Reducing fluid capacitance and conductance effects on piezoelectric resonator measurements

摘要

An apparatus for estimating a property of a fluid in a borehole penetrating the earth includes a piezoelectric material configured to be at least partially immersed in the fluid and embedded with a first electrode pair and a second electrode pair. An electronic unit is coupled to the first electrode pair and the second electrode pair and configured to measure motion impedance of the fluid caused by motion of the piezoelectric material by applying a first electrical stimulus to the first electrode pair and a second electrical stimulus to the second electrode pair and by receiving a first electrical signal from the first pair of electrodes and a second electrical signal from the second pair of electrodes to estimate the property. The resulting motion impedance measurement has a reduced influence from electrical properties of the fluid.