Drilling assembly for drilling holes in subsurface formations

A drilling assembly for drilling holes in subsurface formations comprises a drill bit 10, a drive unit 12 including a housing and a rotor 11 operatively coupled to the drill bit to rotate the drill bit relative to the housing, and a modulated bias unit 14 coupled to rotate with the drive unit housin...

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Bibliographic Details
Main Author FULLER; JOHN MICHAEL
Format Patent
LanguageEnglish
Published 14.07.1998
Edition6
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 drilling assembly for drilling holes in subsurface formations comprises a drill bit 10, a drive unit 12 including a housing and a rotor 11 operatively coupled to the drill bit to rotate the drill bit relative to the housing, and a modulated bias unit 14 coupled to rotate with the drive unit housing and apply a lateral bias thereto in synchronism with rotation of the housing. The modulated bias unit 14 comprises one or more hydraulic actuators including members 16 which, in use, bear against the sides of the borehole, and means for modulating the pressure of fluid supplied to the actuators in synchronism with rotation of a component of the drilling assembly, and in selected angular phase relation thereto, whereby each hydraulic actuator is actuated in a selected rotational position of the component.
Bibliography:Application Number: US19960733060