04909336 is referenced by 54 patents and cites 29 patents.

A method for steering the direction of drilling for oil, gas, or other boreholes drilled in locations such that the level of magnetic interference from nearby magnetic materials or fields is so large that conventional methods using magnetic compass steering tools cannot meet required accuracies. The method is based upon using gyroscope-based survey tools having an inertial angular rate sensor with one or more axes of rate sensitivity and an inertial acceleration or tilt sensor with one or more axes of sensitivity to perform both the normal survey purpose for such tools and the steering function during drilling.

The method includes the measurement of initial azimuthal direction, tilt angle, gyro tool face and high side tool face at the beginning of the borehole and the continuous measurement of one or more of these quantities as drilling progresses.

Title
Drill steering in high magnetic interference areas
Application Number
7/250361
Publication Number
4909336
Application Date
September 29, 1988
Publication Date
March 20, 1990
Inventor
Fred L Watson
Templeton
CA, US
David C Brown
Los Osos
CA, US
Agent
William W Haefliger
Assignee
Applied Navigation Devices
CA, US
IPC
G01C 19/38
E21B 47/12
E21B 47/022
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