Gain Compensated Directional Propagation Measurements

摘要

A method for obtaining gain compensated propagation measurements includes rotating an electromagnetic logging while drilling tool having at least one axial transmitter antenna, at least one transverse transmitter antenna, at least one axial receiver antenna and at least one transverse receiver antenna in a subterranean wellbore. Electromagnetic voltage measurements are acquired from the axial and transverse receiver antennas while rotating. The acquired voltage measurements are processed to compute harmonic voltage coefficients. Ratios of selected ones of the harmonic voltage coefficients are in turn processed to compute at least one gain compensated quantity including an axial cross term.

主权项

1. A method for making downhole electromagnetic logging while drilling measurements, the method comprising
(a) rotating an electromagnetic logging while drilling tool in a subterranean wellbore, the logging tool including at least one axial transmitter antenna, at least one transverse transmitter antenna, at least one axial receiver antenna, and at least one transverse receiver antenna; (b) acquiring a plurality of electromagnetic voltage measurements from the axial and transverse receiver antennas while rotating in (a); (c) processing the voltage measurements acquired in (b) to compute harmonic voltage coefficients; (d) processing a ratio of selected ones of the harmonic voltage coefficients to compute at least one gain compensated quantity including an axial cross term.