REDUCING ERROR CONTRIBUTIONS TO GYROSCOPIC MEASUREMENTS FROM A WELLBORE SURVEY SYSTEM

摘要

A method reduces error contributions to gyroscopic measurements from a wellbore survey system having two gyroscopic sensors adapted to generate signals indicative of at least one component of the Earth's rotation substantially perpendicular to the wellbore and indicative of a component of the Earth's rotation substantially parallel to the wellbore The method includes generating a first signal indicative of the at least one substantially perpendicular component while the first sensor is m a first opentation, generating a second signal indicative of the at least one substantially perpendicular component while the first sensor is in a second opentation, generating a third signal indicative of the substantially parallel component while the second sensor is in a first opentation, and generating a fourth signal indicative of the substantialy parallel component while the second sensor is in a second opentation The method further includes calculating information regarding at least one of a mass unbalance offset error and a quadrature bias error using the first, second, third and fourth signals.