ABSTRACT
A 5 inch diameter high accuracy borehole surveying instrument has been developed using a full 3 axis inertial navigation system (INS).
It has the following features:
3 Ring Laser Gyros
No mechanical gimbals
Real-time surface readout
Obtains position data directly without the need for intermediate depths stops.
Requires no stopping for drift checks
Uses wireline velocities up to 600 ft/min
Reduces INS's typical drift error to less than 6 ft/hr.
This tool achieves a survey accuracy that is close to that of the 10" INS tool, while at the same time offering a smaller diameter and continuous survey capability.
Keywords:
inclination,
spe 16679,
centralizer,
gyro,
gyro drift,
cavity,
rotation,
correction,
borehole,
accuracy
Copyright 1987, Society of Petroleum Engineers
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