Patent ID: 8374793
Filing Date: 2013-02-12
Classification: E21B

Abstract:
1. A method of reducing error contributions to gyroscopic measurements, the method comprising: receiving a first set of measurement signals indicative of at least one component of the Earth's rotation substantially perpendicular to a portion of a wellbore, the first set of measurement signals generated by a first gyroscopic sensor within the portion of the wellbore; receiving a second set of measurement signals indicative of a component of the Earth's rotation substantially parallel to the portion of the wellbore, the second set of measurement signals generated by a second gyroscopic sensor within the portion of the wellbore; receiving one or more measurement signals generated by a plurality of accelerometers within the portion of the wellbore; and calculating, using one or more measurement signals from the first set of measurement signals, one or more measurement signals from the second set of measurement signals, and the one or more measurement signals from the plurality of accelerometers, a first mass unbalance offset for the first gyroscopic sensor and a second mass unbalance offset for the second gyroscopic sensor.