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

摘要

Oil-based mud imaging systems and methods having leakage current compensatio n. In some embodiments, disclosed logging systems include a logging tool in communication with surface computing facilities. The logging tool is provide d with a sensor array having at least two voltage electrodes positioned betwee n 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 electrode s in response to different current frequencies from the current electrodes. Fr om 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.