Two-pipe on-grade directional boring tool and method

A method and apparatus for boring a close tolerance on-grade subsurface borehole. A downhole tool assembly for use with a dual member drill string comprises a directional boring tool. The dual member drill string comprises an outer member and an inner member disposed within the outer member and rota...

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Bibliographic Details
Main Authors KNECHT PAUL W, DIMITROFF TED
Format Patent
LanguageEnglish
Published 07.12.2004
Edition7
Subjects
EARTH DRILLING
EARTH DRILLING, e.g. DEEP DRILLING
FIXED CONSTRUCTIONS
MINING
OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS
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Summary:A method and apparatus for boring a close tolerance on-grade subsurface borehole. A downhole tool assembly for use with a dual member drill string comprises a directional boring tool. The dual member drill string comprises an outer member and an inner member disposed within the outer member and rotatable independently of the outer member. The downhole tool assembly permits the directional boring tool to be connected to the inner member of the drill string. Rotation of the inner member of the drill string causes rotation of the boring tool. The borehole is drilled in a straight manner by rotating the boring tool with the inner member of the drill string and simultaneously advancing the drill string through the earth. The borehole direction is changed by orienting the directional boring tool with the inner member of the drill string and then advancing the drill string without rotation.
Bibliography:Application Number: US20020210195