode de forage et de cuvelage simultanes de puits, Apparatus and method for simultaneous drilling and casing wellbores. Baker Hughes Incorporated, Baker Hughes Incorporated, SIM & MCBURNEY, September 13, 2005: CA2327920

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 maintai ...