Dual-Guard Imager Probe

A method, comprising:

• conveying a downhole formation resistivity measurement tool within a wellbore that extends into a subterranean formation, wherein the downhole formation resistivity measurement tool comprises a probe that comprises:
• a button electrode;
• a first guard electrode insulated from the button electrode;
• a second guard electrode insulated from the button and first guard electrodes, wherein the second guard electrode surrounds the button electrode;
• a return electrode positioned external to the second guard electrode;
• an electrical source for setting a voltage drop between the second guard electrode and the return electrode;
• a first impedance (RBOG) electrically coupled between the button electrode and the second guard electrode;
• and
• a second impedance (RIGOG) electrically coupled between the first guard electrode and the second guard electrode;
• applying a voltage between the second guard electrode and the return electrode via the electrical source;
• measuring a current circulating through at least one of the first and second impedances;
• and
• determining a resistivity of the subterranean formation based on the measured current.