Communications – electrical: acoustic wave systems and devices – Wellbore telemetering – Through well fluids
Patent
1992-08-21
1994-12-20
Eldred, J. Woodrow
Communications, electrical: acoustic wave systems and devices
Wellbore telemetering
Through well fluids
367 84, 175 40, 3408531, H04H 900
Patent
active
053750985
ABSTRACT:
A LWD tool is disclosed comprising, a stator, a rotor which rotates relative to the stator thereby effecting a signal in the borehole fluid flowing therethrough, a brushless DC motor coupled to the rotor for driving the rotor, a position sensor coupled to the motor for sensing the rotational position of the motor, motor drive electronics coupled to motor for driving the motor, and a microprocessor coupled to the position sensor and to the drive electronics for controlling the drive signals to the motor based on the actual and desired positions of the motor. By controlling the drive signal to the motor, the speed of the motor is controlled, thus effecting changes in frequency and/or phase of the signal in the borehole fluid or mud. With the ability to change the frequency and/or phase, different encoding techniques such as PSK-type and FSK-type can be used. Other preferred aspects of the invention include: choosing carrier frequency based on system noise; the use of magnetic positioner and the coordination of the decelaration and acceleration of the modulator to correspond to desired magnetic positioner positions in effecting a phase shift; and jamming avoidance techniques utilizing the position sensor and microprocessor.
REFERENCES:
patent: Re29734 (1978-08-01), Manning
patent: Re30055 (1979-07-01), Claycomb
patent: 3309656 (1967-03-01), Godbey
patent: 3705603 (1972-12-01), Hawk
patent: 3764968 (1973-10-01), Anderson
patent: 3764969 (1973-10-01), Cubberly, Jr.
patent: 3789355 (1974-01-01), Patton
patent: 3792428 (1974-02-01), Harrell et al.
patent: 3792429 (1974-02-01), Patton et al.
patent: 3820063 (1974-06-01), Sexton et al.
patent: 3821696 (1974-06-01), Harrell et al.
patent: 3932836 (1976-01-01), Harrell et al.
patent: 3982224 (1976-09-01), Patton
patent: 4100528 (1978-07-01), Bernard et al.
patent: 4103281 (1978-07-01), Strom et al.
patent: 4167000 (1979-09-01), Bernard et al.
patent: 4785300 (1988-11-01), Chin et al.
patent: 4847815 (1989-07-01), Malone
patent: 5146433 (1992-09-01), Kosmala et al.
patent: 5182731 (1993-01-01), Hoelscher et al.
patent: 5237540 (1993-08-01), Malone
patent: 5249161 (1993-09-01), Jones et al.
T. Kenjo et al., Permanent-Magnet and Brushless DC Motors, pp. 79-102, 1985, Oxford, England.
Clifton Precision, Litton Systems, Inc., Synchro and Resolver Engineering Handbook, 1989, Clifton Heights, Pa.
Johnson Mike
Malone David
Eldred J. Woodrow
Gordon David P.
Kanak Wayne I.
Ryberg John J.
Schlumberger Technology Corporation
LandOfFree
Logging while drilling tools, systems, and methods capable of tr does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Logging while drilling tools, systems, and methods capable of tr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Logging while drilling tools, systems, and methods capable of tr will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2389539