06267185 is referenced by 79 patents and cites 10 patents.

Apparatus and methods are utilized for controlling downhole equipment attached to a drill string by the transmission of commands from the surface of the earth. The drill string is rotated at the surface of the earth sequentially through one or more discrete angles of rotation to generate a command code. The sequence of discrete angular rotations is sensed downhole by a gyroscope and decoded as a command in a microprocessor. Alternately, a command code is transmitted by sequentially rotating the drill string at different angular rates which are likewise sensed by the gyroscope and decoded in the microprocessor. The microprocessor then transmits the decoded command to the controlled equipment.

Title
Apparatus and method for communication with downhole equipment using drill string rotation and gyroscopic sensors
Application Number
9/368097
Publication Number
6267185 (B1)
Application Date
August 3, 1999
Publication Date
July 31, 2001
Inventor
Remi Hutin
New Ulm
TX, US
Bernard Mougel
Sugar Land
TX, US
Agent
D Delos Larson
US
Steven L Christian
US
John J Ryberg
US
Assignee
Schlumberger Technology Corporation
TX, US
IPC
E21B 25/16
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