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Title:
OSCILLATING SHEAR VALVE FOR MUD PULSE TELEMETRY
Document Type and Number:
WIPO Patent Application WO2002068797
Kind Code:
B1
Abstract:
An anti-plugging oscillating shear valve system for generating pressure fluctuations in a flowing drilling fluid comprising a stationary stator and an oscillating rotor, both with axial flow passages. The rotor (103) oscillates in close proximity to the stator (102), at least partially blocking the flow through the stator and generating oscillating pressure pulses. The rotor passes through two zero speed positions during each cycle, facilitating rapid changes in signal phase, frequency, and/or amplitude facilitating enhanced data encoding. The rotor is driven by an electric motor (104) disposed in a lubricant filled housing (108). In one embodiment, the housing to shaft seal is a flexible bellows (107). In one embodiment, a torsional spring (105) is attached to the motor and the resulting spring mass system is designed to be near resonance at the desired pulse frequency. The torsion spring may be a solid torsion bar or a magnetic spring.

Inventors:
HAHN DETLEF
PETERS VOLKER
ROUATBI CEDRIC
Application Number:
PCT/US2002/005936
Publication Date:
March 06, 2003
Filing Date:
February 27, 2002
Export Citation:
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Assignee:
BAKER HUGUES INC (US)
International Classes:
H04H60/31; E21B7/08; E21B47/18; G01V11/00; (IPC1-7): E21B47/18
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