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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