LOGGING TOOL EMPLOYING A MONOPOLE CURRENT INJECTION ELECTRODE FOR MICRORESISTIVITY IMAGING

摘要

A microresistivity logging tool (100) includes a monopole current injection electrode (160) and first and second potential electrodes (212,214) deployed on a downhole tool body (110). A controller (250) is configured to apply a high frequency alternating current between the monopole current injection electrode (160) and a return (170) and measure a corresponding AC potential difference (?V) between the first and second electrodes (212,214).