DISPLACED ELECTRODE AMPLIFIER

摘要

A displaced electrode amplifier is provided that comprises: a first operational amplifier ("op-amp") having a inverting input, at non-inverting input, and an output, wherein the output is coupled to the inverting input to configure the op-amp as a unity gain buffer; and a first feedback impedance coupled between the output and the non-inverting input to at least partly compensate for parasitic shunt impedance coupled to the non-inverting input; a second op-amp having an inverting input, a non-inverting input, and an output, wherein the output of the second op-amp is coupled to the inverting input of the second op-amp to configure the second op-amp as a unity gain buffer; a second feedback impedance coupled between the output of the second op-amp and the non-inverting input of the second op-amp to at least partly compensate for a parasitic input shunt impedance; and a differential amplifier stage coupled to the outputs of the first and second op-amps to produce an amplified difference signal. A corresponding sensing method and oil-based mud imaging tool that comprises the aforementioned displaced electrode amplifier is also provided.