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Title: Logging while drilling tools utilizing magnetic positioner assisted phase shifts

Abstract

An apparatus is described for use in a borehole having borehole fluid flowing there through, said tool comprising: (a) a brushless DC motor having a rotating drive shaft; (b) an encoder means including a stator, and a rotor coupled to said rotating drive shaft, said rotor rotating relative to said stator thereby creating a signal in the borehole fluid; (c) a position sensor coupled to said rotating drive shaft of said brushless DC motor, said position sensor providing indications related to the rotational position of said brushless DC motor; (d) motor drive circuitry; (e) a magnetic positioner means coupled to said rotating drive shaft, said magnetic positioner means having inner magnets rotating relative to said outer magnets; and (f) a microprocessor means coupled to said position sensor and coupled to said motor drive circuitry, said microprocessor means for causing said motor drive circuitry to provide drive signals to said brushless DC motor based on actual rotational positions of said brushless DC motor as provided by said indications of said position sensor, and upon desired rotational positions as determined by said microprocessor, wherein, said microprocessor encodes data by providing drive signals which cause said brushless DC motor to decelerate over amore » first predetermined period of time, and to accelerate over a second predetermined period of time, and said microprocessor chooses said first predetermined period of time to substantially include when said inner magnets are at first positions relative to said outer magnets, which first positions cause deceleration of said drive shaft, and said microprocessor chooses said second predetermined period of time to substantially include when said inner magnets are at second positions relative to said outer magnets which second positions cause acceleration of said drive shaft.« less

Inventors:
Publication Date:
OSTI Identifier:
6279071
Patent Number(s):
US 5237540; A
Application Number:
PPN: US 7-934083
Assignee:
Schlumberger Technology Corp., Houston, TX (United States)
Resource Type:
Patent
Resource Relation:
Patent File Date: 21 Aug 1992
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; MWD SYSTEMS; DESIGN; COMPUTERIZED CONTROL SYSTEMS; ELECTRIC MOTORS; MAGNETS; OPERATION; POSITIONING; ROTORS; CONTROL SYSTEMS; ENGINES; MOTORS; ON-LINE CONTROL SYSTEMS; ON-LINE SYSTEMS; 580000* - Geosciences

Citation Formats

Malone, D. Logging while drilling tools utilizing magnetic positioner assisted phase shifts. United States: N. p., 1993. Web.
Malone, D. Logging while drilling tools utilizing magnetic positioner assisted phase shifts. United States.
Malone, D. 1993. "Logging while drilling tools utilizing magnetic positioner assisted phase shifts". United States.
@article{osti_6279071,
title = {Logging while drilling tools utilizing magnetic positioner assisted phase shifts},
author = {Malone, D},
abstractNote = {An apparatus is described for use in a borehole having borehole fluid flowing there through, said tool comprising: (a) a brushless DC motor having a rotating drive shaft; (b) an encoder means including a stator, and a rotor coupled to said rotating drive shaft, said rotor rotating relative to said stator thereby creating a signal in the borehole fluid; (c) a position sensor coupled to said rotating drive shaft of said brushless DC motor, said position sensor providing indications related to the rotational position of said brushless DC motor; (d) motor drive circuitry; (e) a magnetic positioner means coupled to said rotating drive shaft, said magnetic positioner means having inner magnets rotating relative to said outer magnets; and (f) a microprocessor means coupled to said position sensor and coupled to said motor drive circuitry, said microprocessor means for causing said motor drive circuitry to provide drive signals to said brushless DC motor based on actual rotational positions of said brushless DC motor as provided by said indications of said position sensor, and upon desired rotational positions as determined by said microprocessor, wherein, said microprocessor encodes data by providing drive signals which cause said brushless DC motor to decelerate over a first predetermined period of time, and to accelerate over a second predetermined period of time, and said microprocessor chooses said first predetermined period of time to substantially include when said inner magnets are at first positions relative to said outer magnets, which first positions cause deceleration of said drive shaft, and said microprocessor chooses said second predetermined period of time to substantially include when said inner magnets are at second positions relative to said outer magnets which second positions cause acceleration of said drive shaft.},
doi = {},
url = {https://www.osti.gov/biblio/6279071}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 17 00:00:00 EDT 1993},
month = {Tue Aug 17 00:00:00 EDT 1993}
}