OIL BASED MUD IMAGING TOOL THAT MEASURES VOLTAGE PHASE AND AMPLITUDE

摘要

Oil-based mud imaging systems and methods using phase information. 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 (504) positioned between at least two current electrodes (506, 508) 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 and two current flows from separate ones of the current electrodes. The differential voltage and current flows are measured as phasors defined by their magnitude and phase. The computing facilities determine borehole wall resistivity from the differential voltage and multiple current flows that include phase and magnitude information, and may display the resistivity as a borehole wall image.