MULTIPLE FREQUENCY BASED LEAKAGE CURRENT CORRECTION FOR IMAGING IN OIL-BASED MUDS

摘要

Oil-based mud imaging systems and methods having leakage current compensation. In some embodiments, disclosed logging systems include a logging tool in communication with surface computing facilities. The logging tool is provided with a sensor array having at least two voltage electrodes positioned between at least two current electrodes that create an electric field in a borehole wall, and is further provided with electronics coupled to the current electrodes to determine a differential voltage between the voltage electrodes in response to different current frequencies from the current electrodes. From the voltage measurements at different frequencies, the computing facilities determine borehole wall resistivity as a function of depth and azimuth, and may display the resistivity as a borehole wall image.