AZIMUTH INITIALIZATION AND CALIBRATION OF WELLBORE SURVEYING GYROSCOPIC AND INERTIAL INSTRUMENTS BY MEANS OF AN EXTERNAL NAVIGATION SYSTEM

摘要

It is described a system and a method for for azimuth initialization of a gyroscopic and/or inertial instrument for wellbore surveying, said system comprising:—a rigid reference structure to which the gyroscopic and /or inertial instrument is rigidly connectable;—an external navigation system for providing an azimuth measurement as a function of time, and wherein the rigid reference structure provides a rigid orientation between the external navigation system and the gyroscopic and/or inertial instrument; —a processor operable to synchronize the azimuth measurement as a function of time with an orientation as a function of time of the gyroscopic and/or inertial instrument.