04763258 is referenced by 33 patents and cites 3 patents.

The cyclic angular dependence of the output of gravitational inclinometers and magnetometers is used to communicate from the well surface to a microprocessor downhole. The microprocessor controls an arbitrary downhole function. Information is communicated to the microprocessor via the inclinometer and magnetometer by selectively rotating the drill string during a data time interval through a predetermined magnitude of angular displacement or angular velocity. Each additional multiple of angular displacement or angular velocity is interpreted as a distinguishable unit of information. A command word is assembled from a sequential plurality of units of information in the microprocessor and a downhole function is executed according to the command word.

Title
Method and apparatus for trelemetry while drilling by changing drill string rotation angle or speed
Application Number
6/833139
Publication Number
4763258
Application Date
February 26, 1986
Publication Date
August 9, 1988
Inventor
Paul D Engelder
Rancho Palos Verdes
CA, US
Assignee
Eastman Christensen Company
UT, US
IPC
G01V 1/40
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